Comparison of Moringa stenopetala seed extract as a clean coagulant with Alum and Moringa stenopetala-Alum hybrid coagulant to remove direct dye from Textile Wastewater

Aleppo pine seeds (Pinus halepensis Mill.) as a promising novel green coagulant for the removal of Congo red dye: Optimization via machine learning algorithm

Consideration is now being given to the use of metal coagulants to remove turbidity from drinking water and wastewater. Concerns about the long-term impact of non-biodegradable sludge on human health and the potential contamination of aquatic systems are gaining popularity. Recently, alternative biocoagulants have been suggested to address these concerns. In this study, using a 1 M sodium chloride (NaCl) solution, the active coagulating agent was extracted from Pinus halepensis Mill. Seed, and used for the first time to remove Congo red dye, the influence of numerous factors on dye removal was evaluated in order to make comparisons with conventional coagulants. The application of biocoagulant was shown to be very successful, with coagulant dosages ranging from 3 to 12 mL L^-1 achieving up to 80% dye removal and yielding 28 mL L^-1 of sludge. It was also found that biocoagulant is extremely pH sensitive with an optimum operating pH of 3. Ferric chloride, on the other hand, achieved similar removal rate with higher sludge production (46 mL L^-1) under the same conditions. A Fourier Transform Infrared Spectroscopy and proximate composition analysis were undertaken to determine qualitatively the potential active coagulant ingredient in the seeds and suggested the involvement of proteins in the coagulation-flocculation mechanism. The evaluation criteria of the Support vector machine_Gray wolf optimizer model in terms of statistical coefficients and errors reveals quite interesting results and demonstrates the performance of the model, with statistical coefficients close to 1 (R = 0.9998, R² = 0.9995 and R² adj = 0.9995) and minimal statistical errors (RMSE = 0.5813, MSE = 0.3379, EPM = 0 0.9808, ESP = 0.9677 and MAE = 0.2382). The study findings demonstrate that Pinus halepensis Mill. Seed extract might be a novel, environmentally friendly, and easily available coagulant for water and wastewater treatment.

Moringa oleifera seed oil extracted by pressurized n-propane and its effect against Staphylococcus aureus biofilms

Staphylococcus aureus is often associated worldwide with foodborne illnesses, and the elimination of biofilms formed by this bacterium from industrial surfaces is very challenging. To date, there have been few attempts to investigate plant oils obtained by recent green technologies, applied against biofilms on usual surfaces of the food industry and bacteria isolated from such environment. Therefore, this study evaluated the activity of Moringa oleifera seed oil (MOSO), extracted with pressurized n-propane, against standard and environmental S. aureus biofilms. Additionally, a genotypic and phenotypic study of the environmental S. aureus was proposed. It was found that this bacterium was a MSSA (methicillin-sensitive S. aureus), a carrier of icaA and icaD genes that has strong adhesion (OD₅₅₀=1.86 ± 0.19) during biofilm formation. The use of pressurized n-propane as a solvent was efficient in obtaining MOSO, achieving a yield of 60.9%. Gas chromatography analyses revealed the presence of a rich source of fatty acids in MOSO, mainly oleic acid (62.47%), behenic acid (10.5%) and palmitic acid (7.32%). On polystyrene surface, MOSO at 0.5% and 1% showed inhibitory and bactericidal activity, respectively, against S. aureus biofilms. MOSO at 1% allowed a maximum reduction of 2.38 log UFC/cm² of S. aureus biofilms formed on PVC (polyvinyl chloride) surface. Scanning electron microscopy showed disturbances on the surface of S. aureus after exposure to MOSO. These unprecedented findings suggest that MOSO extracted with pressurized n-propane is potentially capable of inhibiting biofilms of different S. aureus strains, thus, contributing to microbiological safety during food processing.

Recent advances in biopolymer-based advanced oxidation processes for dye removal applications: A review

Over the past few years, synthetic dye-contaminated wastewater has attracted considerable global attention due to the low biodegradability and the ability of organic dyes to persist and remain toxic, causing numerous health and environmental concerns. As a result of the recalcitrant nature of those complex organic dyes, the remediation of wastewater using conventional wastewater treatment techniques is becoming increasingly challenging. In recent years, advanced oxidation processes (AOPs) have emerged as a potential alternative to treat organic dyestuffs discharged from industries. The most widely employed AOPs include photocatalysis, ozonation, Fenton oxidation, electrochemical oxidation, catalytic heterogeneous oxidation, and ultrasound irradiation. These processes involve the generation of highly reactive radicals to oxidize organic dyes into innocuous minerals. However, many conventional AOPs suffer from several setbacks, including the high cost, high consumption of reagents and substrates, self-agglomeration of catalysts, limited reusability, and the requirement of light, ultrasound, or electricity. Therefore, there has been significant interest in improving the performance of conventional AOPs using biopolymers and heterogeneous catalysts such as metal oxide nanoparticles (MONPs). Biopolymers have been widely considered in developing green, sustainable, eco-friendly, and low-cost AOP-based dye removal technologies. They inherit intriguing properties like biodegradability, renewability, nontoxicity, relative abundance, and sorption. In addition, the immobilization of catalysts on biopolymer supports has been proven to possess excellent catalytic activity and turnover numbers. The current review provides comprehensive coverage of different AOPs and how efficiently biopolymers, including cellulose, chitin, chitosan, alginate, gelatin, guar gum, keratin, silk fibroin, zein, albumin, lignin, and starch, have been integrated with heterogeneous AOPs in dye removal applications. This review also discusses the general degradation mechanisms of AOPs, applications of biopolymers in AOPs and the roles of biopolymers in AOPs-based dye removal processes. Furthermore, key challenges and future perspectives of biopolymer-based AOPs have also been highlighted.

