Enhancing Adsorption and Desorption of Arsenic on Carbon Xerogel Nanocomposites in Aqueous Solution: Process Optimization (original) (raw)
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Water Supply, 2020
Magnetic xerogels monoliths (MCs) were simultaneously prepared and formed by the cross-linking polymerization of resorcinol and formaldehyde using the alkaline catalyst and magnetite. The varying of molar ratio of resorcinol and catalyst (R/C) was studied and characterized by isoelectric point (IEP), point of zero charge (pHpzc), scanning electron microscopy–energy dispersive X-ray spectroscopy (SEM-EDX), X-ray diffraction (XRD), N2 adsorption and Fourier transform infrared spectroscopy (FTIR). The result of XRD and EDX confirmed the presence of magnetite into the gel at 1.19% with low molar ratio of magnetite and resorcinol ratio at 0.01. The surface morphology and textural properties of MCs affect directly with SBET, total pore volume and volume of mesopore increase when molar of R/C increases. The behavior of arsenic (As(V)) adsorption by using MCs, was studied in groundwater into the ranges of pH from 2.0 to 7.0. MC50 shows the maximum As(V) uptake and removal were 72 μg/g and 7...
Processes, 2021
Arsenic contamination of groundwater is still a global problem due to the toxicity at low dose on human health confirmed by epidemiological studies. Magnetic xerogel monoliths (MXs) were synthesized by the sol-gel polymerization using resorcinol, formaldehyde, alkaline catalyst and magnetite. The varying molar ratios of magnetite and resorcinol (M/R) in the gel were evaluated for As(V) removal from groundwater. The surface chemistry, structure and morphology of MXs related to arsenic adsorption were characterized by X-ray diffraction, scanning electron microscopy, energy-dispersive X-ray spectroscopy, Fourier transform infrared spectroscopy and point of zero charge. Batch adsorption experiments were carried out to investigate the effects of Fe contents, initial pH and adsorbent dose on As(V) removal performance. The MXs with molar ratio of M/R at 0.15 gave the maximum As(V) adsorption capacity and removal with values of 62.8 µg/g and 86.7%, respectively. The adsorption data were wel...
Arsenic Removal from Water by Adsorption onto Iron Oxide/Nano-Porous Carbon Magnetic Composite
Applied Sciences, 2019
This study aimed to develop magnetic Fe 3 O /sugarcane bagasse activated carbon composite for the adsorption of arsenic (III) from aqueous solutions. Activated carbon (AC) was prepared from sugarcane bagasse by chemical activation using H 3 PO 4 as an activating agent at 400 • C. To enhance adsorption capacity for arsenic, the resultant AC was composited with Fe 3 O 4 particles by facile one-pot hydrothermal treatment. This method involves mixing the AC with aqueous solution of iron (II) chloride tetrahydrate, polyvinyl pyrrolidone (PVP), and ethanol. Batch adsorption experiments were conducted for the adsorption of As (III) onto the composite. The effects of pH, adsorbent dosage, and contact time on the arsenic adsorption were studied. The result showed that the composite could remove the arsenic from the water far more effectively than the plain AC. The highest percentage of arsenic removal was found at pH at 8, adsorbent dose of 1.8 g/L, and contact time of 60 min. Langmuir and Freundlich adsorption isotherm was used to analyze the equilibrium experimental data. Langmuir model showed the best fit compared to the Freundlich model with a maximal capacity of 6.69 mg/g. These findings indicated that magnetic Fe 3 O 4 /sugarcane bagasse AC composite could be potentially applied for adsorptive removal of arsenic (III) from aqueous solutions.
Facile Synthesis of Magnetic Activated Carbon Composite for Arsenic Adsorption
Journal of the Institute of Engineering
Porous activated carbon (AC) and magnetic iron oxide nanoparticles (NPs) are widely used for the removal of arsenic from water body. Fabrication of composite material of iron oxide NPs on the surface of porous AC can further enhance this activity for commercial application. In this research, a magnetic AC composite for arsenic adsorption was prepared by facile hydrothermal treatment of aqueous solution containing activated carbon obtained from lapsi seed stone, iron(II) chloride, polyvinylpyrrolidone (PVP) and ethanol. Several analytical techniques such as scanning electron microscopy (SEM), energy dispersive x-ray (EDX), X-ray diffraction (XRD) and Fourier-transform infrared spectroscopy (FTIR) confirmed the formation of magnetite (Fe3O4) nanoparticles on the surface of porous AC. The prepared materials were accessed for their arsenic adsorption capacity using arsenic (III) trioxide solution and found that composite Fe2O3/AC can remove the arsenic from water far more effectively th...
