Removal Of Cr Research Articles

In-Situ Remediation of Chromium Contaminated Soil by Biochar Co-Modified by CMC and Nano Zero-Valent Iron: Effects of Acid Rain and Freeze-Thaw Conditions

ABSTRACT In this study, by simulating acid rain and freeze-thaw conditions, the remediation effect of biochar modified by carboxymethyl cellulose stabilized nano zero-valent (CMC-nZVI@BC) on hexavalent chromium Cr(VI) contaminated soil was explored. Simulated acid rain was prepared according to the actual situation in Shenyang, China. Soil samples underwent 16 freeze-thaw cycles (frozen at −15°C for 12 h, then cultured at 15°C for 12 h). Samples were taken to measure pH, conductivity, cation exchange capacity (CEC), soil organic matter (SOM) and Cr(VI) concentrations. The toxicity characteristic leaching procedure (TCLP) and simplified bioaccessibility extraction test (SBET) were conducted to assess the leachability and in vitro bioaccessibility of Cr. ICP-OES was used to test the Cr(VI) and total Cr ions concentrations. The analysis of soil Cr forms adopted the BCR continuous extraction method. CMC-nZVI@BC showed improved dispersion stability and oxidation resistance with optimal CMC loading (0.25%) and nZVI ratio (4:3). After 14 days, Cr(VI) removal decreased from 97.7% to 92.9%. Under acid rain and freeze-thaw conditions, Cr(VI) concentrations in leachate remained below the 0.05 mg/L standard. TCLP, SBET, and 16S rRNA results confirmed that CMC-nZVI@BC reduced Cr leaching toxicity and bioavailability, while enhancing soil microorganism richness and diversity. In-situ remediation of chromium contaminated soil revealed that CMC-nZVI@BC could remain stable and not cause pollution to groundwater under the conditions of acid rain leaching and freeze-thaw cycles, providing certain references for the treatment of Cr(VI) contaminated sites.

Crystal Facet Regulation and Photocatalytic Properties of α-FeOOH: Crystal Facet Effects on the Built-In Electric Fields Coupled with Coordination Adsorption.

The α-FeOOH (021) crystal facet has a high density of active sites, and as a reactive facet, it has good adsorption of pollutants and good photocatalytic performance. In this paper, nano α-FeOOH with different (021)/(110) crystal facet ratios was prepared using crystal facet inducers (ethanol, ethylene glycol, and glycerol) via a hydrothermal method, with a (021)/(110) crystal facet ratio reaching 16% in the FG-2 sample. The results of photocatalytic experiments show that this sample's removal rate of Cr(VI) reaches 60.70% in 4 h, which is 61.00% higher than for FC with unregulated crystal facets, and the apparent normalized photocatalytic reaction rate constant is 8.28 times higher than for FC. Kelvin probe force microscope characterization (KPFM) results and density functional theory (DFT) calculation show that FG-2's higher rate of removal of Cr(VI) was due in large part to the different electric potentials of the (021) and (110) crystal facets. When the ratio of (021)/(110) crystal facets was changed, different electric fields resulted. Meanwhile, the high site density of the (021) crystal facet created high coordination efficiency and in addition higher reactivity resulted from the chromium ion's lower adsorption energy that the coupling effect produced.

Emerging trends and future outlook on chromium removal in the lab, pilot scale, and industrial wastewater system: an updated review exploring 10years of research.

Chromium (Cr) is widely recognized as a carcinogenic metal, and numerous technologies have been studied on a lab scale to manage the pollution caused by Cr contamination in wastewater. However, the removal of Cr presents several challenges and limitations in industrial wastewater management. These issues highlight the ongoing need for research to discover more efficient methods for remediating Cr from wastewater. The proposed review summarizes the current limitations, gaps, and state-of-the-art technologies on Cr removal in industrial wastewater systems over the past 10years. It aims to lay the groundwork for future research and innovation in Cr remediation for industrial applications. The review emphasizes that conventional physicochemical techniques are often insufficient and highlights the necessity of implementing advanced integrated systems. The limitations related to industrial scaling up are also deeply investigated. Special attention is given to differentiating research conducted at laboratory, pilot, and industrial levels. The findings reveal that limited research has been conducted on an industrial scale, with most investigations focusing on treating tannery and electroplating wastewater. A few studies have also been reported on wastewater from textile, mining, steel mills, pigments, and wood processing. Despite the existence of high-performance systems demonstrated in lab-scale studies, only a handful of treatment techniques have effectively removed Cr at an industrial scale. Nevertheless, innovative breakthroughs in advanced integrated systems show promise for improved performance in the future.

