Effective Removal Of Cr Research Articles

Effective removal of Cr(VI) from water by ball milling sulfur-modified micron zero-valent iron：Influencing factors and removal mechanism

To address the issues of ZVI's susceptibility to oxidation and aggregation, ball milling and Na2S·9H2O modification were employed on ZVI to enhance its efficiency in removing Cr(VI) from effluent. The characterization results expressed that S-mZVIbm had mesoporous and macroporous structures, enabling successful capture of Cr(VI). Moreover, S-mZVIbm had the highest adsorption capacity for Cr(VI) (350.04 mg/g) at pH = 2.00 and reached kinetic equilibrium within 420 min. Furthermore, the adsorption of Cr(VI) by S-mZVIbm conformed to the Avrami-fractional-order model, demonstrated that the adsorption process indicated a complex multi-adsorption process. Meanwhile, the adsorption also fit to Langmuir and Sips models, suggesting monolayer-level adsorption with heterogeneous sites located on S-mZVIbm. The S-mZVIbm could enhance Cr(VI) adsorption through various synergistic mechanisms, such as electrostatic interaction, chemical precipitation, surface complexation, and reduction. Overall, this research presented an innovative perspective for the modification of ZVI, and S-mZVIbm could be widely applied in the practical remediation of wastewater containing Cr(VI).

Study on the preparation of Nano-Fe3O4 by steel pickling waste liquor and its effective removal of Cr (VI) from wastewater

In order to comprehensively treat and utilize steel pickling waste liquor (SPWL), this study used SPWL as raw material to prepare two different crystalline forms of Nano-Fe3O4 by co-precipitation and precipitation-oxidation methods, and investigated their removal effect on Cr(VI) in wastewater. The two kinds of Nano-Fe3O4 were characterized using SEM, XRD, and VSM, and the results showed that the Nano-Fe3O4 synthesized by the co-precipitation method has better properties. The two kinds of Nano-Fe3O4 were used to remove Cr(VI) in wastewater, the adsorption capacity could reach 38.38 mg/g and 15.83 mg/g, respectively. Five adsorption kinetic models and five isothermal adsorption models were used to study the adsorption mechanism of Fe3O4 on Cr(VI). The adsorption process of Cr(VI) by Nano-Fe3O4 was explained well using the pseudo-second-order and Freundlich isotherm model, and the results showed that the adsorption process mainly involved physical and chemical adsorption. Through the characterization analysis before and after the reaction, the removal mechanism of Cr(VI) by Nano-Fe3O4 prepared from SPWL is mainly attributed to electrostatic adsorption and reduction reaction. According to the market survey and analysis, the production cost is reduced by at least 58.33 % compared to that of Nano-Fe3O4 prepared using analytical purity in the market. Therefore, the preparation of Nano-Fe3O4 by steel pickling waste liquor provides an economical and effective way to remove heavy metal ions in wastewater.

Effective removal of Cr (VI) from an aqueous solution using a carbon coated NiFe2O4 nano-adsorbent

Exploration of cubic ferrites for chromium removal is ongoing. Ferrites offer a promising avenue for chromium removal because of their unique properties, high surface area, magnetic recoverability, and potential for surface modifications to enhance adsorption capacities. Herein, the work highlights the synthesis of carbonaceous nickel ferrite (NiFe2O4/C) through an inert ambient pyrolysis process, where metal acetylacetonates are used as the sources of metal ions and carbon. The synthesized NiFe2O4/C was successfully characterized for its structure and morphology using X-ray diffraction (XRD), Fourier transform infrared (FT-IR), Field emission scanning electron microscopy (FESEM), Energy Dispersive X-ray analysis (EDX), Raman spectroscopy, Transmission electron microscopy (TEM) and Brunauer-Emmett-Teller (BET) analysis. The study confirmed that, the size of nanostructure was of ∼29 nm, with a surface area of 56.925 m2/g, pore volume of 0.085 cc/g with type IV hysteresis loop. The regular spherical shape was observed through FESEM, and a carbon coating was evident and confirmed from TEM. Synthesized NiFe2O4/C was efficiently used for the Cr (VI) removal, it was found that at an equilibrium time of 60 min, nearly 85% of the chromium was removed using 0.01 g of adsorbent at native pH and efficiency was further improved by lowering the pH. The investigation further examined the isotherm and kinetics models. The material was regenerated for 5 cycles with a removal percentage of 57%.

