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Current and future development of nanocarbon and its biocomposites production
Abstract
Over the past several years, CNCs have emerged as the most promising and cutting-edge materials in nanoscience and technology. The next generation of BNC materials could be built on nanocarbons because of their adaptability, affordability, low toxicity, and exceptional biocompatibility. Especially the exceptional biocompatibility of BNCs makes them well-suited for integration into biological systems. This quality is crucial
for applications such as the administration of drugs, tissue engineering, and biological sensors. These nanocarbon composites and BNCs are suitable for a variety of applications due to their remarkable pore size distribution, wide surface area, ease of modifying the porous texture, mechanical and thermal stability, and chemical deformation. Overall functional
groups associated with nanocarbon are bonded to particular substances or metals and improve the composite's electrical, thermal, and other desirable qualities. Significantly, future research in membrane technology with such BNCs highlights the potential of these materials for advancing filtration, separation, biomaterial technologies, and advanced medical devices.
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Polyaniline/nanocarbon (PANI/NC) nanocomposites have been prepared by in situ polymerization of aniline monomer in the presence of a stable colloidal solution of nanocarbon NC using ammonium persulfate as an initiator and silver ions (Ag⁺) as oxidizing agents to produce PANI/NC and PANI/NC/Ag2O nanocomposites, respectively. The morphological studies of the formed nanocomposites have been elucidated via transmission and scanning electron microscopes (TEM and SEM). Further characterization of the prepared nanocomposites has been done via infrared spectroscopy (IR), X-ray diffractometer (XRD), X-ray photoelectron spectroscopy (XPS), particle size distribution analysis (PSD), fluorescence microscope (FM), UV–VIS spectroscopy, and finally surface analysis. XRD results confirmed the presence of silver oxide Ag2O nanoparticles, and the obtained data is well matched with the JCPDS card number 76–1393 of silver oxide. XPS analyses have shown two prevailing characteristic peaks for Ag 3d5/2 and Ag 3d3/2 at 367.1 and 373 eV, respectively, representing Ag2O nanoparticles, which are matchable with the XRD analysis. The PSD analysis revealed that the sizes of the prepared nanocomposites are in the size range from 60 to 140 nm. The FM measurements showed luminescence from the prepared nanocomposites upon irradiation with different lights. This recommends that the fluorophores present in the prepared nanocomposites have the potential to both absorb and emit light. The AC conductivity and the dielectric permittivity of the obtained nanocomposites at room temperature and at different frequency ranges have been investigated. At higher frequency ranges, the maximum ac conductivity obtained was 1.06 × 10–2 and 2.5 × 10–2 S.Cm⁻¹ for the PANI/NC and PANI/NC/Ag2O, respectively. As far as we know, these new nanocomposites with superior optical and electrical characteristics have not been described yet in the literature.
Bionanocomposites based on poly(trimethylene 2,5‐furandicarboxylate)‐block‐poly(tetramethylene oxide) (PTF‐b‐F‐PTMO) with various contents of carbon nanofibers, graphene nanoplatelets and a hybrid system of these nanoparticles are synthesized via in situ polymerization. The dispersion of nanoparticles in the nanocomposites is determined using a scanning electron microscope and optical microscopy images. The thermal properties are studied employing differential scanning calorimetry, dynamic mechanical thermal analysis, and thermogravimetric analysis. The melt viscosity of the synthesized materials is determined using rheological measurements. Mechanical properties, along with the thermal and electrical conductivity, are also analyzed. The synthesized polymer nanocomposites are processed using injection molding and they display mechanical properties of elastomers during mechanical testing, which indicates that the obtained materials are, in fact, thermoplastic elastomers (TPE). Compared to a neat matrix (PTF‐b‐F‐PTMO 50/50), the incorporation of nanoparticles causes an increase in the value of the degree of crystallinity and the value of the tensile modulus values (E) of the nanocomposites. Such reinforced bionanocomposites are especially interesting from an applicative point of view. They can be used as components of fuel systems, bumpers, or cupholders.
The growing demand for energy and environmental issues are the main concern for the sustainable development of modern society. Replacing toxic and expensive materials with inexpensive and biodegradable biomaterials is the main challenge for researchers. Nanocomposites are of the utmost consideration for their application in energy storage devices because of their specific electrochemical properties. Cellulose-based bionanocomposites have added a new dimension to this field since these are developed from available renewable biomaterials. Studies on developing electrodes, separators, collectors, and electrolytes for the batteries have been conducted based on these composites rigorously. Electrodes and separators made of these composites for the supercapacitors have also been investigated. Researchers have used a wide range of micro-and nano-structural cellulose along with nanostructured inorganic materials to produce cellulose-based bionanocomposites for energy devices, i.e., supercapacitors and batteries. The presence of cellulosic materials enhances the loading capacity of active materials and uniform porous structure in the electrode matrix. Thus, it has shown improved electrochemical properties. Therefore, these can help to develop biodegradable, lightweight, malleable, and strong energy storage devices. In this review article, the manufacturing process, properties, applications, and possible opportunities of cellulose-based bionanocomposites in energy storage devices have been emphasized. Its challenges and opportunities have also been discussed.
Supercapacitors have attained a special stance among energy storage devices such as capacitors, batteries, fuel cell, and so forth. In this state-of-the-art overview on green synthesis approaches and green materials for supercapacitors, the cutting-edge green polymer/nanocarbon nanocomposite systems were explored by focusing on the design and related essential features. In this regard, various polymers were reconnoitered including conjugated polymers, thermosetting matrices, and green-cellulose-based matrices. Nanocarbon nanomaterials have also expanded research thoughtfulness for green-technology-based energy storage devices. Consequently, green polymer/nanocarbon nanocomposites have publicized fine electron conduction pathways to promote the charge storage, specific capacitance, energy density, and other essential features of supercapacitors. Future research directions must focus on the design of novel high performance green nanocomposites for energy storage applications.
Different microorganisms are present in nature, some of which are assumed to be hazardous to the human body. It is crucial to control their continuing growth to improve human life. Nanomaterial surface functionalization represents a current topic in continuous evolution that supports the development of new materials with multiple applications in biology, medicine, and the environment. This study focused on the antibacterial activity of different nanocomposites based on functionalized multi-walled carbon nanotubes against four common bacterial strains. Two metal oxides (CuO and NiO) and two antibiotics (azithromycin and ciprofloxacin) were selected for the present study to obtain the following nanocomposites: MWCNT-COOH/Antibiotic, MWCNT-COOH/Fe3O4/Antibiotic, and MWCNT-COOH/Fe3O4/MO/Antibiotic. The present study included two Gram-positive bacteria (Staphylococcus aureus and Enterococcus faecalis) and two Gram-negative bacteria (Escherichia coli and Pseudomonas aeruginosa). Ciprofloxacin (Cip) functionalized materials (MWCNT-COOH/Fe3O4/Cip) were most efficient against all tested bacterial strains; therefore, we conclude that Cu and Ni reduce the effects of Cip. The obtained results indicate that the nanocomposites functionalized with Cip are more effective against selected bacteria strains compared to azithromycin (Azi) functionalized nanocomposites. The current work determined the antibacterial activities of different nanocomposites and gave fresh insights into their manufacture for future research regarding environmental depollution.
