Pseudo 2nd Order Research Articles

Adsorptive Removal of Famotidine Drug from Aqueous Medium by Ocimum Basilicum

AbstractThe present study investigated the potential of basil seeds as adsorbent in order to remove famotidine drug from aqueous media. The optimum conditions for the adsorption of famotidine on the basil seeds were found to be 50 min contact time, 50 °C temperature, pH 1, 100 ppm concentration of famotidine, 0.03 g adsorbent mass and 50 rpm agitation rate. Pseudo 2nd order kinetics with a higher correlation coefficient (R2=0.9942) suggested chemisorption as preferable mechanism of adsorption. However, the enthalpy of adsorption (ΔH=+33.67 KJ/mol) was less than that of chemisorption but higher than that of physisorption which was attributed to strong hydrogen bonding between famotidine molecules and basil seed surface. The Langmuir isotherm with higher R2 (0.9960) than Freundlich isotherm (R2=0.8798) predicted maximum adsorption capacity (qm) of 99 mg/g while suggesting monolayer and favourable adsorption. The adsorption was endothermic (+ΔH) and spontaneous (−ΔG) in nature. The FT‐IR spectroscopy confirmed that famotidine was adsorbed on basil seed via strong hydrogen bonding. The study proposed that the simultaneous intake of famotidine and basil seeds should be strictly avoided as the drug readily adsorbs on basil seeds in acidic environment (gastric pH) thereby reducing its curing effect.

A sustainable peroxide assisted dissolution of uranium oxides in ionic liquids and electrochemical Recovery: A feasibility study

The present manuscript demonstrated the dissolution of oxides of uranium, mainly UO2, via surface oxidation by H2O2 into ionic liquid at ambient temperature within 4 h of equilibration. The dissolution was found to be endothermic (ΔH ∼ 30.8 kJ mol-1 and 3.20 kJ mol-1) predominantly following the pseudo 2nd order rate kinetics (k ∼ 0.004 g−1 min and 0.0009 g−1 min) with activation energies of 54.12 J mol-1 and 26.69 J mol-1, for H2O2 and RCO3H, respectively. The extent of dissolution for different oxides of uranium followed the trend UO3 > UO2 > U3O8. Within 8 h of equilibration, quantitative dissolution of 50 mg mL−1 of UO2 can be achieved with optimized experimental conditions of 0.4 M HD2EHP as the complexing agent and 10 µL H2O2 as the oxidizing agent. The oxidative dissolution followed the trend C8mim.NTf2 > C8mim.PF6. In C8mim.NTf2, the most probable species was UO2(HDEHP)2+ associated to Σg+→Γg transition involving the σu+ϕu configuration with a D3d (D3) symmetry; while for C8mim.PF6 the predominate species was UO2F2(HDEHP)- with a D3h symmetry. Four hours of electro-deposition resulted a black solid deposit on the Cu electrode resulting the change in surface morphology and enhancement in the surface roughness as analyzed by the SEM images. The EDXRF analysis revealed the presence of the uranium peak; whereas the XRD pattern showed the fluorite structure revealing the deposit of UO2 phase upon electro-deposition latter confirmed by FTIR.

Process modeling of direct Red-28 dye eradication by biopolymeric composite of polyaniline with mango leafy biowaste material

The use of biopolymers and synthetic adsorbents for wastewater treatment is gaining more importance due to their ease of preparation and nontoxic nature. This study focuses on developing a new biopolymeric composite using Polyaniline and a leafy mulch of mango plants (PANI/ML) and applied to remove an anionic dye, i.e.: Direct Red-28 from water on a lab scale. Samples were characterized by various spectrochemical methods, like FT-IR, UV–Vis, and SEM analysis, and then used for adsorption studies. Results indicated that PANI/ML nanomaterial removed 203.25 ± 0.57 mg/g of Direct Red-28 dye, following chemisorption and pseudo-2nd order kinetic model with inter-layer diffusion mode. Desorption studies indicated that it can be recycled three times effectively. So, this composite can be used for adsorptive bioremediation of synthetic anionic pollutants.