Coagulation activity of liquid extraction of Leucaena leucocephala and Sesbania grandiflora on the removal of turbidity

Turbidity is removed by adding a chemical coagulant, which produces a secondary toxic of alumina residues in the water. Therefore, the aim of study was to evaluate the coagulation activity of NaCl extract from Leucaena leucocephala and Sesbania grandiflora seeds on the removal of turbidity for water purification. The proximate composition of the seeds was determined. Fourier transform infrared spectroscopy was used to identify the functional groups of protein, and the surface morphology was observed by SEM-EDS. To obtain the optimized condition, all experiments were evaluated by artificial turbid water before being applied on the natural water (i.e., Selokan Mataram). The coagulation process was evaluated by concentration (M), dosage (mL/L), and pH in terms of turbidity, total dissolved solids, and transmittance of light. The results showed that both coagulant seeds contained 25.32 and 30.81% of protein. These coagulants could remove the turbidity by 99.7% for L. leucocephala and 94.24% for S. grandiflora from artificial turbid water at the optimized concentration of 1.0 M, and dosage of 5 and 10 mL/L, respectively. At pH 5 the removal of turbidity from Selokan Mataram was 99.4% for L. leucocephala and 97.23% for S. grandiflora.

Multivariate optimization approach applied to natural polymers from Ceratonia siliqua L. and Moringa oleifera Lam as coagulating/flocculating agents

In this study, a multivariate 23 experimental design was applied to optimize the operational conditions (seed mass, salt concentration, and pH) to employ Ceratonia siliqua L. (carob) and Moringa oleifera Lam (moringa) as coagulating/flocculating agents for water treatment. Currently, the coagulation stage in water treatment uses aluminium compounds, due to the characteristic reaction to natural alkalinity in raw water, and for its low market value. Considering that aluminium effects on human health are not sufficiently studied to acknowledge its toxicity, and its significant environmental impacts, it is suitable for the studies to search for alternatives to be employed in the water treatment that will be distributed to human consumption. This study was carried out with raw water of high turbidity level, 83.7 NTU. The raw water collected was also characterized according to pH, colour, Total Organic Carbon (TOC), Dissolved Organic Carbon (DOC), and Dissolved Organic Matter (DOM), with values of 6.7, 178 NTU, 6.80, 2.45 and 138.58 mg/L, respectively. The optimized results showed that with 2 g of seed, 0.5 mol L-1 of NaCl, and pH 11.0 In these conditions, moringa coagulant reached 90%, 86%, 6%, 67%, and 81% for turbidity, colour, DOC, TOC, and DOM removal, respectively, whereas the carob coagulant achieved 85%, 76%, 5%, 55.6%, 66.7%, respectively for the same parameters' removal. Both coagulants presented lower sludge formation, 1.1 mL L^-1 for moringa coagulant, and 1.1 mL L^-1 for carob coagulant. The results could be considered promises, and natural polymers carob and moringa can be suggested as alternatives agents in coagulation/flocculation stages for water treatment.

Acid red 18 removal from aqueous solution by nanocrystalline granular ferric hydroxide (GFH); optimization by response surface methodology & genetic-algorithm

The need for fresh water is more than before by population growth, and industrial development have affected the quality of water supplies, one of the important reason for water contamination is synthetic dyes and their extensive use in industries. Adsorption has been considered as a common methods for dye removal from waters. In this study, Acid Red18 removal in batch mode by using Granular Ferric Hydroxide (GFH) was investigated. The GFH characterized by XRD, FESEM and FTIR analysis. Experiments were designed using RSM-CCD method. The maximum removal efficiency was obtained 78.59% at pH = 5, GFH dosage = 2 g/l, AR18 concentration = 77.5 mg/l and 85 min of contact time. Optimization with RSM and Genetic Algorithm carried out and is similar together. The non-linear adsorption Isotherm and kinetic fitted with Freundlich (R2 = 0.978) and pseudo-second-order (R2 = 0.989) models, respectively. Thermodynamic studies showed that the AR18 adsorption is endothermic process and GFH nature was found spontaneous.

