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Removal of tetracycline from contaminated water by Moringa oleifera seed preparations
Environmental Technology
Abstract
ABSTRACT
The aim of this study was to evaluate tetracycline antibiotic (TA) removal from contaminated water
by Moringa oleifera seed preparations. The composition of synthetic water approximate river natural
contaminated water and TA simulated its presence as an emerging pollutant. Interactions between
TA and protein preparations (extract; fraction and lectin) were also evaluated. TA was determined by
solid-phase extraction followed by high-performance liquid chromatography-mass spectrometry.
Moringa extract and flour removed TA from water. The extract removed TA in all concentrations,
and better removal (40%) was obtained with 40 mg L−1; seed flour (particles < 5 mm), 1.25 and
2.50 g L−1 removed 28% and 29% of tetracycline, respectively; particles > 5 mm (0.50 g L−1)
removed 55% of antibiotic. Interactions between TA and seed preparations were assayed by
haemagglutinating activity (HA). Specific HA (SHA) of extract (pH 7) was abolished with
tetracycline (5 mg L−1); fraction (75%) and lectin HA (97%) were inhibited with TA. Extract SHA
decreased by 75% at pH 8. Zeta potential (ZP) of extract 700 mg L−1 and tetracycline 50 mg L−1 ,
pH range 5–8, showed different results. Extract ZP was more negative (−10.73 to −16.00 mV)
than tetracycline ZP (−0.27 to −20.15 mV); ZP difference was greater in pH 8. The focus of this
study was achieved since Moringa preparations removed TA from water and compounds
interacting with tetracycline involved at least lectin-binding sites. This is a natural process, which
do not promote environmental damage.
... [134] Food Industry and Livestock Wastewater Dairy industry wastewater treated by Moringa Oleifera seed was reported to have no better removal results. Using an increased dose of coagulant of 3 g/L (11% removal of COD, 53% removal of color, and 60%turbidity) is shown in Table 6 [234]. Reduction in the removal rate of COD can be caused by a transfer of a portion of the organic compounds from Moringa Oleifera seed to the effluent [13]. ...
In this review, collected information related to Moringa Oleifera seeds was evaluated, such as their properties and the main active components involved in their processes, as well as their dual efficiency as both antimicrobials and natural coagulants for treating contaminated effluents. Furthermore, discussions were completed about perspectives on progress related to this field of research to understand the bioactive properties of these seed compounds, including their antibacterial, antifungal, and antiviral activity. In addition to the coagulant properties that have been quantitatively assessed, studies have examined the underlying coagulating mechanism, and seed processing techniques. In addition, the challenges associated with the use of conventional coagulants (metals or polymers) have led to numerous research efforts towards the development of natural plant-based coagulants that are eco-friendly to treat wastewater and offer a large variety of other advantages, such as their wide availability, the reduction of by-product generation, the reduction of costs, and greater biodegradability. Based on the results of different researchers, and regarding the appraisals using Moringa Oleifera seeds for wastewater treatment processes, many studies encourage their use for those operations. Due to their extensive and potent properties as an antibacterial and a coagulant, Moringa Oleifera seeds are still used today as a promising wastewater treatment method. Finally, this paper provides suggestions and comments, as well as identifies the knowledge gaps, and makes recommendations for future research development strategies, such as studying the contents of Moringa Oleifera seeds, their interactions with colloids present in wastewater, understanding their stability and behavior, assessing the performance of seed-derived flocculants according to pH values, isolating and characterizing the active compounds to determine the toxicity and optimum dose to be used as effective antimicrobials, and removing heavy metals.
... Its effectiveness has been demonstrated in removing a wide variety of contaminants, such as turbidity, heavy metals, emerging contaminants, Escherichia coli, and organic matter, among others [18,19,21,22,[27][28][29][30][31][32][33]. Additionally, the sludge produced by this seed during coagulation is not only harmless but also has a volume four to five times lower than that produced by coagulation with alum [34]. ...
The scarcity of water has become a growing problem worldwide. The search for new sources has therefore intensified, and one of these sources is greywater. The objective of this article is to evaluate the effectiveness of three different coagulants obtained from Moringa oleiferaseed (seed husk, ground seed, and degreased) in synthetic greywater. The methodology is planned in stages; in the first stage, these seeds were selected, unsheathed, and dried in the sun for 24 hours, and the coagulant was synthesized by a 1 M NaCl solution. In the second stage, the synthetic greywater was prepared in a laboratory and included personal cleaning products and additional chemical components. Finally, a statistical test was employed to evaluate the removal of turbidity and the incidence and behavior of the turbidity, pH, alkalinity, and dissolved oxygen over seven periods and the type of coagulant. It was found that the coagulant degreased obtained the highest percentage of removal (85%) and the coagulant from seed husk had the lowest efficiency with 75%. On the other hand, it was found that parameters such as pH and dissolved oxygen depend on the type of coagulant, while conductivity and alkalinity do not depend on time or the type of coagulant. Doi: 10.28991/CEJ-2022-08-12-013 Full Text: PDF
... The removal percentages were 88% for diclofenac and 50% for oxytetracycline. Santos et al. [82] examined tetracycline removal from river water by using Moringa oleifera seeds. The results show 50% tetracycline removal efficiency at 0.5 g/L Moringa oleifera dosage. ...
Pharmaceutical contamination threatens both humans and the environment, and several technologies have been adapted for the removal of pharmaceuticals. The coagulation-flocculation process demonstrates a feasible solution for pharmaceutical removal. However, the chemical coagulation process has its drawbacks, such as excessive and toxic sludge production and high production cost. To overcome these shortcomings, the feasibility of natural-based coagulants, due to their biodegradability, safety, and availability, has been investigated by several researchers. This review presented the recent advances of using natural coagulants for pharmaceutical compound removal from aqueous solutions. The main mechanisms of natural coagulants for pharmaceutical removal from water and wastewater are charge neutralization and polymer bridges. Natural coagulants extracted from plants are more commonly investigated than those extracted from animals due to their affordability. Natural coagulants are competitive in terms of their performance and environmental sustainability. Developing a reliable extraction method is required, and therefore further investigation is essential to obtain a complete insight regarding the performance and the effect of environmental factors during pharmaceutical removal by natural coagulants. Finally, the indirect application of natural coagulants is an essential step for implementing green water and wastewater treatment technologies
... The removal percentages were 88% for diclofenac and 50% for oxytetracycline. Santos et al. [82] examined tetracycline removal from river water by using Moringa oleifera seeds. The results show 50% tetracycline removal efficiency at 0.5 g/L Moringa oleifera dosage. ...