PREPARATION AND CHARACTERIZATION OF NEW IMINE- FUNCTIONAL GROUP FOR FAST REMOVAL OF Cr (III) IN SOME SUPPLEMENTS FROM SHRIMP SHELL

A new imine-Schiff base adsorbent is prepared from extracted chitosan to make taking away exoskeletons of crustacean shrimp shells low-cost and environmentally friendly with the fast and high ability to remove Cr (III) from aqueous solution. The resulting composites were verified by different techniques FTIR, H-NMR, FESEM, EDX, XRD. On applying the adsorption kinetic model, the pseudo 2nd order model was best characterised, using adsorption equilibrium data; the Langmuir model provided a superior description. Further, the negative value of ∆G shows a spontaneous process in nature. Finally, the prepared adsorbent has been applied to a real sample of bodybuilder supplements.

Effective Co2+ removal from aqueous solution and industrial wastewater using ZIF-7 and MnFe2O4-modified walnut shell biochar composite

In this study, we developed a novel magnetic composite of walnut shell biochar (WSB) and modified it with ZIF-7 for the purpose of removing Co2+ ions. We conducted a comprehensive evaluation of its performance in Co2+ removal, considering various factors such as contact time, temperature, adsorbent dose, pH, and initial Co2+ concentration. Utilizing response surface methodology-central composite design (RSM-CCD), we examined the interactions between these variables. The specific surface area and magnetic saturation value of the WSB/MnFe2O4/ZIF-7 composite were determined as 170.560 m2.g−1 and 23.469 emu.g−1, respectively. ANOVA analysis indicated that our model effectively captures the interactions between variables, with a high R2 value of 0.9982, explaining 99.82 % of the experimental data. Optimal conditions for maximum Co2+ adsorption efficiency (99.05 %) were identified as follows: a contact time of 44.82 min, pH of 6.04, adsorbent dose of 0.947 mg.L-1, temperature of 25.55 °C, and Co2+ concentration of 11.13 mg.g−1. Kinetic studies revealed that the Pseudo 2nd order kinetic model provided the best fit to the experimental data. The negative entropy parameter indicated a decrease in disorderliness during the adsorption process, while the exothermic nature of adsorption was confirmed by enthalpy values of −92.751 and −40.511 kJ.mol−1 for WSB/MnFe2O4/ZIF-7 and WSB, respectively. Furthermore, the Langmuir isotherm model demonstrated excellent fitting to the isotherm results, suggesting the dominance of homogeneous surfaces in adsorption. The maximum adsorption capacities for Co2+ using WSB/MnFe2O4/ZIF-7 and WSB were determined to be 29.26 and 22.39 mg.g−1, respectively. The WSB/MnFe2O4/ZIF-7 magnetic composite demonstrates promising potential for efficiently removing Co2+ from both natural water sources and industrial wastewater, highlighting its versatility and effectiveness in environmental remediation applications.

Carbohydrate polymers based MnO2 nanostructures for catalytic and antibacterial activity; kinetic modeling and molecular docking analysis

In this project, cellulose nanocrystal-CNC, chitosan-CS, and starch-St doped MnO2 nanostructures (NSs) were synthesized by a co-precipitation approach. The motive of this research was to evaluate the effect of CNC, CS, and St on catalytic activity, kinetic adsorption, and antimicrobial potency with molecular docking (MD) analysis of MnO2. The hydrophilic head of polymers interacts with MnO2 NSs to regulate the growth, recombination rate, and stability of nanostructures. Notably, St-doped MnO2 exhibited the highest catalytic potency in an acidic medium in comparison to basic and neutral media. The kinetic modeling (pseudo-1st, pseudo-2nd order, Elovich, and intra-particle diffusion model) suggests that the adsorption of RhB dye by the NSs follows the pseudo-second-order kinetics. Among all samples, CNC-MnO2 and St-MnO2 proved to be an efficient antibacterial agents against E. coli and s. aureus bacteria, respectively. Findings revealed that polymer-based MnO2 nanostructures were the most efficient inhibitors of DNA gyrase against E. coli and S. aureus.

Enhanced fluoride removal using montmorillonite clay modified with CoFe2O4 and metal-organic frameworks