Wastewater, which is rich with heavy elements, dyes, and pesticides, represents one of the most important environmental pollutants. Thus, it has been significant to fabricate environmentally friendly polymers with high adsorption ability for those pollutants. Herein, crosslinked chitosan (C-Cs) was prepared using isopropyl acrylamide and methylene bisacrylamide. Carbon nanoparticles (C-NPs) were also obtained by the treatment of the agricultural wastes, which was used with C-Cs to prepare C-Cs/C-NPs nanocomposite (C-Cs/C-NC). Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), and transmission electron microscope (TEM) were used to investigate the prepared adsorbent. C-Cs, C-NPs, and C-Cs/C-NC were used in water treatment for the adsorption of lead ions (Pb+2) and methylene blue (MB). The adsorption process occurred by the prepared samples was investigated under different conditions, including contact time, as well as different doses and concentrations of adsorbents. The findings exhibited that the adsorption of Pb+2 and MB by C-Cs/C-NC was higher than C-Cs and C-NPs. In addition, the kinetic and isotherm models were studied, where the results showed that the adsorption of Pb+2 and MB by various adsorbents obeys pseudo-second-order and Langmuir isotherms, respectively.
Diabetes is a major health challenge, and it is linked to a number of serious health issues, including cardiovascular disease (heart attack and stroke), diabetic nephropathy (kidney damage or failure), and birth defects. The detection of glucose has a direct and significant clinical importance in the management of diabetes. Herein, we demonstrate the application of in-situ synthesized Ti2C-TiO2 MXene nanocomposite for high throughput non-enzymatic electrochemical sensing of glucose. The nanocomposite was synthesized by controlled oxidation of Ti2C-MXene nanosheets using H2O2 at room temperature. The oxidation results in the opening up of Ti2C-MXene nanosheets and the formation of TiO2 nanocrystals on their surfaces as revealed in microscopic and spectroscopic analysis. Nanocomposite exhibited considerably high electrochemical response than parent Ti2C MXene, and hence utilized as a novel electrode material for enzyme-free sensitive and specific detection of glucose. Developed nanocomposite-based non-enzymatic glucose sensor (NEGS) displays a wide linearity range (0.1 µM–200 µM, R2 = 0.992), high sensitivity of 75.32 μA mM−1 cm−2, a low limit of detection (0.12 μM) and a rapid response time (~3s). NEGS has further shown a high level of repeatability and selectivity for glucose in serum spiked samples. The unveiled excellent sensing performance of NEGS is credited to synergistically improved electrochemical response of Ti2C MXene and TiO2 nanoparticles. All of these attributes highlight the potential of MXene nanocomposite as a next-generation NEGS for on the spot mass screening of diabetic patients.
This study employed response surface methodology to optimize the preparation of biocomposites based on whey protein isolate, glycerol, and nanocrystalline cellulose from pineapple crown leaf. The effects of different concentrations of nanocrystalline cellulose as a filler and glycerol as a plasticizer on the thickness, the tensile strength, and the elongation at break on the resulting biocomposite films were investigated. The central composite design was used to determine the optimum preparation conditions for biocomposite films with optimum properties. The regression of a second-order polynomial model resulted in an optimum composition consisting of 4% glycerol and 3.5% nanocrystalline cellulose concentrations, which showed a desirability of 92.7%. The prediction of the regression model was validated by characterizing the biocomposite film prepared based on the optimum composition, at which the thickness, tensile strength, and elongation at break of the biocomposite film were 0.13 mm, 7.16 MPa, and 39.10%, respectively. This optimum composition can be obtained in range concentrations of glycerol (4–8%) and nanocrystalline cellulose (3–7%). Scanning electron microscope images showed that nanocrystalline cellulose dispersed well in the pure whey protein isolate, and the films had a relatively smooth surface. In comparison, a rough and uneven surface results in more porous biocomposite films. Fourier transform infrared spectroscopy revealed that nanocrystalline cellulose and glycerol showed good compatibility with WPI film by forming hydrogen bonds. The addition of nanocrystalline cellulose as a filler also decreased the transparency, solubility, and water vapor permeability and increased the crystallinity index of the resulting biocomposite film.
Over the past 15 years, numerous studies have been conducted on the use of nanocarbons as biomaterials towards such applications as drug delivery systems, cancer therapy, and regenerative medicine. However, the clinical use of nanocarbons remains elusive, primarily due to short‐ and long‐term safety concerns. It is essential that the biosafety of each therapeutic modality be demonstrated in logical and well‐conducted experiments. Accordingly, the fundamental techniques for assessing nanocarbon biomaterial safety have become more advanced. Optimal controls are being established, nanocarbon dispersal techniques are being refined, the array of biokinetic evaluation methods has increased, and carcinogenicity examinations under strict conditions have been developed. The medical implementation of nanocarbons as a biomaterial is in sight. With a particular focus on carbon nanotubes, these perspectives aim to summarize the contributions to date on nanocarbon applications and biosafety, introduce the recent achievements in evaluation techniques, and clarify the future prospects and systematic introduction of carbon nanomaterials for clinical use through practical yet sophisticated assessment methods.
The misuse of many types of broad-spectrum antibiotics leads to increased antimicrobial resistance. As a result, the development of a novel antibacterial agent is essential. Photodynamic antimicrobial chemotherapy (PACT) is becoming more popular due to its advantages in eliminating drug-resistant strains and providing broad-spectrum antibacterial resistance. Carbon dots (CDs), zero-dimensional nanomaterials with diameters smaller than 10 nm, offer a green and cost-effective alternative to PACT photosensitizers. This article reviewed the synthesis methods of antibacterial CDs as well as the recent progress of CDs and their nanocomposites in photodynamic sterilization, focusing on maximizing the bactericidal impact of CDs photosensitizers. This review establishes the base for future CDs development in the PACT field.
Currently, numerous studies have shown that carbon nanofibres have mechanical properties that are replaced by other widely used fibres. The high tensile strength of the carbon fibres makes them ideal to use in polymer matrix composites. The high-strength fibres can be used in short form in a composite and mass-produced to meet the high demands of automotive applications. These composites are capable of addressing the strength requirement of nonstructural and structural components of the automotive industry. Due to these composite lightweight and high-strength weight ratios, the applications can be widely varying. The research for these materials is a never-ending process, as researchers and design engineers are yet to tap its full potential. This study fabricated phenolic resin with different wt% of carbon nanofibre (CNF). The percentage of the CNF as a filler material is varied from 1 to 4 wt%. Mechanical properties such as hardness, tensile strength, and XRD were investigated. Phenolic resin with 4 wt% of carbon nanofibre (CNF) exhibits maximum tensile strength and hardness of 43.8 MPa and 37.8 HV.
