Potential Of Maximum Adsorption Research Articles

Sequestration of chromium by Ananas comosus extract–coated nanotubes: synthesis, characterization, optimization, thermodynamics, kinetics, and antioxidant activities

AbstractHerein, a superior adsorbent was fabricated via immobilizing Ananas comosus juice extract on nanotubes (MWPJ) for the removal of chromium (VI) from simulated wastewater. The batch adsorption technique was used to establish the influence of solution pH, adsorbent dosage, solution temperature, initial Cr(VI) concentration, and contact time on the adsorption of chromium (VI). To comprehend the surface properties and to confirm chromium (VI) adsorption onto MWPJ and MWCNTs, TGA, SEM, and FTIR analyses were performed for MWPJ and MWCNTs before and after the adsorption process. These spectroscopic techniques revealed the temperature and surface characteristics responsible for the effectiveness of MWPJ. MWPJ and MWCNTs demonstrated optimum removal potential at solution pH 2, 0.05 g adsorbent dosage, and 180 min contact time. The MWPJ and MWCNTs had a maximum adsorption potential of 44.87 and 33.38 mg g−1 at 25 °C respectively. The reaction rate kinetics data for MWPJ and MWCNTs fitted well with Elovich and the pseudo-first-order kinetic model, respectively, while the saturated equilibrium data were best described by Freundlich isotherm. The thermodynamics analysis revealed that the uptake of Cr(VI) onto MWPJ and MWCNTs was a spontaneous and exothermic process. After five adsorption–desorption cycles of MWPJ, about 80% removal efficiency of Cr(VI) ions was sustained. Hence, MWPJ has demonstrated a superior capacity for practical applications in environmental remediation practice.

Development of a ZnOS+C Composite as a Potential Adsorbent for the Effective Removal of Fast Green Dye from Real Wastewater.

Wastewater treatment is becoming increasingly important due to the potential shortage of pure drinking water in many parts of the world. Adsorption offers a potential technique for the uptake of contaminants and wastewater purification. In the last two decades, several efforts have been made to remove fast green (FG) dye from wastewater via different adsorbent materials. However, adsorption capacity shown by these adsorbents is low and time-consuming. Herein, we have synthesized for the first time a new powdered adsorbent ZnOS+C, modified zinc peroxide with sulfur and activated carbon to effectively remove FG dye from wastewater. Results of batch adsorption experiments have suggested that ZnOS+C has the maximum adsorption potential of 238.28 mg/g for FG dye within 120 min of adsorption equilibrium for a wide range of pH ranging from 2 to 10 pH. The adsorption process conforms to the Freundlich isotherm model, suggesting a multilayered adsorption process on the outer surface of ZnOS+C. The adsorption kinetics study indicates that the kinetics of the reaction are the intraparticle diffusion model. Briefly, this study shows proof of the application of ZnOS+C powder as a new eco-friendly adsorbent with extremely high efficiency and high surface area for removing FG dye.

The bio-adsorption competence of tailor made lemon grass adsorbents on oils: An in-vitro approach

The oil contamination in aquatic system is considered as most serious environmental issues and identifying a suitable ecofriendly solution for this oil pollution management is critical. Hence, this research was designed to evaluate the oils (petrol, diesel, engine oil, and crude oil) adsorptive features through raw lemon grass adsorbent, physically/chemically treated adsorbents. Initially, such raw and treated adsorbents were characterized by Scanning Electron Microscope (SEM), Fourier transform infrared spectroscopy (FTIR), and Energy-Dispersive X-ray Spectroscopy (EDS) analysis. These characterization techniques revealed that the lemon grass adsorbent had considerable level of pollutant adsorption potentials owing to porous morphological structure, active functional groups and pollutants interaction with chemical elements. The physically treated adsorbent exhibited better adsorption characteristics than others. Accordingly, the petrol adsorption potential of raw adsorbent, physically treated and chemically treated ones was discovered as their weight incremented up to 2.0, 3.0, and 1.5 times their initial weight, respectively. Similarly, the weight of raw form, physically and chemically treated ones on diesel had increased significantly, up to 2.5 times, 4.0 times, and 2.0 times, respectively. It was evaluated that the weight of these tested adsorbents on engine oil incremented by 3.5, 5.0, and 3.0 times their initial weight, while on crude oil these incremented by 4.0, 6.0, and 4.0 times their initial weight respectively. When the media are compared, it's indeed evident about absorption which is preferred as follows: Crude oil, engine oil, diesel, and petrol. The physically treated lemon grass adsorbent showed maximum adsorption and retention potential than others. The kinetic study reveals that the pseudo second order kinetics is the best fit for the adsorption of oil with R2 value of 0.99.

