CHEMOSPHERE
·
2023
·
IF 8.8
Yang-xiao-xiao Shi,Jia-qi Cui,Feng Zhang,Ke-wei Li,Jun Jiang,Ren-kou Xu
Hexavalent chromium (Cr(VI)) is a toxic heavy metal and its mobility and bioaccessibility in soils are influenced by soil properties. In this study, the soil pH and organic carbon contents of Ultisol , Alfisol , and Inceptisol were adjusted before they were polluted with 230 mg kg −1 Cr(VI). Alkaline digestion, sequential extraction, and an in vitro experiment were conducted to study the valence state, species, and bioaccessibility of Cr in the soils. The results showed that a high soil pH was not favorable for reduction of Cr(VI); therefore the Cr(VI) and exchangeable Cr contents were positively related to soil pH. Soil organic carbon promoted the reduction of Cr(VI). Almost all Cr(VI) was reduced to Cr(III) when the soil organic carbon content reached 10 g kg −1 . Chromium bioaccessibility in simulated gastric and intestinal phase solutions was influenced by Cr(VI) and Cr(III) adsorption/desorption, dissolution/precipitation, and redox reactions. Chromium bioaccessibility differences between the gastric and intestinal phases were associated with the Cr(VI)/Cr(III) ratio. Acidic conditions and a high organic carbon content promoted the conversion of Cr(VI) to Cr(III). When soil pH was increased from 4.01 to 5.85, Cr(VI) in Alfisol without the addition of humic acid increased from 96.38 to 174.78 mg kg −1 , the exchangeable Cr proportion increased from 9.7% to 22.6%, and Cr bioaccessibility increased from 41.29% to 49.14% in the gastric phase and from 41.32% to 48.24% in the intestinal phase. When the organic carbon content increased from 3.95 to 9.28 g kg −1 in Alfisol, Cr(VI) content decreased from 167.66 to 20.52 mg kg −1 , which led to a decrease in Cr bioaccessibility from 49.15% to 13.8% in the gastric phase and from 45.85% to 7.67% in the intestinal phase. Therefore, acidic conditions and increasing soil organic carbon levels can reduce the health risk posed by Cr in soils.
研究领域:
环境科学
·
土壤学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
LANGMUIR
·
2023
·
IF 3.9
Qing Qing,Xian-ying Shi,Shao-zhong Hu,Liang Li,Ting Huang,Nan Zhang,Yong Wang
Increasing environmental problems intensify the demand for high-performance environmental purification materials. MXene is a typical transition-metal carbide/nitride material with a two-dimensional geometric feature and a good deal of functional groups, and it is considered as an efficient adsorbent for removing pollutants from wastewater. However, the easy oxidation and relatively low adsorption capacity greatly restrict its application. In this study, the MXene/polydopamine (PDA) composite particles were fabricated through the biomimetic modification method of inducing the self-polymerization of dopamine in an MXene aqueous solution. Microstructure characterizations demonstrate that PDA facilitates the exfoliation of MXene. Adsorption measurements show that MXene and PDA exhibit an apparent synergistic effect in removing chromium hexavalent Cr(VI) from aqueous solution, and more PDA content leads to a larger synergistic effect. Consequently, the composite particles exhibit an ultrahigh adsorption capacity (862.3 mg/g). Specifically, even if the composite particles were stored in aqueous solution for 2 months, they still exhibit high adsorption ability with only a 3.3% loss in adsorption capacity, indirectly confirming the enhanced stability of MXene induced by PDA. Furthermore, the composite particles also show reduction ability to Cr(VI) and about 54.3% Cr(VI) can be reduced to harmless chromium trivalent Cr(III). This study provides a new method for the preparation of MXene-based adsorbents with excellent adsorption capacity and high stability, which has broad application prospects in the field of wastewater treatment.