While conventional dental implants focus on mechanical properties, recent advances in functional carbon nanomaterials (CNMs) accelerated the facilitation of functionalities including osteoinduction, osteoconduction, and osseointegration. The surface functionalization with CNMs in dental implants has emerged as a novel strategy for reinforcement and as a bioactive cue due to their potential for mechanical reinforcing, osseointegration, and antimicrobial properties. Numerous developments in the fabrication and biological studies of CNMs have provided various opportunities to expand their application to dental regeneration and restoration. In this review, we discuss the advances in novel dental implants with CNMs in terms of tissue engineering, including material combination, coating strategies, and biofunctionalities. We present a brief overview of recent findings and progression in the research to show the promising aspect of CNMs for dental implant application. In conclusion, it is shown that further development of surface functionalization with CNMs may provide innovative results with clinical potential for improved osseointegration after implantation.
High strength application of biopolymers requires good mechanical strength. The tensile properties of polylactic acid (PLA) are relatively low for major industrial applications such as packaging, biomedical and automobile spare parts. In this study, the mechanical strength of polylactic acid was enhanced with nanocarbon isolated from diesel engine combustion soot. The isolated nanocarbon was characterised using spectrometry and Fourier transform infrared (FTIR) spectroscopy analysis. After that, the nanocarbon was used as a reinforcement in plasticised PLA to produce a composite. The PLA-nanocarbon composite was produced using the compression moulding technique. The nanocarbon composition was varied between 2 wt% and 8 wt% in the PLA matrix. The tensile, hardness and morphological properties of the composite were analysed with the tensile test, hardness test, optical microscope and X-ray diffraction (XRD) analysis. The ultraviolet (UV) spectrometer and FTIR analysis results confirmed the successful isolation of nanocarbon from the diesel engine combustion soot. The tensile and hardness properties of the PLA matrix increased with addition of nanocarbon. The morphological images showed good miscibility between the PLA and the nanocarbon reinforcement, responsible for the increase in mechanical properties. The potential use of the composite for high strength application showed great possibility based on the result obtained.
Advanced nanostructured materials like nanobiochar have come up with the sustainable solutions for a range of problems of modern era. In recent years, carbon nanomaterials have been developed as powerful tools due to their unique characteristics and number of applications in various areas like energy, materials, agriculture and the environment, specifically in phytoremediation of various organic, inorganic and heavy metal contaminants. Biochar technology and nanobiotechnology may result in production of carbon-based nanomaterials including nanobiochar and biochar nanocomposites to revolutionize the research in concerned fields. Nanobiochar is nanosized biochar material with better physical, chemical and surface properties. It has numerous advantages such as improvement in plant growth and soil properties, plant disease management, bioremediation of contaminants and pesticides, treatment of wastewater and it is also used as support material for enzyme immobilization. It may become the best alternative over conventional approaches due to its cost effectiveness, sustainability and environmental friendliness. It also can mitigate climate change by carbon sequestration function. As compared with biochar, nanobiochar has excellent capability of absorbing pollutants, nutrients and contaminants and has mobility in soil thus offering a potential waste management substitute.
This review paper is an extensive compilation about production of nanobiochar and biochar based nanocomposites, their diverse applications in agriculture and environment sectors with some other novel applications and recent developments in the fields such as energy, catalysis, material science, biomedical etc.
Recently, antibacterial coatings based on graphene oxide (GO) nanocomposites have attracted many studies around the world. The use of polymers as the matrices of GO nanofillers in the nanocomposites has been explored to produce efficient coatings against bacteria. One of the most prospective applications is the incorporation of GO into biocompatible polymers, which can produce antibacterial coatings. Here, recent progresses on the antibacterial coatings of nanocomposites based on biocompatible polymers and GO are reviewed. The effect of GO filler concentrations, biocide materials, and biocompatibility are discussed to find the most efficient antibacterial activity and biocompatibility of nanocomposites. Among biocompatible polymers, chitosan (Cs), poly vinyl alcohol (PVA), and poly lactic acid (PLA) are the most popular matrices used for the nanocomposites. This review also elaborates challenges in the use of other biocompatible polymers. Future works on biocompatible antibacterial coatings should be conducted by considering the concentration of GO nanofillers or adding other materials such as essential oils to suppress the toxicity toward functional cells.
Advanced materials were used and are being implemented in structural, mechanical, and high-end applications. Contemporary materials are used and being implemented in structural, mechanical, and high-end applications. Composites have several major capabilities, some of them being able to resist fatigue, corrosion-resistance, and production of lightweight components with almost no compromise to the reliability, etc. Nanocomposites are a branch of materials within composites, known for their greater mechanical properties than regular composite materials. The use of nanocomposites in the aerospace industry currently faces a research gap, mainly identifying the future scope for application. Most successes in the aerospace industry are because of the use of suitable nanocomposites. This review article highlights the various nanocomposite materials and their properties, manufacturing methods, and their application, with key emphasis on exploiting their advanced and immense mechanical properties in the aerospace industry. Aerospace structures have used around 120,000 materials; herein, nanocomposites such as MgB2, multi-walled carbon nanotubes, and acrylonitrile butadiene styrene/montmorillonite nanocomposites are discussed, and these highlight properties such as mechanical strength, durability, flame retardancy, chemical resistance, and thermal stability in the aerospace application for lightweight spacecraft structures, coatings against the harsh climate of the space environment, and development of microelectronic subsystems.
Further development of medical devices for children is required in Japan, but the development of such devices is delayed compared to that of medical devices for adults. Herein, we investigated policies for advancing the development of pediatric medical devices in Japan and the United States. Considering the achievements of each policy, we proposed a strategy to promote further development of pediatric medical devices in Japan. We investigated policies for supporting the development of pediatric medical devices and approved cases in Japan and the United States by searching contents of websites of regulatory bodies and other related administrations, and scientific papers. We found the main six policies in Japan and nine main policies in the United States for the development of pediatric medical devices. In the United States, various measures have initiated mainly in the 2000s, while in Japan, the main measures have been in place since 2013. Similarities were found in both countries, such as subsidies for application fees and research and development expenses, exemption of requirements for regulatory approval, and priority review and consultation by the regulatory body. Our study revealed that there are similarities in initiatives by both countries. To promote further development of pediatric medical devices in the future, improvements to expediting the review process to approval by the regulatory body, global development, and implementation of alternative measures to ensure the efficacy and safety of the device instead of large-scale clinical trials should be anticipated through cooperation among industry, government, and academia.
