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Ultrafiltration membranes for wastewater and water process engineering: A comprehensive statistical review over the past decade
Abstract
The primary intention of this review is to showcase and quantify the level of research interest and current research trends, concerning UF membrane applications and processes within the past decade (2009–2018). Detected statistics manifested a resurgent interest in the UF technology on a yearly basis. "Journal of Membrane Science" and "Desalination and Water Treatment" were the primary journals dominating the size of the annual publication among more than 120 ones, with 854 and 683 papers, respectively. Based on ScienceDirect research platform, fouling (27%), modelling (17%) and wastewater (12%), were the dominating research topics and counting for more than half of total scientific articles published (4547 articles) within the specified period of the research. Unsurprisingly, topics like UF membrane fabrication and modification, food processing, hybrid membrane process have disclosed a distinguished growing up trends in terms of annual publications. The current review unrevealed the present-day significance of the UF membranes along with their prospective opportunities for attaining sustainable water industries and materializing the efforts of future researchers into the right orientation.
... Initially developed as a fractionation technique in the late 1960s, UF membranes have since evolved and are now used in a diverse range of applications, including chemical recovery, cell harvesting, dairy production, medical applications, wastewater reclamation, water treatment, and juice concentration. UF is particularly recognized as a clarification and disinfection process with extensive applications [6,7]. The advantages of UF over conventional purification and disinfection methods include its simplicity, cost-effectiveness, low energy consumption, minimal or no chemical use, moderate operating temperatures, and high-quality treatment outcomes [7,8]. ...
... UF is particularly recognized as a clarification and disinfection process with extensive applications [6,7]. The advantages of UF over conventional purification and disinfection methods include its simplicity, cost-effectiveness, low energy consumption, minimal or no chemical use, moderate operating temperatures, and high-quality treatment outcomes [7,8]. However, NOM components such as humic substances, proteins, and polysaccharides are prevalent fouling agents in UF systems across many industrial applications. ...
Natural organic matter (NOM) constitutes a significant contaminant in water sources, adversely affecting drinking water quality and complicating purification processes. To mitigate these contaminants, the current state of the application uses membrane filtration along with structural and surface modification of membranes. This study presents the development of polysulfone (PSU) flat-sheet ultrafiltration (UF) membranes, modified with three different concentrations of chitosan (0.05, 0.06, and 0.08 g), a natural polymer, to enhance NOM removal. The membranes were rigorously characterized using Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM), and water contact angle (WCA), porosity, and pore size analysis. Furthermore, the study delves into the interaction mechanisms between chitosan and the PSU polymer matrix, as well as the transport phenomena involved. The findings indicate that increasing the chitosan content from 0.05 to 0.08 g markedly enhanced the membrane’s surface properties, reducing the contact angle from 72.8◦ to 53.5◦ and nearly doubling the permeation rate despite the decrease in porosity and pore size. The PSU UF membrane with 0.08 g chitosan demonstrated a superior humic acid (HA) rejection rate of 90 %, underscoring chitosan’s potential for improving polymeric membranes in NOM removal applications.
... However, unmodified ZnO often suffers from aggregation and leaching issues during membrane fabrication and operation. This necessitates further modification-such as surface functionalization with silica (via tetraethyl orthosilicate, TEOS)-to improve their stability and compatibility with polymer matrices UF membranes play a pivotal role in applications such as biotechnology, pharmaceuticals, and reverse osmosis pre-treatment-where high flux and selectivity are critical for macromolecule removal (e.g., bovine serum albumin, BSA) [17][18][19][20]. Enhancing UF membrane performance using robust, nanomaterial-based strategies remains an active area of research. ...
In this study, polyethersulfone (PES) membranes were modified by incorporating different amounts of surfacemodified zinc oxide (ZnO) nanoparticles (0, 0.1, 0.2, 0.3, and 0.4 g) to fabricate two sets of ultrafiltration (UF) nanocomposite membranes. The first set (denoted as air) involved a 5-minute evaporation step before phase inversion, while the second set (denoted as water) was immersed immediately in the coagulation bath without
evaporation. A comprehensive characterization spectrum of the membranes was conducted using field emission scanning electron microscopy (FESEM), atomic force microscopy (AFM), contact angle (CA) measurements, Fourier-transform infrared (FTIR) spectroscopy, pore size and porosity analysis, and membrane thickness evaluation. The membranes’ permeation performance and separation efficiency were evaluated using a laboratoryscale UF system. The interaction mechanisms between PES, ZnO nanoparticles, and water molecules were also
investigated. The results revealed that all ZnO-modified PES membranes exhibited significantly improved morphological and performance characteristics compared to the unmodified PES membrane. Increasing ZnO content led to greater surface roughness and reduced pore size. The optimal membrane, containing 0.2 g of modified ZnO nanoparticles and fabricated with a 5-minute evaporation step (air set), achieved the highest water flux of 80.3 LMH, a bovine serum albumin (BSA) rejection of 94.5 %, and a flux recovery ratio (FRR) of 85.9 %. Additionally, the incorporation of modified ZnO nanoparticles enhanced membrane hydrophilicity, porosity, and antibacterial properties. Notably, membranes prepared with the 5-minute evaporation time exhibited minimal nanoparticle leaching.
... Este proceso de separación se dirige a moléculas que contienen un mayor peso molecular y sólidos suspendidos, dependiendo del límite de peso molecular. El principal mecanismo utilizado para la uf es la exclusión por tamaño; sin embargo, dependiendo de los compuestos presentes, las reacciones entre las partículas y la membrana podrían impedir el máximo eficiencia del proceso (Al Aani et al., 2020). En las membranas de ultrafiltración el tamaño de poro ronda entre 10-100 nm y su valor de corte es de 1-100 kDa. ...
El libro “Tópicos Selectos de Contaminación Ambiental” reúne investigaciones de expertos en ciencias ambientales de diversas instituciones académicas, como parte de los Programas Multidisciplinarios de Posgrados y de los Programas de Licenciaturas afines a las Ciencias Ambientales que se imparten en las diferentes instituciones participantes. En este libro han colaborado Universidades y Centros de Investigación pertenecientes a la Red Delfín de Contaminación Atmosférica (reduca) incluyendo las Facultades de Química, de Ingeniería, de Recursos Naturales y de Ciencias Económico-Administrativas de la Universidad Autónoma del Carmen, el Centro de Investigación en Corrosión (cicorr) de la Universidad Autónoma de Campeche; el Instituto de Ciencias de la Atmósfera y Cambio Climático de la unam, la Facultad de Química de la Universidad Autónoma de Nuevo León, el Instituto Politécnico Nacional, la Universidad de Guayaquil, la Universidad de Quintana Roo, el Centro de Estudios Tecnológicos del Mar No. 29, El Colegio de la Frontera Sur, la Facultad de Química de la unam, el Instituto de Ecología, Pesquerías y Oceanografía de la Universidad Autónoma de Campeche (epomex), la Universidad Tecnológica de Xicotepec de Juárez, la Facultad de Química de la Universidad Autónoma Metropolitana, y el Instituto de Geo-ciencias de la unam. El objetivo del libro es profundizar en la comprensión de los problemas ambientales a través de estudios de caso a nivel local, regional y global; enfocándose en los principios de sustentabilidad, y promoviendo a su vez, la protección del ambiente y el conocimiento de los procesos ambientales relacionados con factores sociales, económicos y culturales. Se espera, además, que fomente prácticas sostenibles y aumente el conocimiento científico sobre cuestiones ambientales en diferentes contextos.
... Ultrafiltration (UF) membranes have gained considerable attention, due to their widespread use in drinking, domestic, and industrial wastewater treatment. Besides their physicochemical stability and mechanical strength, their ability to operate at low pressure means they require lower energy inputs than other membrane treatment process to yield high-quality water [1][2][3]. However, like other membrane processes, UF membranes suffer deteriorating permeability and selectivity over time because of fouling by various substances [4,5]. ...
... Most suspended particles, colloids, bacteria, and macromolecule organic matter can be removed from the water by the membrane ultrafiltration process combined with another physical separation process [19]. As the big particulate can be removed completely from the water using the ultrafiltration process, the turbidity will be automatically decreased significantly. ...
... As another version of the filtering option, cellulosic fibers and other fibers also would be fully retained on membrane filters, e.g. nanofiltration or ultrafiltration (Mohammad et al. 2015;Hubbe et al. 2016;Al Aani et al. 2020), which are sometimes employed as a polishing step when needed at the end of a wastewater treatment operation. ...
Cellulose fibers are an abundant material that is well known for its biodegradability. Various forms of cellulose, such as cotton, paper pulp fibers, and microcrystalline cellulose can be regarded as benchmarks for biodegradability, when comparing other materials. However, as revealed by the literature, broad ranges of time and extent of biodegradation have been reported for cellulose. These large ranges can be attributed not only to environmental factors but also to the presence of lignin, the degree and perfection of crystallinity, the size and density of the physical specimens, and chemical modifications to the cellulose, if any. Studies also have shown differences in biodegradability associated with the selection of test methods. Although cellulose is subject to well-known enzyme-promoted mechanisms of biodegradation, the evolution of plant materials has favored development of some resistance to decay, i.e. recalcitrance. Cellulosic materials are clearly less biodegradable than starch. However, they are more biodegradable than various synthetic or bio-based plastics, as well as some cellulose derivatives, which persist in ocean water or soils for very long periods. This review indicates that cellulose biodegradability, while generally rapid and natural, has a rate and extent that depends on a complex and sometimes subtle set of environmental and chemical factors.
... In recent decades, the industry has rapidly developed in various fields, resulting in large volumes of wastewater, particularly oily (Al Aani et al. 2020). ...
The impact of oily wastewater on the environment and ecosystems due to industrial development could negatively affect the aquatic environment and wastew-ater treatment sectors. The proposed action plan uses coagulation-flocculation, using different coagulants and flocculants to minimize environmental impact. Color verification was done to identify the most suitable and economically advantageous conditions for pollution reduction. The combination of Amerfloc coagulant and Drewfloc 2448 flocculant proved to be the best for more effective treatment. This combination delivers excellent performance even at relatively low concentrations, bringing significant economic benefits to industries seeking to implement cost-effective and efficient treatment systems. The combination achieved impressive water quality removal rates, including a 98.2% reduction in color.
... Ultrafiltration (UF) membranes, developed since their initial use in 1970 for electrophoretic oil separation, have evolved into a reliable, clean, cost-effective, and efficient tool for separating diverse components and contaminants from water and wastewater. UF has a rich history dating back to 1907 when Benchold first introduced the concept, describing it as a method to mechanically separate components from mixtures using membranes operated under pressure, making it highly attractive for groundwater and surface water treatment, especially for removing particles, colloids, and microorganisms [72]. Additionally, the pretreatment of UF with coagulants can enhance water quality and minimize membrane fouling. ...
