Sorbent Dosage Research Articles

Kinetics of glyphosate and aminomethylphosphonic acid sorption onto montmorillonite clays in soil and their translocation to genetically modified corn

The co-occurrence of glyphosate (GLP) and aminomethylphosphonic acid (AMPA) in contaminated water, soil, sediment and plants is a cause for concern due to potential threats to the ecosystem and human health. A major route of exposure is through contact with contaminated soil and consumption of crops containing GLP and AMPA residues. However, clay-based sorption strategies for mixtures of GLP and AMPA in soil, plants and garden produce have been very limited. In this study, in vitro soil and in vivo genetically modified corn models were used to establish the proof of concept that the inclusion of clay sorbents in contaminated soils will reduce the bioavailability of GLP and AMPA in soils and their adverse effects on plant growth. Effects of chemical concentration (1–10 mg/kg), sorbent dose (0.5%-3% in soil and 0.5%-1% in plants) and duration (up to 28 days) on sorption kinetics were studied. The time course results showed a continuous GLP degradation to AMPA. The inclusion of calcium montmorillonite (CM) and acid processed montmorillonite (APM) clays at all doses significantly and consistently reduced the bioavailability of both chemicals from soils to plant roots and leaves in a dose- and time-dependent manner without detectable dissociation. Plants treated with 0.5% and 1% APM inclusion showed the highest growth rate (p ≤ 0.05) and lowest chemical bioavailability with up to 76% reduction in roots and 57% reduction in leaves. Results indicated that montmorillonite clays could be added as soil supplements to reduce hazardous mixtures of GLP and AMPA in soils and plants.

Synthesis of TiO2 nanoparticles loaded on magnetite nanoparticles modified kaolinite clay (KC) and their efficiency for As(III) adsorption

Arsenic pollution is one of important environmental issues in the world. In this study, kaolinite clay coated with titanium oxide-magnetic iron oxide nanoparticles (KC/TiO2-Fe3O4) was synthesized as a new and effective adsorbent by simple precipitation method for influential adsorption of As(III) from the aquatic system. The factorial design method was employed for determining the significance level of the optimized batch experimental parameters. The optimum levels of the parameters in the factorial designing were validated by response surface methodology (RSM) analysis. The isotherm modelling investigations showed that the developed KC/TiO2-Fe3O4 composite had a high monolayer adsorption capacity of 462.0 mg g−1 at optimized conditions, pH 5, sorbent dose (300 mg L−1), initial As(III) concentration (10 mg L−1) and contact time (40 min). Adsorption mechanism based on kinetic evaluations well followed the pseudo-second-order model with higher regression values (>0.99). Adsorption/recovery performance at first, 3rd, 6th and 10th cycles were found to be 92/90 %, 80/77 %, 60/52 % and 20/12 %. All results revealed that the synthesized composite would be promising sorbent for As(III) adsorption from aquatic media due to its beneficial characteristics such as cost-effectiveness, stability, reusable performance and high adsorption capacity.

Methylene blue removal from aqueous solutions using a biochar/gellan gum hydrogel composite: Effect of agitation mode on sorption kinetics

Hydrogel membranes are prepared by casting a mixture of gellan gum (associated with PVA) and biochar produced from a local Egyptian plant. The mesoporous material is characterized by a specific surface area close to 134 m2 g−1, a residue of 28 % (at 800 °C), and a pHPZC close to 6.43. After grinding, the material is tested for Methylene Blue sorption at pH 10.5: sorption capacity reaches 1.70 mmol MB g−1 (synergistic effect of the precursors). The sorption isotherms are fitted by both Langmuir and Sips eqs. MB sorption increases with temperature: the sorption is endothermic (∆H°: 12.9 kJ mol−1), with positive entropy (∆S°: 125 J mol−1 K−1). Uptake kinetics are controlled by agitation speed (optimum ≈200 rpm) and resistance to intraparticle diffusion. The profiles are strongly affected by the mode of agitation: the equilibrium time (≈180 min) is reduced to 20–30 min under sonication (especially at frequency: 80 kHz). The mode of agitation controls the best fitting equation: pseudo-first order rate agitation for mechanical agitation contrary to pseudo-second order rate under sonication. The sorption of MB is poorly affected by ionic strength (loss <6 % in 45 g L−1 NaCl solution). Desorption (faster than sorption) is completely achieved using 0.7 M HCl solution. At the sixth recycling, the loss in sorption is close to 5 % (≈ decrease in desorption efficiency). The process is successfully applied for the treatment of MB-spiked industrial solution: the color index decreases by >97 % with a sorbent dose close to 1 g L−1; a higher dose is required for maximum reduction of the COD (60 % at 3 g L−1).