研究领域:
环境科学
·
材料科学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
ENVIRONMENTAL RESEARCH
·
2023
·
IF 8.3
Junjun Ma,Tao E,Shuyi Yang,Liang Chen,Ying Cheng,Jia Yu,Yun Li
Stabilizing Cr(III) in tannery sludge (TS) via harmless method has always been the goal of environmental pollution treatment. In this study, a simple method to stabilize Cr(III) in TS is proposed via adding kaolin, based on the fact a large amount of organic matter contained in TS. Comprehensive characterizations confirm that kaolin can stabilize Cr(Ⅲ) via its abundant –OH and lamellar structure. Moreover, there are hydrogen bond interactions and ligand exchange-surface complexation between organic matter and kaolin, which is more conducive to form a stable ternary complex with Cr(III), in a state of organic matter-Cr(III)-kaolin. Simultaneously, the BCR sequential extraction experiment shows that the unstable water and acid soluble state of Cr(III) are reduced (from 0.61% to 0.35%), which further indicates that the stabilization of Cr(III) is successful.
研究领域:
环境科学
·
污染治理
✓ 已验证
产品关联
DOI
PubMed
高影响因子
JOURNAL OF HAZARDOUS MATERIALS
·
2019
·
IF 7.65
Heming Wang,Xueyong Song,Huihui Zhang,Pan Tan,Fanxin Kong
An ion exchange membrane (IEM) is an important component in dual-chamber microbial fuel cells (MFCs) to separate cathodic chromium from anode bacteria to avoid toxicity. Common used IEMs (e.g., BPM, CEM, PEM, AEM) have different ionic transfer abilities which could influence MFC performance and chromium removal. Additionally, to distinguish chromium “removal” or “reduction” by MFCs, the chromium removal in this study was further analyzed into cathodic reduction, adsorption on the membrane and permeation through membrane to the anode chamber. It was found that BPM achieved the best performance in removing hexavalent chromium (99.4 ± 0.2 %) and balancing pH and conductivity in both chambers, followed by AEM (97.9 ± 0.8 %) and CEM (95.6 ± 0.8 %), while PEM can not well maintain pH and conductivity leading to the worst anode performance and lowest chromium removal efficiency. However, the adsorption of chromium on the AEM accounts for 91.1 ± 0.7 %, which was much higher than the other three membranes. The permeation of chromium through the membrane were all lower than 0.2% which can be ignored. SEM and EDS results showed that chromium deposits and bacteria were detected on the membrane facing cahtode and anode, respectively, indicating that membrane scaling and fouling were inevitable and happened within 24 h operation.
研究领域:
环境工程
·
化学工程
·
电化学
·
水处理
✓ 已验证
产品关联
DOI
PubMed
高影响因子
Desalination and Water Treatment
·
2016
·
IF 1.272
Fenglian Fu,Weijiang Han,Zihang Cheng,Bing Tang
This paper deals with the treatment of hexavalent chromium (Cr(VI)) and its removal mechanism using acid-washed zero-valent aluminum (ZVAl). The acid-washed ZVAl before and after reaction was characterized by scanning electron microscope, X-ray diffraction, and X-ray photoelectron spectroscopy. The influence factors such as ZVAl loading, acid washing time, and pH values on Cr(VI) removal were studied. Cr(VI) removal by acid-washed ZVAl was also evaluated under different humic acid and Fe2+ concentrations. The removal of Cr(VI) was accelerated with increasing acid-washed ZVAl loadings and decreasing initial pH. The addition of humic acid inhibited the Cr(VI) removal, while Fe2+ significantly accelerated the Cr(VI) removal. More than 98% Cr(VI) was removed from synthetic wastewater containing 20.0 mg/L Cr(VI) in 180 min by 0.4 g/L acid-washed ZVAl at initial pH 2.0. Cr(VI) removal by acid-washed ZVAl is proved by reduction, not by adsorption. The remarkable capacity of acid-washed ZVAl in removing Cr(VI) from wastewater displays its potential application in the treatment of wastewater-containing Cr(VI).