Water resources are vital for humanity, but their quality has degraded in recent years due to increasing industrial activities. One significant issue is fluoride contamination, prevalent worldwide. Fluorides exist in combined states such as calcium fluoride, fluorapatite, and cryolite, originating from industrial processes like aluminum and fertilizer manufacturing. The World Health Organization warns against fluoride levels above 1.5 mg/L in drinking water due to health risks, including dental and skeletal fluorosis. Industrial activities also release fluoride-containing wastes into the environment, endangering ecosystems and human health. Overexposure to fluoride leads to disorders affecting organs including the kidneys, liver, and nervous system. Despite fluoride’s benefits in controlled doses, excessive intake causes health problems, as evidenced by rising dental fluorosis cases in Brazil. Thus, effective and affordable fluoride removal strategies are crucial. Various methods exist, including adsorption, membrane technology, ion exchange process, electrodialysis, and electrocoagulation. Regulation of fluoride levels in drinking water is imperative to safeguard public health from its detrimental long-term effects.
... Massive exploitation of water in the evolution of civilization that continues to develop for various industrial and household purposes is one of the causes of the decreasing availability of clean water [1]. Therefore, in several decades, various methods have been carried out to deal with this crisis, such as adsorption [2], coagulation [3] and aerobic degradation [4]. ...
Due to their ability to combine the physical separation of membrane filtration with organic degradation in one unit, photocatalytic membranes have demonstrated enormous potential for application in energy-efficient water purification and wastewater treatment. Titanium dioxide (TiO2) is the substance most frequently utilized to create photocatalytic membranes. However, TiO2's use is constrained by its substantial band gap (3.2 eV). On the other hand, tungsten trioxide (WO3) has a fairly small band gap (2.7-2.8 eV) which makes it able to absorb visible light, making the photocatalytic process more efficient. This article examines recent developments in WO3 photocatalytic membranes for wastewater treatment and water purification with a focus on the photocatalytic mechanism, photocatalytic membrane fabrication and development. The mechanism of WO3 semiconductor in pollutant removal is explained in detail. Blending, coating and grafting methods, which are three methods commonly used when fabricating photocatalytic membranes, are discussed. Likewise with the development of WO3 photocatalytic membranes using pure WO3, heterojunction or doping with metal.
... With the advancement of industrialization and increased demand in recent decades, membrane technology has been dramatically developed and improved. 1 Polymer membranes have dominated the market owing to their low processing costs. However, the poor performance of polymer films in terms of operating temperature, chemical stability, and mechanical strength limits their applications. ...
Porous silicon carbide ceramics are ideal candidates for filters, separation membranes, and high‐temperature structural materials, for which high porosity and precise pore size control are required. However, high porosity and large pore sizes usually lead to degradation in mechanical properties. In this work, silicon carbide powder with two different particle sizes was used as the raw material, and C powder and SiO2 powder were used as pore‐forming agents. A series of pure silicon carbide porous ceramics with micron‐sized pores were prepared by recrystallization sintering. The porosity and pore size of obtained samples were controllable and adjustable, and the mechanical properties were significantly enhanced. The microstructure, pore size distribution, porosity, and crystal phase of silicon carbide porous ceramics were characterized by scanning electron microscope, pore size analyzer, Archimedes method, and X‐ray diffraction. The effect of adding C/SiO2 on the porosity, the pore size, and the micro‐morphology of sintering samples was studied. The results show that C/SiO2 can adjust the porosity and pore size of pure silicon carbide porous ceramics in a wide range. The highest porosity of the obtained sample adding 40% C/SiO2 was up to 64.42%, and the average and maximum aperture are 5.42 and 11.98 µm, respectively.
... In recent decades, the industry has rapidly developed in various fields, resulting in large volumes of wastewater, particularly oily (Al Aani et al. 2020). ...
The impact of oily wastewater on the environment and ecosystems due to industrial development could negatively affect the aquatic environment and wastewater treatment sectors. The proposed action plan uses coagulation-flocculation, using different coagulants and flocculants to minimize environmental impact. Color verification was done to identify the most suitable and economically advantageous conditions for pollution reduction. The combination of Amerfloc coagulant and Drewfloc 2448 flocculant proved to be the best for more effective treatment. This combination delivers excellent performance even at relatively low concentrations, bringing significant economic benefits to industries seeking to implement cost-effective and efficient treatment systems. The combination achieved impressive water quality removal rates, including a 98.2% reduction in color.
... The treatment of wastewater is one of the most important applications for membranes. In the early stages of its manufacture, ultra-modern UF was used to treat sewage and wastewater in order to remove particulate matter and macromolecular constituents [30]. There have been many applications developed for this technology, including water treatment and replicas handling as well as biotechnology and food processing. ...
Synthetic membranes play a crucial role in a wide range of separation processes, including dialysis, electrodialysis, ultrafiltration, and pervaporation, with growing interest in synthetic emulsion membranes due to their precision, versatility, and ion exchange capabilities. These membranes enable tailored solutions for specific applications, such as water and gas separation, wastewater treatment, and chemical purification, by leveraging their multi-layered structures and customizable properties. Emulsion membrane technology, particularly in pressure-driven methods like reverse osmosis (RO) and nanofiltration (NF), has shown great potential in overcoming traditional challenges, such as fouling and energy inefficiency, by improving filtration efficiency and selectivity. This review explores the latest advancements in emulsion membrane development, their adaptability to various industrial needs, and their contribution to addressing long-standing limitations in membrane separation technologies. The findings underscore the promise of emulsion membranes in advancing industrial processes and highlight their potential for broader applications in water treatment, environmental management, and other key sectors.
... On the other hand, ultrafiltrationmethod ensures high separation efficiency, high salt penetration with improved permeation fluxand maintains high throughputs due to low osmotic pressure. Commonly, ultrafiltrationmembranescontainingpolysulfone, polyacrylonitrile, polyethersulfone, cellulose acetate, and poly (vinylidene fluoride) have been commercially used [46,47]. ...
In order to meet the demand for portable water and replenish depleting water resources caused by industrialization, urbanization, and population growth; wastewater purification has become crucial. Emerging contaminants (ECs), which include organic dyes, pesticides, pharmaceutical drugs, polyaromatic compounds, heavy metal ions, and fertilizers, among others, have caused significant disruptions to environmental balance and severe health complications. As a result, considerable effort has been devoted to the development of technologies that eliminate wastewater from effluents via adsorption, photocatalysis, and other means. However, considering the economic and environmental implications of the adopted technologies, green technology has gained significant attention owing to their eco-friendly approaches, cost-effectiveness, avoiding use of toxic and harmful chemicals and production of less-toxic by-products. Currently green-synthesized nanomaterials have seen tremendous growth in emerging as sustainable nanoadsorbents, nanocatalysts for the removal of the emerging contaminants from wastewater in highly efficient and eco-friendly manner. Thus, this review presents an overview of the various techniques utilized in wastewater treatment with a particular emphasis on the production and application of environmentally friendly transition metal/metal oxide nanoparticles as sustainable tools in wastewater treatment technology. This article also discusses the limitations and future potential of using green-synthesized transition metal/metal oxide based nanoparticles in advancing the technology on a broad scale.
... Water pur ification necessitates systems with precisely engineered porosity and customized morphologies, considering that the pollutants contained in wastewater have different sizes and functionalities (Abdulhamid and Muzamil, 2023). Previous studies in the literature have widely discussed the potential of membrane technology in wastewater treatment, highlighting its separation efficiency, selectivity, easily achievable operating conditions, the absence of chemical modifications, and versatility in managing the different characteristics of pollutants (Al Aani et al., 2020;Hube et al., 2020;Bera et al., 2022). Membrane processes also have better stability than conventional processes, as their efficiency does not depend particularly on water quality. ...
This work aims to apply carbon quantum dots (CQDs) from agriculture cellulosic waste (agro wastes), produced
via an economically and eco-friendly single-step method, to be used into cellulose acetate composite microfibrous membranes as an innovative solution specifically designed to adsorb methylene blue (MB) and other
cationic dyes that are present in various water effluents. Batch adsorption tests were conducted, with variations
in contact time (1–24 h), initial MB concentration (25–300 ppm), and adsorbent doses (1–20 g/L). The maximum
adsorption capacity of the membrane was 198 mg/g with an initial concentration of 300 ppm at 298 K. Thermodynamic parameters showed that the process is endothermic. Equilibrium experimental data for MB
adsorption onto electrospun adsorbent were fitted using different isothermal models, with the Freundlich model
showing the best fit. The pseudo-second-order model accurately described the kinetic data with high reliability
(R2 > 0.99), and the calculated adsorption capacity was very close to the experimental data. N-CQDs loaded
membranes were also tested for removing methyl violet and rhodamine B, demonstrating remarkably high dye
removal efficiency. The underlying adsorption mechanism was also reported. Finally, it is worth mentioning that
composite adsorbents can be efficiently applied to actual industrial cases because of the possibility of reusing
them, opening the route to the fabrication of novel and highly performant adsorbents. These findings underscore
N-CQDs’ effectiveness in enhancing pollutant removal efficiency from wastewater, highlighting their environmental benefits and promoting a more sustainable approach to water treatment. Therefore, the prepared adsorbent, showing excellent adsorption performance, places them among adsorbents for practical applications
in wastewater purification.
... To address the difficulties associated with wastewater, several techniques are used, including membrane-based treatment techniques which remain feasible and sustainable (Dhiman and Mukherjee) [30]. These techniques have advantages in terms of effluent treatment stability (Vo et al. [32]), cost-effectiveness and flexible application for heterogeneous wastewater systems (Al Aani et al. [31]). ...
The leather sector remains one of the sectors that encounters a multitude of problems on an international scale, particularly in Morocco. Therefore, we carried out a literature review through which we were able to identify the major problems found within the leather sector. After that, we conducted a case study on the Chouara tannery in the Fes Meknes region where we studied the problems found within the sector by using the 5M and SWOT methods as well as the proposal of certain improvement actions with a view to revitalizing the sector. The novelty of our work lies in the proposal of certain functionalities that could play the role of product lifecycle management (PLM) within the sector, such as life management, complaint management and cost management since the notion of PLM is absent within traditional tanneries. In addition, we propose integrating ecological PLM to limit the amount of garbage generated during the execution of tasks.
To address the increasing scarcity of freshwater supplies, there is a growing need to renovate and recycle wastewater to supplement alternative water resources for the non-potable purposes. Widescale reclamation of wastewater necessitates the development of cost-effective, energy-efficient and user-friendly treatment technologies. In comparison to all other processes of wastewater treatment reported in recent literature, membrane bioreactors (MBRs) have been considered to be extremely efficient for the treatment of high organic-loaded wastewater. MBR systems coupled with ceramic membrane-based filtration units (CMBRs) offer several advantages for efficient wastewater treatment including fouling control, scope of backwashing for regeneration of membrane performance, stability towards aggressive conditions, high resistance to biodegradation and chemical abrasion as well as longer life of the membranes. This chapter deals with different aspects of CMBRs including low-cost ceramic membranes, MBR configurations and performance efficiency of CMBRs for the treatment of organic-pollutant-loaded wastewater. It also provides a lucid discussion of the ecotoxicological aspects and reusability potential of the CMBR-treated wastewater. A comparative assessment has also been made on the efficiency, advantages and limitations of different processes of wastewater treatment reported in recent literature.