Pharmaceutical contamination threatens both humans and the environment, and several technologies have been adapted for the removal of pharmaceuticals. The coagulation-flocculation process demonstrates a feasible solution for pharmaceutical removal. However, the chemical coagulation process has its drawbacks, such as excessive and toxic sludge production and high production cost. To overcome these shortcomings, the feasibility of natural-based coagulants, due to their biodegradability, safety, and availability, has been investigated by several researchers. This review presented the recent advances of using natural coagulants for pharmaceutical compound removal from aqueous solutions. The main mechanisms of natural coagulants for pharmaceutical removal from water and wastewater are charge neutralization and polymer bridges. Natural coagulants extracted from plants are more commonly investigated than those extracted from animals due to their affordability. Natural coagulants are competitive in terms of their performance and environmental sustainability. Developing a reliable extraction method is required, and therefore further investigation is essential to obtain a complete insight regarding the performance and the effect of environmental factors during pharmaceutical removal by natural coagulants. Finally, the indirect application of natural coagulants is an essential step for implementing green water and wastewater treatment technologies.
... Studies revealed that among the large number of plant materials that have been used over the years, the seeds from Moringa oleifera have been proved to be one of the most effective primary coagulants for water treatment especially in rural communities [22,27,28]. The studies on Moringa oleifera's competence in water and wastewater treatment process had been undertaken by numerous scholars [29][30][31][32][33]. ...
... It was not until five years ago that M. oleifera gained attention in Ecuador due to the powerful health benefits of this so-called "miracle tree " ( Pandey et al., 2019 ;Shija et al., 2019 ;Barhoi et al., 2020 ;Rocchetti et al., 2020 ), thus environmental-related research of M. oleifera cultivars in Ecuador is fairly new. The M. oleifera has been used for water treatment applications to remove inorganics, emerging organic compounds, dyes, and others ( Beltrán-Heredia and Sánchez-Martín, 2009 ;Alfarra et al., 2014 ;Abolore Idris, 2016 ;Santos et al., 2016 ;Wuana et al., 2016 ). In other countries, the environmental benefits of M. oleifera, especially for water treatment, are already well understood. ...
The projection of world population growth with concurrent generation of large volumes of agro-industrial waste that negatively affect the environment is of great concern. Therefore, this review article describes the nexus between concepts of Circular Bioeconomy, Zero Waste Technology, Sustainable Development, Biorefineries, and alternatives and research efforts to generate less environmental impact. A brief analysis of the Ecuadorian industry and exports is described, emphasizing the fact that, to improve the Ecuadorian trade balance, it is necessary to increase industrial competitiveness. It is important to have emerging technologies and innovation in order to promote the replacement of fossil-derived raw materials with renewable raw materials and develop more environmentally friendly processes and industries. This paper analyses the state of biomass research and its transformation in Ecuador, together with current pretreatment research on biomass to obtain bioproducts and biofuels in a biorefinery that promotes clean production for the extraction of phytochemicals using green solvents, such as deep eutectic solvents; and technologies to recover high-value added materials with enhanced properties. In conclusion, the need to develop technologies and markets to commercialize high value-added products coming from biorefineries is highlighted, as this will increase the income both in rural and urban areas and will strengthen the productivity and profitability of the Ecuadorian agroindustry. Our goal through this analysis is to improve Ecuador's trade balance while also contributing to the circular bioeconomy that promotes sustainable development.
... First, systematic studies on the potential of MO seeds to remove priority and emerging contaminants are needed. Few studies on the removal of emerging pollutants such as surfactants [91,92], pharmaceuticals [93], posttreatment chemicals [89], and detergents [94] are available. As an example, a research on agricultural and urban wastewater treatment using chitosan and MO seed flour to remove Mn, Pb and turbidity concluded that pollutant removal mechanism does not depend on the nature of the water submitted to remediation when MO seed flour was analized, nevertheless they acknowledge the impact of emerging contaminants on MO behavior [95]. ...
Using “greener” processes to treat wastewater has become increasingly popular because these processes are environmentally friendly and offer a wide variety of other benefits, such as reducing costs, reducing the generation of by-products, and providing greater biodegradability. In particular, Moringa oleifera (MO) has historically been used as a natural coagulant to treat contaminated effluents and it continues to be used today. This paper is a collection of information related with using MO in contemporary applications, mainly wastewater treatment. It reviews the main active components involved in the processes, the most significant mechanisms identified, seed processing techniques and some practical applications, and the main trends in the field, as well as provides comments and recommendations for further developments and identifies knowledge gaps and future research directions
... Probably, seeds are the most studied part of the so-called miraculous plant, especially because this is the raw material for obtain the reputed "Ben oil", which has been recognized since ancient times as one of the best base oils for perfumery. However, interest in Moringa's seeds has been more recently moving towards other fields, particularly trying to promote cheap water treatment systems to be applied in poor regions, including reduction of parasite eggs counts in agricultural irrigation systems [14], bioremediation of water contaminated with usual [15,16] or emerging [17] pollutants, flocculation of microalgae [18], etc. ...