Lead Ions Removal Using Pineapple Leaf-Based Modified Celluloses

Pineapple leaves are largely discarded in the harvest area and considered as agricultural waste. Herein, the extracted pineapple leaves fiber was altered with chelating agents to become an adsorbent for lead ions (Pb2+) removal from aqueous solutions. The initial investigation determined that the most appropriate conditions for extracting cellulose fiber from pineapple leaves were stirring at 90–100 °C in 10%w/v NaOH for 1 h. Next, carboxymethyl, amide, and amidoxime were used to modify with the extracted cellulose fiber, denoted as Cell-CMC, Cell-AM, and Cell-AMX, respectively. At pH 6, Cell-CMC, Cell-AM, Cell-AMX, and the extracted cellulose fiber had maximum adsorption potential values of 9.3, 1.5, 3.6, and 6.3 mg g–1, respectively. In the kinetic analysis, Cell-CMC, Cell-AM, and extracted cellulose adsorption behaviors were well represented using a model of pseudo 1st order, while the adsorption behavior of Cell-AMX was best represented using a model of pseudo 2nd order. Further investigation demonstrated that the desorption efficiency of each adsorbent increased as the pH value was lowered from 3, 4, and 6.

Deliberated system of ternary core–shell polythiophene/ZnO/MWCNTs and polythiophene/ZnO/ox-MWCNTs nanocomposites for brilliant green dye removal from aqueous solutions

In recent times, great attention has been given to developing extremely competent adsorbents for removing organic dyes from wastewater. Thus, to enhance their adsorption capability, a general strategy based on adsorbent surface modification with polymers has been proposed. This report demonstrates the potential of a ternary mixture of polythiophene/zinc oxide/multiwalled carbon nanotubes (PTh/ZnO/MWCNTs) and tertiary PTh/ZnO/oxidized multiwalled carbon nanotubes (ox-MWCNTs), which have been incorporated via an in-situ method of chemical polymerization through a simplistic two-way method. SEM and EDX outcomes show that ZnO and MWCNTs, or ox-MWCNTs, are well covered with PTh. Raman, FTIR, and XRD demonstrated the effective synthesis of PTh/ZnO/ox-MWCNTs and PTh/ZnO/MWCNTs nanocomposites with good interfacial interactions between the components. This report also examined the potential of these nanocomposites to remove brilliant green (B.G.) (a toxic dye) from a water solution. In addition, the influence of adsorption parameters, such as concentration, adsorption temperature, pH, and stirring time, was evaluated. B.G.’s adsorption percentage was affected by concentration, temperature, and time. B.G.’s maximum adsorption potential was 9.1 mg g −1 for PTh/ZnO/ox-MWCNTs and 8.3 mg g −1 for PTh/ZnO/MWCNTs, demonstrating the nanocomposites’ (NCs) potential for effective B.G. adsorption. The outcomes of the dye removal show that the dye removal process was spontaneous and endothermic, as evaluated by thermodynamic and kinetic criteria.

Effect of high-temperature treatment on the desorption efficiency of gas in coalbed methane reservoirs: Implication for formation heat treatment