In this work, zeolitic imidazolate framework‐8 (ZIF‐8) and modified ZIF‐8 with polyethyleneimine (PEI) were incorporated into the PSF (polysulfone) matrix. The fabricated PSF/ZIF‐8‐PEI mixed matrix membranes (MMMs) showed better results (rejection of bovine serum albumin (BSA) 98.9 %) for oil–water emulsion than PSF/ZIF‐8 MMMs. It is noticed that the steady‐state pure water flux (PWF) of PSF/ZIF‐8‐PEI MMMs is 2.73 times greater than PSF/ZIF‐8 MMMs. During the membrane performance for ultrafiltration (UF), various parameters are affected, such as pH, loading of additives, and feed concentration. To determine the optimization performance of the membrane (both filler MMMs), the response surface methodology (RSM) (Box–Behnken method) is used to design the experiment. The optimized results investigated the maximum BSA rejection of 99.99 % and flux recovery ratio (FRR) of (0.97) 97 %. This is the novelty of the present work. The MMMs were characterized in PXED, Fourier transform infrared (FTIR), TGA, SEM, and water contact angle (WCA) for confirmation of filler materials.
Ultrafiltration (UF) membranes are widely employed in water treatment. However, their limited selectivity restricts their effectiveness in removing soluble contaminants, such as dyes in textile wastewater or smaller organic compounds. Tight ultrafiltration (tight-UF) membranes have emerged as an advanced alternative, offering improved selectivity while operating at lower pressures, bridging the performance gap between UF and nanofiltration (NF) membranes. The tight-UF membranes have promising performance, achieving up to 99% turbidity removal, 90% dye rejection in textile wastewater, and over 85% recovery of phenolic compounds from agro-food by-products. Their capability to effectively remove low-molecular-weight contaminants while preserving high permeability underscores their suitability for treating complex water matrices and facilitating resource recovery. Moreover, their enhanced separation performance and lower energy demands make tight-UF membranes highly suitable for sustainable water treatment processes. This review explores recent advancements in tight-UF fabrication, material innovations, and performance evaluation. Emerging trends are explored to identify opportunities for improving tight-UF membranes in sustainable water treatment, industrial separation processes, and zero-liquid discharge systems.
Recently, the utilization of antibiotics is gradually increasing in many fields. Concerns have been raised regarding the potential threats to human health and the environment caused by antibiotics pollutants. Due...
The water sector is going under tremendous changes in current scenarios. The sector is now a days being transformed through digitalization which has not only increased its efficiency but has also contributed to enhanced sustainability and resilience. One important point of utilizing digitalization is that well informed decision can be made easily resulting in improved management of resources and detection of leaks saving the resource. Intelligent systems allow for further improvement in distribution and utilization of water saving time and other resources. Forecasting maintenance of pipelines enabled by Internet of Things devices and Artificial Intelligence enables early prevention of equipment malfunctions, minimizes downtime and prolongs the infrastructure lifespan. Digital platform also enhances customer engagement by offering immediate updates for water consumption and service-related problems. Nevertheless, many challenges are also presented by digitalization of water industry as they face considerable threats from cybersecurity vulnerabilities and are always at risk of being attacked by cybercriminal and disruptions in supply. Moreover, the incorporation of newer technologies is also not very cost effective. The present review examines the opportunities and threats being faced by the digitalization of water sector. This also puts focus on utilization of emerging Industry 5.0 in the sector and discusses use of these technologies for better management.
Water scarcity and wastewater pollution are major health issues, yet traditional wastewater treatment technologies are limited by high operational costs and energy demands, and membrane fouling. Here we review low-cost ceramic membranes for wastewater treatment and bioenergy production, with emphasis on bioreactors, and microbial fuel cells to generate electricity. Ceramic membranes display high filtration performance and resistance to harsh conditions, achieving water flux rates up to 250 L/m2 per h, significantly outperforming polymeric membranes. Ceramic membranes are now affordable due to recent advances in as clay-based ceramics, extrusion and electrospinning. Ceramic membranes integrated into microbial fuel cells and anaerobic bioreactors could enhance power generation by 20% and biogas yield by 15–30%. Surface modifications and nanomaterial use have reduced fouling by up to 60%, yet issues of biofouling and high fabrication costs persist.
With the emergence of global challenges, sustainability has become a pivotal element in the world’s development agendas. To achieve global development, 17 sustainability development goals (SDGs) were developed by the United Nations in 2012. Recently, membrane technologies have been rising to the spotlight as a promising green alternative for the accomplishment of these SDGs. This is due to their numerous advantages, including high selectivity, lower cost, relatively easy upscaling, mild processing conditions, compact system with minimized steel usage, and reduced energy consumption. Despite its growing importance in sustainable development, membrane technologies have not been reviewed and rigorously analyzed for all SDGs. This review critically analyzes membrane technologies' significant position in SDGs to fill this gap in the literature. More precisely, this review uniquely delves into the versatile role of membrane technologies in contributing to the SDGs with state-of-the-art examples, hence, aiding in solving pressing global challenges such as clean water, affordable and clean energy, climate action, poverty, life below water, etc. Furthermore, by evaluating the economic and social dimensions of membrane technologies in sustainable development, this review comprehensively highlights the holistic advantages offered by various membrane processes in the accomplishment of SDGs. This paper concludes by discussing future directions that could be implemented to harness the full potential of membrane technologies in SDGs accomplishment.
This study deals with the morphology and performance properties of a novel thin flat sheet ultrafiltration membrane; Malachite Green (MG) dye filtration behavior was evaluated in the cross-flow filtration system. The prepared membranes included the incorporation of 16 wt. % of polyether sulfone (PES)/DMF and 5 wt.% of Polyethylene Glycol (PEG) via the phase inversion process. Adding PEG decreased the internal concentration polarization, improved the membrane hydrophilicity, changed pore morphologies, and enhanced membrane performance. The SEM and AFM tests were used to characterize the composition and structure of the membrane. With different casting conditions, the membrane shape changed. The effect of membrane thickness (100, 150, and 200) µm and coagulation bath properties temperature (15, 25, and 35) °C and composition DMF (10, 20, 30 %) in water on the fabricated membrane were investigated. To evaluate the membrane filtration performance, the fabricated membranes were applied in an ultrafiltration system to treat Malachite Green dye solution at a concentration of (10 ppm) as a model pollutant. Based on the obtained results, the ideal membrane parameters were150 µm in thickness, 35°C in temperature, and 10% in composition DMF; the removal efficiency was observed to be (94.5%, 93%, and 99.5%) while the permeate flux (45, 35 and 30) LMH, respectively.
The symbiotic relationship between microbial life and the environment has become a focal point in the pursuit of sustainable solutions for pressing global challenges. In order to sustain the demands of the rapidly expanding population, the use of chemical in the form of pesticides and fertilizers have has drastically increased. Uncontrolled use of these chemicals has detrimental effect on soil health. To reconcile agricultural productivity with environmental preservation, the strategic utilization of beneficial microorganisms emerges as a promising avenue. The forefront of biopesticide innovation emphasizes the strategic use of beneficial microorganisms for sustainable pest management while minimizing environmental impact. Simultaneously, the progression of biofertilizers unveils the symbiotic relationships between microbes and plants that optimize nutrient acquisition and contribute to agricultural sustainability by reducing reliance on chemical inputs. Biopesticides and biofertilizers not only enhance soil health but also increase productivity. Additionally, microbes play a crucial role in the restoration of contaminated terrestrial and aquatic ecosystems.
The advancement of pharmaceutical science has resulted in the development of numerous tailor-made compounds, i.e., pharmaceuticals, tuned for specific drug targets. These compounds are often characterized by their low biodegradability and are commonly excreted to a certain extent unchanged from the human body. Due to their low biodegradability, these compounds represent a significant challenge to wastewater treatment plants. Often, these compounds end up in effluents in the environment. With the advancement of membrane technologies and advanced oxidation processes, photocatalysis in particular, a synergistic approach between the two was recognized and embraced. These hybrid advanced water treatment processes are the focus of this review, specifically the removal of pharmaceuticals from water using a combination of a photocatalyst and pressure membrane process, such as reverse osmosis or nanofiltration employing photocatalytic nanocomposite membranes.
Os recursos hídricos sofrem com o aumento de sua demanda resultado do crescimento populacional somado ao desenvolvimento do setor industrial. Este último tem se esforçado em buscar soluções e medidas que auxiliem na atenuação das demandas hídricas dos seus processos produtivos. Diante dessa questão, o reuso de efluentes é uma alternativa capaz de dirimir essa problemática e está demonstrando excelentes resultados na redução da demanda hídrica. Neste contexto, os processos de separação por membranas vêm sendo muito aplicados, especialmente, em sistemas de tratamento de efluentes já existentes como etapa de pós-tratamento. Portanto, o presente estudo tem como objetivo avaliar a instalação de uma unidade piloto de ultrafiltração (UF) como tratamento quaternário em uma Estação de Tratamento de Efluente localizada em Niterói, no estado do Rio de Janeiro. Foi empregado no piloto um cartucho de membrana de fibra-oca de UF modelo AQUA-MEM, fornecido pela AQUASMART, o piloto foi operado por 10 dias úteis onde foram feitas coletas da entrada e saída do processo e levadas para análise laboratoriais. Analisou-se, então, alguns parâmetros e comparou-se os resultados com os padrões mínimos requisitados na legislação estadunidense, europeia e do estado de São Paulo, a fim de avaliar em qual classe o efluente tratado pelo piloto melhor se enquadrava. O permeado apresentou resultados médios que melhor enquadrou na Classe B para legislação paulista e europeia e uso urbano restrito, segundo a legislação do EUA, destaca-se apenas que houve um desvio no atendimento ao valor máximo de E. coli permitido nas legislações. O piloto performou com resultados satisfatórios na produção de água de reuso para fins urbanos com restrições.