Effective removal of Cr(VI) and Pb(II) ions from mining wastewater using eco-friendly synthesized magnesium oxide nanoparticles incorporated rice husk ash

This study explored the effective adsorptive performance of magnesium oxide (MgO) nanoparticles incorporated rice husk ash (RHA) to address the removal of Chromium (VI) and Lead (II) from mining wastewater from aqueous environment. MgO nanoparticles were synthesized using a magnesium salt precursor and moringa oleifera leaf extract and then impregnated onto RHA to create MgO-RHA nano composite. Different analytical techniques were employed to characterize the RHA and MgO-RHA nanocomposites. The prepared adsorbents were used in batch adsorptive studies and the concentrations of the metal ions were measured before and after treatment using atomic absorption spectrophotometry. Morphological analysis confirmed that the adsorbents developed exhibited a dispersed and porous nature. BET analysis revealed that RHA, MgO, and MgO-RHA had surface areas of 93.04, 32.02, and 102.71 m2/g, respectively. MgO-RHA outperforms RHA in removing metal ions due to its increased surface area and functionality. MgO-RHA demonstrated higher removal percentages of up to 79.20 % and 96.02 % for Cr(VI) and Pb(II), respectively. The Pseudo-second order kinetics and Langmuir isotherm demonstrated the highest degree of conformity to the experimental data, considering the coefficient of determination (R2), smallest value of SSE and chi-square (ᵪ2). Thermodynamic results indicated that the adsorption process was characterized by endothermicity, spontaneity and chemisorption controlled. In summary, the performance of the MgO-RHA nanocomposite surpassed that of RHA alone, which serves as a better adsorbent for metal ion removal.

An efficient hexavalent chromium scavenger: Polyaniline

Hexavalent chromium ions are a significant type of heavy metal pollutant in water, posing a severe threat to the environment and biological health. Various methods are employed for treating heavy metal wastewater, including traditional, biological, physical, and chemical adsorption, and membrane separation methods. This study focuses on utilizing chemical oxidation polymerization to synthesize polyaniline, followed by structural characterization and performance evaluation. The research shows the material’s exceptional adsorption capacity for Cr(VI) ions under different conditions. The experiments specifically demonstrate a direct relationship between the rate of removal and the proportion of adsorbent utilized in comparison to the Cr(VI) initial concentration. Furthermore, adjusting the pH level during testing shows an increase in the removal rate as the pH decreases, with a peak removal rate of 57.94% at pH 1.02. By aligning with a pseudo-second-order kinetic model, the material demonstrates its potential for efficient and effective removal of Cr(VI) contaminants.

Production of hydrochar from corn silk by hydrothermal carbonization technique and its modification for more effective removal of Cr(VI)

AbstractThe objective of this project was to develop a new bioproduct that will utilize agricultural waste and modify the product to increase its present adsorption capacity. After the hydrothermal carbonization of corn silk, a novel hydrochar was generated and treated using sulfuric acid to boost its adsorption capacity. FT‐IR, SEM–EDX, TGA, and BET surface analysis studies were used to analyze the structure of the produced biosorbents. According to the EDX analysis results, there are C, H, and N elements in the hydrochar structure, and the treated hydrochar contains S in addition to these elements. While the presence of several functional groups was indicated by FT‐IR data, post‐adsorption EDX analysis proved that Cr ions were adhering to hydrochar. The proper parameters for the adsorption processes for both biosorbents were established. By analyzing the outcomes of kinetics tests at various concentrations and isotherm experiments, the adsorption procedure was identified. The pseudo‐second‐order kinetic model was shown to be consistent with the kinetic pathways of adsorptions. Although the results of the isotherm experiments also suited the Langmuir isotherm, the Freundlich isotherm had higher R2 values and was more consistent with the results. The outcomes demonstrated that sulfuric acid‐modified hydrochar offered greater Cr(VI) adsorption capacity. qm values defining the maximum adsorption capacities of HC and THC at a temperature of 333 K were estimated to be 263.16 and 294.12 mg g−1, in that order. Based on the qm values, the adsorption capabilities of HC and THC were compared with those of a few other adsorbents. THC (29.11 m2 g−1) had a 29% larger surface area than HC (22.57 m2 g−1), according to the surface area of BET test results.

Effective removal of Cr(VI) in water by bulk-size polyaniline/polyvinyl alcohol/amyloid fibril composite beads.