Formation heat treatment has been considered as a potential stimulation technology for the enhanced recovery of coalbed methane. However, the influence of heat treatment on the desorption efficiency of coalbed methane has not been clarified. In this study, isothermal adsorption experiments of a cylindrical anthracite coal treated at 25 °C, 200 °C, 400 °C, 600 °C, and 800 °C were conducted to investigate the variation in the methane adsorption potential and desorption efficiency. The pore structure of coal was characterized by nuclear magnetic resonance measurements and scanning electron microscopy. Changes in the organic matter and functional group content of coal were monitored by proximate analysis and Fourier transform infrared spectroscopy. Results reveal that pore structure and composition are the main factors that affect the coal adsorption potential. With the increase in the temperature to 200–600 °C, the maximum adsorption potential of coal increased by 7% due to the increase in the pore volume and the functional group content. At a heat-treatment temperature of 800 °C, the functional group content decreased, which in turn reduced the maximum adsorption potential by 76%. Comparison of isothermal adsorption data of coals with different ranks reveals that the Langmuir parameter of bituminous coals is more easily affected by heat treatment in comparison with that of anthracite coal. Based on the reversible theory of coalbed methane isothermal adsorption and desorption process, weighted pressure was proposed, which could comprehensively evaluate the desorption efficiency of coal after heat treatment at different temperatures, and the heat treatment temperature for the optimal desorption efficiency can be determined by the weighted pressure.

The Performance of Different AgTiO2 Loading into Poly(3-Nitrothiophene) for Efficient Adsorption of Hazardous Brilliant Green and Crystal Violet Dyes

The in-situ polymerization technology was used to successfully produce nanostructured binary nanocomposites (NCs) made from a poly (3-nitrothiophen) matrix (P3NT) that were loaded effectively with nanoparticles (NPs) of silver titanium dioxide (AgTiO2), of varying percentages (10%, 20%, and 30%). A uniform coating of P3NT covers the AgTiO2 NPs. Various methods were performed to confirm the fabrication of the binary P3NT/AgTiO2 NCs adsorbents, such as FTIR, XRD, SEM, and EDX. Both dyes (brilliant green (B.G.) and crystal violet (C.V.)) were removed from liquid media by using the binary P3NT/AgTiO2 NCs. A range of batch adsorption studies was used to optimize various factors that impact the elimination of B.G. or C.V. dyes, including the pH, weight of the binary P3NT/AgTiO2 NC, proportion of AgTiO2 NP, time, and temperature. The pseudo-second-order kinetics ( R 2 = 0.999 ) was better adapted for the adsorption procedure’s empirical data whereby the maximum adsorption capacity of the C.V. dye was 43.10 mg/g and ( R 2 = 0.996 ) the maximum adsorption potential was 40.16 mg/g for B.G. dye, succeeded by the pseudo-second-order kinetics. Moreover, the adhesion of B.G. and C.V. pigments on the layers of NCs involves an endothermic reaction. In addition, the concocted adsorbent not only exhibited strong adsorption characteristics during four consecutive cycles but also possessed a higher potential for its reuse. According to the findings, the NCs might possibly be used as a robust and reusable adsorbent to remove B.G. and C.V. pigments from an aqueous medium.

Effective adsorptive removal of anionic dyes from aqueous solution

AbstractCongo Red (CR) and Reactive Black 5 (RB5) anionic dyes were removed from aqueous solution using Porous Magnetite Fe3O4 nanospheres (PMNs) as a high‐performance adsorbent. Various methods, such as Fourier transform infrared spectroscopy and X‐ray diffraction, were used to classify the synthesized PMNs. The Brunauer Emmett‐Teller (BET) method was used to calculate the sample's high specific surface area of 143.65 m2.g‐1, as well as its pore volume and pore size. The PMNs have a very uniform spherical morphology, with an average particle size of 25.84 nm, as revealed by transmission electron microscopy (TEM) and scanning electron microscopy (SEM) image analysis. Variables such as initial pH, adsorbent dosage, contact time, and temperature were investigated to determine optimal adsorption conditions for the extraction of Congo Red (CR) and Reactive Black 5 (RB5) from aqueous solutions. The optimal pH for extracting the anionic dyes tested from water solutions was 3 and 4 for CR and RB5, respectively. The maximum adsorption potential of the CR and RB5 dyes, respectively, was 1621.59 and 1070 mg.g‐1. pH, temperature, initial concentration, contact time, salinity, and PMNs dosing were all studied in depth. Since the PMNs Zero‐charge point (pHPZC) equals 4.3, these dyes were ideal for adsorption at an acid pH. The Langmuir, Freundlich, Dubinin ‐ Radushkevich, and Temkin adsorption isotherms were used to determine adsorption results. For both dyes, the adsorption isotherm was fitted to the Langmuir model. The mean adsorption energy (Ea) for CR and RB5, respectively, is 20.2 and 24.8 kJ.mol‐1, suggesting a chemisorption mechanism. The kinetics of adsorption was discovered to adopt a pseudo‐second‐order kinetic model. Thermodynamic experiments confirmed that the adsorption mechanism is endothermic and spontaneous. They experimented with ethanol as a solvent for desorption of adsorbed anionic dyes.