A simple and relatively inexpensive method was developed in order to separate and purify the water soluble fraction of proteins present in dry dehulled Moringa seeds directly collected from local trees. Procedure includes: (a) extraction of the oil fraction from M. oleifera seeds using petroleum ether at room temperature; (b) aqueous extraction of defatted seeds; (c) fractionation of the resulting aqueous phase by cooling at 4 oC and separating the precipitated solid by centrifugation; and (d) freezing and vacuum drying of the wet solid. Protein fraction obtained consists of a mixture of molecular species of different sizes, with those around 26.5, 21.0 and < 14.2 KDa present in greater proportion, which shows interesting acid/base properties. Moreover, two important aspects have emerged from analyses performed to this protein sample: (a) a slightly acidic character was observed by potentiometric and conductimetric titrations which could be justified by the presence of tyrosine phenolic groups in the protein chains forming the mixture, as it has been inferred by FTIR studies, and (b) bathochromic displacements observed during UV-visible studies for the signal associated to π → π* transitions of the peptide bonds can be attributed to conformational changes which modify natural α-helix structure of the protein, especially those caused by rupture of hydrogen bonds probably involving phenolic groups of tyrosine.
Health care institutions generate large volumes of liquid effluents from specific activities related to healthcare, analysis, and research. Their direct discharge into the environment has various negative effects on aquatic environments and human health, due to their high organic matter charges and the presence of various emerging contaminants such as disinfectants, drugs, bacteria, viruses, and parasites. Moreover, hospital effluents, by carrying antibiotics, contribute to the development of antibiotic-resistant microorganisms in the environment. This resistance has become a global issue that manifests itself variously in different countries, causing the transmission of different infections. In this respect, an effort is provided to protect water resources by current treatment methods that imply physical–chemical processes such as adsorption and advanced oxidation processes, biological processes such as activated sludge and membrane bioreactors and other hybrid techniques. The purpose of this review is to improve the knowledge on the composition and impact of hospital wastewater on man and the environment, highlighting the different treatment techniques appropriate to this type of disposal before discharge into the environment.
This study focuses on the batch adsorption of doxycycline in simulated wastewater using Carica papaya L. (papaya) peels. Sorbate concentration (120-1,000 mg/L) and pH (3, 6, and 9) were varied while adsorbent dosage (0.1 g) and contact time (180 min) were fixed. Based on the observations done for both ripe and unripe papaya peels (PP), as the sorbate concentration increases while the pH decreases, the removal efficiency increases. The highest removal efficiency (87.97% for ripe PP and 87.52% for unripe PP) was achieved at 1,000 mg/L and pH=3. The adsorptive capacity for ripe and unripe PP was 215.09 and 213.99 mg/g adsorbent, respectively. Langmuir model fits the data for samples, which indicates a monolayer adsorption on surface of the adsorbent. The data also fits the pseudo-first order kinetic model which suggests that the reaction operates only at the monolayer of papaya peel. Overall, both ripe and unripe PP are capable of adsorbing DC in aqueous solution at 28°C, 3-hour contact time, 0.1g of adsorbent dosage, and at pH 3 under acidic condition.
Herbal pharmaceutical industrial wastewater contains a high amount of suspended solids and alkaline (pH > 8); therefore it requires approprite coagulant and flocculant compounds for its wastewater treatment. The most widely used flocculant is a synthetic that has certain problems such as non-biodegradability and releases of toxic residual monomers. The use of eco-friendly flocculants as alternative materials for conventional flocculant in water and wastewater treatments is increasing. Numerous factors influence the performance of coagulation-flocculation process, such as coagulant dosage, flocculant dosage, initial potential of hydrogen (pH) and velocity gradient of coagulation-flocculation. The main aim of this research is to evaluate the capability and effectiveness of Moringa oleifera extract for removal of suspended solid in herbal pharmaceutical industry. A coagulation-flocculation test was done by performing jar test at various speeds, according to the variation of the conducted treatment research. In this study, response surface methodology (RSM) approach was used to optimize the concentration of coagulant dosage, flocculant dosage and flocculation velocity gradient (G), and the results were measured as maximum percentage of suspended solid removal. The wastewater used in this research originally came from the inlet of herbal pharmaceutical industry wastewater treatment plant, which was collected over 3 days. The wastewater has a total suspended solids of more than 1250 mg/L, and was alkaline (pH 9-10). The moringa extract was made from the extraction of a fat free moringa powder with a salt solution in a certain ratio. The percentage removal of suspended solid was 93.42-99.54%. The final results of the analysis of response surface showed that the variables of flocculant dosage and the flocculation velocity gradient (G) have a huge impact on the amount of suspended solid removal, compared with the coagulant dosage. The model generated from the response analysis is a quadratic model. The optimum point of the removal suspended solid quadratic model is at 10.6566 mg/L alum dosage, 13.8185 ml/L Moringa oleifera extract dosage, and G velocity of flocculation 84.845 sec⁻¹.
Coagulation, flocculation and agglutination are terms that usually cause confusion. Coagulation is a process of making colloidal matter dispersed/suspended in a liquid to join in a coherent mass. Flocculation is a physical process of contact and adhesions wherein the aggregates form larger-size clusters called flocs being excluded from suspension. These processes have several remarkable applications such as water treatment. The agglutination phenomena can be defined as the linkage of particles or cells in a liquid resulting in formation of clumps. In detail, aggregation/agglutination is the outcome of connections established by agglutinating agents among different components of the particulate materials. Antibodies and lectins, proteins which bind to specific targets (epitopes or carbohydrates, respectively) can be highlighted as agglutinating agents. The interaction can be used to identify microorganisms, proteins and carbohydrates; when agglutination involves erythrocytes, the technique is called hemaglutination. The aim of this chapter is to clarify differences about the important phenomena coagulation, flocculation, agglutination, and hemaglutination; characteristics and applications of molecules and substances able to exert these processes are also discussed.