Sustainable remediation of hazardous environmental pollutants using biochar-based nanohybrid materials

Biochar is a well-known carbon material with diversified functionalities and excellent physicochemical characteristics with high wastewater treatment potential. This review aims to summarize recent advancements in the development of biochar and biochar-based nanohybrid materials as a potential tool for the removal of harmful organic compounds such as synthetic dyes/effluents. The formation of biochar using pyrolysis of renewable feedstocks and their applications in various industries are explained hereafter. The characteristics and construction of biochar-based hybrid materials are explained in detail. Diversity of feedstocks, including municipal wastes, industrial byproducts, agricultural, and forestry residues, endows different biochar types with a wide structural variety. The production of cost-effective biochar drives the interest in manipulating biochars and induces desire functionality using nanoscale reinforcements. Various types of biochars, such as magnetic biochar, layered nanomaterial coated biochar, nanometallic oxide composites, chemically and physically functionalized biochar, have been produced. With the aid of nanomaterial, hybrid biochar exhibits a high potential to remove toxic contaminants. Depending upon biochar type, dyes/effluents can be removed via different mechanisms, including the Fenton process, photocatalytic degradation, π-π interaction, electrostatic interaction, and physical adsorption. In conclusion, desired physicochemical features, and tunable surface properties of biochar present high potential material in removing organic dyes and other effluents. The blended biochar with different materials/nanomaterials endows broader development and multi-functional opportunities for treating dyes/effluents.

A review on disinfection technologies for controlling the antibiotic resistance spread

The occurrence of antibiotic-resistant bacteria (ARB) in water bodies poses a sanitary and environmental risk. These ARB and other mobile genetic elements can be easily spread from hospital facilities, the point in which, for sure, they are more concentrated. For this reason, novel clean and efficient technologies are being developed for allowing to remove these ARB and other mobile genetic elements before their uncontrolled spread. In this paper, a review on the recent knowledge about the state of the art of the main disinfection technologies to control the antibiotic resistance spread from natural water, wastewater, and hospital wastewater (including urine matrices) is reported. These technologies involve not only conventional processes, but also the recent advances on advanced oxidation processes (AOPs), including electrochemical advanced oxidation processes (EAOPs). This review summarizes the state of the art on the applicability of these technologies and also focuses on the description of the disinfection mechanisms by each technology, highlighting the promising impact of EAOPs on the remediation of this important environmental and health problem.

Functionalized magnetite nanoparticles with Moringa oleifera with potent antibacterial action in wastewater

Contaminations by Staphylococcus aureus in food industry environments have been extended to industrial Effluent Treatment Plant (ETP). The methodologies used in ETP for bacterial removals and quality parameters adjustment commonly use products toxic to the environment, being mostly inefficient against virulent bacteria such as S. aureus. Seeds of Moringa oleifera Lam. (MO) have potential to be used in ETP as an alternative to harmful products, as it has both the ability to regulate the physicochemical parameters of water and has antibacterial action. Functionalization of MO with magnetite magnetic nano particles (Fe₃O₄) at nano scale focusing on coagulation and flocculation of wastewater has been gaining prominence. Therefore, the present study evaluated the potential use of the magnetic coagulant MO-Fe₃O₄ in the elimination of S. aureus in synthetic dairy effluent; concomitantly sought to adjust the quality levels of physicochemical parameters. MO-Fe₃O₄ added to synthetic dairy effluent at different concentrations amounted to 16 treatments, which were evaluated for removal of color, turbidity, UV_254nm and S. aureus on the effluent surface and sludge after 30 min of sedimentation. The results confirmed the efficient elimination of S. aureus simultaneously with a significant reduction of the physicochemical values, with constant efficiency up to 30 min. Scanning electron microscopy images confirm the removal of S. aureus on the effluent surface and sludge. Thus, this study was able to present a natural coagulant capable of remove bacteria and adjust the quality levels of the effluent after 10 min of sedimentation, making this biotechnological innovation highly applicable to ETP.

Methylene blue removal with ZnO coated montmorillonite: thermodynamic, kinetic, isotherm and artificial intelligence studies

In this study, montmorillonite clay was coated with zinc oxide (ZnO) nanoparticles. The study's primary aim is to investigate the adsorption properties of zinc oxide coated montmorillonite adsorbent against methylene blue (MB), and determine ZnO's effectiveness in adsorption. First, the surface properties of the ZnO-coated montmorillonite (ZnO/MMT) adsorbent were determined by FTIR Spectroscopy, XRD, and SEM/EDS. In the adsorption studies, the effects of different parameters such as contact time (5-150 min), adsorbent dosage (0.05-0.5 g), initial concentration (50-200 mg/L), temperature (298-318 K), and initial pH (4-12) were investigated. In addition, a fuzzy model was developed by using adsorption parameters so that the removal rates could be calculated more quickly. Adsorption kinetics and equilibrium results were explained by the pseudo-second-order model and the Langmuir isotherm model, respectively. The highest adsorption capacity was calculated as 384.62 mg/g at 318 K. The enthalpy value was calculated as 2.16 kJ/mol. The entropy value was calculated as 0.04 kJ/mol K. The negative entropy value in the thermodynamic parameters calculated at all temperatures shows that the adsorption was spontaneous. According to the data we obtained, ZnO/MMT nanoparticles can be successfully applied for MB removal from aqueous solutions.