The use of modified clays can play an effective role as an effective adsorbent in removing fluoride (Flu) ions from water and aqueous solutions. In the present research, montmorillonite clay (MMt) was modified using CoFe2O4 magnetic particles and Al–Fe fumarate metal-organic framework (Al–Fe Fum) and was utilized as an efficient adsorbent for removing Flu from aqueous solution. The properties of MMt and MMt/CoFe2O4/Al–Fe Fum samples were investigated using different techniques. The results showed that with the modification of MMt using CoFe2O4 magnetic particles and the metal-organic framework of Al–Fe Fum, the BET surface has increased notably from 13.217 to 365.80 m2/g. To investigate the effect of independent variables and their interaction on the efficiency of the Flu adsorption, response surface method-central compound design (RSM-CCD) was served. Based on the results of ANOVA, the F-value and p-value parameters for the desired model were determined to be 783.09 and < 0.0001, respectively, which confirms the success and high ability of the model. The number of R2, adjusted R2, and Predicted R2 for adsorption of Flu ion was determined to be 0.998, 0.997, and 0.995, respectively, which shows that the proposed regression model can describe the process of adsorption and interaction between variables well. Compared to other kinetic models, the pseudo 2nd order kinetic model has a greater ability to describe the Flu adsorption behavior. The R2 parameter value determined that the Freundlich isotherm model has a suitable ability to investigate the isotherm behavior and confirms the effect of heterogeneous surfaces in the process. Generally, the outcomes signified that the MMt and MMt/CoFe2O4/Al–Fe Fum samples can be reused several times in the process of Flu adsorption, while the efficiency is more than 90%.

Biosorption of Cd&lt;sup&gt;2+&lt;/sup&gt; Ni&lt;sup&gt;2+&lt;/sup&gt; and Zn&lt;sup&gt;2+&lt;/sup&gt; from Contaminated Well Water by Garlic Peel

The application of garlic peel was investigated as a low-cost biosorbent for Cd2+, Ni2+, Zn2+, and Pb2+ from aqueous solutions in a continuous system. Experiments were carried out in a fixed bed column, and the influence of different flow rates (from 2.0 to 3.3 ml min-1) on the breakthrough was studied. Column data obtained at different conditions were described using the Bohart-Adams, Thomas, and Yan models. The maximum amount of absorption was obtained for a lead ion with the amount of 490.68 mg g-1. The column removed 472.78 and 135.17 mg g-1 of cadmium and nickel ions, respectively, and the minimum value was obtained for zinc ions (55.08 mg g-1). The garlic peel was regenerated and reused two to four times in successive biosorption-desorption cycles. Differential pulse voltammetry (DPV) was used to measure kinetic models for the biosorption of lead and cadmium ions on garlic peels. Using DPV for lead and cadmium ions, the amount of adsorbed material was obtained at 2.58 and 2.23 mg g-1 using the pseudo 1st order equation and this value was obtained at 8.26 and 4.70 mg g-1 using the pseudo 2nd order equation for lead and cadmium ions, respectively. The results show that garlic peel absorbs lead and cadmium ions more than zinc and nickel ions. Because it is made up of several sulfur compounds, sulfur as a soft atom has a stronger interaction with lead and cadmium than other ions.

Zinc oxide nanoparticles encapsulated in alginate beads: a promising and recyclable adsorbent for simultaneous uptake of toxic metals

Heavy metal toxicity is a known problem and various methods are used for treatment. Adsorption has some advantages and it would be promising if environmentally friendly and cheap materials were utilized. Alginate and zinc oxide nanoparticles were selected and composite alginate beads were used for the removal of mixed metals from aqueous solutions. Batch and column experiments were conducted to determine some parameters’ effects and the adsorbent’s real application potential. According to the batch experiments, zinc oxide nanoparticles to alginate ratio of 0.5 g g−1, and pH levels nearby to the neutral range led to better metal removals. 0.5 ml min−1 of flow rate supplied better metal removal efficiencies in columns, with the highest treatment as 86% of Pb2+. Acid treatment can be successfully applied for the regeneration of the adsorbent, at least three times only with a 4% reduction in the adsorption efficiency. Heavy metal uptake was compatible with the pseudo 2nd order model indicating chemisorption as a dominant mechanism. Also, the intraparticle diffusion model illustrated adsorption might govern more than one step. The Langmuir model had the best fit and suggested monolayer covering for Pb2+, 76.3 mg g−1. Alginate-based nanocomposite beads were useful for mixed metal removal and could be used.