Equilibrium, kinetics, and thermodynamics study on the biosorption of reactive levofloxacin antibiotic on Pithophora macroalgae in aqueous solution.

Since untreated wastewater from hospitals and residential areas is being discharged directly into surface waterways, pharmaceutical contaminants have been shown to be higher in many countries. Therefore, the development of novel and effective techniques to extract antibiotic substances from wastewater is of utmost importance. The present work aims at the use of green Pithophora macroalgae to remove levofloxacin antibiotic from an aqueous solution through biosorption. Biosorption is an economical and eco-friendly method for treating wastewater. The macroalgae were dried, grounded, and used as biosorbent to remove the levofloxacin (LVX) antibiotics from the aqueous solution. The influence of operating conditions such as initial antibiotic concentration, biosorbent dosage, agitation speed, pH, and temperature was studied. The biosorbent was characterized by FTIR, SEM, and point zero charge. The experimental data were evaluated using Langmuir and Freundlich isotherms. The experimental data best fit the Freundlich isotherm model (R2 = 0.969), while the kinetic model for the experiment follows the pseudo-second-order (R2 = 0.998) with a maximum biosorption capacity of 17.8mg/g. Maximized removal of LVX occurs at favorable conditions of 298K temperature, 150mg/L initial concentration of antibiotic, 0.5g sorbent dose, and 6.5 pH. The calculated thermodynamic parameters reveal that the biosorption of LVX antibiotics occurs by an endothermic process. This study deduces that Pithophora macroalgae biomass proved to be an effective biosorbent for biosorption of LVX antibiotics and may be a novel alternative method for antibiotics removal from aqueous solutions.

Exploring the performance of magnetic methacrylic acid-functionalized β-cyclodextrin adsorbent toward selected phenolic compounds

In this study, the removal of bisphenol A (BPA), 2,4-dinitrophenol (2,4-DNP), and 2,4-dichlorophenol (2,4-DCP) using a new magnetic adsorbent methacrylic acid-functionalized β-cyclodextrin (Fe3O4@MAA-βCD) was evaluated. The materials were characterized by Fourier transform infrared spectroscopy, scanning electron microscope, transmission electron microscopy, and X-ray diffraction. The batch adsorption experiments optimized and evaluated various operational parameters such as pH, contact time, sorbent dosage, initial concentration, and temperature. The result shows that DNP possessed the most excellent affinity toward Fe3O4@MAA-βCD adsorbents compared to BPA and DCP. Also, BPA showed the lowest removal and was used as a model analyte for further study. The adsorption kinetic data revealed that the uptake of these compounds follows the pseudo-second order. Freundlich and Halsey isotherms best-fitted the adsorption equilibrium data. The desorption process was exothermic and spontaneous, and a lower temperature favored the adsorption. Furthermore, hydrogen bonding, inclusion complexion, and π–π interactions contributed to the selected phenolic compound’s adsorption.

Removal of Ammonium Ions from Aqueous Solutions Using Alkali-Activated Analcime as Sorbent

Five alkali-activated analcime (ANA) sorbents (ANA-MK 1, ANA 2, ANA 3, ANA-MK 4, and ANA-MK 5) were developed for ammonium (NH4+) ion removal. Acid treatment and calcination were used as pre-treatments for analcime, and metakaolin (MK) was used as a blending agent in three sorbents. Sorption experiments were performed to evaluate the effects of sorbent dosage (1–20 g L−1), initial NH4+ ion concentration (5–1000 g L−1), and contact time (1 min–24 h). ANA-MK 1, ANA 2, and ANA-MK 4 were the most efficient sorbents for NH4+ ion removal, with a maximum experimental sorption uptake of 29.79, 26.00, and 22.24 mg g−1, respectively. ANA 3 and ANA-MK 5 demonstrated lower sorption capacities at 7.18 and 12.65 mg g−1, respectively. The results for the sorption of NH4+ ions onto the alkali-activated analcime surfaces were modeled using several isotherms. The Langmuir, Freundlich, Sips, and Bi-Langmuir isotherms were the best isotherm models to represent the studied systems. The results of the kinetic studies showed the maximum NH4+ ion removal percentage of the sorbents was ~80%, except for ANA-MK 5, which had a ~70% removal. Moreover, the pseudo-first-order, pseudo-second-order, and Elovich models were applied to the experimental data. The results showed that the sorption process for ANA-MK 1, ANA 2, ANA 3, and ANA-MK 4 followed the Elovich model, whereas the pseudo-second-order model provided the best correlation for ANA-MK 5.

