Sorbent For Removal Of Arsenic Research Articles

Magnetite interaction with arsenic during sorptive removal from groundwater: a mechanistic study

A magnetic mixed iron oxide, magnetite (Fe3O4), was synthesized in the laboratory and characterized before its use as sorbent for arsenic removal. The characterization techniques used were X-ray diffraction (XRD), specific surface area, zeta potential and particle size measurements. The sorbent was applied for arsenic removal, without any pre or post treatment, from groundwater. The efficiency of sorption can only be improved by understanding the sorbent–sorbate interaction. For onsite monitoring of the sorbent-sorbate interaction, an electrochemical investigation using cyclic voltammetry (CV) measurement was developed. The study confirmed that the sorption of As(III) on Fe3O4 is dynamic (reversible) whereas that of As(V) is static (irreversible) in nature. Detailed investigation after the sorption was carried out utilizing X-ray photoelectron spectroscopy (XPS) measurement. The complexation of As(III)-Fe3O4 and As(V)-Fe3O4 without any redox transformation was evident from the XPS data. By careful examination of the results, a mechanism of arsenic removal by Fe3O4 was proposed.

Feasibility of iron‐based sorbents for arsenic removal from groundwater

AbstractBACKGROUNDArsenic is one of the most serious drinking water contaminants around the world. The development of iron oxide materials, including nanoparticles, as sorbents for arsenic remediation has shown promising results in recent years. Some of these materials are already used as commercial‐grade arsenic sorbents. However, the use of iron‐oxide nanoparticles (IONPs) has barely been used in real‐world conditions. This work compares commercial IONPs with three proven arsenic sorbents.RESULTSThe full chemical characterization includes electron microscopy, X‐ray diffraction and X‐ray photon spectroscopy to determine morphology, crystalline structure and elemental analysis, respectively. Arsenic remediation studies also were conducted in both batch and column set‐ups with real water samples from Salamanca, Mexico. The conditions (pH 8, high concentration of silica and presence of other interferences) found in this site are outside the recommended parameters of operations for most of the arsenic sorbents. All of the materials observed a negative effect because of silica presence. However, the effects observed in batch did not correlate directly to the column tests. This is important when evaluating the viability of using sorbents in specific conditions.CONCLUSIONSA feasibility analysis revealed that some commercial sorbents can treat water with the conditions presented in the selected site, but the cost of treatment is not viable for developing countries. In addition, the generated waste by using these sorbents would be substantial. These challenges could be diminished by using nanoparticles, yet the commercially‐available IONPs do not fill this gap. Better designed nanomaterials are still needed for arsenic removal. © 2022 Society of Chemical Industry (SCI).

Fabrication of PVA/ZnO fibrous composite polymer as a novel sorbent for arsenic removal: design and a systematic study

PVA/ZnO nanofibrous composite polymer was synthesized as a novel sorbent via electrospinning method at ambient conditions. Physicochemical characteristics of the samples were analyzed using XRD, SEM, EDS, TGA/DSC, and BET techniques. Efficiency of the composite samples for arsenic removal [i.e., As (III) and As (V) anions] was studied under different conditions using RSM optimization approach. Experimental results of adsorption tests indicated that the synthesized PVA/ZnO polymer with the maximum removal of 97% is a highly efficient sorbent for arsenic comparable with other sorbents studied for arsenic removal. The effect of some cations on arsenic removal was also studied in this research. Results showed that the tested ions do not cause a significant reduction in the removal rate. PVA/ZnO composite polymer, which is highly biocompatible, can be considered as a new adsorbent for removal of arsenic from contaminated water.

Synthesis of diatom–FeOx composite for removing trace arsenic to meet drinking water standards

This study presents the synthesis of diatom–FeOx composite as a novel sorbent for arsenic removal from water. The unique porous architecture of the diatom was utilized to immobilize iron oxide to form the composite. The surface area was as high as 70m2/g. The adsorption isotherms for As (III) and As (V) followed the Langmuir, Freundlich and D-R models. Langmuir monolayer adsorption capacity for arsenite (As III) was 10,000μg/g and arsenate (As V) was 12,500μg/g. The pseudo-second order rate equation was found to effectively describe the kinetics of arsenic adsorption. This study opens the door for the development of bio derived materials for environmental remediation.