Management of caffeine in wastewater using MOF and perovskite materials: optimization, kinetics, and adsorption isotherm modelling

Pharmaceuticals and personal care products (PPCPs) have been increasingly used all over the world and they have been reported on water cycle and cause contamination. Among these pharmaceuticals is caffeine (CAF). In this work, CAF removal from aqueous samples by metal–organic framework (UIO-66) and perovskite (La0.7Sr0.3FeO3) was achieved. Detailed studies on the preparation of MOFs and perovskite oxides compounds have been presented. Extensive characterizations such as X-Ray diffraction (XRD), field emission scanning electron microscope (FESEM), Fourier transform infrared spectra (FT-IR), N2 adsorption–desorption isotherms were also carried out to assure proper formation and to better understand the physico-chemical behavior of the synthesized samples before and after adsorption. Batch experiments of CAF adsorption onto both MOFs and perovskite were performed to compare the effectiveness of both materials on the removal competence of the CAF residue at different conditions including the effect of pH, initial concentration, and contact time. It was observed that the adsorption capacity of CAF by MOF increased with increasing acidity. On the other hand, the adsorption capacity of perovskite is stable in pH 4–10. The maximum adsorption capacities of UiO-66 and perovskite toward CAF are high as 62.5 mg g−1 and 35.25 mg g−1, respectively. Equilibrium isotherms were investigated by numerous models: Langmuir, Freundlich, Temkin, Redlich-Peterson, Sips, Langmuir-Freundlich, Toth, Kahn, Baudu, and Fritz Schlunder. Moreover, the kinetics of the CAF@MOF and CAF@Perovskite systems have been studied by five kinetic models (Pseudo-1st -order (PFO), Pseudo-2nd -order (PSO), Mixed 1st, 2nd-order, Intraparticle diffusion and Avrami). The best model described the adsorption of CAF onto both of MOF and perovskite was the mixed 1st, 2nd-order model. The metal–organic framework and perovskite were applied to quickly extract CAF from water samples successfully. The maximum removal percentage obtained for MOF and perovskite was 0.89% and 0.94% respectively within 30 min contact time which suggests that these materials are considered as promising adsorbents for CAF.

Composite electrospun membranes based on PET-PAN modified with LDH-hybrid as promising adsorbent for pollutants removal from wastewater

&lt;p&gt;The current work reveals the fabrication of a novel nanofiber composite membrane of PET-PAN modified with Mg-Al-LDH-PVA through electrospinning process. The nanocomposite membranes characterization was conducted with different techniques i.e. SEM, EDS, FTIR, XRD, and water contact angle to evaluate the structure and surface morphology. The optimized nanomembrane was utilized as a useful adsorbent for removal of toxic anionic dye Eriochrome Black T (EBT) and cationic dye Methylene blue (MB) from wastewater. Experimental results identified that PPLP3 membrane has a potential for the removal of EBT (83%) and MB (52%) at pH 3 and 7, respectively, from aqueous solution. The optimum adsorption capacity of PPLP3 nanocomposite membrane was identified and calculated as 7.3 mg.g-1 followed by the pseudo 2nd order kinetics and Langmuir adsorption isotherm fit well with R2 values of 0.964 and 0.997, respectively. The synthesized nanocomposite membrane could be utilized for effective adsorption of contaminations from different wastewaters.&lt;/p&gt;

Silica@poly(chitosan-N-isopropylacrylamide-methacrylic acid) microgels: Extraction of palladium (II) ions and in situ formation of palladium nanoparticles for pollutant reduction

Most of the transition metal ions and organic dyes are toxic in nature. Therefore, their removal from water is imperative for human health. For this purpose, various types of systems have been developed to tackle either transition metal ions or organic dyes individually. A core-shell microgel system is introduced which is capable of effectively removing both types (toxic organic dyes and transition metal ions) of pollutants. A long-rod-shaped silica@poly(chitosan-N-isopropylacrylamide-methacrylic acid) S@P(CS-NIPAM-MAA) S@P(CNM) core-shell microgel system was developed by free radical precipitation polymerization method (FRPPM). S@P(CNM) was utilized as an adsorbent for extracting palladium (II) (Pd (II)) ions from water under different concentrations of S@P(CNM), several agitation times, palladium (II) ion content, and pH levels. The adsorption data of Pd (II) ions on S@P(CNM) was evaluated by various adsorption isotherms. The kinetic study was investigated by employing pseudo-2nd order (Ps2O), Elovich model (ElM), intra-particle diffusion (IPDM), and pseudo-1st order (Ps1O). Additionally, palladium nanoparticles (Pd NPs) were generated via in-situ reduction of adsorbed Pd (II) ions within the P(CNM) shell region of S@P(CNM). The resulting Pd NPs loaded S@P(CNM) exhibited the capability to reduce organic pollutants like methyl orange (MeO), 4-nitrophenol (4NiP), methylene blue (MeB), and Rhodamine B (RhB) from aqueous medium. 0.766 min−1, 0.433 min−1, 0.682 min−1, and 1.140 min−1 were the values of pseudo 1st order rate constant (kobs) for catalytic reduction of MeB, 4NiP, MeO, and RhB respectively. The S@Pd-P(CNM) system exhibits significant catalytic potential for various organic transformations.