Removal of heavy metals from polluted aqueous media using berry leaf

ABSTRACT The routine of low-cost adsorbents derived from plant or agricultural by-products as a substitute for expensive traditional removal methods of heavy metal from discarded streams has been investigated. The effectiveness of powder’s mulberry leaves in extracting Pb2+, Ni2+, Cu2+, and Co2+ from an aqueous solution by batch adsorption at lab ambient temperature (25 ± 0.4°C) was investigated in this report. The impact of pH, contact time, biosorbent dosage, and preliminary concentration of metal ions on the exclusion percentage were investigated in experiments. The findings demonstrated that the elimination of metal ions by mulberry leaves powder was influenced by all adsorption parameters. At pH = 6 and 7, the maximum removal of Ni2+, Pb2+, Cu2+, and Co2+ occurred. The obtained data were subjected to two different isotherm models Langmuir and Freundlich. The models of Pb2+, Ni2+, and Co2+ results all complement the Langmuir isotherm well (R2 = 0.99). However, the Freundlich isotherm was found to match Cu2+ adsorption with (R2 = 0.98). For Pb2+, Cu2+, Ni2+, and Co2+, the maximum monolayer adsorption potential was found to be 0.50, 2.88,1.14, and 1.15 mg/g, respectively. A sample of real industrial wastewater was collected and treated with mulberry leaf powder. The findings illustrate that mulberry leaves powder has a 69, 85, and 100% performance in removing Pb2+, Cu2+, Zn2+, ions, respectively. The findings of different treatments; synthetic and real wastewater, suggest that mulberry leaves powder may be applied as a low-cost alternative to more expensive heavy metal adsorbents. The pseudo-second-order kinetic model was applied to fit the model and describe the adsorption mechanism.

Statistical Physics Model of EBT Adsorption on Pb(II) doped Zinc Oxide Nanoparticles: Kinetics, Isotherm and Reuse Study

ABSTRACT Pb(II) doped zinc oxide nanoparticles (Pb-ZnONPs) was synthesised using the co-precipitation method. The average size distribution of the Pb-ZnONPs is 42.8 nm and further used as an adsorbent to remove Erichrome Black T (EBT) from wastewater. The adsorption of EBT onto the Pb-ZnONPs was best fitted for pseudo-second-order kinetics model, indicating that the adsorption phenomena depend on EBT and Pb-ZnONPs, showing chemisorption phenomenon. The maximum adsorption potential of Pb-ZnONPs (qmax = 200 mgg−1) for EBT is far better than that of the already available adsorbents. The high regression coefficient of freundlich shows that the adsorption can be shown by multi-layer process. The value of ΔG° is negative and temperature increases with an increase in the absolute value increases, suggesting the adsorption of dye onto the Pb-ZnONPs is spontaneous. The decrease in the concentration of adsorbed monolayer (Q0 = nNM) from 411 to 43.55 mg/g with the change in temperature revealed that the adsorption process is exothermic in nature. The Pb-ZnONPs have exhibited a variation of about 7–8% of adsorption compared to the fresh sample after 5th regeneration.

Adsorption of Acid Dye by Activated Carbon from Agricultural Solid Waste Leucona Leucocephala Seed Shell Waste: Kinetics, Equilibrium and Isotherm Study

Activated carbons from Leucaena leucocephala Seed Shell left over were generated accompanied by 10% phosphoric acid solution in the N2 atmosphere by chemical activation and their characteristics were investigated. SEM, FTIR and XRD analysis were used to analyse the characteristics of the triggered preparations. Isothermal models, namely the Freundlich and Langmuir representations, were the equilibrium studies carried out.. The equilibrium adsorption result was better suited to the isotherm model of Langmuir and its maximum monolayer adsorption potential for acid blue was 70.67 mg/g. Adsorption kinetics studies have shown that the best fit is provided by the pseudo second-order dynamic model. An intraparticle dispersion model demonstrated that the dissemination of the intraparticle was not a step of rate control. Studies of thermodynamics have shown that the sorption mechanism is spontaneous and exothermic in nature. The findings suggest that the seed shells of Leucaena leucocephala may be used as a possible adsorbent for Acid blue1 adsorption.