Modified Moringa oleifera Lam. Seed husks as low-cost biosorbent for atrazine removal

Atrazine is an herbicide which is widely applied in sugarcane and corn crops. Its frequent use has resulted in environmental impacts, and its traces have been verified in surface and groundwater. Thus, it is necessary to remove this pollutant, and an alternative is the adsorption due to its universal nature, low-cost and ease of operation. Therefore, the objective of the present work was to study the adsorption capacity of atrazine by modified Moringa oleifera Lam. seed husks, a low-cost adsorbent. The biosorbent was subjected to c hemical and thermal treatment and was characterised by structural, morphological and textural analysis, which showed porous and heterogeneous characteristics, with a specific surface area of 5.77 m² g^-1. The kinetic study demonstrated equilibrium at 1200 min, with an adsorption capacity of 1.90 mg g^-1 and the best fit was for the pseudo-second-order model. The isotherms were obtained at 298, 308 and 318 K. The Freundlich, Temkin and Langmuir models were applied to the experimental data, the latter being the best. The values of the thermodynamic parameters indicated that the biosorption was spontaneous, endothermic and reversible. The highest adsorption capacity obtained was 10.32 mg g^-1, which was higher than several values found in the literature. The biosorbent was regenerated over three cycles, indicating its potential of atrazine removal from surface water.

Bioactive components and anti-diabetic properties of Moringa oleifera Lam

Moringa oleifera Lam. is a perennial tropical deciduous tree with high economic and pharmaceutical value. As an edible plant, M. oleifera Lam. is rich in nutrients, such as proteins, amino acids, mineral elements and vitamins. Besides, it also contains an important number of bioactive phytochemicals, such as polysaccharides, flavonoids, alkaloids, glucosinolates and isothiocyanates. M. oleifera for long has been used as a natural anti-diabetic herb in India and other Asian countries. Thus, the anti-diabetic properties of Moringa plant have evolved highly attention to the researchers. In the last twenty years, a huge number of new chemical structures and their pharmacological activities have been reported in particularly the anti-diabetic properties. The current review highlighted the bioactive phytochemicals from M. Oleifera. Moreover, evidence regarding the therapeutic potential of M. oleifera for diabetes including experimental and clinical data was presented and the underlying mechanisms were revealed in order to provide insights for the development of novel drugs.

Characterization of Two Cactus Formulation-Based Flocculants and Investigation on Their Flocculating Ability for Cationic and Anionic Dyes Removal

Dye invasion in wastewaters is undeniably one of the crucial environmental concerns in addition to the supplement of toxic synthetic chemical flocculants used for color removal using the conventional coagulation-flocculation process. With the aim to improve the flocculation stage in terms of reagents safety and ensure dyes removal, the present study explores the flocculating effectiveness of two natural, stable, and eco-friendly cactus formulations, namely 60 °C oven-dried (DP) and lyophilized (LP) cladodes. Both formulations were assessed to treat cationic (Methylene blue; MB) and anionic (Methyl Orange; MO) dye solutions as a substitution attempt for the currently questioned employed synthetic chemical flocculants. Obtained results demonstrate that, in conjunction with alum as coagulant, the lyophilized powder (LP) bio-based flocculant appears to be the most efficient cactus formulation, showing a significant color (83%) and a turbidity (69%) abatement for the cationic dye (MB) and, respectively, 63% and 62% for the anionic one (MO). Additionally, the flocculation activity of the LP formula remained high over an eight-month period of storage. Moreover, based on the Fourier transform infrared (FTIR) spectroscopic analysis and the chemical characterization of cactus formulations, the occurring flocculation mechanisms of the dye removal are presumed to be based on both adsorption and bridging phenomena. Further, the significant color and turbidity decline achieved upon the addition of the lyophilized cactus cladodes powder (LP), enhancing thus the coagulation performance of the alum-based coagulant, proved the effectiveness of this bio-flocculant compared to the commonly used chemical flocculant (polyacrylamide). Hence, it was suggested that lyophilized cactus cladodes as a natural flocculant could be one of the effective surrogates to chemical flocculants conventionally used in wastewater treatment for the sake of a safer and sustainable environment.

Elucidation of the potential of Moringa oleifera leaves extract as a novel alternate to the chemical coagulant in water treatment process

In recent years, several studies have been developed to search for sustainable and eco-friendly natural coagulants as an alternative to inorganic and synthetic coagulants to obtain drinking water. Despite the performance and cost-effectiveness of these coagulants, they require pH and alkalinity adjustments, they generate high volumes of sludge, and their residuals in treated water (e.g., aluminum) are linked with neurodegenerative diseases such as Alzheimer's, as well as neurotoxic and carcinogenic effects. Moringa oleifera seeds had shown better coagulation properties but have numerous limitations which have prompted us to find better alternatives. To the best part of my knowledge, utilization of its leaves extract obtained from different organic solvents in water purification has rarely been reported. Our findings clearly revealed that M. oleifera leaves hexane extract has significantly improved the water quality parameters including pH (8.2-7.1), TDS (512-221), hardness (246-138), turbidity (15.6-6.1), fluoride (2.3-1.1), and Escherichia coli count (315-41) whereas alum effectively improved these parameters at a dose of 50 mg/L. Moringa oleifera showed significant removal capability in comparison to alum but slightly at higher dose, thus our results strongly supported the efficacy of M. oleifera leaves extracts as better alternative to chemical coagulant in water purification. PRACTITIONER POINTS: Chemical coagulants pose severe side effects to humans such as neurodegenerative diseases. Use of Moringa oleifera leaves as natural coagulants in water purification is a cost-effective approach due to its easy availability throughout the year. Moringa oleifera leaves exhibited significant coagulating efficiency by improving water quality parameters including pH, turbidity, total dissolved solids, fluoride, hardness, and E. coli count.