On-Line pH Measurement Cation Exchange Kinetics of Y3+-Exchanged Alginic Acid for Y2O3 Nanoparticles Synthesis.

A new sol-gel method that employs cation exchange from an aqueous metal ion solution with H+ ions of granulated alginic acid was developed for synthesizing high-purity Y2O3 nanoparticles. In this study, the cation exchange kinetics of H+~Y3+ in aqueous solution were analyzed using on-line pH technology and off-line inductively coupled plasma-atomic emission spectrometry (ICP-AES) analysis. Pseudo 2nd-order models were utilized to evaluate the parameters of the kinetics, suggesting that the concentration of H+~Y3+ involved in the cation exchange reaction was 1:1.733. Further, a comprehensive understanding of the Y-ALG calcination process was developed using thermo-gravimetric analysis, along with results obtained from differential scanning calorimetry (TGA/DSC). A detailed analysis of the XRD Rietveld refinement plots revealed that the crystallite sizes of Y2O3 nanoparticles were about 4 nm (500 °C) and 15 nm (800 °C), respectively. Differential pulse voltammetry (DPV) was employed to investigate the electrochemical oxidation of catechol. The oxidation peak currents of catechol at Y2O3 (500 °C)/GCE and Y2O3 (800 °C)/GCE showed two stages linear function of concentration (2.0~20.0 × 10-6 mol/L, 20.0~60.0 × 10-6 mol/L). The results indicated that the detection limits were equal to 2.4 × 10-7 mol/L (Y2O3 (500 °C)/GCE) and 7.8 × 10-7 mol/L (Y2O3 (800 °C)/GCE). The study not only provided a method to synthesize metal oxide, but also proposed a promising on-line pH model to study cation exchange kinetics.

Removal of chromium(III) from contaminated waters using cobalt ferrite: how safe is remediated water to aquatic wildlife?

The release of hazardous elements by industrial effluents to aquatic ecosystems is a potential threat to the environment. Chromium (Cr) is one of the elements whose levels in several freshwater ecosystems should be reduced to promote water reuse. In recent years, magnetic materials have gained increasing interest as sorbents because of their easy removal from treated water through magnetic separation. In this study, colloidal cobalt ferrite (CoFe2O4) particles were investigated as magnetic sorbents for chromium-aqueous chemical species. The oxidative stress responses of Mytilus galloprovincialis mussels exposed to 200 μg/L of Cr, resembling remediated water, were evaluated. More than 95% of Cr was removed from contaminated solutions by CoFe2O4 aqueous suspensions at pH 6 and pH 10. The kinetics of sorption experiments were examined using pseudo-1st order, pseudo-2nd order and Elovich models to evaluate which mathematical model has a better adjustment to the experimental data. The present study revealed that the levels of Cr that remained in remediated water induced limited biochemical changes in mussels, being considered safe for aquatic systems. Overall, the use of cobalt ferrite–based sorbents may constitute a promising approach to remediate contaminated water.

Synthesis, characterization and adsorption studies of hydroxy ethyl cellulose grafted polyacrylic acid hydrogels; using basic yellow-28 as model dye