This study aimed to evaluate the efficacy of using the byproduct of Moringa oleifera Lam. seeds as an adsorbent for removal of cadmium (Cd) from contaminated water. The material characterization was performed by scanning electron microscopy, infrared spectroscopy, and point of zero charge. The effects of the adsorbent mass, solution pH, contact time, and temperature were evaluated. In the preliminary studies, the mass of adsorbent (200–1200 mg) and pH conditions (5.0, 6.0, and 7.0) were varied. The time studies were performed at 20–180 min and the temperature studies at the range of 25–65 °C. The optimal conditions of adsorption obtained were 400 mg of adsorbent mass, 7.0 pH, and 160 min contact time with the adsorbent. The isotherms of adsorption were linearized according to Langmuir, Freundlich, and Dubinin–Radushkevich (D-R) models. The results showed better fit by the Freundlich and D-R models for Cd adsorption, describing a multilayer adsorption and, according to the value of the sorption energy (E), it has chemical nature. The maximum capacity of adsorption (Q
m) obtained was 7.864 mg g−1. For a comparative study, the activated carbon (P.A.) was used applying the same optimal conditions used in the adsorption isotherms and desorption process for the biosorbent, obtaining a Q
m as 32.884 mg g−1. The average desorption percentage showed that adsorbents have strong interaction with the metal. Based on these results, it was concluded that the biosorbent was effective in remediation of solutions containing Cd and thus the use of this alternative material is a viable option, since it has low cost and it is a byproduct which has not undergone previous treatment.
Moringa oleifera seed extract was confirmed as a feasible coagulant in removing surfactants from aqueous effluents. Amongst them, long-chain anionic detergents such as Polyoxyethylene (3.5) sodium lauryl ether sulfate (SLES) was selected as a model compound for evaluating the coagulation response. The system coagulant–detergent was stable with different temperatures and pH, and the efficiency was very promising. M. oleifera was an effective coagulant since it was capable to reach up to 0.245 mg mg−1 coagulation capacity according to Gu–Zhu model. Design of experiments presented an optimum combination of coagulant dosage and initial surfactant concentration of 234 mg L−1 and 76 mg L−1, respectively.
The aim of this work was to characterise the affinity of protein preparations from Moringa oleifera seeds, specifically extract (seeds homogenised with 0.15 M NaCl), fraction (extract precipitated with 390 mg mL−1 of ammonium sulphate) and cMoL (coagulant M. oleifera lectin) to bind humic acids using a haemagglutinating activity assay with rabbit erythrocytes and a radial diffusion assay
in agarose gel. Specific haemagglutinating activity (SHA) decreased by 94 % for the extract and cMoL and by 50 % for the fraction
in the presence of humic acid. Precipitation bands were observed in the diffusion gel. Both results suggested humic acid-cMoL binding. Carbohydrates, potassium, and calcium ions and pH affected the SHA of cMoL. As an example of application, cMoL was immobilised on a column packed with sepharose receiving 20 mg mL−1 of carbon humic acid solution, 30 mg of humic acid per gram of support was removed. This result suggested that protein preparations
might be used in water treatment to remove humic acids.
Keywordshumic acid–lectin–
Moringa oleifera
–protein preparations–water treatment
This study investigated the occurrence of tetracyclines (TCs), namely minocycline (MIN), TC, and its epimer epitetracycline (ETC), and doxycycline (DC), in four hospital wastewater effluents and its fate in municipal wastewater treatment plants (WWTPs), in Coimbra, Portugal. Analytical determination was carried out by solid-phase extraction followed by liquid chromatography with fluorescence detection. A gradient system with a mobile phase containing oxalic acid 0.02 M and acetonitrile was used. After postcolumn derivatization with magnesium reagent, TCs were detected at λ
exc 386 nm and λ
em 500 nm. The proposed method allowed good sensitivity, accuracy, and precision. LOQs were 0.5 μg l−1 for ETC and TC and 15 and 5 μg l−1 for MIN and DC, respectively. The recovery values ranged between 66.4% and 117.1%, and intraday and interday repeatability was lower than 6.8%. The method was successfully used to determine the presence of the above-mentioned TCs in 24 wastewater composite samples obtained from hospital effluents and from influent and effluent of the WWTP located in Coimbra, Portugal. MIN and TC were found in 41.7% of the samples; ETC and DC were found in 25% and 8.3% of the samples, respectively. The levels found ranged from 6 to 531.7 μg l−1 in hospital effluents, while its concentrations in WWTP ranged from 95.8 to 915.3 μg l−1. A seasonal influence in the concentrations found has also been observed, the levels found in samples collected during spring being higher than those observed in samples collected during autumn; however, these are only preliminary results. The WWTP removal rate ranged between 89.5% and 100%.
Moringa oleifera extract is a high-capacity flocculant agent for turbidity removal in surface water treatment. A complete study of a pilot-plant installation has been carried out. Because of flocculent sedimentability of treated water, a residual turbidity occured in the pilot plant (around 30 NTU), which could not be reduced just by a coagulation-flocculation-sedimentation process. Because of this limitation, the pilot plant (excluded filtration) achieved a turbidity removal up to 70%. A slow sand filter was put in as a complement to installation. A clogging process was characterized, according to Carman-Kozeny's hydraulic hypothesis. Kozeny's k parameter was found to be 4.18. Through fouling stages, this k parameter was found to be up to 6.36. The obtained data are relevant for the design of a real filter in a continuous-feeding pilot plant. Slow sand filtration is highly recommended owing to its low cost, easy-handling and low maintenance, so it is a very good complement to Moringa water treatment in developing countries.