This study aimed to improve the properties of labneh from skim milk fortified at (25%, 50%, 75%, and 100%). The best treatment was also selected and supplemented with tomato juice extract in proportions. The aim of fortification with tomato juice extract was to improve the product and increase the nutritional and health value. Properties were determined in fresh and stored. The data showed that the chemical properties increased while the acidity decreased in labneh compared to other treatments. The results showed that the rheological properties including hardness decrease with increasing storage period for all treatments. Microbiological examination of the labneh showed an increase in total bacterial throughout the storage. As for Molds and yeasts, they were not detected in fresh labneh and were detected slightly at the end of the storage. Coliform bacteria were not observed in all treatments. The data showed that the sensory qualities of labneh decrease with increasing storage period. The best treatments in terms of sensory are (Labneh made fresh buffalo's skim milk without adding milk retentate Labneh made 25% milk retentate and 75% buffalo's skim milk and Labneh made 50% milk retentate and 50% buffalo's skim milk for fresh labneh, respectively. In the end, the best treatment was Labneh made 25% milk retentate and 75% buffalo's skim milk) compared to the other samples. Sensory tests conducted on labneh made with 25% retentate and fortified with tomato juice showed that labneh fortified with 8% tomato juice was highly similar to the control.
Sulfate removal from an aqueous system having ternary ions consisting of sodium and magnesium cations was modeled using Donnan-Steric-Pore model (DSPM). The ability of DSPM to characterize a membrane on the basis of diffusion, convection and electromigration (Donnan effect) makes it suitable for this process. A flat sheet hydrophilized polyamide (HPA50) nanofiltration membrane was used for experimental work. Membrane parameters such as hydraulic permeability (4.2*10⁻¹² m³ m⁻² s⁻¹ Pa⁻¹), effective pore radius (rp) and membrane charge density (Xm) were estimated. The effect of various operating parameters such as feed concentration, transmembrane pressure and feed flow rate was also studied for membrane performance. The model prediction was compared with the experimental data, and it was found that model prediction ability was excellent. The model was capable of predicting permeate concentration, and rejection percentage within 8% error was observed. This confirms the efficacy of our proposed model.
Conventional wastewater treatment is not sufficient for the removal of hygienically relevant bacteria and achieves only limited reductions. This study focuses on the reduction efficiencies of two semi-industrial ultrafiltration units operating at a large scale municipal wastewater treatment plant. In total, 7 clinically relevant antibiotic resistance genes, together with 3 taxonomic gene markers targeting specific facultative pathogenic bacteria were analysed via qPCR analyses before and after advanced treatment. In parallel with membrane technologies, an ozone treatment (1 g ozone/g DOC) was performed for comparison of the different reduction efficiencies. Both ultrafiltration units showed increased reduction efficiencies for facultative pathogenic bacteria and antibiotic resistance genes of up to 6 log units, resulting mostly in a strong reduction of the bacterial targets. In comparison, the ozone treatment showed some reduction efficiency, but was less effective compared with ultrafiltration due to low ozone dosages frequently used for micro-pollutant removal at municipal wastewater treatment plants. Additionally, metagenome analyses demonstrated the accumulation of facultative pathogenic bacteria, antibiotic resistance genes, virulence factor genes, and metabolic gene targets in the back flush retentate of the membranes, which opens further questions about retentate fluid material handling at urban wastewater treatment plants.
Background: Increasing attention is being paid to the treatment of shale gas fracturing wastewater, including
flowback and produced water (FPW). Energy-efficient pretreatment technologies suitable for desalinating and
reusing FPW are of paramount importance.
Objectives: This work focused on enhanced fouling alleviation of ultrafiltration (UF) as a pretreatment for desalinating
shale gas FPW in Sichuan Basin, China. The UF fouling behaviors under various backwash water
sources or coagulant dosages were evaluated, and membrane surface characteristics were correlated with UF
fouling. The feasibility of Fourier transform infrared (FTIR) microscope mapping technique in quantifying UF
fouling was also assessed.
Methods: Various backwash water sources, including UF permeate, ultrapure water, nanofiltration (NF)
permeate, reverse osmosis (RO) permeate, RO concentrate and forward osmosis (FO) draw solution, were used to
clean UF membranes fouled by shale gas FPW. The UF fouling behaviors were characterized by total and nonbackwashable
fouling rates. Membrane surface characteristics were analyzed by scanning electron microscopy
(SEM), total tension surface and FTIR spectra.
Results: Protein-like substances in terms of fluorescence intensity in the backwash water decreased with the
order of UF permeate, RO concentrate, NF permeate, RO permeate and FO draw solution. Compared with UF
permeate backwashing, alleviated UF fouling was observed by using demineralized backwash water including
ultrapure water and RO permeate, irrespective of hollow fiber and flat-sheet membranes. NF permeate and RO
concentrate after NF used as backwash water resulted in low and comparable membrane fouling with that in
integrated coagulation-UF process under optimal dosage. Among the backwash water tested, FO draw solution
backwashing corresponded to the lowest UF fouling rates, which were even lower than that in the presence of
coagulant under optimal dosage. The superiority of these backwash water sources to UF permeate was further
confirmed by SEM images and FTIR spectra. The residual foulant mass on membrane surface and the total
surface tension correlated well with non-backwashable and total fouling rates, respectively.
Conclusions: FTIR microscopy was a powerful surface mapping technique to characterize UF membrane fouling
caused by shale gas FPW. Backwash water sources significantly influenced the fouling of UF membranes. In the
integrated UF-NF-RO or UF-FO process, RO concentrate or FO draw solution were proposed as backwash water
to enhance UF fouling control and decrease waste discharge simultaneously.
The study aims to utilize Hybrid Membrane Technology (UF-RO) in reducing turbidity, iron and zinc in the liquid waste of the rubber industry. The pre-treatment process used was filtration and adsorption. The filtration process used filter columns containing silica sand and activated carbon, while the adsorption process used an adsorbent column containing bentonite. After the pre-treatment process, it was continued with the application Hybrid Membrane (UF-RO). The variables of the study were operation time of 15 to 90 minutes and flow rates of 7 and 14 L/min. The results showed that the optimum removal percentage of iron and zinc in the Reverse Osmosis Membrane was 84.86% and 96.29% at the feed flow rate of 14 L/min. The optimum removal percentage turbidity of 99.70% was achieved at the feed flow rate of 7 L/min in the Reverse Osmosis Membrane. Finally, rubber industry wastewater treatment using Hybrid Membrane (UF-RO) was able to reduce turbidity, iron and zinc content, and the results were accordanced with the quality standards regarding Water Quality.
Haemodialysis effectively removes small solutes and smaller-sized middle molecules from the blood; however, the clearance of larger middle molecules, which have been associated with negative effects, is poor. The novel medium cut-off (MCO) dialysis membrane has larger pore sizes and a more open structure than other high-flux membranes, providing improved removal of larger middle molecules while retaining albumin. However, larger pore sizes may potentially increase permeability to pyrogens, including endotoxins and other bacterial contaminants, that could be present in the dialysis fluid. In this study, we tested the capacity of low-flux, high-flux, MCO and high cut-off dialyser membranes with different pore sizes to prevent pyrogens crossing from dialysate to the blood side in a closed-loop test system, differentiating among lipopolysaccharides, peptidoglycans and bacterial DNA using a toll-like receptor assay. Even though the bacterial contamination levels in our test system exceeded the acceptable pyrogen dose for standard dialysis fluid, levels of lipopolysaccharides, peptidoglycans and bacterial DNA in the blood-side samples were too low to identify potential differences in pyrogen permeability among the membranes. Our results suggest that MCO membranes are suitable for haemodialysis using ISO standard dialysis fluid quality, and retain endotoxins at a similar level as other membranes.
Petroleum industry is one of the fastest growing industries, and it significantly contributes to economic growth in developing countries like India. The wastewater from a petroleum industry consist a wide variety of pollutants like petroleum hydrocarbons, mercaptans, oil and grease, phenol, ammonia, sulfide, and other organic compounds. All these compounds are present as very complex form in discharged water of petroleum industry, which are harmful for environment directly or indirectly. Some of the techniques used to treat oily waste/wastewater are membrane technology, photocatalytic degradation, advanced oxidation process, electrochemical catalysis, etc. In this review paper, we aim to discuss past and present scenario of using various treatment technologies for treatment of petroleum industry waste/wastewater. The treatment of petroleum industry wastewater involves physical, chemical, and biological processes. This review also provides scientific literature on knowledge gaps and future research directions to evaluate the effect(s) of various treatment technologies available.
In this study, a mathematical model was developed to assess fouling as well as membrane regeneration in a pressurized, hollow-fiber membrane system for the treatment of highly turbid surface water using periodical cleaning by backwashing and forward flushing. The model was validated using experimental data of trans-membrane pressure obtained when filtering separately, a SiO2 solution, a mixed SiO2/sodium alginate (SA) solution, a mixed SiO2/bovin serum albumin (BSA) solution and a mixed SiO2/humic acid (HA). Experimental and theoretical studies highlighted the synergistic fouling effect between SiO2 simulating the colloidal particles and the different elements (HA, SA and BSA) simulating the natural organic matter. Protein fouling was mitigated when mixed with SiO2. While the highest fouling rate was obtained for mixed SiO2/SA solution, the majority of this fouling was removed by periodic cleaning. Moreover, mixed SiO2/HA solution showed also high fouling which was mainly irreversible.
This viewpoint describes the concept of incorporating polymer into inorganic matrix to form composite material. The coupling of both the materials enhanced the electrotransport properties and hence more efficient and highly selective membrane is formed. This approach was demonstrated by introducing 25% PVC into cobalt arsenate matrix which resulted in higher chemical, mechanical and thermal stabilities confirmed by different characterization techniques such as XRD, TG/DTA, FTIR, SEM, TEM and EDS. Electrotransport properties have been evaluated and compared with a mathematical model called as TMS model which clearly indicates the good agreement between calculated and theoretical values of membrane potential. Also, fixed charge density, charge effectiveness and transport number were being calculated from the model. All the parameters found to show dependence on electrolyte concentration and applied pressure during the fabrication of membrane. Membrane potential, transport number and mobility ratio of different univalent electrolytes followed the trend as LiCl> NaCl> KCl which is in accordance with the size of cations. Fixed charge density gave the opposite trend. Membrane showed positive values of membrane potential that confirms the cation selective nature of the membrane. Thus results revealed that the synthesized membrane is a promising candidate for use in practical applications.
Textile industry represents an important source of toxic substances rejected in environment. Indeed, effluent of these industries contains dyes and chemicals. They are rejected in environment without any treatment. The aim of this work is to evaluate ecotoxicological effect of industrial textile effluents on the sludge harvested from activated sludge treatment plant of Marrakech city (Morocco). For this, we are interested in determining the inhibition condition that corresponds to 50% decrease of bacterial activity in sludge. Obtained results showed that inhibition percentage of bacterial activity depends narrowly on contact time and on added effluent volume, until a limit concentration where there is no degradation of substratum. In fact, substratum degradation speed shows about 65 times decrease when 80% (v/v) of textile wastewater is added, in comparison with the controlled one. Consequently the inhibition constant (Ki) that corresponds to 50% of bacterial inhibition activity is estimated to 0.65 mg l⁻¹ of dye. These studies confirm a real ecotoxicological risk of these effluents. Therefore, a treatment is mandatory before their rejection in environment.