Novel hydrogels of hydroxy ethyl cellulose and polyacrylic acid (HEC-G-pAAc) were created by varying the ratio of hydroxy ethyl cellulose to acrylic acid and were characterized using analytical techniques. The synthesized hydrogels were characterized through SEM, TGA, FTIR, pH studies and Fick’s law. The SEM images revealed that the fabricated hydrogels have different adsorption sites for the dyes. According to the TGA results the decomposition of the hydrogels occurs in three successive stages (22–200 °C, 200–310 °C, 310–500 °C). The optimum pH for the adsorption of basic yellow-28 is on the HEC-G-pAAc is pH-8 as it was observed in the pH studies. The optimum temperature for the adsorption of basic yellow-28 is on the HEC-G-pAAc was found to be 293 K.The Basic Yellow-28 dye was successfully removed from wastewater with a 98% effectiveness using synthetic hydrogels as an adsorbent. The adsorption parameters were calculated using a number of different kinetic models like pseudo-second order, Elovich, intraparticle-diffusion and Bangham kinetic models. The pseudo-2nd order kinetics model was found to best fit the kinetics data, while the Langmuir isotherm offered the most thorough explanation of the adsorption process. Basic Yellow-28 dye was removed to the greatest extent by the synthesized hydrogels (pAAc = 156 mg/g, 10%HEC-G-pAAc =166.3 mg/g, 20%HEC-G-pAAc =176.2 mg/g) after 90 min of contact at 293 K. The process was exothermic because the values of ΔH were found to be negative (ΔH = −4.93, −6.49 and −5.741 kJ/mol for pAAc, 10%HEC-G-pAAc and 20%HEC-G-pAAc respectively). The adsorption process in this study is spontaneous, as clear from the negative values of ΔG, (ΔG = −4.81, −5.34 and −5.40 kJ/mol for pAAc, 10%HEC-G-pAAc and 20%HEC-G-pAAc at 293 K respectively). The adsorption process on synthesized hydrogels showed decrease in dis-orderness that was clear from its negative values.

Adsorption of ciprofloxacin from aqueous solution and fresh synthetic urine by graphene oxide: Conventional and statistical physics modeling approaches

This work uses conventional and statistical physics modeling approaches to address ciprofloxacin (CIP) adsorption by graphene oxide (GO) from aqueous solution and fresh synthetic urine. Instrumental techniques such as FTIR, XRD, SEM, TGA, BET, and EDS were employed to characterize the adsorbent material. The adsorption experiments were performed in a typical batch using different initial concentrations of CIP, adsorbent dosage, pH, and temperatures. Besides, the statistical physics approach was employed to investigate the CIP adsorption onto GO. Five models based on mono, double, and multilayers were used to describe the equilibrium isotherms. Steric and energetic parameters such as the number of adsorbed molecules per site, receptor site density, and half-saturation were considered. The kinetic data were adjusted using three conventional models (pseudo 1st order, pseudo 2nd order, and general order). The pH effect and influence of adsorbent dosage on adsorption performance were also investigated and discussed. In addition, adsorption mechanisms hypotheses were proposed based on experimental data and adsorption modeling using a statistical physics approach. Furthermore, the current work reports the removal of CIP at concentrations commonly found in urine considering factors such as fraction excreted in unmetabolized form, daily defined dose, and average daily urine volume excreted. The adsorption capacity values in aqueous medium and fresh synthetic urine were were 354.24 and 291.39 mg g−1, respectively.

Efficient removal of Rhodamine B dye using biochar as an adsorbent: Study the performance, kinetics, thermodynamics, adsorption isotherms and its reusability

Removal of toxic dyes such as Rhodamine B is essential as it pollutes aqueous and soil streams as well. This comprehensive study explores the potential of Calophyllum inophyllum seed char as an efficient bio-adsorbent based on their characteristic properties and a comparative study between various carbon-based adsorbents on the adsorption capacity of Rhodamine B dye. In this study, the char was prepared from Calophyllum inophyllum seed using a slow pyrolysis process (298 K/min) at an optimum temperature of 823 K and used as an adsorbent for the removal of Rhodamine B from water. The resulting char was mesoporous and had 155.389 m2/g surface areas (BET) and 0.628 cc/g pore volume. The formation of pores was observed from the SEM analysis. The adsorption studies were tested and optimized through various parameters such as solution pH, adsorbent dosage, initial dye concentration, stirring speed, contact time, and solution temperature. Maximum 95.5 % removal of Rhodamine B was possible at the pH: 2, stirring speed: 100 rpm, time: 25 min, temperature 308 K, and dose: 1.2 g/L. The highest adsorption capacity at equilibrium was determined to be 169.5 (mg/g) through Langmuir adsorption isotherm studies and followed pseudo 2nd order kinetics. The thermodynamics study confirmed the adsorption processes were spontaneous (ΔG°=−0.735 kJ/mol) and endothermic (ΔH° = 4.1 kJ/mol) processes. The reusability study confirmed that the mesoporous char can be reused as an efficient adsorbent for up to 3 cycles for environmental remediation.

Efficient sorption of As(III) from water by magnetite decorated porous carbon extracted from a biowaste material.