Effective and Low-Cost Adsorption Procedure for Removing Chemical Oxygen Demand from Wastewater Using Chemically Activated Carbon Derived from Rice Husk

Wastewater treatment by adsorption onto activated carbon is effective because it has a variety of benefits. In this work, activated carbon prepared from rice husk by chemical activation using zinc chloride was utilized to reduce chemical oxygen demand from wastewater. The as-prepared activated carbon was characterized by scanning electron microscope, Fourier transform infrared spectroscopy and nitrogen adsorption/desorption analysis. The optimum conditions for maximum removal were achieved by studying the impact of various factors such as solution pH, sorbent dose, shaking time and temperature in batch mode. The results displayed that the optimum sorption conditions were achieved at pH of 3.0, sorbent dose of 0.1 g L−1, shaking time of 100 min and at room temperature (25 °C). Based on the effect of temperature, the adsorption process is exothermic in nature. The results also implied that the isothermal data might be exceedingly elucidated by the Langmuir model. The maximum removal of chemical oxygen demand by the activated carbon was 45.9 mg g−1. The kinetic studies showed that the adsorption process follows a pseudo-first order model. The findings suggested that activated carbon from rice husk may be used as inexpensive substitutes for commercial activated carbon in the treatment of wastewater for the removal of chemical oxygen demand.

Green synthesis of nanostructured zinc oxide by Ocimum tenuiflorum extract: characterization, adsorption modeling, cytotoxic screening, and metal ions adsorption applications

Nano-ZnO was synthesized by the reduction of Zn (CH3COO)2.2H2O salt using the extract of Ocimum tenuiflorum leaves. The generated ZnO NPs were characterized by FT-IR, XRD, SEM, and EDX techniques. FT-IR results approved the characteristic peaks, the formation of ZnO bonds, and the morphology changes after the adsorption of Cd2+ and Pb2+ from solutions. The outlined data of the XRD pointed to the formation of a hexagonal wurtzite structure. SEM images showed the spherical nature of the synthesized particles with an average diameter of 19 nm. Moreover, the best conditions for the adsorption of Cd2+ and Pb2+ by ZnO NPs were evaluated and fitted to isotherm and kinetic models. Short contact time of ~ 20 min and a small sorbent dosage of 40 mg were sufficient conditions for attaining maximum Pb2+ adsorption capacity. Based on the modeling parameters, the adsorption follows pseudo-second-order kinetics where ZnO and metal ions are involved in the rate-determining step. Two important applications were thoroughly studied. The nanoparticles significantly removed Pb2+ and Cd2+ contaminants from real environmental water samples collected from different locations in Egypt. Additionally, the cytotoxic activity results provided perfect evidence for the higher efficacy of the synthesized ZnO NPs as an anticancer agent against Panc-1, PC-3, and CACO-2 cell lines with IC50 of 1.70, 3.67, and 5.70 μgml−1, respectively, compared to cisplatin (IC50 = 3.57, 5.09, and 7.75 μgml−1). Furthermore, a low cytotoxic effect was observed on the normal human lung cell line (MRC-5, IC50 = 22.40 μgml−1). The data can be used as a preliminary study for anticancer drug design after further clinical investigations.Graphical

Design of [BmIm]3PW12O40 Ionic Liquid Encapsulated-ZIF-8 Nanocomposite for Cationic Dye Adsorptive Removal: Modeling by Response Surface Methodology