Ceramic membrane filtration is a viable option for recovery of hot discharges due to their high mechanical, chemical and thermal durability. Recovery of hot discharges in textile industry with this method has not been studied in detail previously. In this study, the potential recovery of hot textile wastewater discharges was assessed in situ taking into consideration the amount, pollutant content and costs of the water. Samples were selected from potential recovery points according to wastewater amount, temperature and accessibility
and were evaluated using laboratory scale ceramic membrane filtration with four different MWCO (300 kDa, 50 kDa, 15 kDa and 3 kDa) membrane sizes. The pollutant size distribution correlated with removal efficiency of the method and the highest pollutant removal efficiency was achieved with the 3 kDa ceramic membrane.
However, the mixed hot wastewater and disperse printing washing baths mix permeate from the 3 kDa membrane had high COD and TOC contents and was not optimal for reuse without additional treatment. The printing washing baths hot discharges mix was the most appropriate option for reuse with 67 ± 12 mg COD/L, 21 ± 4 mg TOC/L and 23 ± 7.7 mg CaCO3/L Total Hardness values which could be reused in dense dyeing and printing baths washing after 3 kDa ceramic membrane ultrafiltration. In order to define the fouling mechanism, resistance-in-series model was used and physically removable resistance was the main contributor to overall fouling.
With this method, not only the reuse requirements will be met but also 22% of total water consumption may be reused and thus wastewater, energy and water related expenses may be reduced significantly in textile industry.
Ultrafiltration (UF) with ceramic membrane has attracted growing attention in drinking water treatment. In this regard, a ceramic and a polymeric UF membrane process with in-line preoxidation has been applied for iron and manganese control in water. The effect of water chemistry including pH, ionic strength and hardness on the characteristics of oxidized iron and manganese aggregates, and subsequent UF fouling behavior were evaluated. The fouling of constant flux dead-end UF membranes was assessed using blocking low and resistance-in-series model analyses. Results suggest that the water chemistry has not possessed notable impact on the overall iron and manganese removal efficiencies but did contribute to the extent of fouling caused by manganese dioxide aggregates. The resistance of the cake layer and its compressibility could be explained by the manganese dioxide aggregate properties, such as size, -potential and fractal dimension, which were controlled by the water chemistry. However, the cake formed by ferric hydroxide aggregates induced very low and comparable resistance to the membranes under all conditions, in line with the similar aggregate properties. The fouling behavior of ceramic membrane was generally similar to that of polymeric one, however, the reversibility of the fouling differed from one another. Overall, this work provides further insight on the fouling of ferric hydroxide and manganese dioxide in water treatment.
Since its inception in the 19th century, microfiltration (MF) has evolved as a membrane-based separation technology for treating various effluents and wastewaters. This review aims to familiarize its readers with general and specific research trends on various topics in MF. The level of research interest has been measured by the number of publications in that area for each year. An increasing research trend was observed from the number of publications since 2009 to 2018 with MF as the major topic. During the past decade, MF articles have spanned in about 150 different journals, with The Journal of Membrane Science, Desalination and Separation and Purification Technology being the major ones. Major topics of interest include membrane fabrication and modification, waste water treatment and fouling studies, while a significant research increase was seen in various fabrication methods and MF application in the food sector. MF modeling still remains a topic which needs further research output, and has experienced a decline over the past years. Several potential research areas are also identified in this review which will help future researchers to materialize their efforts into the right direction.
The growing water demand across the world necessitates the need for new and improved processes as well as for a better understanding of existing processes. This level of understanding includes predicting system performance in scenarios that cannot always be evaluated experimentally. Mathematical modelling is a crucial component of designing new and improved engineering processes. Through mathematically modelling real life systems, we gain a deeper understanding of processes while being able to predict performance more effectively. Advances in computational capacity and the ease of assessing systems allow researchers to study the feasibility of various systems. Mathematical modelling studies enable optimization performance parameters while minimizing energy requirements and, as such, have been an active area of research in desalination. In this review, the most recent developments in mathematical and optimization modelling in desalination are discussed with respect to transport phenomena, energy consumption, fouling predictions, and the integration of multiple scaling evolution on heat transfer surfaces has been reviewed. Similarly, developments in optimization of novel reverse osmosis (RO) configurations have been analyzed from an energy consumption perspective. Transport models for membrane-based desalination processes, including relatively less understood processes such as nanofiltration and forward osmosis are presented, with recent modifications to allow for different solutes and solutions. Mathematical modelling of hybrid systems integrated with RO has also been reviewed. A survey of the literature shows that mathematical and optimization modelling of desalination processes is an exciting area for researchers in which future scholarship includes coupling of renewable energy systems with desalination technologies, as well as more advanced descriptions of fouling evolution other than that of cake filtration in membrane-based processes.
Tight ultrafiltration (UF) membranes with high permeances have gained growing attention in the separation of biomacromolecules. Herein, we report the preparation of gradient carbonaceous structures filled in macroporous polyvinylidene fluoride (PVDF) substrates and their efficient separation of polypeptides. Gradient phenolics composed of nanoparticles with sizes increasing from top side to bottom side are firstly synthesized inside PVDF substrates. When soaked in concentrated H2SO4, phenolic nanoparticles are partially carbonized and foamed to form micropores while the PVDF substrate maintains intact. Thus-produced carbonaceous membranes are mechanical robust and exhibit narrowed pore sizes and enhanced hydrophilicity. Their permselectivity can be adjusted simply by changing the dosages of phenolic precursors filling into the PVDF substrates. Low dosages lead to remarkably high water permeances up to 1721 L/(m²·h·bar). At higher dosages, the membrane is tightened to show a molecular-weight-cut-off (MWCO) down to 3.7 kg/mol and high permeances several times larger than other membranes with similar MWCOs. We demonstrate that such a tight UF membrane efficiently separates polypeptides with molecular weights of only a few kg/mol (angiotensin Ⅱ and thymosin β4). Our work opens a new avenue for the synthesis of high-flux tight UF membranes with narrowed pores, enabling the precise separation and fractionation of biomacromolecules.
This study investigates chemical cleaning mechanisms of a tubular ceramic UF membrane. The effect of cleaner type (ozone (O 3 ), sodium hypochlorite (NaOCl) and sodium hydroxide (NaOH)), clean in place (CIP) pH (11 vs. 12), and cleaning sequence on the removal of irreversible fouling of hydrophobic (humic acids) and hydrophilic (alginate with and without calcium (alginate + Ca ⁺² and alginate - Ca ⁺² , respectively)) NOM fractions were investigated. Results showed that different NOM types responded differently to chemical cleaning. Alginate-Ca ⁺² and humic acids were equivalently removed by NaOCl or NaOH whereas a lower cleaning efficiency of alginate + Ca ⁺² was observed. Increasing the pH of NaOCl and NaOH CIP increased the removal of the chemically reversible fouling index (UMFI cr ). The efficiency of NaOCl was always lower than that of NaOH at the same pH, which was attributed to surface tension (λ) differences in the CIP water and potential differences in cleaning mechanism. The ceramic UF CIP cleaning using O 3 (0.50 mg O 3 /mgC) for 1 h demonstrated higher cleaning efficiency for humic acids and alginate ± Ca ⁺² , (%UMFI cr > 98%), than NaOCl or NaOH alone (%UMFI cr >80%). The O 3 CIP was as effective as 4 h cleaning using a sequential NaOH/NaOCl or combined NaOCl + NaOH CIP.
Artificial intelligence (AI) is a powerful tool that is commonly applied in engineering multi-disciplines owing to its functionality to resolve real-world problems where deterministic solutions are arduous to achieve. Revolution in water treatment and desalination process automation has been emerging recently. Several challenges are present in the water sector related to data structur-ing and smart water services through which AI would have great potential once those issues are addressed. The distinctive tools of AI, mainly; artificial neural networks (ANNs), as a regression model, and genetic algorithm (GA), as one of the global optimization techniques, have been im-mensely applied in desalination and water treatment for multi-purpose applications. Modelling desalination and water treatment processes and optimizing the operating condition are few among the many applications. In the current review, paramount applications of AI tools in desali-nation and water treatment have been thoroughly reviewed. In addition, benchmarking ANNs with the conventional modelling approaches were highlighted, along with the shortcomings and challenges expected to associate with these common tools in some complex nature practical ap-plication. It was concluded that the use of AI tools will undoubtedly pave the way in the water sector towards better operation, process automation, and water resources management in an in-creasingly volatile environment.
Recovery of natural gas and oil from unconventional (shale) reservoirs relies on horizontal drilling and hydraulic fracturing to make it economical. Hydraulic fracturing generates vast quantities of flowback and produced water (FPW) and its composition exhibits huge spatial and temporal variations among shale plays. This review focuses on the characteristics and management of wastewaters originating for oil and gas extraction. Wastewater characteristics, including the quantity and chemical composition of the FPW, are discussed. The future of unconventional oil and gas industry hinges on effective management of FPW. Membrane technologies have the potential to offer solutions to sustainable reuse of this water resource. The performance of a range of membrane processes is evaluated and compared. Emerging membrane-based technologies employed in similar fields are also discussed. The results in peer-reviewed publications could offer a guide for the selection of appropriate technologies based on the desired application. Membrane fouling, lack of pilot- and full-scale experience and high energy consumption are primary challenges for membrane applications in FPW. Then challenges and future research needs are addressed, advances in membrane materials, systematic analyses of organics and electric generation from salinity gradient are promising approaches to address the issues.
Many numerical models for membrane filtration have been developed to explain and predict fouling mechanisms. The models can simulate flux decline, transmembrane pressure increase, and fouling thickness based on theoretical equations. However, the simulated fouling layer thicknesses have not been validated by in-situ observations on membrane surfaces because the membrane system is operated under a sealed and pressurized condition. In this study, humic acid fouling layers on nanofiltration and reverse osmosis membranes were monitored in-situ and in real-time using optical coherence tomography (OCT). The OCT system detected fouling layer growth over time, and showed that the compact and thick fouling layer had an estimated thickness of 80 µm. When comparing the thickness of the fouling layer between OCT and scanning electron microscopy (SEM) images, the OCT images showed values that were approximately 8 times higher than those of the SEM images. By comparing the obtained fouling thickness values with the estimated results, two existing models (Faridirad model and pore blockage-cake filtration model) were validated in terms of root mean square error (RMSE), Akaike Information Criteria (AIC), and coefficient of determination (R²). Both models showed similar high R² (≥0.97) and low RMSE (<10⁻⁵) values, but the pore blockage-cake filtration model had lower AIC values than the Faridirad model. This study highlighted that the in-situ and real-time monitoring of fouling thickness can provide significant information for developing an accurate and precise membrane model.