Evaluation of a magnetic coagulant based on Fe3O4 nanoparticles and Moringa oleifera extract on tartrazine removal: coagulation-adsorption and kinetics studies

The lack of data regarding the mechanisms at work in the coagulation processes of different substances using magnetic coagulants makes it difficult to understand the phenomena involved and, consequently, makes it difficult to elucidate the mechanisms involved in the coagulation process. Thus, the present study aimed at evaluating the performance of a magnetic coagulant composed of iron oxide (Fe₃O₄) functionalised with Moringa oleifera (MO) salt extract in the treatment of a synthetic food industry wastewater simulated by the addition of dye to distilled water. From the data obtained in the coagulation/flocculation assays followed by magnetic sedimentation, the different mechanisms involved were evaluated for their fit to pseudo-first order, pseudo-second order, Langmuir and Freundlich theoretical models. The adjustments to the models were evaluated from the kinetic data and indicated that at pH 3 the best fit was to the pseudo-second order model, whereas for pH 6 and 9 the best fit was for the pseudo-first order model. The isothermal data were adjusted to the Langmuir model, suggesting adsorption of a monolayer, characterising chemical processes with selective adsorption. In relation to the mechanisms involved in the process, it is suggested that the neutralisation of charges was the predominant mechanism in the removal of tartrazine at pH 3, whereas at the other pH values evaluated the mechanism that prevailed was monolayer adsorption. Thus, the proposed magnetic coagulant was found to be an efficient alternative material for tartrazine removal, allowing easy separation in the sedimentation stage while also being compatible with environmental issues.

Natural polymer matrix as safe flocculant to remove turbidity from kaolin suspension: Performance and governing mechanism

Conventional flocculants bear environmental and health concerns which could be avoided by applying natural materials, particularly polysaccharide and glycoprotein-containing ones. In the present study, yeast cell wall (YCW), a natural polymer matrix, was used as natural flocculant. To prepare YCW, Saccharomyces cerevisiae was cultivated in bench scale fermenter. After characterization, YCW was employed as anionic flocculant in jar tests to remove turbidity from kaolin suspensions at different conditions where either alum or poly aluminum chloride (PAC) was coagulant. Generally, the lower coagulant consumption, higher turbidity removal or faster sedimentation was observed by using YCW as flocculant. The developed flocculant was more effective in the presence of PAC compared to alum. At best, by applying 300 mg/L YCW, the highest turbidity removals of 98 and 97% were achieved using 10 ppm PAC at pH 6.5 and 50 ppm alum at pH 7.5, respectively. The presence of the flocculant in the structure of the flocs was proved by FTIR analysis. The final pH of the treated suspensions was suitable for discharge purpose without the need for neutralization. The excess positive charge neutralization and bridging were the governing mechanism in coagulation-flocculation process. YCW with proper performance, GRAS designation and readily availability can be considered as natural alternative to chemical anionic flocculants where the process needs safe compounds.

Modeling of azo dyes adsorption on magnetic NiFe2O4/RGO nanocomposite using response surface methodology

BACKGROUND

Azo group dyes are the largest group of synthetics dyes that widely used in industries, especially in textile industry. The presence of these organic compounds in wastewaters and their discharge into environment without efficient treatment may cause adverse effect on human, living and aquatic environment. The purpose of this study was to optimize the adsorption of azo dye of Direct Red 81 (anionic dye) and Basic Blue 41 (cationic dye) from aqueous solution onto magnetic NiFe₂O₄/RGO nanocomposite.

METHODS

In this study the response surface methodology (RSM) based on the central composite design (CCD), was used to optimization and modeling of adsorption process DR81 and BB41 dye on NiFe₂O₄/RGO. in order to investigating the effect of the operating parameters on the adsorption efficiency DR81 and BB41, four influential factors were chosen that includes of pH (3-9), contact time (5-25 min), adsorbent amount (0.02-0.05 g) and initial dye concentration (40-200 mg/L). A total of 30 experiments were performed for each dye in this study. The concentration of dye in solution was measured by spectrophotometer. The structure of synthesized adsorbent was investigated using Scanning Electron Microscope (SEM), X-ray diffraction (XRD), Fourier transform irradiation (FTIR), transmission electron microscope (TEM) and vibrating sample magnetometer (VSM).