Pollutant removal from industrial effluents is a big challenge for industries. These pollutants pose a great risk to the environment. Nanotechnology can reduce the expenditure made by industries to mitigate these pollutants through the production of eco-friendly nanomaterials. Nanomaterials are gaining attention due to their enhanced physical, chemical, and mechanical properties. Using microorganisms in the production of nanoparticles provides an even greater boost to green biotechnology as an emerging field of nanotechnology for sustainable production and cost reduction. In this mini review, efforts are made to discuss the various aspects of industrial effluent bioremediation through microbial nanotechnology integration. The use of enzymes with nanotechnology has produced higher activity and reusability of enzymes. This mini review also provides an insight into the advantages of the use of nanotechnology as compared to conventional practices in these areas.
Generally, the coating properties of polymeric compounds are enhanced by using nanomaterials as fillers which are non-biobased. In this project, the hydroxyapatite (HAP) was obtained from waste fish scales and the biobased hyperbranched polyol (HyBP) was synthesized from castor oil. The series of nanocomposites were prepared by adding various amounts of HAP (0.5% wt, 1% wt, and 2% wt) in HyBP along with isophorone diisocyanate (IPDI) (maintaining the NCO:OH, ratio at 1.2:1). These mixtures were coated on mild steel panels and glass plates. The synthesized HyBP was characterized by FTIR, ¹HNMR, and ¹³CNMR techniques. The HAP was characterized by FTIR, FESEM, and XRD techniques. The surface morphology of prepared nanocomposites was studied by FESEM, XRD, and AFM techniques. The nanoparticle size was determined by TEM technique. The thermal behavior of nanocomposites was studied by TGA technique. The coating properties were determined by impact strength, crosscut adhesion, and flexibility test. The corrosion properties of the coatings were determined by the immersion test as well as electrochemical test.
Graphic Abstract
The presence of dyes in wastewater streams poses a great challenge for sustainability and brings the need to develop technologies to treat effluent streams. Here, we propose a mixture of high superficial area carbon-based nanomaterial strategy to improve the removal of basic blue 26 (BB26) by blending porous carbon nitride (CN) and graphene oxide (GO). We prepared CN and GO pristine materials, as well the nanocomposites with mass/ratio 30/70, 50/50, and 70/30, and applied them into BB26 uptake. Nanocomposite 50/50 CN/GO was found to be the better adsorbent, and the optimization of the adsorption revealed a fast equilibrium time of 30 min, after sonication for 2 min, nanocomposite 50/50, and BB26 dye loading of 0.1 g/L and 100 mg/L, respectively. The pH variation had great influence on BB26 uptake, and at ultrapure water pH, the dye removal capacity by the composite reached 917.78 mg/g. At pH 2, a remarkable removal efficiency of 3510.10 mg/g was obtained, probably due to electrostatic interactions among protonated amine groups of the dye and negatively charged CN/GO nanocomposite. The results obtained were best fitted to the pseudo-second-order kinetic model and the Dubinin-Radushkevich isotherm. The adsorption process was thermodynamically spontaneous, and physisorption was the main mechanism, which is based on weak electrostatic and π-π interactions. The dye attached to the CN/GO nanocomposite could be removed by washing with ethyl alcohol, and the adsorbent was reused for five consecutive cycles with high BB26 uptake efficiency. The CN/GO nanocomposite ability to remove the BB26 dye was 21 times higher than those reported in the literature, indicating CN/GO composites as potential filtering materials to basic dyes.
Efficient removal of heavy metals from water and wastewater is a necessity for human and environmental well-being. Agricultural, domestic, and industrial waste discharges increase with the increase in the global population. Discharges are loaded with toxic metallic substances that inevitably reach water sources. Conventional treatment methods are in many cases inadequate in their removal efficiencies. Alternatively, recently developed advanced treatment approaches, such as nanotechnologies, offer advantages in water treatment. Nanotechnology brought about materials with high specific surface areas and adsorption capacities for the removal of undesirable heavy metals present in water. A detailed review of the use of nanotechnologies and nanomaterials for the removal of heavy metals from aqueous solutions is presented in this study. Limitations, research gaps, and suitability of nanotechnology in water treatment for the removal of heavy metals at a large scale are discussed, and relevant conclusions are accordingly deduced.
Membrane based separation system is considered as a promising technology to purify water, owing to its simplicity and efficiency in operation. However, the application is limited by membrane fouling, which can lead to the declination of water flux and premature failure of membrane. The fouling can be controlled through membrane surface modification by blending hydrophilic materials during the casting solution preparation. Polyethersulfone (PES) membrane is naturally hydrophobic due to lack of oxygen functional group, which limits its application in the filtration of water. Therefore, modification of PES-based membranes is required. In this work, modification of the PES membrane was carried out by incorporating carbon-based nanomaterials (graphene oxide (GO)) and a well-known organic polymer (polyvinylpyrrolidone (PVP)). The effect of each additive toward the hydrophilicity of composite PES membrane was then investigated. GO was synthesized using modified Hummers method due to its simpler and shorter process. Each additive was added during the casting solution preparation and the amount added was varied from 0.5 to 1.0 wt%. The resultant composite PES membranes were characterized using XRD, FTIR and TGA prior to hydrophilicity and pure water flux (PWF) measurement. It was observed that the additives (PVP and GO) have significantly affected the membranes hydrophilicity, resulting in lower contact angle and higher pure water flux. The highest value of PWF (230 L/m2.h) with lowest contact angle (42 °) were observed for PES-1.0GOPVP membrane due to high amount of GO and PVP. Improved PWF performance of composite PES-1.0GOPVP membrane was attributed to the better dispersibility of the PVP and GO and increased surface hydrophilicity of the modified composite membranes. This study indicated that PVP and GO are effective modifiers to enhance the performance of PES membrane
Purpose of Review
This review paper summarizes recent research studies on the pathways to convert lignin into a micro and nanosize materials and their use in advanced applications as these materials are being utilized in greater amounts in recent years.
Recent Findings
Research, development, and applications carried out demonstrate the potential of lignin products (e.g., micro- and nanospheres, nanofibers, and nanotubes) for use in drug delivery, pesticide-controlled release, biocarbon fiber, electrochemical energy storage, purification, and nanocomposites.
Summary
The key benefits being exploited are the cost reduction associated to the use of lignin instead of synthetic polymers and the utilization of renewable raw materials instead of petroleum resources which encourage further development of technical lignins with high value-added applications such as micro- and nanosize lignins.
Biochar-based compound fertilizers (BCF) and amendments have proven to enhance crop yields and modify soil properties (pH, nutrients, organic matter, structure etc.) and are now in commercial production in China. While there is a good understanding of the changes in soil properties following biochar addition, the interactions within the rhizosphere remain largely unstudied, with benefits to yield observed beyond the changes in soil properties alone. We investigated the rhizosphere interactions following the addition of an activated wheat straw BCF at an application rates of 0.25% (g·g-1 soil), which could potentially explain the increase of plant biomass (by 67%), herbage N (by 40%) and P (by 46%) uptake in the rice plants grown in the BCF-treated soil, compared to the rice plants grown in the soil with conventional fertilizer alone. Examination of the roots revealed that micron and submicron-sized biochar were embedded in the plaque layer. BCF increased soil Eh by 85 mV and increased the potential difference between the rhizosphere soil and the root membrane by 65 mV. This increased potential difference lowered the free energy required for root nutrient accumulation, potentially explaining greater plant nutrient content and biomass. We also demonstrate an increased abundance of plant-growth promoting bacteria and fungi in the rhizosphere. We suggest that the redox properties of the biochar cause major changes in electron status of rhizosphere soils that drive the observed agronomic benefits.