Evaluation of a Novel Water Treatment Residual Nanoparticles as a Sorbent for Arsenic Removal

A novel sorbent, water treatment residual nanoparticles (nWTR), was synthesized and used to remove As(V) from water solutions. The kinetics and equilibrium of As(V) adsorption by nWTR were evaluated. The kinetic data for nWTR at 3 different pH values indicate that As(V) sorption is biphasic, is favored at low pH values, and followed the power function and first-order kinetics models fit. The results of the batch adsorption study showed that nWTR was effective in As(V) removal and its removal capability was 16 times higher than that of bulk WTR. Fourier transmission infrared (FTIR), SEM-EDX spectra, and As fractionation results indicate the crucial role of surface hydroxyl groups in As retention onto nWTR and the high capability of nWTR to immobilize As(V). The stability of As-nWTR surface complexes is suggested as less than 2% of adsorbed As(V) was released from nWTR after 4 consecutive desorption cycles.

Adsorption and removal of arsenic (V) using crystalline manganese (II,III) oxide: Kinetics, equilibrium, effect of pH and ionic strength

Manganese (II,III) oxide (Mn3O4) crystalline powder was evaluated as a potential sorbent for removal of arsenic (V) from water. Adsorption isotherm experiments were carried out to determine the adsorption capacity using de-ionized (DI) water, a synthetic solution containing bicarbonate alkalinity, and two natual groundwater samples. Adsorption isotherm data followed the Langmuir and Freundlich equations, indicating favorable adsorption of arsenic (V) onto Mn3O4, while results from the Dubinin–Radushkevich equation were suggestive of chemisorption of arsenic (V). When normalized to the sorbent surface area, the maximum adsorption capacity of Mn3O4 for arsenic (V) was 101 μg m−2, comparable to that of activated alumina. Arsenic (V) adsorption onto Mn3O4 followed pseudo–second-order kinetics. Adsorption of arsenic (V) was greatest at pH 2, while adsorption at pH 7–9 was within 91% of maximum adsorption, whereas adsorption decreased to 32% of maximum adsorption at pH 10. Surface charge analysis confirmed the adsorption of arsenic (V) onto the acidic surface of the Mn3O4 sorbent with a pHPZC of 7.32. The presence of coexisting ions bicarbonate and phosphate resulted in a decrease in arsenic (V) uptake. Comparable adsorption capacities were obtained for the synthetic solution and both groundwater samples. Overall, crystalline Mn3O4 was an effective and viable sorbent for removal of arsenic (V) from natural water, removing greater than 95% of arsenic (V) from a 1 mg L−1 solution within 60 min of contact time.

Removal of arsenic from Laminaria japonica Aresch juice using As(III)-imprinted chitosan resin

An As(III)-imprinted chitosan resin (As-ICR) was successfully prepared to selectively remove arsenic from Laminaria japonica Aresch (LJA) juice. Batch adsorption experiments and column adsorption experiments were performed to evaluate the adsorption conditions, selectivity, and reusability. The results showed that the minimum total arsenic concentration of the juice was 4.16 mg/L at pH 6.0, 40 °C, with equilibrium time 4 h. The selectivity of As-ICR for arsenic was much higher than that of non-imprinted chitosan resin. As-ICR could be reused for 10 times with only about 13% regeneration loss. FTIR spectra demonstrated that the adsorption of As-ICR for arsenic occurred on amino and hydroxyl groups. Total arsenic concentration of the juice decreased significantly, while the other metal ions decreased except Zn2+ insignificantly. This suggests that As-ICR is a very promising sorbent for selective removal of arsenic from the juice.