With the rapid expansion of industrial activities, chromium ions are discharged into the environment and cause water and soil pollution of various extents, which seriously endangers the natural ecological environment and human health. In this study, polyaniline/polyvinyl alcohol/amyloid fibril (PANI/PVA/AFL) composite gel beads (PPA) were prepared from polyaniline and amyloid fibrils with HCl as doping acid and PVA as a cross-linking agent. The results showed that PPA was an irregular composite bead with a diameter of 6 mm. The adsorption of Cr(VI) on the PPA gel beads followed the pseudo-second-order kinetics model, suggesting that chemical reactions were the controlling step in the Cr(VI) adsorption process. Though the Redlich-Peterson isotherm model had the best fit for the adsorption data, the isothermal adsorption process can be simplified using the Langmuir model. The maximum adsorption capacity for Cr(VI) in water was 51.5 mg g-1, comparable to or even higher than some PANI-based nanomaterials. Thermodynamic parameters showed that the adsorption process was a spontaneous, endothermic, and entropy-increasing process. Microscopic analysis revealed that the capture of Cr(VI) on PPA was mainly governed by electrostatic attraction, reduction, and complexation reactions. PPA can be used as a kind of effective remediation agent to remove Cr(VI) in water.

Effective removal of Cr (VI) from aqueous solution by reinforced sodium alginate/polyethyleneimine/graphene oxide composite aerogels.

A reinforced composite aerogel absorbent was synthesized using a green chemistry method and an environmentally friendly freeze-drying technique. The absorbent consisted of sodium alginate, polyethyleneimine (PEI), and graphene oxide (GO). The ability of the absorbent to remove Cr (VI) ions from aqueous solutions was studied. PEI was a nitrogen source for Cr (VI) removal and a cross-linking agent for GO sheets, while SA was a reinforcing material. The aerogel was investigated using X-ray diffraction, scanning electron microscopy, Fourier transform infrared (FTIR) spectroscopy, texture analysis, Raman spectroscopy, and thermogravimetric analysis (TGA). Batch studies were conducted to investigate the effect of pH and contact time on adsorption. The results indicated that the SA/PEI/GO aerogel had a maximum adsorption capacity of 174.05 mg·g-1 for Cr (VI) at pH 2. The adsorption mechanism was described using the Langmuir isotherm and pseudo-second-order kinetic models. Thermodynamic studies revealed that the adsorption process was spontaneous and endothermic. The aerogel demonstrated good regeneration ability and satisfactory recovery for Cr (VI) even after five cycles. These findings suggest that the composite aerogel could be a promising adsorbent for efficiently removing Cr (VI) from wastewater.

Effective removal of Cr(VI) from solution by three-dimensional polyaniline loaded composite porous hydrogel

Effective removal of Cr(VI) from solution by three-dimensional polyaniline loaded composite porous hydrogel

Effective removal of Cr(VI) ions from aqueous solution using low-cost adsorbents (orange mesocarp, Bengal gram husk, and Khangar): equilibrium, kinetic, and thermodynamic study

Effective removal of Cr(VI) ions from aqueous solution using low-cost adsorbents (orange mesocarp, Bengal gram husk, and Khangar): equilibrium, kinetic, and thermodynamic study

Fabrication of ZnO decorated porous chitosan beads for the sustainable bioremediation of Cr(VI) contaminated water

Chromium contamination, particularly in industrial and mining sectors, has become a serious issue for the aquatic system, globally. Until now, the removal of Cr(VI) have been accomplished by a variety of approaches. However, these existing techniques are economically not efficient. Here, we demonstrate quick and effective removal of Cr(VI) from water by biosorption method using simple polymer modification technique. Specifically, we synthesized native chitosan beads (NCB) and ZnO NPs modified chitosan beads (ZMCB) for the adsorptive elimination of Cr(VI) from aqueous medium. Some advanced analytical techniques such as BET, SEM-EDX, XRD and FTIR were applied to characterize the biosorbents. Both NCB and ZMCB followed Langmuir isotherm model and maximum adsorption capacity of 23.16 mg/g and 130.28 mg/g, respectively was observed at optimal conditions (1.5 g dose, pH 2, initial concentration 50 ppm at 293 K). The results showed that pseudo 2nd order (PSO) kinetic was best fitted for the biosorption process, as coefficient regression constant for PSO have highest value (R2 > 0.999). Additionally, it was observed that the ZMCB composite may be used in many Cr(VI) adsorption cycles with little decrease in adsorption efficiency (91% adsorption up to the 5th cycle). Overall, this study offers a quick and easy approach for synthesizing low-cost materials that will be extremely useful for environmental applications.