Based on the results of research papers reflected in the scientific literature, the main examples, methods and perspectives for the development of technical textiles are considered. The focus of this work is to concentrate the results obtained for different textile applications (technical textiles) through the use of biodegradable polymers modified and improved with nanoparticles. The techniques for obtaining polymeric nanocomposites, finishing processes, type and structure of textiles are specified. In general, key aspects are identified for a better understanding of the technical challenges and physicochemical effects of the fibers. Nanocompuestos poliméricos biodegradables aplicados a textiles técnicos: una revisión Resumen Con base en los resultados de trabajos de investigación reflejados en la literatura científica, se consideran los principales ejemplos, métodos y perspectivas para el desarrollo de textiles técnicos. El enfoque de este trabajo consiste en concentrar los resultados obtenidos para diferentes aplicaciones textiles (textiles técnicos) mediante el uso de polímeros biodegradables modificados y mejorados con nanopartículas. Se especifican las técnicas para obtención de nanocompuestos poliméricos, procesos de acabado, tipo y estructura de textiles. En general, se identifican aspectos clave para una mejor comprensión de los retos técnicos y efectos fisicoquímicos de las fibras.
Abstract Nanotechnology is an advanced field of science having the ability to solve the variety of environmental challenges by controlling the size and shape of the materials at a nanoscale. Carbon nanomaterials are unique because of their nontoxic nature, high surface area, easier biodegradation, and particularly useful environmental remediation. Heavy metal contamination in water is a major problem and poses a great risk to human health. Carbon nanomaterials are getting more and more attention due to their superior physicochemical properties that can be exploited for advanced treatment of heavy metal-contaminated water. Carbon nanomaterials namely carbon nanotubes, fullerenes, graphene, graphene oxide, and activated carbon have great potential for removal of heavy metals from water because of their large surface area, nanoscale size, and availability of different functionalities and they are easier to be chemically modified and recycled. In this article, we have reviewed the recent advancements in the applications of these carbon nanomaterials in the treatment of heavy metal-contaminated water and have also highlighted their application in environmental remediation. Toxicological aspects of carbon-based nanomaterials have also been discussed.
The increasing environmental concerns and regulatory requirements have led to the development of eco-friendly bio-adsorbents for wastewater remediation. Natural biopolymers have drawn significant attention in this field due to their renewable and biodegradable nature. Among the various natural biopolymers, polysaccharides such as alginate, cellulose, starch, chitosan, and natural gums have attracted significant attention due to their availability and low cost. The main objective of this review is to provide a detailed account of bio-adsorbents derived from polysaccharides, covering their practical application and effectiveness in removing a broad range of pollutants from aqueous media. Each polysaccharide is comprehensively discussed based on the type of pollutants it can remove. Specifically, research papers from 2021 and onwards have been reviewed to present the latest progress in this field. Additionally, the synthesis, adsorption mechanism, and recyclability of each polysaccharide are briefly discussed. Finally, insights into future directions and perspectives for the development of polysaccharide-based adsorbents for wastewater remediation are provided. Overall, this review emphasizes the potential of natural biopolymers, particularly polysaccharides, as eco-friendly and cost-effective bio-adsorbents for wastewater treatment. Moreover, it provides valuable insights into potential avenues for future investigations within this domain, thereby offering significant benefits to both novice and seasoned researchers engaged in the study of wastewater remediation.
Nowadays, the most common approaches in the prognosis, diagnosis, and treatment of diseases are along with undeniable limitations. Thus, the ever-increasing need for using biocompatible natural materials and novel practical modalities is required. Applying biomaterials, such as chitosan nanoparticles (CS NPs: FDA-approved long-chain polymer of N-acetyl-glucosamine and D-glucosamine for some pharmaceutical applications), can serve as an appropriate alternative to overcome these limitations. Recently, the biomedical applications of CS NPs have extensively been investigated. These NPs and their derivatives can not only prepare through different physical and chemical approaches but also modify with various molecules and bioactive materials. The potential properties of CS NPs, such as biocompatibility, biodegradability, serum stability, solubility, non-immunogenicity, anti-inflammatory properties, appropriate pharmacokinetics and pharmacodynamics, and so forth, have made them excellent candidates for biomedical applications. Therefore, CS NPs have efficiently applied for various biomedical applications, like regenerative medicine and tissue engineering, biosensors for the detection of microorganisms, and drug delivery systems (DDS) for the suppression of diseases. These NPs possess a high level of biosafety. In summary, CS NPs have the potential ability for biomedical and clinical applications, and it would be remarkably beneficial to develop new generations of CS-based material for the future of medicine.
Organic and inorganic contaminants polluting global water resources are concerning the world. Generally, being non-biodegradable synthetic and/or highly soluble in water, pollutants get easily mobilized in the environment. Their interaction with and accumulation in environment has adverse effects on ecosystems and human health.Deterioration of environment thanks to human activities is increasing daily which results in the discharge of toxic effluents, like pesticides, heavy metals and toxic dyes into environment, causing serious health problems to humans and pollution to environment. Nanocomposites have wide applications in different fields like air purification, wastewater treatment via heavy metal removal, soil improvement, fertilizers delivery systems, food packaging and flame retardency. Nanocomposite composition gives a large surface area with special properties. Lately nanocomposite structures are employed to purify water, develop fertilizer retention in soil, and enhances plant growth resulting in agricultural development, food packaging and flame retardancy. Properties of these nanocomposites rely upon both the properties of their constituents and also the combination between polymer/nano-filler.This chapter covers the advances on nanocomposites aimed at water decontamination through remediation of metal ions and synthetic organic chemicals, especially dyes, from wastewater.KeywordsNanocompositesMetal uptakeAntimicrobial activityDelivery system
The marine arena is our largest source of food supplies and one of the highest and biggest diversity products or byproducts supplier. Due to this diversity, its products and byproducts have a great potential to be used as reinforcement in biocomposites. From fish scales, bones, and crabs, all these parts can be used as reinforcement due to their exceptional properties. This chapter discusses the potential, properties, processes, and applications for marine-based sources as reinforced materials for biocomposites. Marine-based materials have comparable properties with other biocomposites, especially in term of degradability and strength, which are directly influenced by its environment.