RESULTS

Analysis of variance (ANOVA) showed that regression model for both dye adsorption with value of P value <0.001 is significant statistically. The correlation coefficient (R²) for DR81 (R² = 0.9968) and BB41 (R² = 0.9948) indicated which there is a good agreement between predicted values and the results of the experiments and the model also well predict the adsorption efficiency. Furthermore, the factors of pH, dye concentration and adsorbent dose, have the greatest effect on adsorption, respectively, while contact time have the lowest effect on adsorption of both dyes. The adsorption behavior of the DR81 and BB41 onto NiFe₂O₄/RGO was best described by the Langmuir and Freundlich isotherm, respectively. The optimum conditions for maximum removal of DR81 (96.41%) was found to be at pH 3, contact time 19.68 min, adsorbent dose 0.02 g and initial dye concentration 40 mg/L. However, the optimum conditions for maximum removal of BB41 (97.87%) was found to be at pH 9 contact time 18.16 min, adsorbent dose 0.02 g and initial dye concentration 40 mg/L.

CONCLUSION

The present study shows that magnetic NiFe₂O₄/RGO nanocomposite have much potential as a powerful adsorbent for the rapid adsorption of anionic (DR81) and cationic dyes (BB41) from aqueous solution.

Comparative study of flocculation and adsorption behaviour of water treatment proteins from Moringa peregrina and Moringa oleifera seeds

Trees of Moringa oleifera are the most widely exploited species of Moringa and proteins extracted from its seeds have been identified as the most efficient natural coagulant for water purification. Largely for climatic reasons, other Moringa species are more accessible in some regions and this paper presents a comparative study of the adsorption to different materials of the proteins extracted from seeds of Moringa peregrina and Moringa oleifera to explore their use as flocculating agents in regions where each is more readily accessible. Results showed that Moringa peregrina seed proteins had higher adsorption to alumina compared to silica, in contrast to opposite behavior for Moringa oleifera. Both species provide cationic proteins that can act as effective coagulants for the various impurities with different surface potential. Despite the considerable similarity of the amino acid composition, the seed proteins have significantly different adsorption and this presents the opportunity to improve processes by choosing the optimal species or combination of species depending on the type of impurity or possible development of separation processes.

Dependence of Dye Molecules Adsorption Behaviors on Pore Characteristics of Mesostructured MOFs Fabricated by Surfactant Template

In this work, mesostructured metal-organic frameworks (MOFs) of MIL-101-Crs with different specific surface areas were synthesized successfully under solvothermal conditions using cationic surfactant cetyltrimethyl ammonium bromide (CTAB) as a structural template. It was found that crystallinity degrees, specific surface areas, and pore size distributions strongly depended on the loading of CTAB. Nitrogen adsorption and positron annihilation lifetime spectroscopy (PALS) results showed that the mean mesopore size increased with loading more CTAB due to the formation of larger templated mesopores. Although Langmuir adsorption of both methylene blue (MB) and methyl orange (MO) was confirmed in MIL-101-Crs, the experimental results showed different adsorption behaviors for them depending on the dye molecular size, pore structure, and charge properties of dye molecules/MOFs in solution. The MB molecules were found to be mainly adsorbed in the interspaces between grains and the templated mesopores, whereas the MO molecules were adsorbed in the inherent pores as well as the templated ones in MOFs due to the unsaturated metal sites' electrostatic attraction on them. Remarkably, MO adsorption capacity was observed to be proportional to the specific surface area, which allowed one to get a good linear fitting of experimental data. Interestingly, the good consistence between the fitting experimental parameter, that is, the number of adsorbed MO^-s per unit specific surface area, and the calculated one according to our rough estimation strongly suggests that MO^-s are electrostatically attracted and rotating around the unsaturated metal sites on MOFs' inner surfaces, which exclude other MO^-s to be adsorbed around due to the "hindering effect" of the rotating motion.

Potential of the Moringa oleifera saline extract for the treatment of dairy wastewater: application of the response surface methodology

In this work, the coagulation/flocculation/sedimentation treatment of dairy wastewater samples was investigated through serial factorial designs utilizing the saline extract obtained from Moringa oleifera (Moringa) as a coagulant. The sedimentation time (ST), pH, Moringa coagulant (MC) dose and concentration of CaCl₂ have been evaluated through the response surface methodology in order to obtain the ideal turbidity removal (TR) conditions. The empirical quadratic model, in conjunction with the desirability function, demonstrated that it is possible to obtain TRs of 98.35% using a coagulant dose, concentration of CaCl₂ and pH of 280 mg L^-1, 0.8 mol L^-1 and 9, respectively. The saline extract from Moringa presented its best efficiency at an alkaline pH, which influenced the reduction of the ST to a value of 25 min. It was verified that the increase in the solubility of the proteins in the Moringa stimulated the reduction of the coagulant content in the reaction medium, and it is related to the use of calcium chloride as an extracting agent of these proteins. The MC proved to be an excellent alternative for the dairy wastewater treatment, compared to the traditional coagulants.