Three-Dimensional Porous Artemia Cyst Shell Biochar-Supported Iron Oxide Nanoparticles for Efficient Removal of Chromium from Wastewater

Chromium-containing wastewater poses severe threats to ecosystems and human health due to the high toxicity of hexavalent chromium (Cr(VI)). Although iron oxide nanoparticles (IONPs) show promise for Cr(VI) removal, their practical application is hindered by challenges in recovery and reuse. Herein, a novel three-dimensional porous nanocomposite, Artemia cyst shell biochar-supported iron oxide nanoparticles (ACSC@ IONP), was synthesized via synchronous pyrolysis of Fe3+-impregnated Artemia cyst shells (ACSs) and in situ reduction of iron. The optimized composite C@Fe-3, prepared with 1 mol/L Fe3+ and pyrolyzed at 450 °C for 5 h, exhibited rapid removal equilibrium within 5–10 min for both Cr(VI) and total chromium (Cr(total)), attributed to synergistic reduction of Cr(VI) to Cr(III) and adsorption of Cr(VI) and Cr(III). The maximum Cr(total) adsorption capacity was 110.1 mg/g at pH 2, as determined by the Sips isothermal model for heterogeneous adsorption. Competitive experiments demonstrated robust selectivity for Cr(VI) removal even under a 64-fold excess of competing anions, with an interference order of SO42− > NO3− > Cl−. Remarkably, C@Fe-3 retained 65% Cr(VI) removal efficiency after four adsorption–desorption cycles. This study provides a scalable and eco-friendly strategy for fabricating reusable adsorbents with dual functionality for chromium remediation.

Mesoporous hydrochar from Acacia falcata leaves by hydrothermal process for hexavalent chromium adsorption

This study evaluates mesoporous-hydrochar derived from Acacia falcata leaves via a single-step hydrothermal treatment for Cr(VI) adsorption. Material characterization indicated that the adsorbent has a rough and porous structure. FTIR analysis confirmed Cr(VI) adsorption through functional group interactions, evidenced by peak intensity changes and the emergence of a Cr–O bond vibration at 669 cm-1. Two new peaks were observed in XPS spectra, corresponding to Cr 2p at 577.04 eV (Cr 2p3/2) and 586.67 eV (Cr 2p1/2) after adsorption, further substantiating the adsorption and Cr(VI) reduction. Batch experiments showed an improved adsorption capacity of 30.47 mg/g. Kinetic investigation adhered to the pseudo-second-order model, whereas the equilibrium dataset satisfied the Freundlich model, indicating a heterogeneous adsorption mechanism involving physisorption and chemisorption. The thermodynamic evaluation confirmed spontaneous and endothermic adsorption. Regeneration studies showed reduced Cr(VI) removal performance after four cycles, attributed to pore blockage and loss of functional groups while maintaining effective reuse potential. Spiked studies in various water matrices showed a slight decrease in Cr(VI) removal efficiency, yet it maintained over 95% efficiency, demonstrating its potential for real-world water treatment applications.

Pumice modified with didodecyldimethylammonium bromide as a cost-effective, eco-friendly adsorbent for Cr(VI)

ABSTRACT Various types of organically modified minerals have already attracted the attention of researchers due to their promising and environmentally friendly properties and their diverse application. This study aims to develop a cost-effective and efficient adsorbent for Cr(VI) removal from wastewater by modifying pumice with acid activation and cationic surfactant treatment. The research focuses on optimising adsorption conditions, understanding the adsorption mechanisms, and evaluating the material’s reusability for large-scale applications. This study improves the properties of pumice (Pmc), surface organomodification using 5 M H2SO4 activation and a double-chain cationic surface active agent as an organic modifier, didodecyldimethylammonium bromide (DDAB) for the sorption of Cr(VI). Physicochemical characteristics of natural-pumice and organo-modified one were studied by EDX, SEM, FTIR, TGA, DTA, XRD and N2 adsorption/desorption tools. The influence of time, Cr(VI) concentrations, solution pH, weight of adsorbent, and temperature were measured and discussed in batch equilibration technique. The results showed rapid adsorption (60 min) with optimal efficiency at pH = 2 for Cr(VI) anions. The removal data fitted the Langmuir model, with a maximum adsorption capacity of 7.81 mg/g. The sorption of these anions onto DDAB/Pmc followed pseudo-second-order rates. Thermodynamic parameters for anions adsorption have been evaluated. The parameters gained from experiments and others can be utilised to design an economical treatment plant for water polluted with Cr(VI) anions or wastewater resulting from industrial.