Composite products made from bioresources, recycled materials, waste energy, and their variations are gaining popularity. The use of biocomposites in the construction of lightweight components have piqued the interest of automotive manufacturers. Manufacturing developments have been rendered possible by a hybrid biocomposites made of petrochemical-based and bioresources products. More biobased biocomposites based on plant-derived fiber and crop-derived plastics are being developed. Biodegradable composites have demonstrated a lot of promise in terms of sustainable packaging. Recycled plastic components that would otherwise wind up in landfill may be redirected and repurposed for use in composite applications, reducing reliance on virgin petroleum-based materials. Compatibility studies of recycled and waste materials with other elements in composite structures for increased interface and mechanical efficiency raise significant technical challenges. Therefore, this chapter discusses the potential to help achieve a major global sustainability target.
The chapter emphasizes a variety of points, including the issue of plastic waste and its major environmental and human health consequences. Plastics that are commonly used in various industries are also discussed. The industry’s solution to recycling such plastics is also demonstrated. Additionally, this chapter also covers a short history of composite manufacturing. Some uses of plastic waste in composites and biocomposites manufacturing are explored. As companies transition to renewable technology and packaging, more biocomposites using plastic waste will be manufactured. As a result, the harmful consequences of improper plastic waste management will be greatly minimized.
Nano biosensors is a device with excellent sensing property having dimension in the range of 100nm. Biosensors will recognize the biological molecules and have heterogeneous type of reaction with analyte. Biosensors are indispensable in medical field for metabolite measurement, monitoring diabetes and biomolecules due to its reproducibility and stability. Metal nanocomposite as biosensors have proven attention to biotechnologist due to its attractive properties. The properties include large surface area which will enhance immobilization of bio recognizers and receptor molecule, improved electro chemical properties and good biocompatibility. This review article covers the classification, characteristics and current development of biosensors with different nano composite materials.
Either as a filler or reinforcement for polymers, cellulose fibers are known to exhibits a significant contribution on the properties of the composites made. Due to extensive research, in the last decade, synthetic fiber reinforced polymer composites have been
developed for applications involve high performance structural or nonstructural materials (Piggott, 1980; Rahman et al., 2019; Zadorecki, Karnerfors, & Lindenfors, 1986; Zadorecki & Michell, 1989). Due to the high cost production and maintenance of existing metallic components for certain application, especially those involve in the aircraft and automobile applications, this create many limitations,...
In this chapter, the structure of cellulose, molecular weight of cellulose, chemical structure characterization techniques, X-ray and neutron small angle scattering technique, surface area analysis, thermal properties of cellulose characterization techniques, and mechanical properties of cellulose characterization techniques were reviewed and discussed in details. Plant-based resources include wood pulp, cotton fibers, bagasse, straw, ramie, sisal, flax, and hemp can also be used for cellulose synthesis. Currently, there are many industrial facilities are available to harvest, process, and extract cellulose from plant resources. The sources of cellulose such as algae, bacteria, and tunicates were also reported in this study.
Biomass materials have attracted extensive attention in functional composites because of the unique microstructure, renewability and electrochemical performance. Herein, porous NiO/C composites were synthesized through a hydrothermal reaction and calcination using cellulose-rich natural cotton as carbon source. The BET specific surface area of NiO/C composites was calculated to be 314.4 m² g⁻¹ basing on the Brunauer-Emmett-Teller model. As the LIB anode, NiO/C composites presented a high specific capacity of 727 mA h g⁻¹ over 150 cycles at 100 mA g⁻¹. Increasing the current density to 2 A g⁻¹, enabled the specific capacity of NiO/C the electrode to reach 476 mA h g⁻¹. Obviously, the unique nanostructure and synergistic effect of NiO and carbonaceous matrix made NiO/C composites exhibit the excellent lithium storage performance. The NiO/C composites are interconnected with each other and form nanopores leading to the large specific surface area, enabling the enhancement of electrolyte diffusion and providing additional routes for ion diffusion. In addition, the hybridized carbon substrate can mitigate the volume expansion and external bending stress of NiO/C composites during the lithiation/delithiation process.
The objective of this study is the applications of hybrid magnetic nanocomposites as catalyst as well as an adsorbent. Four magnetic nanocomposites (graphene and chitosan based) were fabricated using single pot solvothermal carbonization co-precipitation (STCC) route by integrating biomass functionalized with iron oxide nanoparticles. All hybrid nanocomposites were characterized for their magnetic, thermal, chemical and structural properties. Adsorption isotherms and kinetics studies were performed for adsorption of multi-heavy metals including Cd, Ni, Cu and Cr. Finally, the hybrid magnetic carbon nanocomposites were tested as catalysts to produce bio-oil through catalytic liquefaction of rice husk in supercritical ethanol. It was found that the bio-oil yield and overall conversion was enhanced significantly from 29.5% and 48.11% without catalyst, to 36.8% and 60.81% respectively with the presence of magnetic carbon nanocomposites as catalyst. Furthermore, the bio-oil energy quality was enhanced in energy content from 21.72 to 23.21 MJ/kg with the presence of catalyst and H/C and O/C ratios were reduced. Finally, GCMS revealed that the bio-oil produced using catalysts showed higher mass fraction of esters, hydrocarbons and reduced acid groups as compared to bio-oil. This study provides insights to the understanding of the role of hybrid magnetic nanocomposites for its expansion for future applications.
Conducting polymer composites (CPCs) have been versatily utilized in actualizing advanced devices such as supercapacitors, biosensors, photovoltaic cells, batteries, catalysts, chemical sensors, and so on. Conducting polymer nanocomposites (CPNCs) are derived from hybridization of intrinsically conductive polymers (CPs) with inorganic entities thereby fabricating multifunctional materials with enhanced performances. Conducting polymer bionanocomposites (CPBs) are electrically conducting biocomposites derived from mixing of CPs with biopolymers such as proteins, cellulose, guar-gums, chitosan, chitin, gelatin, and so on, resulting in emancipation of CBs for use in biomedical, agricultural and food engineering due to attainment of biocompatibility, biodegradability, and electrical conductivity. Therefore, this paper presents recently emerging trends in synthesis, characterization, and properties of CP composites, nanocomposites, bionanocomposites, and applications.
Because ultrahigh-molecular-weight polyethylene (UHMWPE) is susceptible to frictional wear when used in sliding members of artificial joints, it is common practice to use cross-linked UHMWPE instead. However, cross-linked UHMWPE has low impact resistance; implant breakage has been reported in some cases. Hence, sliding members of artificial joints pose a major trade-off between wear resistance and impact resistance, which has not been resolved by any UHMWPE. On the other hand, multiwall carbon nanotubes (MWCNTs) are used in industrial products for reinforcement of polymeric materials but not used as biomaterials because of their unclear safety. In the present study, we attempted to solve this trade-off issue by complexing UHMWPE with MWCNTs. In addition, we assessed the safety of these composites for use in sliding members of artificial joints. The results showed the equivalence of MWCNT/UHMWPE composites to cross-linked UHMWPE in terms of wear resistance and to non-cross-linked UHMWPE in terms of impact resistance. In addition, all MWCNT/UHMWPE composites examined complied with the requirements of biosafety testing in accordance with the ISO10993-series specifications for implantable medical devices. Furthermore, because MWCNTs can occur alone in wear dust, MWCNTs in an amount of about 1.5 times that contained in the dust produced from 50 years of wear (in the worst case) were injected into rat knees, which were monitored for 26 weeks. Although mild inflammatory reactions occurred in the joints, the reactions soon became quiescent. In addition, the MWCNTs did not migrate to other organs. Furthermore, MWCNTs did not exhibit carcinogenicity when injected into the knees of mice genetically modified to spontaneously develop cancer. The MWCNT/UHMWPE composite is a new biomaterial expected to be safe for clinical applications in both total hip arthroplasty and total knee arthroplasty as the first sliding member of artificial joints to have both high wear resistance and high impact resistance.