Effective removal of Cr(VI) ions from the aqueous solution by agro-waste-based biochar: an exploration of batch and column studies

Effective removal of Cr(VI) ions from the aqueous solution by agro-waste-based biochar: an exploration of batch and column studies

Effective removal of Cr (VI) ions using low-cost biomass leaves (Sambucus nigra L.) in aqueous solution.

The tannery industries have become an important part of societal growth; however, these processes have produced huge volumes of effluents containing heavy metals, particularly Cr(VI) oxyanions. The study is crucial and cost-effective for reducing the chromium (VI) from industrial wastewater. In order to meet the sustainable development goal (SDG) objective 6.3, the capacity of Sambucus nigra L. to adsorb heavy metal is established with the purpose of eradicating hazardous chemical contamination and reducing pollution. In this study, discontinuous tests were carried out to determine the efficiency of Cr(VI) sorption on leaves of Sambucus nigra L. Adsorption factors such as pH, temperature, adsorbent dosage, and contact time were evaluated. At a dosage of 3g/L and pH 2, an efficiency of 98.22% was achieved under favorable conditions. The equilibrium and kinetic models that best fitted the experimental data are non-linear Freundlichand; pseudo-second order, and intra-particle diffusion, respectively. The thermodynamic parameters of the adsorption process, including Gibbs free energy (ΔG0), enthalpy (ΔH0), and entropy (ΔS0), were measured at 291, 303, 323, and 343K, indicating that the phenomena was spontaneous and endothermic. The chemical analyses and surface morphology of the adsorbent were analyzed using SEM (scanning electron microscopy), EDS (energy dispersive spectroscopy), FTIR (Fourier transform infra-red), XRD (X-ray diffraction), and ICP-OES (inductively coupled plasma optical-emission spectroscopy) techniques. The results showed that Sambucus nigra L. has a significant removal efficiency of Cr(VI) in the contaminated solutions, establishing adsorbent as a low cost, readily available, and environmentally friendly and ensuring its potential for industrial usage.

Effective removal of Cr(VI) from aqueous solution by iron‐carbonized solid waste composite: behavior mechanism and factor analysis

AbstractBACKGROUNDThe spent bleaching earth (SBE) is a solid waste produced during the refining of vegetable oil, with features of high residual oil and difficult disposal. At present, pollution control by the treatment of waste is a hot issue to attract more and more attention. This study used SBE as the raw materials and developed a new type of iron‐carbon composite (FexOy/SBE@C) by loading iron on spent bleaching earth carbon (SBE@C) to remove Cr(VI) in water. SBE@C was obtained by the pyrolysis of SBE.RESULTSThe behavior mechanism and factor analysis of FexOy/SBE@C for Cr(VI) removal in water were investigated for the first time. At first, one‐factor experiments in the preparation process were adopted to obtain FexOy/SBE@C with optimal performance. By characterization analysis of the optimal FexOy/SBE@C before and after Cr(VI) removal, it was found that the Cr(VI) removal mechanism was adsorption followed by reduction. Specifically, the adsorption kinetic and isotherm behaviors of FexOy/SBE@C for Cr(VI) belong to the pseudo‐second‐order kinetic model and Langmuir isotherm, respectively. Cr(VI) removal by FexOy/SBE@C is spontaneous (△G<0) and endothermic (△H>0). The presence of coexisting anions (i.e., BrO3− < SO42− < PO43−) and the increase of pH (only adsorption at pH>7) are not conductive to Cr(VI) removal by FexOy/SBE@C. Fortunately, N2 atmospheres can promote Cr(VI) removal (~100%) that is significantly higher than those in air atmosphere (63.34%) and natural conditions (82.25%).CONCLUSIONOverall, FexOy/SBE@C has the satisfactory Cr(VI) removal performance through physical adsorption and chemical reduction, and exhibits great potential application value in Cr(VI) elimination from water. © 2022 Society of Chemical Industry.