Fabrication of magnetic flower-shaped Fe3O4@In2S3 composite for efficient removal of aqueous Cr(VI)

Fabrication of magnetic flower-shaped Fe3O4@In2S3 composite for efficient removal of aqueous Cr(VI)

Exploring graphene oxide and bacterial cellulose for Cr(VI) removal from water

AbstractIn this study, nanocomposite membranes based on bacterial cellulose (BC) and graphene oxide (GO) were synthesized at different volume ratios of BC to GO. The mechanical properties of these membranes were investigated to determine the optimal combination ratio. Furthermore, the adsorption capacity of the membranes for Cr(VI) heavy metal ions was evaluated under various conditions, including time, temperature, pH, stirring rate, and adsorbent dosage. The mechanical strength analysis revealed that the membrane with a BC to GO volume ratio of 1:6 exhibited the highest tensile strength of 96.79 MPa. Scanning electron microscopy (SEM) images confirmed the successful integration of nanocellulose fibers and graphene oxide in this ratio, forming a novel composite structure. Subsequent adsorption experiments demonstrated that the optimal conditions for Cr(VI) adsorption were as follows: 160 min of adsorption time, a temperature of 313 K, a stirring rate of 150 rpm, pH = 3, and an adsorbent dosage of 0.1 g. The maximum adsorption capacities of the BC/GO‐1, BC/GO‐2, BC/GO‐3, and BC/GO‐4 membranes were determined to be 17.36, 17.76, 18.69, and 17.06 mg g−1, respectively. The adsorption process followed Langmuir and Freundlich isotherm models. The study highlights the potential of BC/GO nanocomposite membranes for efficient adsorption of Cr(VI) heavy metal ions from water. The optimized conditions identified can serve as guidelines for practical applications of these membranes in water treatment processes. Additionally, the successful synthesis and characterization of the BC/GO membranes underscore their promising prospects for environmental remediation and sustainable materials development.

Adsorption and ecotoxicology studies with aqueous solution of Cr(VI) ions using adsorbent materials derived from Inga edulis.

Adsorption and ecotoxicology studies with aqueous solution of Cr(VI) ions using adsorbent materials derived from Inga edulis.

Preparation and Characterization of Low-Cost Bio-Sorbent and a Novel Activated Carbon from Agro-Wastes for Efficient Cr(VI) Removal

This study focuses on the preparation and characterization of a novel highly efficient activated carbon (new-AC) and a low-cost adsorbent (BM) from a mixture of agro-based wastes to remove toxic Cr(VI). BM was obtained by mixing wastes subjected to some specific preparation processes in equal proportions, while new-AC was produced by pyrolyzing BM chemically activated with KOH. Various techniques such as elemental analysis, BET-surface area (SBET), pore size and volume measurements, pHpzc, FTIR, Boehm titration, and SEM–EDX analysis were employed for the characterization of adsorbents. The findings revealed that new-AC exhibited a greater SBET, carbon content, and more acidic surface (1413 m2/g, 91.9% C, and pHpzc of 6.8) compared to BM (5.32 m2/g, 51.08% C, and pHpzc of 7.8). Adsorption experiments were performed to evaluate the efficiency of each adsorbent, with results compared against a commercial activated carbon (com-AC) for Cr(VI) removal. The optimal conditions for removing 50 mg-Cr(VI)/L were identified as pH 2, 4 g/L dosage, and 30 min contact time for new-AC; pH 2, 5 g/L dosage, and 90 min for com-AC; and pH 2, 20 g/L dosage, and 60 min for BM. The maximum adsorption capacities observed for BM, new-AC, and com-AC were 6.46, 51.55, and 41.67 mg/g of Cr(VI), respectively. The adsorption behavior for all three adsorbents aligned well with the Langmuir isotherm model, and thermodynamic analysis suggested that the adsorption processes were exothermic, spontaneous, and favorable.

Constructing Porous Polyacrylonitrile/Polyethylenimine Microspheres by Polymer Crystallization Vapor-Induced Phase Separation for Efficient Adsorption and Separation of Chromium Ion.