Nanocellulose, as a promising building block for preparing eco-friendly composites, has gained substantial attention due to its distinctive features such as biodegradability, renewability, and outstanding mechanical properties. Especially, the one-dimensional architecture of nanocellulose makes it difficult to fully encapsulate thermally conductive fillers, which is very beneficial to reduce the insulating contacts between adjacent fillers and enhance the thermal conductivity of the resulting composites. Consequently, recent years have witnessed a growing interest in nanocellulose-based thermally conductive composites. Herein, recent progress in this field is reviewed to deliver the readers a comprehensive understanding of the thermal conduction properties of various nanocellulose-based composites, and thus provide valuable inspiration for designing and constructing green thermal management materials. We begin with an introduction of the structure and properties of nanocellulose, and reveal the thermal conduction mechanisms of nanocellulose and nanocellulose-based composites. Subsequently, we highlight recent advances in nanocellulose-based highly thermally conductive composites distinguished by the nanostructure of thermally conductive fillers (e.g., 0D, 1D, 2D nanofillers and nanohybrids), which involve their manufacturing techniques, design concepts, structure-properties relationships, and underlying principles. Finally, remaining challenges and future perspectives for nanocellulose-based highly thermally conductive composites are discussed.
Self-healing materials have become more and more interesting for the space industry, since they can lead to the creation of space systems and structures able to repair autonomously after accidental damages caused by collision with micrometeoroids and orbital debris during the entire operational life. The implementation of these novel materials results in higher protection and safety for astronauts, and longer missions in the perspective of lunar bases establishment and manned exploration of Mars.
The present study aims to experimentally and numerically characterize an intrinsic self-healing supramolecular polymer that is potentially applicable to space suits, habitats and inflatable structures in general. A dedicated test device has been developed to evaluate the sealing performance of the material through flow rate measurements after a puncture event. The experimental part is followed by the study of the material's constitutive relations including hyperelastic and viscoelastic responses. The related model parameters are computed and calibrated through optimization and data matching tools in order to simulate damage and healing events.
Results show that the selected supramolecular polymer possesses effective self-healing abilities also under pressurized conditions, demonstrating its applicability to the considered specific fields in the space sector. Furthermore, for what concerns the analyzed puncture experiments and field of solicitation, the developed model can follow the relaxation process related to the self-healing behavior, since it can predict whether the material is effectively able or not to flow and repair.
In an age of rapid acceleration toward next-generation energy storage technologies, lithium-sulfur (Li-S) batteries offer the desirable combination of low weight and high specific energy. Metal-organic frameworks (MOFs) have been recently studied as functionalizable platforms to improve Li-S battery performance. However, many MOF-enabled Li-S technologies are hindered by low capacity retention and poor long-term performance due to low electronic conductivity. In this work, we combine the advantages of a Zr-based MOF-808 loaded with sulfur as the active material with a graphene/ethyl cellulose additive, leading to a high-density nanocomposite electrode requiring minimal carbon. Our electrochemical results indicate that the nanocomposites deliver enhanced specific capacity over conventionally used carbon/binder mixtures, and postsynthetic modification of the MOF with lithium thiophosphate results in further improvement. Furthermore, the dense form factor of the sulfur-loaded MOF-graphene nanocomposite electrodes provides high volumetric capacity compared to other works with significantly more carbon additives. Overall, we have demonstrated a proof-of-concept paradigm where graphene nanosheets facilitate improved charge transport because of enhanced interfacial contact with the active material. This materials engineering approach can likely be extended to other MOF systems, contributing to an emerging class of two-dimensional nanomaterial-enabled Li-S batteries.
Biomaterials have gained attention in automotive industries for their renewability and environmental benefits. This study evaluates the life cycle environmental impacts and benefits of the automotive component produced from biocomposite (biomaterials, i.e., polypropylene (PP) reinforced with biocarbon and Miscanthus fiber) relative to the component produced from conventional composite (PP reinforced with talc and colorant; hereafter referred to composite) using the life cycle assessment (LCA) methodology. To accomplish this study, the LCA software (SimaPro 8.0.4.26) and the Ecoinvent database (v3.1) are used. Miscanthus, an energy crop grown on the marginal land in Ontario, Canada, is used for producing biocarbon. Then PP is reinforced with biocarbon for producing biocomposite and the automotive components. The functional unit is considered to be an automotive component (441 cm³). Among the materials used in automotive components, colorant has the highest environmental impacts for each unit mass, followed by Miscanthus fiber, PP, talc, and biocarbon, respectively. Interestingly, each unit mass of biocomposite has slightly greater environmental impacts compared with composite. However, the innovative component is emerged to be environmentally favorable over the conventional component. The global warming potential (GWP) of innovative components and conventional components are 11.08 kg CO2 eq. and 12.53 kg CO2 eq., respectively. Consequently, any replacement of conventional components with innovative components would lead to meeting the fuel economy emission regulations of the automotive industries.
Heavy metal contamination has been a serious threat to environment and human health. Carbon-based materials, from biochar/activated carbon to modified materials (i.e. carbon nanotubes-based materials, and graphene-based materials), have been widely studied as efficient adsorbents for the heavy metal removal from aqueous solutions. This review discussed the recent achievements in adsorption isotherms, adsorption kinetics and adsorption mechanism according to the existing forms of heavy metals in water. The effect of process conditions, such as temperature, pH value, and coexisting ions, on adsorption performance are combed, and the universal guidance law is obtained. The physical adsorption, electrostatic interaction, ion exchange, surface complexation, and precipitation/coprecipitation play important roles in heavy metals adsorption process. In addition to the common activated carbon(AC), biochar(BC) and the emerging carbon nanotubes(CNTs) and graphene(GN) adsorbent show good development potentials. Meanwhile, though the modified carbonaceous materials can achieve high adsorption capacity and removal efficiency of heavy metals, the modification operation is complex, especially chemical modification. Acid and alkali solution are often used to regenerate spent materials in desorption, however, further studies of other desorption reagent are really needed. This review highlights the removal of heavy metal ions from aqueous solution using carbon-based materials as adsorbents, and discusses the existing deficiencies and suggestions on further study.