In vitro drug release testing for parenteral drug formulations could benefit from more regulatory guidance and compendial information as this testing is a part of current expectations for drug product approval. This Stimuli article discusses in vitro drug release methods for those parenteral drug formulations that are not solutions and explores the challenges involved in using these methods for each formulation type. © 2018. The United States Pharmacopeial Convention. All rights reserved.
Seawater desalination using reverse osmosis (RO) process has increased substantially in the recent past and is expected to grow at an increasingly rapid pace in the future. Successful operation of a seawater reverse osmosis (SWRO) plant depends on the ability of the pretreatment system to consistently produce adequately treated filtered water for the subsequent RO process. Both conventional (e.g., conventional/lamella sedimentation, dissolved air flotation, granular media gravity/pressure filtration) and membrane-based pretreatment processes (e.g., microfiltration, ultrafiltration) have found practical application worldwide. Although most of the currently operational pretreatment systems are conventional, low-pressure membrane based pretreatment systems are increasingly being considered for future plants. Thus, selection of conventional versus membrane based pre-treatment is increasingly becoming difficult. Both water quality perspectives and non-water quality based criteria (ease of operation, facility footprint, construction costs, operating costs, economy of scale, design specifications , contractual agreements, etc.) need to be critically reviewed to make a prudent decision. This paper provides a critical review of both conventional and membrane-based pretreatment technologies by presenting water quality issues impacting their performances, critical design characteristics and their impacts on pre-treatment selection, non-water quality based selection criteria, and a conceptual decision matrix for selection of pretreatment technologies for site specific conditions.
Low energy consumption and less fouling propensity of forward osmosis (FO) processes have been attractive as a promising water filtration technology. The performance of this process is however significantly influenced by its operating conditions. Moreover, these operating parameters have both favourable and adverse effects on its performance. Therefore, it is very important to optimize its performance for efficient and economic operation. This study aims to develop a software to analyze a full-scale FO system for optimum performance. A comprehensive theoretical framework was developed to estimate the performance of FO system. Analysis results were compared with the experimental results to validate the models. About 5% deviation of simulation results and the experimental findings shows a very good agreement between them. A novel optimization algorithm was then developed to estimate the minimum required draw solution (DS) inlet flowrate and the number of elements in a pressure vessel to attain the design objectives (i.e. desired final DS concentration and recovery rate at a specific feed solution (FS) flowrate). A detailed parametric study was also conducted to determine the optimum operating conditions for different objectives. It showed that for a specific design objective, higher recovery rate can be achieved by increasing the DS flowrate and number of elements in a pressure vessel. In contrast, lower final concentration can be obtained by lowering the DS flowrate and increasing the number of elements. Finally, a MATLAB based software with graphical user interface was developed to make the analysis process easier and efficient.
A response surface method was used to optimize the purification and concentration of gluconic acid from fermentation broth using an integrated membrane system. Gluconobacter oxydans was used for the bioconversion of the glucose in sugarcane juice to gluconic acid (concentration 45 g∙L–1) with a yield of 0.9 g∙g–1. The optimum operating conditions, such as trans-membrane pressure (TMP), pH, cross-flow rate (CFR) and initial gluconic acid concentration, were determined using response surface methodology. Five different types of polyamide nanofiltration membranes were screened and the best performing one was then used for downstream purification of gluconic acid in a flat sheet cross-flow membrane module. Under the optimum conditions (TMP = 12 bar and CFR = 400 L∙h–1), this membrane retained more than 85% of the unconverted glucose from the fermentation broth and had a gluconic acid permeation rate of 88% with a flux of 161 L∙m–2∙h–1. Using response surface methods to optimize this green nanofiltration process is an effective way of controlling the production of gluconic acid so that an efficient separation with high flux is obtained. Open image in new window
Arid and semi-arid environments have low and unpredictable rainfall patterns resulting in limited availability of surface water for wildlife. In the Central Kalahari Game Reserve (CKGR) wildlife populations have lost access to natural surface water through cordon fences, livestock and human encroachment along the access routes. Artificial waterholes have been developed in the reserve to compensate for this loss. However, there have not been any assessments of the quality of water provided for wildlife and how that may be contributing to populations declines in the CKGR. We assessed water quality from 12 artificial waterholes against both Botswana and international livestock standards for drinking. Overall the quality of water provided is poor and poses a health risk to both animals and humans. Eight out of twelve boreholes tested exceeded the maximum acceptable Total Dissolved Solids (TDS) limits while three and four boreholes have toxic levels of lead and arsenic, respectively. Thus, pumping ground water could have more negative than positive impacts on wildlife thus defeating the intended management purpose. Failure to provide water of acceptable quality is a major concern for wildlife management in the CKGR and it may underlie some wildlife declines in the reserve. These findings confirm that restriction of populations from natural water sources create complex management challenges, especially where safe and sustainable alternative sources are scarce. Restriction of access of the population to natural water sources by fences and provision of poor quality water could compromise the overall fitness of wildlife populations and contribute to their decline.
The surface fouling of UF membranes used upstream as pre-treatment stage is critical for the long-term stability of the subsequent treatment stage (NF/RO membranes). In this paper, an attempt was made to probe and compare the potential of versatile UF membranes structures in terms of flux decline and selectivity, for more convenient pretreatment membranes selection. The role of polyethersulfone (PES) host polymer concentration, on the morphology and surface characteristics of asymmetric flat sheet ultrafiltration (UF) membranes, has been comprehensively investigated. Distinctly, as the casting solution viscosity decrease, a higher pore size, pore size distribution and pure water flux was observed along with lower mechanical properties and wider cross-section morphologies. However, this impact was trivial on water contact angle, surface roughness parameters and charge negativity of the membrane. To further assess the potential performance of the handmade fabricated membranes , they were systematically evaluated against three organic model foulants with dissimilar origins; humic acid (HA)-as natural organic matters (NOM), sodium alginate (NaAlg)-as polysaccharide, and bovine serum albumin (BSA)-as protein, under different initial feed concentration and pH chemistry. A disparate fouling behavior was observed depending on the membrane characteristics and the organic model foulant used. Depending on the UF membrane cutoff used, lower MWCO membranes, PES22 (6 kDa) and PES20 (10 kDa) exhibited a negligible relative flux decline while extremely low relative flux patterns were observed in the filtration with the 100 kDa membrane (PES16), as a result of one or more pore blocking mechanisms observed.
Ultrafiltration (UF) has been proposed as a promising technology in recirculating aquaculture systems (RAS) to remove both organic contaminants and other fine contaminants including viruses and pathogenic bacteria.
However, fouling is still a severe problem during this application. This paper investigated the fouling behavior of three different UF membranes examined using five different aquaculture contaminants. The experiments were performed using UF membranes with molecular weight cut-off 10, 50, and 100 kDa. Humic acid, shrimp feed, Spirulina sp., Vibrio harveyi and IHHNV were used as contaminant models. Scanning electron microscope was used to visualize the presence of foulant on the membrane surface. The results showed that fouling behavior was affected by both membrane cut-off (pore size) and foulant type. Two fouling behaviors were observed: (i) rapid flux decline at the early stage of filtration followed by relatively constant permeate flux until experiments finished, and (ii) rapid flux decline at the early stage of filtration followed by a gradual decrease in permeate flux. Due to its reliable flux value and high rejection, 100 kDa UF membrane should be considered as the most suitable UF membrane for RAS application.
Membrane separation systems represent a hot – spot for biofilm formation in juice industries. Sodium hypochlorite (NaOCl) has been traditionally the disinfectant of choice; however, its effectiveness over well-established biofilms is limited. In this work the study of biofilm formation on ultrafiltration membranes was proposed. The effectiveness of cleaning and disinfection procedures commonly used in juice industry was tested on the removal and killing of cells. The species used (Rhodotorula mucilaginosa, Candida krusei, Candida kefyr and Candida tropicalis) were isolated from ultrafiltration modules of a clarified apple juice industry. Industrial concentrations of NaOCl (200 mg CL ∙ L− 1) showed to be effective against planktonic cultures with > 4 log reductions, whereas their overall efficiency against adhered cells was smaller. Recovery of viable cell counts to initial numbers was evidenced regardless of the time of colonization. The topography of the surface showed to have an impact on the efficiency of the disinfectant, presenting membranes smaller log reductions than stainless steel (~ 1.09–1.53 log CFU). At 200 mg Cl ∙ L− 1 only membrane's cross flow recovery was reached with no long-term effect over the attached cells. The overall results demonstrated the recalcitrance of these biofilms to typical cleaning and disinfection process which may confer them with a selective advantage.
Ultrafiltration membranes are increasingly used in potabilization to remove viral particles. This removal is controlled by electrostatic repulsion, attachment and size exclusion. The effect of electrostatic interaction in virus filtration was investigated. Our work included characterization of bacteriophage PP7 and polyethersulfone membrane with respect to size and surface charge; the removal of this bacteriophage at laboratory scale by ultrafiltration membrane process and the mechanism and limitations were analyzed and discussed under DLVO and XDLVO theories. A partial removal of the bacteriophage was achieved; however, enhanced separation may be achieved considering that the process is affected by the aqueous matrix. The presence of divalent cations diminished the effectiveness of the procedure as opposed to monovalent cations and species with amphoteric behavior such as bicarbonate. DLVO and XDLVO predicted the interactions studied between bacteriophage PP7 and polyethersulfone membrane.
This study examines the feasibility of a novel nanofiltration membrane bioreactor (NF-MBR) followed by reverse osmosis (RO) process for water reclamation at 90% recovery and using an ultrafiltration MBR (UF-MBR)+RO as baseline for comparison. Both MBRs adopted the same external hollow fiber membrane configurations and operating conditions. The collected permeates of the MBRs were subsequently fed to the respective RO systems. The results showed that the NF-MBR (operated at a constant flux of 10 L/m(2)h) achieved superior MBR permeate quality due to enhanced biodegradation and high rejection capacity of the NF membrane, leading to lower RO fouling rates (∼3.3 times) as compared to the UF-MBR. Further analysis indicated that the cake layer fouling that caused the cake-enhanced osmotic pressure (CEOP) effect contributed predominantly to the transmembrane pressure (TMP) increase in the NF-MBR, while irreversible pore fouling was the major reason for UF membrane fouling. Furthermore, it was found that the biopolymers (i.e., organics with MW > 10 kDa) were the main components present in the foulants of the NF/UF membranes and RO membranes. The analysis indicated that the NF-MBR + RO system at recovery of 90% has comparable energy consumption as the UF-MBR + RO system at recovery of 75%. Our findings proved the feasibility of the NF-MBR + RO for water reclamation at a high recovery rate.