In this study, the modification of metal–organic frameworks with polyoxometalate-based ionic liquids was assessed and their efficient role in the improvement of their adsorption performance was studied. Metal–organic framework ZIF-8 was encapsulated with [BmIm]3PW12O40, a polyoxometalate-based ionic liquid, through reaction with the ZIF-8 imidazolate groups. The novel ZIF-8-[BmIm]3PW12O40 nanocomposite was characterized using XRD, FTIR, SEM, EDX, and BET analyses, which confirmed the successful insertion of [BmIm]3PW12O40 on the surface of the ZIF-8 structure. It was used to study the adsorptive removal of a methylene blue (MB) cationic dye model and showed high adsorption performance between pH 2 and 11 with an optimum sorbent dosage of 4 g/L. The adsorption kinetics corresponded well to the pseudo-second-order kinetic model. Moreover, response surface methodology was used to optimize experimental conditions and determine the highest MB removal percentage. The correlation between variables (time, pH, and sorbent dosage) and responses (removal percentage) were well fitted to the second-order polynomial model (R2 = 0.949, Adj. R2 = 0.9032, and pred. R2 = 0.6129). The optimal conditions were found to be adsorbent amount = 0.04 g/L, pH = 11, and contact time = 45 min. Under these conditions, the highest removal percentage and amount of desirability were found to be 95.75% and 0.9, respectively.

Study of the biosorption of phenol by the cell walls of brewing yeast

Sorption capabilities of cell walls of yeast Saccharomyces cerevisiae with respect to phenol have been investigated. Elemental analysis established the composition of yeast cell walls: 47.8–48.6% C; 5.7-6.1% N and 6.86% H. The surface of the sorbent determined by BET, was 118.6 m2/g, ash content – 18-22%. Using FTIR-spectroscopy, it is shown that the prevailing mechanism of phenol adsorption is physical sorption, and not complexation. The adsorption abilities of yeast cell walls with respect to phenol were studied relative to pH, initial phenol concentration, sorbent dose and activation time. It is shown that the sorption efficiency increases in protonated solutions with pH&lt;3. Experimental data were analyzed using Freundlich and Langmuir models. The model of the adsorption isotherm is more precisely described by the Langmuir equation with R2 0.9987. The calculated maximum capacity is 18.9 mg of phenol per 1 g of dry sorbent. The study showed that the cell walls of the yeast Saccharomyces cerevisiae can be used as a new adsorption material for eliminating phenol from aqueous solutions.

Effect of Direct yellow 50 removal from an aqueous solution using nano bentonite; adsorption isotherm, kinetic analysis and also thermodynamic behavior

The developing countries are suffering from the toxicity of different industrial effluents, especially dyes that contaminate water systems. This study successfully explained the preparation and characterization of nano bentonite to extract Direct Yellow Fifty (DY50). Direct Yellow 50 is an organic contaminant that may affect the quality of water. The characterization of prepared nanoparticles was done using Scanning electron microscopy (SEM), X-ray diffraction (XRD), and Fourier-transform infrared (FTIR). The impact of different operating conditions was studied using different pH, dose, temperature, contact time, and initial DY50 concentrations. The obtained results indicated that nano bentonite could adsorb about 94 % at initial concentrations of 40 mg/L, respectively. The optimum removal conditions were observed at an acidic pH (pH 3) using a sorbent material dosage of 0.05 g for 4 h at 30 °C. The adsorption isotherm, kinetic analysis, and thermodynamic behavior were studied using linear equation form, and the adjusted R2 was compared to detect the preferred models. The adsorption behavior pseudo-second order kinetics, and fitted Langmuir isotherm model, respectively, showed the chemisorption interactions between adsorbed and sorbed molecules. Thermodynamic behavior indicated that the reaction was exothermic. Finally, this study strongly recommended using nano bentonite for DY50 removal from an aqueous solution.

Bio-fabrication of porous magnetic Chitosan/Fe3O4 nanocomposite using Azolla pinnata for removal of chromium – Parametric effects, surface characterization and kinetics

In this research, a novel porous nanocomposite, namely Chitosan-iron-oxide @ Azolla pinnata nanocomposite, has been synthesized by co-precipitation and hydrothermal method. The effect of process parameter on adsorption process was investigated. Batch removal of chromium (Cr) was optimized with respect to solution pH, batch stirring time, sorbent dose, initial chromium concentration and temperature. The maximum removal efficiency was found to be 98.58%. The Fourier transform infrared (FTIR) spectroscopy and scanning electron microscope (SEM) analysis of the nano composite confirmed the presence of characteristic functional groups and porous structure of synthesized nanocomposite. The adsorption data fitted well with Langmuir adsorption isotherm (R2 = 0.996) confirming mono layer sorption and the maximum uptake was found to be 294.12 mg/g. The adsorption was found to follow pseudo second order model (R2 = 0.997). Thermodynamic studies revealed that adsorption is endothermic and spontaneous. Reusability studies have confirmed that removal efficiency attained was 85% after completion of five adsorption-desorption cycles. Electrostatic attraction, ion exchange, coordination bonding and reduction are the major mechanisms responsible for removal of chromium. Surface modification of Azolla pinnata with chitosan and iron oxide improved the ability of Azolla in the adsorption of chromium from aqueous media. The combined effects of facile synthesis, improved adsorption features and easier magnetic separation promotes Chitosan-iron-oxide @ Azolla pinnata nanocomposite as a novel adsorbent.