Biofilms are major sites of carbon cycling in streams. Therefore, it is crucial to improve knowledge about biofilms' structure and microbial composition to understand their contribution in the self-purification of surface water. The present work intends to study biofilm formation in the presence of humic substances (HSs) as a carbon source. Two biofilm flowcells were operated in parallel; one with synthetic stream water, displaying a background carbon concentration of 1.26+/-0.84 mg L(-1), the other with added HSs and an overall carbon concentration of 9.68+/-1.00 mg L(-1). From the biofilms' results of culturable and total countable cells, it can be concluded that the presence of HSs did not significantly enhance the biofilm cell density. However, the biofilm formed in the presence of HSs presented slightly higher values of volatile suspended solids (VSS) and protein. One possible explanation for this result is that HSs adsorbed to the polymeric matrix of the biofilm and were included in the quantification of VSS and protein. The microbial composition of the biofilm with addition of HSs was characterized by the presence of bacteria belonging to beta-Proteobacteria, Cupriavidus metallidurans and several species of the genus Ralstonia were identified, and gamma-Proteobacteria, represented by Escherichia coli. In the biofilm formed without HSs addition beta-Proteobacteria, represented by the species Variovorax paradoxus, and bacteria belonging to the group Bacteroidetes were detected. In conclusion, the presence of HSs did not significantly enhance biofilm cell density but influenced the bacterial diversity in the biofilm.
The present work aims to evaluate the bacterial composition and activity (carbon and nitrogen removal) of nitrifying biofilms exposed to 50μgL(-1) of tetracycline. The tetracycline removal efficiency and the occurrence of tetracycline resistance (tet) genes were also studied. Two sequencing batch biofilm reactors (SBBRs) fed with synthetic wastewater were operated without (SBBR1) and with (SBBR2) the antibiotic. Both SBBRs showed similar organic matter biodegradation and nitrification activity. Tetracycline removal was about 28% and biodegradation was probably the principal removal mechanism of the antibiotic. Polymerase chain reaction-denaturing gradient gel electrophoresis analysis of the bacterial community showed shifts leading to not only the fading of some ribotypes, but also the emergence of new ones in the biofilm with tetracycline. The study of the tet genes showed that tet(S) was only detected in the biofilm with tetracycline, suggesting a relationship between its occurrence and the presence of the antibiotic.
The use of antibiotics and growth hormones in human and veterinary medicine has a significant effect on the quality of surface and groundwater. The relevance of an electrocoagulation (EC) process for the removal of an antibiotic selected because of its wide application, high solubility in water, high residual toxicity and an absence of biodegradability, was examined in this study. Metal hydroxides generated during EC were used to remove tetracycline (TC) from aqueous solution. The knowledge regarding the removal mechanism of this substance has not been investigated up to now. Experiments were carried out in a batch electrochemical reactor using aluminum electrodes. The removal of TC was relatively fast and equilibrium was reached within 15 min. The effects of the main operating parameters were examined and showed that irrespective of the initial concentration and for pH ranging from 3 to 10, maximum removal efficiency remained close to 99%; while a sharp decrease was recorded at pH 2 (10% removal). The results of this study also showed that the removal of TC from water was strongly affected by the current intensity. The mechanism of electrocoagulation was modeled using isotherm models and showed that the Sips isotherm matched satisfactorily experimental data, suggesting monolayer coverage of adsorbed molecules and assumed a quasi-Gaussian distribution energy owing to the high correlation also found for the Toth model. In addition, adsorption kinetic studies showed that the EC process followed a pseudo-second-order kinetic model at the various current densities, pH and initial antibiotic concentrations considered.
Samples of municipal and industrial wastewaters were treated by coagulation-flocculation and sedimentation, using a crude water extract of dry Moringa oleifera seeds as a primary coagulant. The quality of the treated wastewater was analyzed and compared to that of the wastewater treated with alum. Experiments were conducted at various dosages of the crude 5% (wt/v) water extract of dry shelled and non-shelled Moringa oleifera seeds, using jar-test equipment. Parameters of quality of the wastewaters were measured before and after the treatment to evaluate the removal efficiency on the major pollutants of concern in wastewater treatment, such as suspended solids, chemical oxygen demand (COD), nutrients (phosphorus and nitrogen), microorganisms and heavy metals. Results showed that Moringa oleifera seeds were efficient as a primary coagulant in wastewater treatment for removal of suspended solids and microorganisms, and also removal of some metals. Nutrients and COD were not successfully removed. COD and nutrients were somehow increased by coagulation using Moringa oleifera seeds. Compared to alum, Moringa oleifera seeds produced 4 to 6 times less sludge volume. Alum was found to be quite effective in phosphorus removal. The increase in COD and nutrients observed in the case of Moringa oleifera seeds might be avoided by using purified proteins instead of the crude water extract.
The present study explores the unexploited sorption property of the shelled Moringa oleifera seeds (SMOS) for decontamination of arsenic from water bodies. Sorption studies (batch experiments) result into the standardization of optimum conditions for removal of 60.21% As(III) and 85.60% As(V) as follows: biomass dosage (2.0 g), metal concentration (25 mg/L), contact time (60 min) and volume of the test solution (200 ml) at pH 7.5 and 2.5, respectively. The adsorption data are fitted with Langmuir isotherm. Surface area has been measured using BET surface area analyzer. Morphological changes observed in scanning electron micrograph of native and treated SMOS indicates the existence of biosorption process. Fourier transform infrared spectrometry of exhausted seed biomass highlights protein/amino acid–arsenic interactions responsible for sorption phenomenon. Regeneration has also been attempted for several cycles with a view to restore the sorbent to its original state. The sorption capacity of the regenerated biomass remained almost constant after three cycles of sorption process, suggesting that the lifetime cycle was sufficient for continuous application. The findings open up new avenues in the decontamination of arsenic using SMOS from arsenic contaminated water, as domestic and environment-friendly safe technology.
The present study concerned the modifications of interfacial characteristics of aluminum oxide (hydrophilic substrate) and a polystyrene latex particle (less hydrophilic substrate) induced by adsorption of humic substances, polyacrylamide, hydrolyzed polyacrylamide or polyacrylic acid in the presence of aluminum ions and aimed at determination of the mode of action of humic substances in the colloid stabilization and destabilization. On the basis of electrophoretic mobility measurements, polyacrylamide and hydrolyzed polyacrylamide interact differently with the oxide and synthetic latex particles, whereas humic and polyacrylic acids similarly modify the surface characteristics of the two substrates. The relative concentration of acid groups and aluminum ions determined the electrokinetic potential of the adsorbed layer. The instability domain of the colloidal suspension was found to depend similarly on adsorption time and zeta potential. When the zeta potential ranged between +20 and −20 mV, the domain where positively and negatively charged chain elements coexist, the suspensions became unstable and flocculated rapidly. Excess of complexed positively charged chain segments present at small polymer dosage or dissociated negatively charged chain segments present at high polymer dosage promoted colloid stabilization.