Novel hybrid nanostructures (HNS) comprising of a mussel-inspired polymer coated metal/metal oxide (M/MO)–carbon nanotubes (CNTs), were successfully synthesised and used to fabricate Thin Film Nanocomposite (TFN) membranes for desalination applications. For comparison, four different M/MO (Aluminium oxide-Al2O3, Iron oxide-Fe2O3, Titanium dioxide-TiO2 and Silver-Ag) nanoparticles (NPs) were in situ synthesized/loaded on the surface of CNTs, and the result-ant HNS were further coated with a thin polymeric film of polydopamine (PDA)., An intermedi-ate layer of HNS was then deposited between a PES substrate membrane and an interfacial polymerization (IP) process was carried out to render a polyamide (PA) thin layer on the inter-mediate layer. Both HNS and TFN were characterized using different characterization tools, in-cluding fourier transforms infrared spectroscopy (FTIR), zeta potential (ZP), X-Ray diffraction (XRD), raman spectroscopy, scanning electron microscopy (SEM), energy-dispersive X-ray spec-troscopy (EDX), X-ray photoelectron spectroscopy (XPS), thermogravimetric analysis (TGA), surface hydrophilicity/hydrophobicity, and the performance of nanofiltration (NF) membranes were evaluated against monovalent and divalent salts solutions. The fabricated TFN-NF mem-branes had higher performance in terms of their permeation characteristics compared to the thin film composite TFC membrane, while maintaining their selectivity against both monovalent and divalent salts solutions with only minor variation depending on the incorporated HNS used to prepare the TFN.
In this study, several novel blend membranes based on ligands-immobilized amphiphilic carbonaceous particles (ACPs) and matrix polymer polyvinylidene fluoride (PVDF) were prepared by immersion phase inversion method. The effects of ACPs content on filtration performance of membrane were investigated. Endotoxin removal by blend membranes at different pH and ionic strength was analyzed and discussed. The results indicated that the use of ACPs not only achieved uniform and stable incorporation of water-soluble ligands into hydrophobic polymer membrane but also improved its filtration properties, including permeability, strength, hydrophilicity and antifouling ability. The blend membranes with the optimum particle content showed good performances in filtration and were highly effective in removing endotoxins from both buffer and protein solutions under properly chosen conditions. More than 99.8 % of endotoxin removal and more than 90 % of BSA recovery were achieved when 1 mg L-1 of BSA solution with 116 EU mL-1 of endotoxin content was treated at pH 4.7. All the above suggested that the carrier-dispersed method described herein was one of effective methods in constructing functionalized blend membrane absorbers.
Nanofiltration technology has come a long way since first inception in the late 1980s. Research activity in this area covers a great many topics and the aim of this review is to quantify the level interest in each of these areas. The number of annual publications directly related to nanofiltration technology has been harvested from ScienceDirect since 2007. This quantification of research has shown that interest in nanofiltration technology has grown over the past decade, particularly over the past five years. The primary journals reporting articles on nanofiltration are the Journal of Membrane Science, Desalination and Separation and Purification Technology, although articles have been spread across a further 139 journals. Unsurprisingly, the major topics of interest have been water processing, membrane fabrication and membrane surface modification. There has been clear growth in the areas of organic solvent nanofiltration, pharmaceutical and biological applications, design and economics of nanofiltration processes and review articles. Nanofiltration modelling has received less support over the period reviewed and has experienced a steady decline.
Clearly the overall growing trend in nanofiltration research indicates that the technology remains popular and this interest should materialise into further applications for a robust and sustainable future.
This chapter focuses on the terminology and traditional treatment of textile wastewater concepts. Textile wastewater (TWW) is one of the most important hazardous wastewaters for ecosystems when it is discharged directly into water streams without proper treatment. The textile industry usually consumes a large amount of water and generates an enormous amount of wastewater which contains many types of pathogens, oxygen-demanding substances and inorganic and synthetic organic chemicals. Effluent guidelines and laws for wastewater treatment plants have been enacted by several protection agencies across the world, based on performance and control technologies. Toxic effluent discharged from various textile industries undergoes several physiochemical processes. Treatment for TWW can be mainly classified into three steps: primary, secondary and tertiary. Conventional treatment methods such as adsorption, coagulation, membrane separation, flotation, ozonation, ion exchange, evaporation and crystallization have been commonly employed for the treatment of TWW. Advanced wastewater treatment can effectively recover water from textile effluents and possibly reuse it in the production process. AWT technologies encourage the design of processes that diminish the spreading and generation of hazardous substances in an aqueous environment. Implementation of suitable AWT processes in textile industries is discussed in a separate section.
The generation of multi-functional drug delivery systems, namely solid dosage forms loaded with nano-sized carriers, remains little explored and is still a challenge for formulators. For the first time, the coupling of two important technologies, 3D printing and nanotechnology, to produce innovative solid dosage forms containing drug-loaded nanocapsules was evaluated here. Drug delivery devices were prepared by fused deposition modelling (FDM) from poly(ε-caprolactone) (PCL) and Eudragit® RL100 (EUD) filaments with or without a channelling agent (mannitol). They were soaked in deflazacort-loaded nanocapsules (particle size: 138 nm) to produce 3D printed tablets loaded with them, as observed by SEM. Drug loading was improved by the presence of the channelling agent and a linear correlation was obtained between the soaking time and the drug loading (r² = 0.9739). Moreover, drug release profiles were dependent on the polymeric material of tablets and the presence of the channelling agent. In particular, tablets prepared with a partially hollow core (50% infill) had a higher drug loading (0.27% w/w) and faster drug release rate. This study represents an original approach to convert nanocapsules suspensions into solid dosage forms as well as an efficient 3D printing method to produce novel drug delivery systems, as personalised nanomedicines.
Commercial nanofiltration (NF) membranes have been used to separate dyes and salts in industry, however, NF membrane’s high rejection to divalent salts (i.e. Na2SO4) leads to a reduction of salt recovery. In this study, a tight ultrafiltration (t-UF) ceramic membrane (MWCO 8800 Da) is proposed to fractionate dyes and mixed salts (NaCl/Na2SO4) for textile wastewater treatment. Performance of the t-UF ceramic membrane and DK polymeric membrane (from GE) has been compared regarding to permeability, retention of reactive dyes and permeation of salts. The t-UF ceramic membrane presents better permeability, competitive rejection of dye molecules (> 98%) and reduced rejection of NaCl (< 10%) and Na2SO4 (< 30%) in comparison with DK membrane; the pure water permeability of t-UF membrane is at least 6 times of DK membrane. In particular, the operation parameters (TMP, temp. and pH) and solution environment (concentration and charges) have been intensively evaluated for dye/dual-salts separation efficiency in the membrane process. It also reveals that the t-UF ceramic membrane has performed negative rejection to chloride ions at low operating pressure in the dye and NaCl/Na2SO4 solution due to the electrostatic Donnan effect. Concentration of salt, valence of inorganic ions and charge of dyes are found as having significant effect on membrane separation performance. In a conclusion, the strong retention of dyes and free permeation of salts (i.e. low retention) by the t-UF ceramic membrane proves that it can be applied to treat dyeing wastewater of high salinity and recover dyes and salts separately in the process.
Pilot scale production of a dairy ingredient enriched in phospholipids (PLs) was generated from a buttermilk powder (BMP) substrate utilising a combined process of targeted enzymatic hydrolysis of the innate milk proteins followed by ultrafiltration with a 50 kDa membrane. An 8.5 fold increase in PL was achieved in the 50 kDa retentate (50 R) compared to the BMP, 11.05 ± 0.02% and 1.30 ± 0.00% total PL, respectively. Simultaneously, total lipid content in the retentate increased 8.7 fold with reference to the BMP, 60.07 ± 0.54% and 6.84 ± 0.17% total lipid respectively. Protein reduced to 10.58 ± 0.09% (50 R) from 31.40 ± 0.57% in BMP. Supercritical CO2 fluid extraction (SFE) was employed to generate a purified lipid fraction. SFE with ethanol as a co-solvent yielded a purified lipid extract with enriched PLs level of 56.24 ± 0.07% on a dry matter basis.
A large number of bioactive peptides isolated from natural sources are known to play important physiological roles in the human body. It is possible to use these as alternative therapy agents. One example is yolkin which can be useful as a food supplement, a natural therapeutic agent for preventing and treating cognitive disorders of various origins, preferably in patients with unsatisfactory responses to known therapies. A new simple method of isolation of yolkin based on precipitation with ethanol or acetone was developed. The best precipitation efficiency of both ethanol and acetone was achieved when stirred into the starting material to a final concentration of 70%. These methods preserved the ability of yolkin to stimulate human whole blood cells to release anti-inflammatory cytokines and neurotrophins. At first we indicated that yolkin displayed a potential neuroprotective effect by the ability to stimulate cells to produce pro-survival brain derived neurotrophic factor (BDNF).
Potable water reuse has been adopted by cities suffering water scarcity in recent years. The microbial safety in water reuse, especially with respect to pathogenic viruses, is still a concern for water consumers. Membrane filtration can achieve sufficient removal of pathogenic viruses without disinfection byproducts, but the required energy is intensive. In this study, we graft-polymerized zwitterionic SPP ([3-(methacryloylamino) propyl] dimethyl (3-sulfopropyl) ammonium hydroxide) on a 150 kDa ultrafiltration polyethersulfone membrane to achieve a significantly higher virus removal. The redox-initiated graft-polymerization was performed in an aqueous solution during filtration of the monomer and initiators, allowing for functionalizing the membrane pores with hydrophilic polySPP. Bacteriophage MS2 and human adenovirus type 2 (HAdV-2) were used as surrogates for pathogenic human norovirus and human adenovirus. The grafting resulted in ∼18% loss of the membrane permeability but an increase of 4 log10 in HAdV-2 removal and 3 log10 in MS2 removal. The pristine and the grafted membranes were both conditioned with soluble microbial products (SMP) extracted from a full-scale membrane bioreactor (MBR) in order to test the virus removal after fouling the membranes. After fouling, the HAdV-2 removal by the grafted membrane was 1 log10 higher than that of the pristine membrane. For MS2, the grafted membrane after fouling with SMP achieved an additional 5 log10 removal compared to the unmodified membrane. The simple graft-polymerization functionalization of commercialized membrane achieving enhanced virus removal efficiency highlights the promise of membrane filtration for pathogen control in potable water reuse.
Ultrafiltration is one of the most fascinating technologies, which makes it possible to improve the quality of traditional medicines for application in the pharmaceutical industry. However, researchers have paid little attention to the effect of ultrafiltration membrane on traditional medicines chemical constituents. In this work, Ophiopogon japonicus (L.f) Ker-Gawl. was used as an example to illuminate the influence of ultrafiltration with different material and molecular weight cut-off (MWCO) membrane on natural chemical constituents as measured by ultra-fast liquid chromatography coupled with ion trap time-of-flight mass spectrometry (UFLC-IT-TOF/MS). Our results indicated that ultrafiltration membrane significantly impacted homoisoflavonoids, especially homoisoflavonoids that were almost completely retained on the polyethersulfone (PES) membrane. We also found that the larger number of aglycone hydroxy and sugar moiety in steroid saponins, the higher the transmittance. Furthermore, the passage rate (%) of ophiogenin type saponins was higher than that of others. The possible adsorptive mechanisms were hydrogen bonding, hydrophobic interactions, and benzene ring interaction by π-π stacking. In conclusion, it is crucial to choose appropriate ultrafiltration membrane based on the characteristics of produce products for application of ultrafiltration technique.