Synthesis of novel carbon-supported iron oxide sorbents for adsorption of dye from aqueous solutions: equilibrium and flow-through studies

Textile effluents contain dyes that negatively affect water bodies and inhibit photosynthesis by reducing sunlight penetration. This study investigated the adsorption capacity of an iron oxide sorbent immobilised on naturally derived carbon foam for the removal of organic methylene blue dye from water. In this study, the carbon precursor and iron oxide precursor were mixed and carbonised in a single vessel. Baking and carbonization of the natural grain combination produce a porous structure that can act as an effective support for the iron oxide particles. The carbon foam prepared had a self-assembled structure with flour as a basic element. Sorbents of 6 weight (wt)%, 15 wt% iron, and a 0 wt% iron control sample were prepared. Transmission electron microscopy (TEM) and Brunauer–Emmett–Teller (BET) techniques were used to examine the synthesised carbon foam physical properties and surface morphology. The adsorption capabilities were investigated in batch tests by determining the effects of an increase in iron content, sorbent dosage, contact time, and dye concentration. Breakthrough curves were obtained by varying the height of the sorbent bed and varying the flowrate of the dye solution. A higher bed height corresponds to a greater amount of adsorbent. The breakthrough and equilibrium adsorption capacities were found to increase with increasing bed height. When the flow rate is high, the dye solution leaves the column before equilibrium, resulting in shorter breakthrough and saturation times. Higher bed heights and lower flow rates resulted in optimal dye removal in the flow through the system. Breakthrough time increases with increasing iron content. The 15 wt% iron sample displayed superior adsorption capabilities than the 6 wt% sample, while the 0 wt% iron control sample displayed minimal adsorptive capabilities. The pseudo-first order kinetic model was the best fit model for this study (R2 > 0.96), and the adsorption equilibrium is best described by the Freundlich isotherm (R2 > 0.99). The results showed that an iron oxide sorbent immobilised on carbon foam made from natural sources is a good adsorbent for removing methylene dye.

Assessment of Cyprinus carpio Scales as a Low-Cost and Effective Biosorbent for the Removal of Heavy Metals from the Acidic Mine Drainage Generated at Rosia Montana Gold Mine (Romania)

In the present study, the biosorptive potential of Cyprinus carpio scales for the removal of Fe, Mn, and Zn ions from real acidic mine drainage (AMD) generated at the Rosia Montana gold mine (Romania) was explored for the first time. The collected AMD solution is very acidic, and the concentrations of Fe, Mn, and Zn ions exceed more than 34 to 56 times the disposal standards imposed by legislation. Batch adsorption experiments were carried out to study the effect of the sorbent dosage, sorbent particle size, pH, and contact time on the adsorption performance of the fish scales. Before and after the adsorption process, the biosorbent was characterized by Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy, and energy-dispersive X-ray spectroscopy (SEM-EDX). In the investigated experimental conditions, about 100%, 87.1%, and 100% of Fe, Mn, and Zn ions were removed from the AMD after 240 min of contact with the finest-grained Cyprinus carpio scale samples using a solid:liquid ratio of 20:1 (g:L). The adsorption data were analyzed using the pseudo-first order, pseudo-second order, intraparticle diffusion rate, and Elovich equations. The adsorption process was found to follow the pseudo-second-order kinetic model. The maximum adsorption capacities of the fish scales were about 2.46 mg/g for Mn and 0.85 mg/g for Zn ions, respectively. Aside from their significant efficiency in the removal of metals from AMD, Cyprinus carpio scales also have the potential to neutralize the acidic wastewater. Thus, the removal process of metal ions from AMD is ruled by a complex mechanism, including adsorption and iron precipitation. The recycled scales are still able to remove the metal ions from AMD with a better performance during the first regeneration cycle. Based on the obtained results, it might be assessed that the low-cost biowaste of Cyprinus carpio scales have great potential and could be effectively used for the remediation of real acidic mine drainage from a sustainable perspective.