Lectins are carbohydrate recognition proteins. cMoL, a coagulant Moringa oleifera Lectin, was isolated from seeds of the plant. Structural studies revealed a heat-stable and pH resistant protein with 101 amino acids, 11.67 theoretical pI and 81% similarity with a M. oleifera flocculent protein. Secondary structure content was estimated as 46% α-helix, 12% β-sheets, 17% β-turns and 25% unordered structures belonging to the α/β tertiary structure class. cMoL significantly prolonged the time required for blood coagulation, activated partial thromboplastin (aPTT) and prothrombin times (PT), but was not so effective in prolonging aPTT in asialofetuin presence. cMoL acted as an anticoagulant protein on in vitro blood coagulation parameters; at least on aPTT, the lectin interacted through the carbohydrate recognition domain.
A quantitatively main molecular form ofCratylia mollis lectin, isoform 1 (iso 1) was purified by affinity chromatography on Sephadex G-75, followed by ion exchange chromatography
on CM-cellulose. Another lectin form was identified in the latter step. Iso 1 is specific for glucose/mannose, with a main
subunit of 31 kDa mol wt; the native protein is basic (pI 8.5-8.6) and the constituent polypeptides had a pI range of 5.15–7.75.
An antibody to the protein was raised in a rabbit, and the conjugate was active in an immunosorbent assay.
Water from wastewater-polluted streams and dug-outs is the most commonly used water source for irrigation in urban farming in Ghana, but helminth parasite eggs in the water represent health risks when used for crop production. Conventional water treatment is expensive, requires advanced technology and often breaks down in less developed countries so low cost interventions are needed. Field and laboratory based trials were carried out in order to investigate the effect of the natural coagulant Moringa oleifera (MO) seed extracts in reducing helminh eggs and turbidity in irrigation water, turbid water, wastewater and tap water. In medium to high turbid water MO extracts were effective in reducing the number of helminth eggs by 94-99.5% to 1-2 eggs per litre and the turbidity to 7-11 NTU which is an 85-96% reduction. MO is readily available in many tropical countries and can be used by farmers to treat high turbid water for irrigation, however, additional improvements of water quality, e.g. by sand filtration, is suggested to meet the guideline value of ≤ 1 helminth egg per litre and a turbidity of ≤ 2 NTU as recommended by the World Health Organization and the U.S. Environmental Protection Agency for water intended for irrigation. A positive correlation was established between reduction in turbidity and helminth eggs in irrigation water, turbid water and wastewater treated with MO. This indicates that helminth eggs attach to suspended particles and/or flocs facilitated by MO in the water, and that turbidity and helminth eggs are reduced with the settling flocs. However, more experiments with water samples containing naturally occurring helminth eggs are needed to establish whether turbidity can be used as a proxy for helminth eggs.
This work aimed to characterize the coagulant properties of protein preparations from Moringa oleifera seeds in the removal of humic acids from water. Three distinct preparations were assayed, namely extract (seeds homogenized with 0.15 M NaCl), fraction (extract precipitated with 60% w/v ammonium sulphate) and cMoL (protein purified with guar gel column chromatography). The extract showed the highest coagulant activity in a protein concentration between 1 mg/L and 180 mg/L at pH 7.0. The zeta potential of the extract (-10 mV to -15 mV) was less negative than that of the humic acid (-41 mV to -42 mV) in a pH range between 5.0 and 8.0; thus, the mechanism that might be involved in this coagulation activity is adsorption and neutralization of charges. Reduction of total organic carbon (TOC) and dissolved organic carbon (DOC) was observed in water samples containing 9 mg/L carbon as humic acid when treated with 1 mg/L of the extract. A decrease in colour and in the aromatic content of the treated water was also observed. These results suggested that the extract from M. oleifera seeds in a low concentration (1 mg/L) can be an interesting natural alternative for removing humic acid from water in developing countries. The extract dose determined in the present study does not impart odour or colour to the treated water.
Moringa oleifera is a tropical plant whose seeds contain an edible oil and water soluble substance which has excellent coagulation properties for treating water and wastewater. The efficiency and properties of Moringa oleifera as a natural coagulant in water treatment were studied and compared with alum, which is presently the most widely used industrial coagulant. It is show that the active agents in aqueous Moringa extracts are dimeric cationic proteins, having molecular weight of 13 kDa and isoelectric points between 10 and 11. The mechanism of coagulation with Moringa oleifera appears to consist of adsorption and neutralization of the colloidal charges. Compared to alum, the optimal dosage of shelled Moringa oleifera seeds was almost the same (50 mg/l). In case of the non-shelled seeds, the dosage is greater (500 mg/l) for low initial turbidity waters. The purified proteins are more effective coagulants than alum. As a coagulant, Moringa is non-toxic and biodegradable. It is environmentally friendly, and unlike alum, does not significantly affect the pH and conductivity of the water after the treatment. Sludge produced by coagulation with Moringa is not only innocuous but also four to five times less in volume than the chemical sludge produced by alum coagulation. So, as a coagulant, Moringa oleifera may be a potentially viable substitute to alum.