New Approach: Waste Materials as Sorbents for Arsenic Removal from Water

The sorption of inorganic arsenic species (arsenite and arsenate) from aqueous solutions onto steel-mill waste and waste filter sand, under neutral conditions, was investigated in this study. Additionally, the steel-mill waste material was modified in order to minimize its deteriorating impact on the initial water quality and to meet the drinking water standards. The influence of contact time and initial arsenic concentration was investigated using batch system techniques. To evaluate the application for real groundwater treatment, the capacities of the obtained waste materials were further compared to those exhibited by commercial sorbents, which were examined under the same experimental conditions. Kinetic studies revealed that waste slag materials are the most efficient in arsenic removal, reaching equilibrium arsenic sorption capacities in the range 47.6–55.2 μg/g, while waste filter sand exhibited capacities of 25.4–29.8 μg/g (for an initial arsenic concentration Co=0.5 mg/L). The higher iron content in the slag materials was considered to be responsible for the better removal efficiencies, and the specific arsenic removal efficiency was estimated to be 220 μgAs/gFe. The specific arsenic removal efficiency of the second active substance found in waste filter sand, manganese, was estimated to be 115 μgAs/gMn. Equilibrium studies revealed the occurrence of both chemisorption and physical sorption processes. All the waste materials exhibited higher performances for As(V). The highest maximum sorption capacity was obtained by waste iron slag: 4040 μg/g for As(V). The waste materials reached the arsenic removal capacities of the examined commercial materials, suggesting the feasibility of their application in real groundwater treatment.

Comparison of inorganic and composite ferric oxide sorbents for arsenic removal

Three different sorbents based on hydrated ferric oxide (GEH, ArsenX(np) and Lewatit FO 36) were compared from the viewpoints of their column operation. Particle size distribution, pressure drop across the column and ferric oxide content were measured. Sorption capacities under the presence of accompanying ions were measured in batch wise and column experiments.

Shrimp shell as a potential sorbent for removal of arsenic from aqueous solution

This study examined the ability of shrimp shell to remove arsenic (As) from aqueous solutions. The shells of two species of shrimp, black tiger shrimp Penaeus monodon and white shrimp Litopenaeus vannamei, were chosen to be the sorbents. Laboratory exposure experiments estimated uptake and depuration rate constants (i.e., k 1 and k 2) as well as the bioconcentration factors (BCF) of the shells of the two shrimps. A first-order one-compartment model was presented to describe the uptake kinetics of As in shrimp shell. The resulting k 1, k 2, and BCF values of black tiger shrimp were 0.034–1.722 ml/g/day, 0.007–0.345 g/g/day, and 5.08 ± 1.56 ml/g, while those for white shrimp were 0.053–0.523 ml/g/day, 0.011–0.237 g/g/day, and 3.95 ± 1.88 ml/g, respectively. The sorption capacities of black tiger shrimp shell and white shrimp shell were 1.08 × 10−4–6.66 × 10−3 and 1.04 × 10−4–3.26 × 10−3 mmol/g, respectively. The sorption capacity of shrimp shell increased with the initial As concentration in water. Shrimp shell, as a waste material, could be potentially used for the removal of As from an aqueous medium. Although the As-removal capacity of shrimp shell was lower than those of natural and chemical sorbents, using shrimp shells as sorbents is less expensive and could increase the additional value of shrimp products.

Arsenic(V) Removal by Sulfate Modified Iron Oxide-Coated Sand (SMIOCS) in a Fixed Bed Column

Abstract A novel granular media developed by the coating of iron, barium and sulfur on quartz sand surface has been demonstrated to be an effective sorbent for removal of arsenic(V) from a 0.01 M NaNO3-spiked distilled water system in laboratory-scale tests. The results of fixed bed studies indicate that arsenic(V) removal is dependent on pH, the size of sorbent and influent arsenic concentrations. The particle size of media has shown significant differences in reactor breakthrough times in similar experimental conditions. The removal of As(V) may be explained using the surface complexation theory. The presence of alkalinity (250–260 mg/L as CaCO3) and hardness (200 mg/L as CaCO3) slightly increases reactor breakthrough time for similar experimental conditions without alkalinity and hardness. Desorption studies using 0.2 M NaOH as elutant resulted in nearly 92% recovery of arsenic(V). A theoretical model based on two parameters has shown good correlation with observed experimental data generated during depth variation studies.