Phosphorylated hyper-crosslinked calix[4]arene for selective uranyl extraction from seawater

Seawater contains abundant uranium, which could provide a long–term supply for developing the nuclear power industry. Developing an efficient uranium–selective adsorbent is therefore an urgent requirement. In this work, we used a simple Friedel–Crafts alkylation reaction and a subsequent phosphorylation reaction to prepare porous phosphorylated hyper-crosslinked calix[4]arene (C4HP) for potential use in the recovery of uranium from seawater. The effect of the initial pH, adsorbent composition, sorbent dose and contact time on the sorption of uranyl ions was investigated. Because of the introduction of the phosphate groups, C4HP shows an excellent adsorption capacity of 336.4 mg·g−1 for uranium, which is much higher than that of hyper-crosslinked calix[4]arene (C4H) without phosphorylation. Meanwhile, C4HP functioned as a promising adsorbent for uranyl extraction with fast capture kinetics (the adsorption equilibrium can be reached in 150 min). After 6 cycles, C4HP maintained its original adsorption capacity of 76.2 % (255.4 mg·g−1). Furthermore, C4HP possesses excellent adsorption selectivity for uranium in artificial seawater, with a KdU of ~4.1 × 104 mL·g−1, much higher than that of other metals. This makes it useful for broad applications and capturing uranium from natural seawater. The effective extraction of uranyl was primarily attributed to the chelation of uranyl ions with phosphate groups.

Preparation of highly efficient and eco-friendly alumina magnetic hybrid nanosorbent from red mud: Excellent adsorption capacity towards nitrate

The effectiveness of using red mud as the aluminum industry waste to fabricat a novel alumina magnetic hybrid (AMH) nanosorbent, which can remove nitrate from contaminated water was evaluated in current study. The characterization of the prepared nanosorbent were addresed by X-ray diffraction (XRD), X-ray fluorescence (XRF), surface area, transmission electron microscopy (TEM), and field emission scanning electron microscopy (FESEM) analysis. The results indicated the crystallite size of the Fe3O4 and γ -Al2O3 of about 18.7 and 19.6 nm, respectively, amount of Fe3O4 and γ -Al2O3 about 48.1 % and 51.2 % in the structure of nanosorbent, the surface area aroun 125.9 m2/g, and nanoparticles with approximately uniform size less than 25 nm along with a slight agglomeration. Studies on adsorption were performed using various contact time and initial nitrate concentrations, different pH and sorbent dosages. Maximum adsorption capacity was obtained at about 69 mg/g using 1 g/L sorbent dispersed in 100 ppm nitrate solution with a pH of 6 after 80 min. The adsorption data was appropriately fitted with Freundlich isotherm model, indicating multilayer adsorption. Regeneration experiments demonstrated that the nanosorbent could perform effective nitrate adsorption even after four regeneration cycles. The significance of this work is in the development of waste-driven, eco-friendly, and cost-effective creation of an AMH nanoadsorbent that effectively removes nitrate from contaminated water, which also has the advantage of rapid separation due to its magnetic properties.

Adsorptive removal of crystal violet from wastewater using sodium alginate-gelatin-montmorillonite ternary composite microbeads

In this study, the performance of the montmorillonite-filled sodium alginate/gelatin (SA-GEL-MMT) ternary biocomposite microbeads on the adsorptive removal of crystal violet (CV) dye was investigated. Firstly, the composites containing different weight ratios of MMT such as 10 %, 15 %, and 20 % were prepared. The composite beads were cross-linked using a calcium chloride (3%wt/v) solution. To determine the optimum sorption conditions the studies were performed at different parameters namely temperature, pH, contact time, sorbent dose, and dye concentration. From the sorption studies, the maximum capacity of the microbeads was found as 1000.0 mg/g whereas the maximum removal of the dye was 92.1 % at pH = 7 and a temperature of 25 °C. Additionally, the kinetic studies showed that the sorption of the dye followed the pseudo-second-order kinetics. Moreover, the adsorptive removal of the dye occurs spontaneously. This study suggests that the use of SA-GEL-MMT can be highly effective and reusable for the treatment of wastewater.