In this work hemagglutinating activity (HA) was investigated in distinct Moringa oleifera tissue extracts. A new lectin from seeds (cMoL) was purified and characterized; hemagglutinating and coagulating activities were evaluated. HA was detected in 0.15 M NaCl extracts from flowers and rachis inflorescence (5%, w/v), seeds, leaves, fundamental tissue of stem and steam bark (10%, w/v). cMoL isolated after saline extraction and guar gel column chromatography was active at pH range 4.0–9.0 agglutinating erythrocytes from rabbit and human blood types. Extracts of tissues and cMoL activities were carbohydrate inhibited; azocasein and asialofetuin abolished cMoL HA. The lectin was thermostable at 100 °C during 7 h. Polyacrylamide gel electrophoresis under reduced conditions revealed a main polypeptide band of 26.5 kDa; native basic cMoL was detected as a unique band. Seed lectin preparations and cMoL showed coagulant activity, similar to aluminium sulphate, the coagulant most widely used in water treatment.
The treatment of palm oil mill effluent, POME is an important issue for the minimization of water pollution. The coagulation–flocculation process using Moringa oleifera seeds after oil extraction as natural coagulant is reported for POME treatment in the present study. The important process parameters pH, settling time, M. oleifera (after oil extraction) dosage and flocculant (NALCO 7751) dosage were optimized using design of experiments (DOE). A full factorial composite experimental design and response surface methodology (RSM) were used to obtain the optimum values of the parameters. The suspended solids of the raw POME were reduced from 17.927 mg/L to 181 mg/L and % recovery of the sludge as 87% was obtained at an optimum pH 5, settling time 114 min, M. oleifera dosage of 3469 mg/L and 6736 mg/L of flocculant (NALCO 7751) dosage in the present study.
This study investigated adsorption of chromium on to a bio-adsorbent, Moringa oleifera seed. Different by-products of the seed processing were used as adsorbents. These include: the Whole Seed Powder (WSP), the Residue after Coagulant Extraction (RaCE) and an Activated Carbon (AC) prepared from the seed husk. Adsorption studies for the removal of Cr(III) and Cr(VI) were carried out in batch experiments and the effects of adsorbent dosage, contact time, pH and initial chromium concentration were analysed. Experimental results showed that maximum removal of Cr(III) and Cr(VI) was observed at pH 7 and pH 2, respectively. The percentage removals of Cr(III) by WSP, RaCE and AC were: 97, 94 and 99.9%, respectively. And the percentage removals of Cr(VI) by RaCE and AC were 47 and 83.2%, respectively. RaCE showed similar adsorption capacity to the WSP, which indicates that it is possible to extract a coagulant and use the waste product for adsorption. By using the RaCE, residual dissolved organic carbon in the treated water was significantly reduced compared to using the WSP. These results indicate that biomaterials can be considered as potential adsorbents for heavy metals removal from water or wastewater systems.
During the ozonation of tetracycline (TC) in aqueous media at pHs 2.2 and 7.0, the effects of pH variations, protonation and dissociation of functional groups and variation in free radical exposure were investigated to elucidate the transformation pathway. Liquid chromatography-triple quadrupole mass spectrometry detected around 15 ozonation products, and uncovered their production and subsequent degradation patterns. During ozonation at pH 2.2, the TC degradation pathway was proposed on the basis of the structure, ozonation chemistry and mass spectrometry data of TC. Ozonation of TC at the C11a-C12 and C2-C3 double bonds, aromatic ring and amino group generated products of m/z 461, 477, 509 and 416, respectively. Further ozonation at the above mentioned sites gave products of m/z 432, 480, 448, 525 and 496. The removal of TOC reached a maximum of approximately 40% after 2 h of ozonation, while TC was completely removed within 4-6 min at both pHs. The low TOC removal efficiency might be due to the generation of recalcitrant products and the low ozone supply for high TC concentration. Ozonation decreased the acute toxicity of TC faster at pH 7.0 than pH 2.2, but the maximum decrease was only about 40% at both pHs after 2 h of ozonation. In this study, attempts were made to understand the correlation between the transformation products, pathway, acute toxicity and quantity of residual organics in solution. Overall, ozonation was found to be a promising process for removing TC and the products initially generated.
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Aedes aegypti larvae have developed tolerance to many insecticides used for mosquito control. Moringa oleifera seeds contain a water-soluble lectin (WSMoL) and this paper reports the effect of M. oleifera seed extracts (MoE(1-15)) and WSMoL on development and survival of A. aegypti larvae. WSMoL peptide from in-gel trypsin digestion is also described. MoE(1-15) showed hemagglutinating activity and WSMoL had similarity with flocculating proteins from M. oleifera seeds. MoE(1) and MoE(3) delayed larval development which stopped in the third instar (L3) in MoE(6) and MoE(15). Significant (p<0.0001) larval mortality was only detected in MoE(15). Native WSMoL showed larvicidal activity (LC(50) 0.197 mg mL(-1)) and heated lectin, without hemagglutinating activity, did not kill fourth instar (L4) larvae. Optical microscopy showed that live L4 from MoE(1) presented underlying epithelium, increased gut lumen and hypertrophic segments; dead L4 from WSMoL were absent of underlying epithelium, had increased gut lumen and hypertrophic segments. The presence of hemagglutinating activity in the extracts suggests that soluble lectin promotes the delay of larval development and mortality; furthermore, the absence of larvicidal activity in heat-denatured WSMoL strengthens the involvement of lectin in this activity mechanism.
We created a database in order to quantitatively assess the occurrence and removal efficiency of pharmaceuticals and personal care products (PPCPs) in wastewater treatment plants (WWTPs). From 117 scientific publications, we compiled 6641 data covering 184 PPCPs. Data included the concentrations of PPCPs in WWTP influents and effluents, their removal efficiency and their loads to the aquatic environment. The first outputs of our database allowed to identify the most investigated PPCPs in WWTPs and the most persistent ones, and to obtain reliable and quantitative values on their concentrations, frequency of detection and removal efficiency in WWTPs. We were also able to compare various processes and pointed out activated sludge with nitrogen treatment and membrane bioreactor as the most efficient ones.