The development of cost-effective wastewater treatment technologies is imperative for heavy metal pollution mitigation, which presents considerable risks to water supplies, ecosystems, and human health. In this context, polyacrylonitrile/polyethylenimine porous microspheres (PAN/PEI PM) were synthesized through a dual-phase strategy combining polymer crystallization and vapor-induced phase separation, leading to effective removal of hexavalent chromium (Cr(VI)) from wastewater. The PAN/PEI PM, characterized by a substantial number of amino groups and a relatively uniform particle size ranging from 1.3 to 1.7 μm, demonstrated commendable thermal stability, a high specific surface area (93.5 m2/g), and a pore volume of 0.7 cm3/g. Furthermore, the PAN/PEI PM exhibited a significantly enhanced Cr(VI) adsorption efficiency, achieving levels of up to 194.5 mg/g. Even after five cycles, they consistently maintained a removal efficiency exceeding 64%, with an adsorption capacity still reaching 125.6 mg/g. The adsorption isotherm and kinetics were found to correlate well with the Langmuir and pseudo-second-order models, respectively. Adsorption experiments demonstrated that the porous microspheres effectively remove Cr(VI) primarily through complexation and electrostatic interactions, which is attributed to the elevated concentration of ionizable functional amino groups (NH2) within the microsphere structure. Additionally, the redox processes are predominantly reliant on the reduction of adsorbed Cr(VI) to Cr(III). These findings underscore the favorable adsorption characteristics and reusability of PAN/PEI PM, offering valuable insights for the development of more effective and sustainable strategies for Cr(VI) removal from wastewater.

Ecotoxicological efficiency of Cr(VI) removal treatment with reductive biogenic iron-based material determined by amphibian larval bioassays.

Ecotoxicological efficiency of Cr(VI) removal treatment with reductive biogenic iron-based material determined by amphibian larval bioassays.

Valorization of agricultural waste and red mud through CO2-mediated pyrolysis system.

Valorization of agricultural waste and red mud through CO2-mediated pyrolysis system.

Modification of iron-containing silicate tailings with oxalic acid to develop a long-efficacy utilization peroxymonosulfate-based system for the efficient decomplexation and removal of Cr(III)-ethylenediamine tetraacetic acid.

Modification of iron-containing silicate tailings with oxalic acid to develop a long-efficacy utilization peroxymonosulfate-based system for the efficient decomplexation and removal of Cr(III)-ethylenediamine tetraacetic acid.

One-step construction of sulfur-vacancy-rich SnS/Bi2S3 Z-scheme heterostructure photocatalyst for significant removal of hazardous Cr(VI)

One-step construction of sulfur-vacancy-rich SnS/Bi2S3 Z-scheme heterostructure photocatalyst for significant removal of hazardous Cr(VI)

Corrigendum to “Piezophotocatalysis of ZnO@PVDF coaxial nanofibers modified with BiVO4 and Ag for the simultaneous generation of H2O2 and removal of pefloxacin and Cr(VI) in water” [Chem. Eng. J. 484 (2024) 149514

Corrigendum to “Piezophotocatalysis of ZnO@PVDF coaxial nanofibers modified with BiVO4 and Ag for the simultaneous generation of H2O2 and removal of pefloxacin and Cr(VI) in water” [Chem. Eng. J. 484 (2024) 149514

Synergistic removal of Atrazine and Cr (VI) from water by FeS-loaded modified montmorillonite activated Persulfates

Synergistic removal of Atrazine and Cr (VI) from water by FeS-loaded modified montmorillonite activated Persulfates

Polysaccharide self-crosslinking and refrigerated air-drying interfacial modification: A new approach for konjac glucomannan-guar gum thin film loaded with NZVI for enhanced Cr(VI) removal

Polysaccharide self-crosslinking and refrigerated air-drying interfacial modification: A new approach for konjac glucomannan-guar gum thin film loaded with NZVI for enhanced Cr(VI) removal

Development of a high-performance core/double-layered sheath nanofibrous membrane for continuous Cr(VI) removal in adsorption-filtration systems

Development of a high-performance core/double-layered sheath nanofibrous membrane for continuous Cr(VI) removal in adsorption-filtration systems

Highly effective adsorption, porous and charged CAP@Ui0-66-NH2@PPy hybrid fibrous membrane based on MOFs for Cr (VI) removal from wastewater

Highly effective adsorption, porous and charged CAP@Ui0-66-NH2@PPy hybrid fibrous membrane based on MOFs for Cr (VI) removal from wastewater