DESALINATION AND WATER TREATMENT
Arsenic contaminated water is a serious threat to human health. Therefore, the aim of this study was to use a new method of stabilization of ZnO/TiO 2 on activated carbon (I ZnO/TiO 2) for the effective removal of arsenic from aqueous solutions. In this experimental study, a container with a useful volume of 3.14 L (height of 40 cm and diameter of 10 cm) was used. For this purpose, four main factors including pH (3-11), nanosorbent dose (1-3 g/L), initial arsenic concentration (1-10 mg/L), and reaction time (30-300 min) as effective factors in the arsenic removal efficiency. The results showed that arsenic adsorption increased with increasing contact time, adsorbent dose, and decreasing pH and arsenic concentration. A quadratic model was selected to estimate the removal of arsenic by the adsorption process with the modified adsorbent under study. The linear regression coefficient (R 2) between experiments and different response values in the model for arsenic was >0.99. The optimal value for the studied variables was obtained for pH of 6.75, arsenic concentration of 9.76 mg/L, reaction time of 287.62 min, and nanosorbent dosage of 2.45 g/L. The maximum arsenic adsorption capacity under optimal conditions was predicted to be 4.53 mg/g. The results showed that the studied adsorbent for arsenic removal follows the Langmuir isotherm and quadratic kinetics (R 2 > 0.99). The results of this study showed that the adsorption process using nano-photocatalytic adsorbents of TiO 2 and ZnO has relatively high efficiency in arsenic adsorption and can be used as a suitable complementary treatment method for water and wastewater containing carcinogenic heavy metals such as arsenic.
Modeling of the adsorptive removal of arsenic: A statistical approach
Arsenic in drinking water has been recognized as a serious community health problem because of its toxic nature and therefore, its removal is highly essential. A series of adsorption experiments (batch and column) were performed utilizing iron impregnated sugarcane carbon (Fe–SCC), a composite adsorbent, to remove arsenic from aqueous systems. Under optimized batch conditions, the Fe–SCC could remove up to 94.5% of arsenic from contaminated water. The artificial neural network (ANN) model was developed from batch experimental data sets which provided reasonable predictive performance (R2 = 0.964; 0.963) of arsenic adsorption. In batch operation, the adsorbent dose had the most significant impact on the adsorption process. For column operation, central composite design (CCD) in response surface methodology (RSM) was applied to investigate the influence on the breakthrough time for optimization and evaluation of interacting effects of different operating variables. The perturbation plot depicted that the breakthrough time is more sensitive to initial concentration and adsorbent dose than flow rate. The optimized result obtained from bar plot revealed that the Fe–SCC was an effective and economically feasible adsorbent; whereas more than 93% desorption efficiency showed the reusability of the adsorbent. The high arsenic adsorptive removal ability and regeneration efficiency of this adsorbent suggest its applicability in industrial/household systems and data generated would help in further upscaling of the adsorption process.
Optimizing adsorption of arsenic(III) by NH2-MCM-41 using response surface methodology
Journal of Industrial and Engineering Chemistry, 2014
Response surface methodology (RSM) was used to optimize process parameters for arsenic (As(III)) removal from aqueous solution using amine-functionalized MCM-41 (NH 2-MCM-41). Four independent variables such as pH, initial metal concentration, temperature and adsorbent dosage were investigated. The optimal conditions to remove As(III) by NH 2-MCM-41 was found to be pH 5.62, initial As(III) concentration 5.00 mg/L, temperature 20 8C and NH 2-MCM-41 dosage 5.00 g/L. XRD, FTIR and SEM analyses testified to the obvious change of the surface morphology and the presence of metal on the sorbent after adsorption.
2020
Arsenic is a highly toxic element for human beings, which is generally found in groundwater. Dissolved Arsenic in water can be seen as As+3 and As+5 states. The adsorption process is one of the available methods to remove Arsenic from aqueous solutions. Thus, this papers aims at removing Arsenic (III) from aqueous solutions through adsorption on iron oxide granules. The relation among four independent variables, namely the initial concentration of Arsenic (III), pH, adsorbent dose, and contact time have been investigated through Response Surface Methodology. Design-Expert software and Central Composite Design method have been used to design and analyze the experiments and results. Also, SEM and FTIR analysis have been conducted to characterize the absorbent morphology. The optimum initial concentration of Arsenic (III), pH, contact time, and adsorbent dosage are 30ppm, 5, 49.99min, and 8g/l, respectively. Under these optimum conditions, the Arsenic (III) removal efficiency is 67%. T...
Journal of contaminant hydrology, 2017
This study aimed to investigate the feasibility of carboxymethyl cellulose-stabilized iron nanoparticles (C-nZVI) for the removal of arsenite ions from aqueous solutions. Iron nanoparticles and carboxymethyl cellulose-stabilized iron nanoparticles were freshly synthesized. The synthesized nanomaterials had a size of 10nm approximately. The transmission electron microscope (TEM) images depicted bulkier dendrite flocs of non-stabilized iron nanoparticles. It described nanoscale particles as not discrete resulting from the aggregation of particles. The scanning electron microscopy (SEM) image showed that C-nZVI is approximately discrete, well-dispersed and an almost spherical shape. The energy dispersive x-ray spectroscopy (EDAX) and X-ray diffraction (XRD) spectrum confirmed the presence of Fe(0) in the C-nZVI composite. The central composite design under the Response Surface Methodology (RSM) was employed in order to investigate the effect of independent variables on arsenite removal...