A flocculating protein from the seeds of Moringa oleifera Lam. was isolated by extraction with phosphate buffer followed by cation exchange chromatography. The molecular mass of the protein determined by SDS-PAGE was about 6.5 kDa, the isoelectric point was above pH 10. Amino acid analysis and sequencing showed high contents of glutamine, arginine and proline, and a total of 60 residues. The amino terminus is blocked by pyroglutamate. The flocculant capacity, determined in glass powder suspension, is comparable to that of a cationic polymer on polyacrylamide basis. Flocculation activity may be explained by the patch charge mechanism due to low molecular weight and high charge density.
This study focuses on the coagulation mechanism by the purified coagulant solution (MOC-SC-PC) with the coagulation active component extracted from M. oleifera seeds using salt solution. The addition of MOC-SC-PC tap water formed insoluble matters. This formation was responsible for kaolin coagulation. On the other hand, insoluble matters were not formed when the MOC-SC-PC was added into distilled water. The formation was affected by Ca2+ or other bivalent cations which may connect each molecule of the active coagulation component in MOC-SC-PC and form a net-like structure. The coagulation mechanism of MOC-SC-PC seemed to be an enmeshment of Kaolin by the insoluble matters with the net-like structure. In case of Ca2+ ion (bivalent cations), at least 0.2 mM was necessary for coagulation at 0.3 mgC l-1 dose of MOC-SC-PC. Other coagulation mechanisms like compression of double layer, interparticle bridging or charge neutralization were not responsible for the coagulation by MOC-SC-PC.
Seed flour from Moringa oleifera is widely used as a natural coagulant for water treatment in developing countries. Extracts obtained by water soaking of M. oleifera intact seeds were investigated for the presence of lectin, trypsin inhibitor, tannin as well as antioxidant activity. A water soluble M. oleifera lectin (WSMoL) detected was mainly active with rabbit cells at pH 4.5; heat treatment, pH 7.0, fructose and porcine thyroglobulin abolished HA of WSMoL. Trypsin inhibitor or tannins were not detected; the antioxidant component (WSMoAC) reduced 1,1-diphenyl-2-picrylhydrazyl radical (DPPH) was slower than catechin and was thermostable. The extracts showed a primary glycopolypeptide band of Mw 20,000; the main native acidic protein showed hemagglutinating activity. WSMoL may be involved in seed coagulant properties.
Two physico-chemical processes, coagulation-flocculation and flotation, have been assessed for enhancing the removal of some selected pharmaceutical and personal care products (PPCPs) present in sewage. Eight compounds, representative of three main groups of PPCPs according to their physico-chemical properties, have been selected: lipophilic compounds (the synthetic musks Galaxolide and Tonalide), neutral compounds (the tranquillizer Diazepam and the antiepileptic Carbamazepine) and acidic compounds (the anti-inflammatories Ibuprofen, Naproxen and Diclofenac). During the coagulation-flocculation assays, the main parameters considered were the selection of the additives, their doses and the temperature of operation (12 or 25 degrees C). Musks-which are highly lipophilic and Diclofenac-with significant sorption affinity-were removed around 50-70% at both temperatures independently of the dose and type of coagulant used. However, the rest of the compounds, which are more hydrophilic, were affected to a lesser degree (with maximum reductions below 25%). The exceptions to this behavior were Carbamazepine and Ibuprofen, which were not removed under any condition tested. During the flotation assays, the parameters studied were the initial content of fat in wastewaters and temperature. Again, musks were removed to a greater degree (35-60%), followed by Diazepam (40-50%) and Diclofenac (20-45%) and, to a lesser extent, Carbamazepine (20-35%), Ibuprofen (10-25%) and Naproxen (10-30%). The best results were always obtained at 25 degrees C, although in some cases the operation at 12 degrees C gave similar results. The removal of musks and neutral compounds was higher in wastewaters with a high fat content (around 150 mgl(-1)).
Moringa oleifera is a pan tropical, multipurpose tree whose seeds contain a high quality edible oil (up to 40% by weight) and water soluble proteins that act as effective coagulants for water and wastewater treatment. The use of this natural coagulant material has not yet realised its potential. A water extract of M. oleifera seed was applied to a wastewater treatment sequence comprising coagulation-flocculation-sedimentation-sand filtration. The study was laboratory based using an actual wastewater. Overall COD removals of 50% were achieved at both 50 and 100mg/l M. oleifera doses. When 50 and 100mg/l seed doses were applied in combination with 10mg/l of alum, COD removal increased to 58 and 64%, respectively. The majority of COD removal occurred during the filtration process. In the tests incorporating alum, sludge generation and filter head loss increased by factors of 3 and 2, respectively. These encouraging treatment results indicate that this may be the first treatment application that can move to large scale adoption. The simple water extract may be obtained at minimal cost from the presscake residue remaining after oil extraction from the seed. The regulatory compliance issues of adopting 'new materials' for wastewater treatment are significantly less stringent than those applying to the production of potable water.
Treatment of seven tetracycline classes of antibiotic (TAs) from raw waters (synthetic and river) was evaluated using coagulation and granular activated carbon (GAC) filtration in this study. Both coagulation and GAC filtration were effective for removal of TAs, and the removal efficiency depended on the type of TAs. GAC filtration was relatively more effective for removal of tetracycline (TC), doxycycline-hyclate (DXC), and chlortetracycline-HCl (CTC), which were difficult to remove by coagulation. It was speculated that TAs would be removed through the charge neutralization and sweep coagulation when poly-aluminum chloride (PACl) was added into the raw waters. The charge neutralization of zwitterionic or negative TAs by cationic Al (III) species drove removal of TAs from the synthetic water. When sufficient alkalinity was available (river water), aluminum hydroxide precipitates were formed. TAs could be removed by being enmeshed into or adsorbed onto the precipitates when PACl was added to the river water.
Structural characterization of coagulant Moringa oleifera lectin and its effect on hemostatic parameters
- La Luz
- Mc Silva
- Rs Ferreira
Luz LA, Silva MC, Ferreira RS, et al. Structural characterization of coagulant Moringa oleifera lectin and its effect
on hemostatic parameters. Int J Biol Macromol.
2013;58:31–36.