Reclaimed water (i.e., reused advanced-treated wastewater) offers an alternative water resource. To reduce the health risks associated with its use, efficient virus removal such as with advanced wastewater treatment processes is important. Virus removal by coagulation followed by ultrafiltration (UF) for the treatment of drinking water has been well examined. But its efficacy in wastewater reclamation purpose using secondary treated effluent (SE) from wastewater treatment plant (WWTP) as feed water is unclear. Here, we optimized the virus removal efficiency of coagulation-UF in pilot-scale wastewater reclamation plants using SE as feed water, using the F-specific RNA bacteriophage MS2 as a model virus, at two wastewater treatment plants in Japan. We investigated how using coagulation as a pretreatment for UF improved virus removal efficiency. The efficiency varied greatly between SEs. To reveal the cause of the variation, we conducted laboratory-scale batch coagulation experiments. The efficiency of viral coagulation was negatively correlated with the concentration of dissolved organic matter in the feed water. The optimum pH for coagulation differed between SEs, and the efficiency of coagulation could be dramatically improved by optimizing the pH. We confirmed that the virus removal efficiency in the pilot-scale facility actually could be improved by adjusting the pH. In addition, we confirmed that coagulation-sedimentation-UF with pH adjustment could operate stably for more than 30 days at the pilot scale, with a high virus removal rate. Thus, the wastewater reclamation process described here offers promise in terms of reduced health risks and practical operation.
Developing advanced filtration membrane with high flux, good solute rejection and excellent antifouling performance is highly demanded. Hydrophilic graphene oxide (GO) nanosheets are attractive fillers for the preparation of composite membranes for water purification. However, strategies that can fully exploit the advantages and remedy the drawbacks of GO nanosheets are still needed. In this work, UiO-66 was specifically anchored to the GO layers as a porous modifier. The incorporated UiO-66 can effectively prevent the GO layers from stacking and introduce unique properties into the composite (UiO-66@GO). A series of novel composite membranes were prepared with the obtained UiO-66@GO composite and polyethersulfone (PES). As a result, the prepared composite membranes (UiO-66@GO/PES) exhibit high hydrophilicity and water purification performance. Especially, the water flux of composite membrane with 3.0 wt% UiO-66@GO loading shows an increase of 351% and 78% respectively in comparison with that of the PES and GO/PES membranes. Moreover, the UiO-66@GO/PES membranes exhibit good solute rejection and impressive antifouling performance, which is appealing for the application of industrial water purification.
A novel technique employing an Uzigirs dip cell arrangement is used in conjunction with Laser Doppler Electrophoresis for the determination of the surface zeta potential for a UF, NF, and RO membrane. To the authors best knowledge this is the first study employing Laser Doppler Electrophoresis and Electro-osmotic Flow Mapping for membrane surface charge determination. High correlation of the regression fit (R2>0.95) for a carboxylated polystyrene latex particle electrophoretic mobility was achieved at low electrolyte concentrations (1mM and 10mM NaCl), but the reliability and accuracy of the extrapolated zeta potential values were problematic at higher concentration due to high measurement uncertainty (>10% in some cases). Changes in the applied electric field increased the phase resolution of 50mM NaCl electrolyte solutions between 0.5-2.0V. However, the effects of Joule heating at higher voltages compromised 50mM NaCl sample integrity. When compared with the established Tangential Streaming Potential method, Laser Doppler Electrophoresis measurements provided similar zeta potential values and trends indicating that this new methodology can indeed be employed for membrane characterization purposes; however, further research needs to be conducted in order to optimize this new technique and set appropriate operating limits.
Palm oil mill effluent (POME), which is rich in organic matter, is one of the major contributors of water pollution. To date, biological treatment has been employed before it is released into water bodies to minimize the environmental hazards. However, the dark brownish colour of the effluent is still a big challenge to be addressed. In regard to this concern, membrane separation can serve as an attractive solution for this issue. This paper aims to investigate the performance of ultrafiltration nanocomposite membrane embedded with coupled zinc-iron oxide (ZIO) for the decolourization of POME. The ZIO was synthesized through the solution combustion technique by employing zinc nitrate hexahydrate and iron (III) nitrate nonahydrate as the precursors and urea as the fuel. The nanocomposite flat sheet membrane was prepared via phase inversion process. The physico-chemical properties of the MMMs were analysed using zeta potential analysis, SEM, BET and contact angle. Continuous filtration test was carried out to evaluate the capability of the MMMs for colour and COD removal. The results showed that the increase in the ZIO loading has drastically increased the membrane surface negativity and led to the colour removal of 70%. In addition, with the addition of M0.5, the permeation and colour removal had increased 25% and 17% respectively, compared to the pristine PVDF membrane. However, the long term filtration test revealed that the structure of M0.5 collapsed after 4 cycles of washing, but M2.0 still retained its performance. In a nutshell, this study demonstrated that negative surface charge has improved the antifouling properties meanwhile hydrophilicity has contributed to increased water flux during the colour removal process.
The objective of this study was to develop sorbitol based powder precursor of cubosomes loaded with tamoxifen citrate (TC), as a model of poorly water soluble drug, aimed at enhancing its oral bioavailability. TC-loaded powder precursor formulations were prepared by sequential spraying of TC/glycerol monooleate (GMO)/poloxamer 407 solution onto the surface of sorbitol powder. Four formulations (F1, F2, F3 and F4) were prepared at four GMO: sorbitol ratios of 1:2.5, 1:5, 1:7.5 and 1:10 w/w, respectively. The prepared powder precursors were subjected to in vitro and in vivo characterization. In vitro, direct correlations were observed between GMO: sorbitol ratio and % yield, drug content, flowability and dissolution efficiency of TC-loaded powder precursors. TC-loaded cubosomes, derived from the prepared powder precursors, exhibited a size range of 67.34 ± 4.40–102.01 ± 4.86 nm and entrapped more than 95% TC. In vivo absorption study in rats showed improved rate and extent of TC absorption from drug-loaded powder precursor (F4) compared to those of plain TC powder, with evidence of a relative bioavailability of 152.50 ± 32.67%. In conclusion, sorbitol based powder precursor of cubosomes may be a promising oral delivery system for enhancing the bioavailability of poorly water soluble drugs.
Here we synthesize a two-step Fr 13 risk assessment (Chem. Eng. Sci. 126 (2015) 106–115; Chem. Eng. Sci. 127 (2015) 133–142) for the first time. We demonstrate it with vulnerability to fouling in an apparent steady-state global process of integrated cross-flow ultrafiltration and osmotic distillation (UF-OD) for concentration of fruit juice. Integrated two-step membrane processing of juices is becoming widespread as an alternative to thermal treatment. The aim was to advance the Fr 13 framework to investigate how naturally occurring, random fluctuations in apparent steady-state plant parameters can be transmitted and impact in progressively multi-step complex (i.e. integrated not ‘complicated’) processes. Membrane behavior is simulated using Monte Carlo (with Latin Hypercube) sampling of transmembrane pressure (∆PUF 1-1) and filtration time (tUF 1-1) with independent data for concentrating pomegranate juice (Punica granatum). Membranes fouling is defined as a permeate flux less than the operational design flux. Overall global failure of the integrated two-step UF-OD is defined as an unwanted OD flux (JOD 1-2 < JOD 1-2, required plus 3 % tolerance). Results show the Fr 13 method is applicable to an integrated two-step process. The integrated UF-OD is expected to be vulnerable to surprise fouling in 10.5 % of all operations, over an extended time. Findings are used to assess re-design for reduced membrane vulnerability to fouling in second-tier studies. Results appear generalizable and could be applied to a range of integrated two-step processing. Outcomes will be of interest to risk analysts and manufacturers of membrane equipment. This work is part of an overall development and investigation of Fr 13 as a new quantitative risk assessment and equipment design tool.
BACKGROUND: Membrane fouling is a main obstacle hindering wider application of membrane technologies, and can cause a decline in flux and increased energy consumption, and more frequent chemical or membrane replacement can increase the operating costs. Membrane fouling is mainly governed by organic fouling and biofouling. In recent years, the development of new materials has provided new methods and thoughts for the research and development of antifouling and antibacterial membranes. RESULTS: In this study, to obtain both a highly hydrophilic, antifouling and antibacterial poly(vinylidene fluoride) (PVDF) membrane, in situ formed silver (Ag) nanoparticles were immobilized with silica (SiO2) nanoparticles, and then chemically bound onto a PVDF ultrafiltration (UF) membrane surface. The surface modification processes were achieved through a remarkably facile and effective dip-coating method. The impacts of Ag/SiO2 nanocomposites on membrane performance were investigated when applied in membrane filtration processes simultaneously. This membrane showed higher hydrophilicity and water permeation flux. The PVDF membrane exhibited antibacterial properties and displayed better anti-fouling performance. CONCLUSION: The superior performance of the Ag/SiO2-PVDF membranes and this facile, effective and scalable modification method hold great promise for their practical application. This work would also be helpful for developing new antifouling and antibacterial membrane and related materials via a convenient and large-scale method.
The potential of stirring assisted dead-end filtration to recover polyphenols from purple sweet potato (PSP) juices was evaluated. For this purpose, the effects of rotation speed (200-600 rpm), transmembrane pressure (TMP) (0.2-0.4 MPa), and membrane molecular weight cut-off (30-100 kDa) were investigated with a lab-scale filtration module. The results showed that the highest protein removal (86%) and polyphenol selectivity (12.2) were both obtained under higher rotation speed (600 rpm). Moreover, filtration flux was more important at 600 rpm due to the anti-fouling effect of shear rate generated by the rotation. The results also revealed that under TMP of 0.4 MPa, the cake resistance was the dominating fouling resistance. In addition, it was shown that the results obtained after fitting the data obtained for the filtration with 100 kDa membranes under the different TMP could be modeled by an exponential model. The optimum ultrafiltration conditions in this study were found under rotation speed of 600 rpm, using a 100 kDa membrane and at TMP of 0.3 MPa. Six main anthocyanins were identified by HPLC-DAD-EI-MS2 analysis in the unfiltered PSP juice and the permeate obtained under UF at the optimum conditions, being the intensities of the peaks lower in the filtrate obtained using ultrafiltration (UF). This study opens the doors of rotation-assisted ultrafiltration as a promising anti-fouling technique, thus avoiding subsequent purification steps.