Effective removal of Cr(VI) and methyl orange by nano magnetite loaded starch/muscovite biocomposite: Characterization, experiments, advanced modeling, and physicochemical parameters interpretation

Magnetite nanoparticles (MNPs) synthesized from heated basalt were used to support a biocomposite prepared from muscovite (Mus) and carbohydrate polymer starch (St). The developed Mus/St/MNPs composite was characterized by XRD, FTIR, FESEM, TGA, DSC, and Zeta potential techniques. This multifunctional composite showed outstanding adsorption properties for hexavalent chromium (Cr(VI)) and methyl orange (MO) removal at 25–55 °C and pH 3.0. The adsorption isotherms were fitted to Langmuir model for Cr(VI) and Freundlich equation for MO. To understand microscopically these systems and to analyze their adsorption geometry and interactions mechanism, three statistical physics models were utilized. Theoretical calculations indicated that Cr(VI) ions were adsorbed on composite surface presenting a combination of horizontal and vertical positions, while the aggregated MO molecules displayed a non-parallel adsorption orientation and multi–interactions mechanism. The saturation adsorption capacity increased from 243.37 to 371.59 mg/g for Cr(VI) and 409.29 to 457.62 mg/g for MO at 25 and 55 °C (i.e., endothermic interactions). Cr(VI) and MO adsorption on Mus/St/MNPs was controlled by van der Waals forces, hydrogen bonding, and electrostatic interactions where the calculated adsorption energies were 12.5–30.62 kJ/mol. The utilized adsorbent was easily reactivated and reused several times where regenerated Mus/St/MNPs composite showed nearly 79 % of Cr(VI) and 85 % of MO adsorption capacities even after the fourth adsorption–desorption cycle. This study contributes to understand the physicochemical factors of Cr(VI) and MO adsorption on multifunctional adsorbents like MNPs/carbohydrate polymers/aluminosilicates interface.

The in-depth revelation of the mechanism by which a downflow Leersia hexandra Swartz constructed wetland-microbial fuel cell synchronously removes Cr(VI) and p-chlorophenol and generates electricity

The composite pollution by Cr(VI) and p-chlorophenol (4-CP) has high toxicity and harms water safety. However, research on the effective removal of Cr(VI) and 4-CP composite-polluted wastewater (C&P) and efficient synchronous electricity generation with reclaimed resources is limited. In this study, a downflow Leersia hexandra constructed wetland-microbial fuel cell (DLCW-MFC) was builded to treat C&P, as well as wastewater singularly polluted by Cr(VI) (SC) and 4-CP (SP), respectively, to reveal the mechanism by which DLCW-MFC treats C&P and synchronously generates electricity. The results demonstrate that the cathode layer had a stronger removal effect on pollutants than the middle layer and anode zone layer. Moreover, SC and SP had stronger pollutant removal effects than C&P. Cr(VI) had more competitive with electrons than 4-CP, and they had a synergistic effect on efficient electricity generation. The L.hexandra in SC and SP had a better growth state and lower Cr enrichment concentration than that in C&P. Cr existed in the DLCW-MFC mainly in the form of Cr(III). Gas chromatography-mass spectrometry was used to investigate the degradation pathway of 4-CP in C&P, and indicated that Phenol, 2,4-bis(1,1-dimethylethyl)- and benzoic acid compounds were the main intermediates formed at the cathode, and further mineralized to form medium-long-chain organic compounds to form CO2. The microbial community distribution results revealed that Simplicispira, Cloacibacterium, and Rhizobium are associated with Cr(VI) removal and 4-CP degradation, and were found to be rich in the cathode of C&P. The anode of C&P was found to have more Acinetobacter (1.34%) and Spirochaeta (4.83%) than SC and SP, and the total relative abundance of electricigens at the anode of C&P (7.46%) was higher than that at the anodes of SC and SP. This study can provide a theoretical foundation for the DLCW-MFC to treat heavy metal and chlorophenol composite-polluted wastewater and synchronously generate electricity.

Multifunctional chitosan non-woven fabrics modified with terylene carbon dots for selective detection and efficient adsorption of Cr(VI)