Experimental modeling, optimization and comparison of coagulants for removal of metallic pollutants from wastewater

Abstract Wastewater treatment coagulation is one of the most important physicochemical operations used in industry. The adsorption capability of marigold leaf powder, tea waste and ferrous sulfate was investigated for domestic and tannery effluents. These adsorbents significantly affected the pH, electrical conductivity (EC) and turbidity of wastewater. Maximum decrease in all the attributes was observed for 10 g of adsorbents application. All the adsorbents significantly affected the physiochemical attributes of both wastewaters. Similarly, maximum adsorption potential was observed in case of tea waste powder. Maximum decrease in all physiochemical attributes such as pH (15%), EC (21%), turbidity (54%), total dissolved solids (TDS; 36%), total suspended solids (TSS; 43%), total hardness (TH; 52%), chloride contents (59%) and phosphate contents (60%) was observed with the application of 10 g of tea waste. Regarding the heavy metals, maximum decrease for cadmium (Cd; 47%), lead (Pb; 81%), arsenic (As; 44%), copper (Cu; 75%), iron (Fe; 49%), chromium (Cr; 68%) and zinc (Zn; 64%) was observed in same treatment. The decreasing order in terms of their adsorption potential for coagulants was tea waste > marigold leaf powder > ferrous sulfate. However, for the wastewater, the maximum effect of adsorbents was observed in case of domestic wastewater as compared to the tannery water. Based on these data, it is suggested that tea waste has maximum adsorption potential for the remediation of wastewater.

Coagulation of Metallic Pollutants from Wastewater Using a Variety of Coagulants Based on Metal Binding Interaction Studies

Abstract In this study, different organic (moringa and neem leaf powder) and inorganic (alum) coagulants were used for the wastewater treatment. Results revealed that all the coagulants at various doses significantly affected the pH, electrical conductivity (EC) and turbidity of wastewater. The maximum decrease in all the attributes was observed when 10 g of coagulants were used. Similarly, maximum adsorption potential was observed in case of moringa leaf powder. Maximum decrease in all physiochemical attributes such as pH (13%), EC (65%), turbidity (75%), total dissolved solids (TDS; 51%), total suspended solids (TSS; 48%), total hardness (TH; 29%), chloride contents (66%) and phosphate contents (44%) was observed. Regarding the heavy metals, maximum decrease for Cadmium (Cd; 96%), Lead (Pb; 88%), Arsenic (As; 23%), Iron (Fe; 90%), Manganese (Mn; 96%) and Zinc (Zn; 48%) was observed in same treatment. The decreasing order in terms of their adsorption potential for coagulants was moringa leaf powder > Alum > neem leaf powder. However, the maximum effect of coagulants was observed in case of textile wastewater as compared to the hospital wastewater. Based on the analyses, it is concluded that the moringa leaf powder has maximum adsorption potential for the remediation of wastewater.

Adsorption of soluble microbial products by sediments

As major precursors of disinfection by-products (DBPs), soluble microbial products (SMPs) generated by sewage discharge can adversely affect drinking water quality. It is essential to understand the adsorption behaviours of SMPs onto sediments and the effect of DBPs formation. In this study, the adsorption ability of sediments was evaluated by adsorption isotherms with respect to temperature and salinity. Adsorption behaviours were investigated using X-ray photoelectron spectroscopy, electron microscopy analysis, and excitation emission matrix fluorescence analysis. Chlorination was also employed to explore the influence of sediment adsorption on drinking water quality. The results indicated that the maximum adsorption potential of sediments to SMPs was 1.60 mg/g, which involved exothermic processes. SMPs adsorption declined with increasing temperature and salinity, and fulvic acid and protein in SMPs were more readily adsorbed on sediments than was humic acid. Correlation analysis results indicated that adsorption behaviours of sediments to SMPs could significantly reduce the generation potential of DBPs (r = 0.882–0.938, p < 0.01). In addition, the decrease of C-DBPs was considerably greater than that of N-DBPs. These research findings are of importance to assessments of the fate and transport of SMPs in water–sediment systems, as well as the effect of following DBPs formation in the drinking water supply.