Isolation of active coagulant protein from the seeds of Strychnos potatorum - a potential water treatment agent

The application of natural coagulants for decentralized water treatment is gaining importance as a part of global sustainable initiative. This study focuses on the isolation of active coagulation components responsible for water clarification with respect to Strychnos potatorum seeds. The active coagulant components, protein and polysaccharide, were successfully isolated, dialysed and subjected to gel permeation chromatography. The polysaccharide was isolated with the saline extraction method and characterized using FTIR and NMR spectroscopy. Protein was precipitated with 80% ammonium sulphate solution combined with dialysis and gel permeation chromatography using Sephadex G-50. SDS-PAGE revealed that the isolated protein has a molecular weight of 12 kDa. The small-scale coagulation assay suggests that the protein fraction has superior coagulation activity than the isolated polysaccharide residue. The active coagulant fractions reported in this study would be helpful in deploying cheaper and simple methods in scaling up the coagulant fraction from these seeds acting as a potential water treatment agent.

Waste Moringa oleifera seed pods as green sorbent for efficient removal of toxic aquatic pollutants

In the present study, biosorption of chromium (Cr(VI)) ions and Naphthol blue black (NBB) dye using Moringa oleifera seed pods powder (MPP) as green biosorbent was investigated. Three different sizes of MPP viz. fine fraction (<53 μm), coarse fraction (>250 μm) and mixed fraction were investigated. The biosorbent was characterized by pHzpc, Fourier transform infrared spectroscopy (FT-IR), and scanning electron microscopy (SEM) in order to get an insight of the surface charge, functional groups, and morphology of the biosorbent, respectively. The biosorption studies were conducted with Cr(VI) and NBB dye and different parameters, such as solution pH, contact time, initial concentration of the pollutant, adsorbent dosage and co-existing ions were examined. Experimental results revealed that the maximum removal of Cr(VI) and NBB dye was observed at pH 1 and 2, respectively and the equilibrium was achieved in ca. 180 min. The removal efficiency of Cr(VI) by fine, mixed and coarse fraction was 91.8, 74.9, 52.6%, respectively, whereas for NBB dye, the removal efficiency for the same fractions was 97.5, 33.6, 18.9%, respectively. The removal efficiency of Cr(VI) and NBB dye was influenced in the presence of competing ions. The biosorption isotherm and kinetic data were best correlated with Langmuir isotherm and pseudo-second order kinetic model, respectively. Column studies were also conducted with MPP by studying different flow rates and adsorbates concentrations to check the practical applicability of MPP in removing target metal and dye pollutants.

Combined use of coagulation (M. oleifera) and electrochemical techniques in the treatment of industrial paint wastewater for reuse and/or disposal

In this work, water-based paint (WBP) wastewater was treated using a natural coagulant, Moringa oleifera aqueous extract (MOAE), fortified with Ca²⁺ (from nitrate and chloride salts). In order to improve the quality of the treated wastewater and render it suitable for disposal, an electrolytic flow process was associated with the wastewater treatment using a filter-press reactor with a boron doped diamond (BDD) electrode. The feasibility of the treatment was evidenced by the reuse of the treated wastewater in the production of a new paint (manufactured by the company supplying the raw wastewater), whose quality was compatible with the water used by the manufacturer. The best conditions for the coagulation-flocculation process involved the use of 80 mL of MOAE (50 g/L of MO and 0.125 mol/L of Ca²⁺) for every 1.0 L of wastewater at pH 6.5. The limiting current density (35 mA/cm²) and an electrolysis time of 90 min (charge passed of 3.68 A h/L) were used in the electrochemical treatment. Biotoxicity assays using the brine shrimp Artemia salina revealed that the mortality (in %) of microcrustaceans was reduced from 100% (raw wastewater) to only 11% at the end of the electrolysis process, in addition to eliminating the strong odor and 85% of the organic load. Moreover, microbiological tests showed that the number of mesophiles decreased by more than six orders of magnitude and there was no growth of thermotolerant coliforms (TC).

Hexavalent chromium removal from aqueous solution using functionalized chitosan as a novel nano-adsorbent: modeling and optimization, kinetic, isotherm, and thermodynamic studies, and toxicity testing

Hexavalent chromium is a highly toxic metal that can enter drinking water sources. Chitosan, which contains amino and hydroxyl functional groups, is considered an appropriate candidate to remove heavy metals through absorption. In this study, a novel adsorbent, magnetic nanoparticles of chitosan modified with polyhexamethylene biguanide (Ch-PHMB NPs) was synthesized and was used to successfully remove chromium from aqueous solution. Quadratic models with independent variables including pH, adsorbent dosage, time, and the initial concentration of chromium were proposed through RSM to describe the behavior of both magnetic chitosan (M-Ch) and Ch-PHMB NPs in Cr(VI) removal. Optimized models with adjusted R² values of 0.8326 and 0.74 for M-Ch and Ch-PHMB NPs were developed. Cr(VI) removal from aqueous solution by both absorbents followed pseudo-second-order kinetics. The experimental data were best fitted to the Temkin and Freundlich models for M-Ch and Ch-PHMB NPs, respectively. M-Ch and Ch-PHMB NPs can effectively remove the hexavalent chromium from aqueous solution with pH above 7. Ch-PHMB NPs have higher removal efficiency than M-Ch, removing up to 70% of Cr(VI) from aqueous solution. However, toxicity evaluation on Daphnia magna revealed that Ch-PHMB NPs was more toxic than M-Ch nanoparticles.