Determination of pyrethroids in water samples by dispersive solid-phase extraction coupled with high-performance liquid chromatography.

A metal-organic framework UiO-66 was prepared and used as a sorbent for dispersive solid-phase extraction combined with high-performance liquid chromatography (DSPE-HPLC) for extracting and determining four pyrethroids in water samples for the first time. The as-synthesized material was confirmed by Fourier transform infrared spectroscopy (FT-IR), transmission electron microscopy (TEM), scanning electron microscopy (SEM), X-ray diffraction (XRD), thermogravimetric analysis (TGA), and N2 adsorption-desorption analysis. In addition, several important parameters affecting DSPE efficiency, including sorbent dosage, extraction time, salt concentration, pH, elution solvent, elution volume, and elution time, were optimized. Under the optimum conditions, the UiO-66 based on the DSPE-HPLC method displayed a wide linear range (10-1000 ng/ml), low limits of detection (2.8-3.5 ng/ml), and good precision (relative standard deviations [RSDs] < 3%) for the four pyrethroids. The recoveries at different spiked levels ranged from 89.3% to 107.7%. In addition, UiO-66 featured good reusability and reproducibility. The results demonstrated that π-π stacking interactions, hydrophobic interactions, and van der Waals forces between UiO-66 and the four pyrethroids played a crucial role in the adsorption process. Meanwhile, the maximum extraction capability could be obtained within 5 min. Thus, the DSPE coupled with the UiO-66 sorbent can be successfully used in the analysis of four pyrethroids in environmental water samples. PRACTITIONER POINTS: Simultaneous determination of four pyrethroids using the developed UiO-66-based DSPE-HPLC method in water samples. The developed method had a short enrichment time, broad linear ranges, a low detection limit, and high enrichment factor. It is showed that π-π stacking interaction, hydrophobic interaction, and van der Waals forces were the main mechanism.

Combination of Moringa Oleifera Seed Powder and Iron Sulfate Heptahydrate Salt as Biopolymer Based Matrix for Application as Adsorbent for Odor Inhibition in Poultry Farms

A biopolymer based matrix of M. Oleifera Seed Powder (MOSP) and Ferrous Sulphate Heptahydrate (FSH) salt was formulated as adsorbent for odor inhibition in poultry farms. The matrix was characterized using FT-IR technique and its performance as adsorbent for NH4+ removal from aqueous solutions was examined via sorption studies. The result showed an excellent sorption performance at 0.1 g sorbent dosage, pH of 9 and 30 min agitation time. This indicates that the matrix possess an excellent ion exchange property and thus a suitable sorbent for NH4+ even in low concentration environment. The study reveals the capacity of the adsorptive matrix as a safe and cost-effective method to be used for ammoniacal odor control from poultry farms which may be applicable to other animal farm operations (AFOs).

A novel floating compound based on a plastic sphere coated with tin titanate for the removal of the herbicide fomesafen

A tin titanate (SnTiO3) composite was synthesized by hydrothermal method (TSn) then impregnated with RhB dye (TSn@RhB powders). This composite was coated on a spheric plastic support from short life daily products with floatable capability (TSn@RhB/PP). The novel composite and synthesized powder were characterized by SEM, XRD and XPS. The SEM images revealed that the powders had an average particle size of 50 nm. Phases related to rutile and SnO2 present in other tin titanates were shown by the XRD analysis. The powders and composite were evaluated in the removal of the fomesafen molecule, which is an herbicide widely used in a variety of crops, by changing the initial pollutant concentration, sorbent dosage and initial pH. The best removal percentages (92 and over 80%) were achieved by slurry and floatable composite systems, respectively, with initial concentration of 10 mg/L of this pesticide. Similarly, experiments with different initial pH and initial dosage of this contaminant (20 ppm) were conducted. Maximal adsorption percentages of 82 and 81% were reached with neutral and acid solutions, respectively. The TOC analysis demonstrated that solutions with higher initial concentration of this herbicide (20 ppm instead of 10 ppm) favored the removal process. The XPS and FTIR analysis revealed that the pollutant could be removed by the effect of electrostatic and electronic attraction between fomesafen and the TSn@RhB composite. The use of practical coating materials and this novel floatable composite as adsorbent material is a promising alternative in the remediation of contaminated agricultural water and other environmental applications.