Magnetite-coated biochar as a soil phosphate filter: From laboratory to field lysimeter

Agriculture is one of the largest anthropogenic contributors of phosphorus (P) to surface waters and reducing these P loads is a target set by many countries. One potential mitigation strategy could be to utilize biochar, functionalized by co-precipitating metal ions onto its surface to adsorb phosphates. We evaluated such an approach in a series of laboratory experiments and a three-year field lysimeter study. Leached phosphates were trapped in a 3-cm layer of a commercially available 20% hardwood/80% Norway spruce biochar, coated with magnetite and placed under the soil root zone. Langmuir maximum adsorption potential (Qmax) was 3.38 mg P g−1 biochar, as determined from batch adsorption studies performed at pH 6.5. Further laboratory experiments revealed that adsorption was strongly negatively correlated with pH (R2 = 0.995). In a laboratory column study using high flow rates, no difference was found in phosphate adsorption between coated biochar and the control (no biochar), after application of ammonium phosphate at a rate corresponding to 22 kg P ha−1. However, differences were observed at higher application rates (285 or 570 kg P ha−1). Calculation of a Fe:P molar ratio to evaluate the magnetite treatment method from laboratory (2:1) to lysimeter (248:1) suggested a relatively effective laboratory performance, but overall poor field efficiency. Nevertheless, biochar in the lysimeter study still reduced phosphate leaching from two organic soils, by 62% (P < 0.05) and 35% (NS). This suggests that, even though the method of magnetite-coating biochar is not necessarily resource-efficient, it is effective in removing P from soil leachate.

Removal of cationic and anionic heavy metals from water by 1D and 2D-carbon structures decorated with magnetic nanoparticles

In this study, cobalt ferrites (C) decorated onto 2D material (porous graphene (PG)) and 1D material (carbon nanofibers (CNF)), denoted as PG-C and CNF-C nanocomposites, respectively, were synthesized using solvothermal process. The prepared nanocomposites were studied as magnetic adsorbents for the removal of lead (cationic) and chromium(VI) (anionic) metal ions. The structural and chemical analysis of synthesized nanocomposites was conducted using different characterization techniques including Brunauer–Emmett–Teller (BET) analysis, field emission-scanning electron microscopy (FE-SEM), Fourier-transform infrared spectroscopy (FTIR), high resolution-transmission electron microscopy (HR-TEM), vibrating sample magnetometer (VSM), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS). Batch mode adsorption studies were conducted with the prepared nanocomposites to examine their maximum adsorption potential for lead and chromate ions. Performance parameters (time, pH, adsorbent dosage and initial ion concentrations) effecting the adsorption capacity of the nanocomposites were optimized. Different kinetic and isotherm models were examined to elucidate the adsorption process. Synthesized nanocomposites exhibited significant potential for the studied metal ions that can be further examined at pilot scale for the removal of metal ions from contaminated water.

Zero valent metal loaded silica nanoparticles for the removal of TNT from water.

Silica nanoparticles with a surface area of 673.60 m2/g and particle size of 8-12 nm were prepared using aerogel process (AP) followed by super critical drying. Zero valent Fe, Co, Pt, and bimetallic Fe/Pt and Fe/Co were loaded using an incipient wetness impregnation technique and subsequent reduction. Scanning electron microscopy-energy dispersive X-ray (SEM-EDX) and transmission electron microscopy-energy dispersive X-ray (TEM-EDX) characterizations indicated fine dispersion of iron on AP-SiO2 +Fe system. Prepared nanoparticles were evaluated for the adsorptive removal of 2,4,6-trinitrotoluene (TNT) from water. Surface area normalized rate constant values indicated the adsorptive removal potential of prepared nanoparticles to be: AP-SiO2 + Fe/Co > AP-SiO2 + Fe > CM (commercial) SiO2 + Fe > AP-SiO2 + Co > AP-SiO2 + Fe/Pt > AP-SiO2 + Pt. Lower pH helped in accelerating the reactive removal of TNT on zero valent iron loaded silica. AP-SiO2 + Fe/Co system showed the maximum adsorption potential (74 mg/g) after five cycles.