Arsenic is a highly toxic metal that causes cancer even at a low concentration and its removal from water resources is challenging. Herein, carbon extracted from waste onion bulbs is activated to cater for porosity and functionalized with magnetite (Fe3O4) nanoparticles (named MCK6) to address the challenge of As(III) removal. Synthesized MCK6 was highly mesoporous having a surface area of 208 m2/g, where magnetite nanoparticles (≤ 10nm) are homogeneously distributed within a porous network. The developed adsorbent inherited functional groups from the biosource and magnetic property from magnetite making it ideal for removal of As(III). Further, MCK6 showed a maximum monolayer adsorption capacity (qm) of 10.2mg/g at 298K and pH 7. The adsorption thermodynamics delineates a non-spontaneous and endothermic reaction, where the kinetics followed pseudo 2nd order (R2 value of 0.977), while monolayer formation is explained by the Langmuir model. Moreover, MCK6 efficiently works to remove As(III) in a competitive metal ions system including Pb+2, Cd+2, and Ca+2, making it a suitable adsorbent to tackle contaminated water.

Core-Shell Adsorbent Granules Fabricated from Sand/Graphene Oxide Nano-Composite for Adsorptive Removal of Pb (II)

Core-shell absorbent granules are produced by coating commercial sand gravels with graphite oxide (few-layer oxidized graphene sheets). Graphite oxide (GO) is synthesized chemically from vein graphite, a rare form of high purity natural graphite. Repeated coatings of graphite oxide on sand followed by low temperature (1200 C) thermal pyrolysis produce core-shell granules with a hierarchical structure in which sand gravels are covered by graphite oxide layers. The intention of this study is to assessment of feasibility of the mitigation of Pb (II) form the water by sand/graphene oxide nano-composite and study the dynamic behavior of the adsorption mechanism using the mathematical modeling. Individual materials and the resulting nanocomposite are characterized using a range of spectroscopic (FTIR, XRD, XPS) and microscopic (SEM/EDXA) techniques to elucidate the process of transforming individual materials into nanocomposite and to assess its suitability for removing Pb (II) from water. Stable sand/graphite oxide nanocomposites were obtained upon five times coating of GO on the sand surface and characterization shows that functionalized and a porous coating developed on the sand. The Pb (II) removal efficiency increases from high-acidic to neutral pH and decreases after basic (pH-8). The adsorption process takes 150 minutes to reach the equilibrium. After 150 minutes, the Pb (II) ion adsorption rate was constant. The maximum dosage of the nanocomposite needed to reach the equilibrium was 0.06g. Under the optimum conditions, 96.3% of Pb (II) removal efficiency was recorded from simulated Pb (II) containing water. According to the mathematical modeling, adsorption follows the Langmuir isotherm and fits well with the pseudo 2nd order kinetics model, indicating a homogeneous adsorption process via a monolayer process and Pb adsorbed onto the surface of the sand/GO nanocomposite by chemisorption. Sand/GO nanocomposite is an excellent candidate for removing Pb (II) from contaminated water.&#x0D; Keywords: Adsorption, Graphene oxide, Sand, Water treatment

Adsorption of crystal violet using a composite based on graphene Oxide-ED@Cellulose: Adsorption modeling, optimization and recycling

The current work, provides the results of a study related to the synthesis of composite based on ethylene diamine modified reduced graphene oxide and cellulose (rGO-ED@Cellulose) to improve the dispersion of GO sheets. After improving its properties, the composite was employed for the adsorption of crystal violet, a cationic dye. Point zero charge (pHPZC) was used to characterize the composite, in addition to other methods including X-ray diffraction, scanning electron microscopy, and energy dispersion X-ray spectroscopy (FTIR, XRD, and SEM/EDS). Studies on batch adsorption were conducted with operational parameters such as contact time, dosage of the adsorbent, concentration of the dye, pH, and temperature. The optimal parameters found were t = 80 min, 10 ppm, pH = 6, m = 0.1 g and T = 25 °C, this resulted in a capacity of adsorption of crystal violet value of 260 mg. g−1 and an adsorption efficiency of 88 %. The kinetic study showed that the adsorption of the cationic CV dye on the composite follows a pseudo 2nd order model kinetic. The Langmuir model was found to be a good fit for the isothermal data of the crystal violet adsorption by the composite study and the adsorption process is exothermic. A statistical model was used to assess the efficacy of CV adsorption on rGO-ED@Cellulose composite surface locations. The evaluation was carried out in a practical setting, utilizing a three-level Response Surface Methodology (RSM) based on Box-Behnken Design and the Expert Design software package.