The preparation of carboxylic-functional carbon-based nanofibers for the removal of cationic pollutants

A simple route is presented to fabricate carboxylic-functional carbon-coated polyacrylonitrile nanofibers (oPAN@C) through preoxidation and hydrothermal carbonization. PAN fibers were firstly preoxidized to form aromatic ladder structure with the resistance to hydrothermal condition, in which more carboxyl groups were introduced on the fiber surface at the present of chitosan and citric acid. The oPAN@C composites exhibit a high adsorption capacity towards methylene blue (MB) and lead ion (Pb²⁺). The adsorption data matched the pseudo-second-order kinetic model and Langmuir model well with the maximum adsorption capacity (153.37 and 143.27 mg g^-1) for methylene blue and Pb²⁺, respectively. Moreover, oPAN@C could be regenerated easily by hydrochloric acid, and still remained high removal efficiency after 5 cycles. Therefore, oPAN@C fibers should have potential application in sewage treatment.

Moringa Genus: A Review of Phytochemistry and Pharmacology

Moringa is a genus of medicinal plants that has been used traditionally to cure wounds and various diseases such as colds and diabetes. In addition, the genus is also consumed as a source of nutrients and widely used for purifying water. The genus consists of 13 species that have been widely cultivated throughout Asia and Africa for their multiple uses. The purpose of this review is to provide updated and categorized information on the traditional uses, phytochemistry, biological activities, and toxicological research of Moringa species in order to explore their therapeutic potential and evaluate future research opportunities. The literature reviewed for this paper was obtained from PubMed, ScienceDirect, and Google Scholar journal papers published from 1983 to March 2017. Moringa species are well-known for their antioxidant, anti-inflammatory, anticancer, and antihyperglycemic activities. Most of their biological activity is caused by their high content of flavonoids, glucosides, and glucosinolates. By documenting the traditional uses and biological activities of Moringa species, we hope to support new research on these plants, especially on those species whose biological properties have not been studied to date.

Selective removal of lead ions from aqueous solutions using 1,8-dihydroxyanthraquinone (DHAQ) functionalized graphene oxide; isotherm, kinetic and thermodynamic studies

The Fe₃O₄@DHAQ_GO nanocomposite can serve as an efficient adsorbent for the selective removal of lead from polluted water.

Challenges and opportunities for Moringa growers in southern Ethiopia and Kenya

Moringa oleifera (MO) and M. stenopetala (MS) are two commonly cultivated species of the Moringaceae family. Some households in southern Ethiopia (S. ETH) and Kenya (KEN) plant MS and MO, respectively. The edible parts of these species are rich in amino acids, vitamins and minerals, especially selenium. Despite their nutritional value, Moringa is sometimes considered as a "famine food". The aim of this study was to determine the extent of dietary utilization of these plants by Moringa Growing Households (MGHs). Moringa growing households were surveyed in 2015. Twenty-four and 56 heads of MGHs from S. ETH and KEN, respectively, were interviewed using semi-structured questionnaires. Subsistence agriculture was the main source of livelihood for all MGHs in S. ETH and 71% of those in KEN. All MGHs in S. ETH cultivated MS while those in KEN cultivated MO. Of the MGH heads in S. ETH, 71% had grown MS as long as they remember; the median cultivation period of MO in KEN was 15 years. All MGHs in S. ETH and 79% in KEN used Moringa leaves as a source of food. Forms of consumption of leaves were boiled fresh leaves, and leaf powder used in tea or mixed with other dishes. Other uses of Moringa include as medicine, fodder, shade, agroforestry, and as a source of income. Although MO and MS have multiple uses, MGHs face several challenges, including a lack of reliable information on nutritional and medicinal values, inadequate access to markets for their products, and pest and disease stresses to their plants. Research and development to address these challenges and to promote the use of these species in the fight against hidden hunger are necessary.

Smart candle soot coated membranes for on-demand immiscible oil/water mixture and emulsion switchable separation

Oil/water separation is of great importance for the treatment of oily wastewater, including immiscible light/heavy oil-water mixtures, oil-in-water or water-in-oil emulsions. Smart surfaces with responsive wettability have received extensive attention especially for controllable oil/water separation. However, traditional smart membranes with a switchable wettability between superhydrophobicity and superhydrophilicity are limited to certain responsive materials and continuous external stimuli, such as pH, electrical field or light irradiation. Herein, a candle soot coated mesh (CSM) with a larger pore size and a candle soot coated PVDF membrane (CSP) with a smaller pore size with underwater superoleophobicity and underoil superhydrophobicity were successfully fabricated, which can be used for on-demand immiscible oil/water mixtures and surfactants-stabilized oil/water emulsion separation, respectively. Without any continuous external stimulus, the wettability of our membranes could be reversibly switched between underwater superoleophobicity and underoil superhydrophobicity simply by drying and washing alternately, thus achieving effective and switchable oil/water separation with excellent separation efficiency. We believe that such smart materials will be promising candidates for use in the removal of oil pollutants in the future.