A novel terylene carbon dots (TCDs) modified on chitosan non-woven fabrics (CNF) were successfully applied to semi-quantitatively detect on a smartphone-integrated-device and efficiently remove Cr(VI) in real samples. • Terylene carbon-dots modified chitosan non-woven fabrics (CNF-TCDs). • CNF-TCDs showed high selectivity for Cr(VI) among different cations and oxyanions. • CNF-TCDs showed high sensitivity for Cr(VI) (LOD 0.15 mg/L). • CNF-TCDs exhibited efficient removal for Cr(VI) repeatedly. • CNF-TCDs semi-quantitatively detected Cr(VI) on a smartphone-integrated-device. A novel terylene carbon dots (TCDs) were successfully synthesized by a one-step solvothermal method, and further modified onto chitosan non-woven fabrics (CNF) for selective detection and effective removal of Cr(VI). Compared with TCDs, chitosan non-woven fabrics modified by carbon dots (CNF-TCDs3) exhibited higher selectivity and lower detection limit for Cr(VI) (The limit of detection (LOD) is 0.15 mg/L). In addition, CNF-TCDs3 showed a rapid and effective removal of Cr(VI), and still maintain a high relative removal rate (above 92%) after five times recirculation. The adsorption equilibrium could be reached in only 8 min, and the maximum adsorption capacity was 203 mg/g. The adsorption process conformed to the Langmuir model, and the fitting correlation is R 2 = 0.99. The fluorescence response and efficient adsorption mechanisms of the CNF-TCDs3 toward Cr(VI) were mainly attributed to the internal filtering effect and the amino and hydroxyl groups in chitosan. Significantly, this functionalized fabrics CNF-TCDs3 were successfully applied to semi-quantitatively detect on a smartphone-integrated-device and efficiently remove Cr(VI) in real samples.

Simultaneous reduction and sequestration of hexavalent chromium by magnetic β-Cyclodextrin stabilized Fe3S4

In this study, β-Cyclodextrin (CD) modified Fe3S4 nanomaterials were synthesized by a one-step facile strategy and investigated for the removal of Cr(VI). The resulted CD-Fe3S4 exhibited enhanced removal efficiency toward Cr(VI) than bared Fe3S4 with a maximum capacity of 220.26 mg·g-1 as the molar ratio of CD-to-Fe3S4 at 0.2. The effective performance of CD-Fe3S4 toward Cr(VI) could well maintain under oxic conditions and a wide pH range of aqueous solution. A high selectivity for Cr(VI) was achieved in the presence of coexisting cations and anions. More significantly, a single treatment step of CD-Fe3S4 effectively removed chromium from actual electroplating wastewater to the detection limit of 0.004 mg·L-1 that far below the WHO limitation of Cr (VI) (<0.05 mg·L-1) combing with the rapid magnetic separation without adjusting the pH value of wastewater at 7. The effective removal of Cr (VI) by CD-Fe3S4 involved a complex process of surface adsorption/reduction, and solution homogenous reduction and subsequent sequestration of Cr(III) achieving the effective removal of aqueous total Cr. The superior Cr (VI) removal capability and facial separation of CD-Fe3S4 attained its prominent potential application as an effective material for the Cr(VI) removal.

Effective removal of Cr(VI) from aqueous solution through adsorption and reduction by magnetic S-doped Fe-Cu-La trimetallic oxides

In this work, magnetic S-doped Fe-Cu-La trimetallic oxides (S-FeCuLaO) were prepared and adopted as an adsorbent to remove Cr(VI) from aqueous solutions. The S-FeCuLaO material was characterized by SEM, XRD, FTIR, XPS and VSM, and batch adsorption experiments were employed to investigate the effects of main interfering factors on Cr(VI) adsorption. The results demonstrated that almost 100% of Cr(VI) was removed at initial pH 3–4 and Cr(VI) removal efficiency sharply declined to 25.3% with initial pH increasing to 10. Cr(VI) adsorption process abided by pseudo-second-order kinetic model and Langmuir model, indicating that Cr(VI) adsorption onto S-FeCuLaO was monolayer chemical adsorption. The maximum adsorption capacity of Cr(VI) achieved from Langmuir model at initial pH 4 reached 157.98 mg/g. XPS analysis indicated 36.7% of adsorbed Cr(VI) anions was converted to non-toxic Cr(III) by Cu(I) and S2−. Furthermore, the removal mechanism of Cr(VI) at pH < pHPZC was proposed as electrostatic attraction, ion-exchange reaction, reduction of partial Cr(VI) and formation of Cr(OH)3. Among the five coexisting anions studied, only SO42− suppressed Cr(VI) adsorption. Moreover, the adsorbent displayed high stability at pH above 4 and great reusability with the removal of above 96% Cr(VI) in the fifth cycle. Therefore, the magnetic S-FeCuLaO composite is a low-cost material for the efficient removal of Cr(VI) from water environment.

Effective Removal of Cr(Vi) from Aqueous Solution Through Adsorption and Reduction by Magnetic S-Doped Fe-Cu-La Trimetallic Oxides

Effective Removal of Cr(Vi) from Aqueous Solution Through Adsorption and Reduction by Magnetic S-Doped Fe-Cu-La Trimetallic Oxides