Sonodynamic therapy (SDT) has established a novel route for treating solid cancers. Low-intensity ultrasound irradiation accompanied by a sonosensitizer has revealed remarkable advantages for cancer therapy such as targeted uptake, access to deeper tumors, insignificant side effects and invasiveness, compared with other therapeutic methods. In this study, we scrutinized synthesis and characterization of a polypyrrole-coated multi-walled carbon nanotubes composite ([email protected]). [email protected] can absorb ultrasound irradiation by both of its components, and it was introduced as a new sonosensitizer. The composite was characterized by field emission scanning electron microscopy (FESEM), and its ability to temperature elevation was explored. FESEM images revealed that [email protected]s comprised nanotubes of 36.3 ± 5.1 nm in diameter with up to several micrometer in length. Ultrasound irradiation at 1 MHz and 1.0 W cm⁻² for 60 s in four steps led to an efficient SDT in vitro (16.3 ± 2.8°C temperature increment for 250 μg mL⁻¹ of [email protected]), in C540 (B16/F10) cell line and a melanoma tumor model in male balb/c mice. In vitro examinations revealed that [email protected] represented a concentration-dependent cytotoxicity on multi-step ultrasound irradiation (a cell viability of 8.9% for 250 μg mL⁻¹ of [email protected]). Histologic analyses and tumor volume decrement after 10 d revealed detrimental SDT effects of [email protected] on tumors (75% necrosis and 50% decrement in tumor volume). Thermal effects and reactive oxygen species generation were the reasons of the working function of [email protected] in SDT.
The current study deals with the preparation of novel poly aniline/zinc/aluminum nanocomposites by polymerization of aniline monomer in presence of Zn⁺² and Al ⁺³ ions of (ratio 1:1) of different weight percent under continuous vigorous stirring in an acidic media. The formed nanocomposites were fully characterized via Fourier-transform infra-red, ultra-violet visible spectroscopy, scanning electron microscopy and thermo-gravimetric analysis. Furthermore, the formed nanocomposites in the form of colloidal solutions have been applied onto cotton fabrics. The treated fabrics have been characterized via scanning electron microscope and energy dispersive X-ray spectroscopy technique. The antimicrobial as well as UV resistance measurements for the treated cotton fabrics before and after washing cycles have been also investigated. The results revealed that the treated cotton fabrics with the prepared nanocomposites showed high antimicrobial as well as UV protection which ascribed to the presence of Zn/Al nanoparticles and the superior morphological structure of the formed nanocomposites.
Heavy metals belong to a group of lethal environmental pollutants. Ongoing efforts targeted at safeguarding public health have led to considerable attention being focused on methods that allow efficient extraction of these toxic substances. Polymer nanocomposites (PNCs) with their special characteristics are a class of adsorbents that demonstrate high potential for use in heavy metal extraction. As this process of removal is predominantly governed by adsorption, various parameters in PNCs’ chemical structure, as well as the metal solutions, can have a significant effect on the adsorption process. Herein, this review undertakes a survey of recently developed PNCs and their metal adsorption studies.
The utilisation of magnetic biosorbents (metal or metal nanoparticles impregnated onto biosorbents) has attracted increasing research attention due to their manipulable active sites, specific surface area, pore volume, pore size distribution, easy separation, and reusability that are suitable for remediation of heavy metal(loid)s and organic contaminants. The properties of magnetic biosorbents (MB) depend on the raw biomass, properties of metal nanoparticles, modification/synthesis methods, and process parameters which influence the performance of removal efficiency of organic and inorganic contaminants. There is a lack of information regarding the development of tailored materials for particular contaminants and the influence of specific characteristics. This review focuses on the synthesis/modification methods, application, and recycling of magnetic biosorbents. In particular, the mechanisms and the effect of sorbents properties on the adsorption capacity. Ion exchanges, electrostatic interaction, precipitation, and complexation are the dominant sorption mechanisms for ionic contaminants whereas hydrophobic interaction, interparticle diffusion, partition, and hydrogen bonding are the dominant adsorption mechanisms for removal of organic contaminants by magnetic biosorbents. In generally, low pyrolysis temperatures are suitable for ionic contaminants separation, whereas high pyrolysis temperatures are suitable for organic contaminants removal. Additionally, magnetic properties of the biosorbents are positively correlated with the pyrolysis temperatures. Metal-based functional groups of MB can contribute to an ion exchange reaction which influences the adsorption capacity of ionic contaminants and catalytic degradation of non-persistent organic contaminants. Metal modified biosorbents can enhance adsorption capacity of anionic contaminants significantly as metal nanoparticles are not occupying positively charged active sites of the biosorbents. Magnetic biosorbents are promising adsorbents in comparison with other adsorbents including commercially available activated carbon, and thermally and chemically modified biochar in terms of their removal capacity, rapid and easy magnetic separation which allow multiple reuse to minimize remediation cost of organic and inorganic contaminants from wastewater.
Most recently, aqueous zinc-ion batteries (AZIBs) are the research focus because of their low cost, high safety, and eco-friendliness. In this respect, flexible binder-free electrodes have been investigated by several studies to keep pace with the development of wearable electronics. However, the mass loading of active materials in these electrodes is usually below 2 mg cm⁻², considerably limiting the areal capacity. Herein, we report a paper electrode prepared via a facile vacuum filtration technique with a high mass loading of 5 mg cm⁻² for the active material, namely, reduced graphene oxide (rGO)/δ-NaxV2O5·nH2O nanocomposite. Thanks to the homogeneous distribution and synergistic effect of the active material, carbon nanotubes, and cellulose fibers, the electrode not only exhibits good mechanical property and high electrical conductivity but also displays impressive performances for AZIBs. It achieves an admirable areal specific capacity of 1.87 mAh cm⁻² (corresponding to 374.9 mAh g⁻¹ for the active material), substantially higher than that of other flexible binder-free electrodes for (hybrid) AZIBs. Meanwhile, this electrode also shows good rate capability and excellent long-term cyclability (with a capacity retention of 92% over 4000 cycles). This work opens new opportunities towards flexible free-standing electrodes.
Lithium-sulfur (Li-S) batteries are one of promising next-generation energy storage systems. Tremendous efforts have been devoted to developing conductive nanoarchitectures for improving sulfur utilization and cycling stability. MXenes, one family of 2D transition metal carbides, nitrides and carbonitrides, have recently captured considerable attentions in energy storage and conversion. Herein, we have summarized recent advances of MXene-based materials in the cathodes, anodes and separators of Li-S batteries, and highlighted the theoretical and experimental importance of high polarity and rich surface chemistry in polysulfides trapping. Their superiorities for suppressing polysulfides shuttling and improving sulfur utilization have been demonstrated. We have also concluded the perspectives and challenges that need to be addressed for MXene-based Li-S batteries, some new strategies have been proposed to improve electrochemical performance, which sheds light on future development of MXene-based materials in high-energy-density Li-S batteries.