Adsorptive Bromate Removal from Aqueous Solution by Commercial Strongly Basic Resin Impregnated with Hydrated Ferric Oxide (HFO): Kinetics and Equilibrium Studies

Commercial strongly basic resin D201-Cl was impregnated with hydrous ferric oxide (HFO) in FeCl3–HCl–NaCl solution for absorptive removal of bromate from aqueous solution. The influences of initial bromate concentration, contact time, initial pH, temperature, and competing anions on the uptake of bromate by HFO-impregnated resin D201-Cl (HFO-201) were investigated by batch adsorption experiments. Experimental results showed that the adsorption process could be described by pseudo-first-order kinetics and be divided into three stages according to the intraparticle diffusion parameter. The maximum adsorption potential of HFO-impregnated resin for bromate was 292.81 mg·g–1 at 298 K, which is much greater than those reported in previous studies. The experimental data fitted well to the Redlich–Peterson isotherm model (R2 > 0.99). Thermodynamic parameters such as free energy, enthalpy, and entropy demonstrated that bromate adsorption on HFO-201 was spontaneous and exothermic and occurred by physisorption. Mean...

Swelling–adsorption interactions during mercury and nickel ions removal by chitosan derivatives

Chitosan derivatives are extensively used as adsorbents for dyes and metal ions. These materials undergo swelling after their immersion in water. The maximum adsorption potential corresponds to completely swollen material. The process rates of swelling and adsorption are comparable leading to a dependence of the apparent adsorption rate on immersion history of the material. The way of performing the adsorption experiments for this type of materials is not clear in literature raising questions on the validity of the results. To clarify the situation a total of six adsorbate–adsorbent systems is studied here with respect to the effect of the swelling degree on the adsorption kinetics. Mercury (Hg(II)) and nickel (Ni(II)) ions were selected to be the model pollutants of this work and cross-linked chitosan microspheres grafted with chlorosulfonic acid (CSSULF) or ethylenimine (CSPEI) as adsorbent materials. It is shown that the adsorption kinetics is sensitive to the time of the adsorbent immersion in water. An attempt for development of a combined swelling–adsorption model is made. It is shown that the interaction between swelling and adsorption is more complex than a single water content dependence of diffusion coefficient. The evolution of diffusion coefficient that reproduces the experimental data is derived. Differences to the behavior between the three material used, are indicated and discussed.

Response surface methodology approach for optimization of adsorption process for the removal of Indosol Yellow BG dye from aqueous solution by agricultural waste

This study was designed to explore the adsorption capacity of agricultural waste biomass for the removal of Indosol Yellow BG dye from aqueous solutions. Screening test was performed to select one adsorbent with maximum adsorption potential. Peanut husk biomass was selected as potential adsorbent after screening test. Peanut husk biomass depicted maximum adsorption capacity (22.47 mg/g) as compared to other adsorbents (sugarcane bagasse, corncobs, cotton sticks, and sunflower). The effect of different physical and chemical treatments on the adsorption capacity of peanut husk biomass was investigated, and acetic acid-treated biomass depicted very good adsorption capacity (25.05 mg/g) for the removal of Indosol Yellow BG dye. Box–Behnken experimental design was used for batch study. Batch experiments were conducted to explore the effect of three important process parameters viz., initial dye concentration, adsorbent dose, and pH. Maximum dye removal (58.01 mg/g) was achieved at 200 mg/L initial dye concentration, 2 pH, and 0.17 g adsorbent dose. Higher initial dye concentration, lower pH, and lower biosorbent dose were found to be feasible conditions for maximum dye removal. Desorption study was also conducted by using different concentrations of NaOH, and maximum desorption (44.5%) was achieved with 1 M NaOH solution. The results indicated that acetic acid-treated peanut husk biomass could be used as potential adsorbent for the treatment of dye containing wastewater.