研究领域:
环境科学
·
化学工程
✓ 已验证
DOI
高影响因子
RSC Advances
·
2019
·Vol. 9
·期 22
·12428-12435
·
IF 3.049
Shifeng Li,Tingting You,Yang Guo,Shuhua Yao,Shuyan Zang,Min Xiao,Zhigang Zhang,Yanming Shen
A one-step carbothermal synthesis and characterization of biochar-supported nanoscale zero-valent iron (nZVI/BC) was performed for the removal of hexavalent chromium (Cr(VI)) from aqueous solution. High dispersions of nanoscale zero-valent iron supported on biochar were successfully synthesized by the pyrolysis of an iron-impregnated biomass (corn stover) as the carbon and iron source under nitrogen atmosphere. The effects of the pyrolytic temperature on the Fe mineralogies formed on the biochar are discussed. In general, the effects of the treatment time, initial solution pH, and nZVI/BC dosage on the Cr(VI) removal are presented. The results showed high crystallinity and purity, and nZVI/BC was obtained at a pyrolytic temperature of 800 °C. The batch experimental results determined that the adsorption capacity of Cr(VI) decreases with the increase in the initial pH value from 4.0 to 10.0. The Cr(VI) adsorption kinetics data effectively followed a pseudo-second-order kinetics with a calculated rate constant of 0.0.3396 g mg−1 min−1. The calculated thermodynamic parameters, such as ΔG°, ΔH°, and ΔS°, were evaluated, and the results indicated that the Cr(VI) reduction on nZVI/BC was a spontaneous and endothermic process. The adsorption mechanism of Cr(VI) was investigated by XRD and XPS analyses and the results demonstrated that Cr(VI) was reduced to Cr(III) and the oxidation of nZVI occurred during the reaction process. These results prove that nZVI/BC synthesized by a one-step carbothermal method can be considered as a potential candidate for the removal of Cr(VI) from aqueous solutions.
研究领域:
环境科学
·
材料科学
✓ 已验证
DOI
高影响因子
ACS ES&T Engineering
·
2022
·
IF 0
Dazhong Yang,Zheting Chu,Xuezhen Feng,Qiuyue Ge,Ranhao Wang,Juan Zhang,Shangying Li,Renji Zheng,Wenfei Wei,Shuping Yi,Hong Chen
Both alkaline heavy metal (HM) contaminated red mud (RM) recycling and Cr(VI) polluted soil remediation are severe hazardous environmental problems. Herein, we developed a novel integrated approach to neutralize and stabilize the hazardous RM via the introduction of Ca2+ and Cl– dual ions. When 3% CaCl2·2H2O is added, the pH of RM is reduced from 11.0 to 8.9, and the Pb, Cr, Zn, Cu, and As leaching concentrations from RM are suppressed lower than the environmental standards of China and the World Health Organization (Pb, Cr, Zn, Cu < 0.50 mg/L; As < 10 μg/L). Detailed mechanism studies reveal that the pH neutralization is attributed to the novel OH– flocculation effect ascribing to Ca2+ charge neutralization and Cl– promoted proton neutralization. Furthermore, as the pH decreases, the HM adsorption capacity of RM is enhanced, achieving stable HM immobilization. The treated RM can be further employed to remediate Cr(VI) contaminated soil (Cr concentration 570 ppm; treated RM weight percentage in soil 5.0%), which can suppress 56.0% Cr mobility in soil and 68.4% bioaccumulated Cr in the harvested vegetables. Overall, this work demonstrates an ecofriendly “waste-to-soil remediation” strategy to solve both the solid waste and soil pollution problems.
研究领域:
环境科学
·
土壤学
✓ 已验证
DOI
STARCH-STARKE
·
2024
·Vol. 77
·期 2
·2400050
·
IF 2.6
Xuesheng Qin,Chengzheng Wang,Zhe Zhang,Wei Ma
Hexavalent chromium (Cr(VI)) has attracted much attention because it is a harmful pollutant. In this study, acid hydrolyzed hydrothermal double modified starch (AHS) and hydroperoxide oxidized starch (HOS) are prepared from natural starch and used for the reduction of chromium (VI) in aqueous systems. The effects of hydrothermal acidolysis and oxidative modification of starch on the reduction rate of Cr(VI) are discussed, including the changes of solubility, swelling power, particle size, content of straight-chain starch, and carbonyl/carboxylic group content. The results of response surface methodology (RSM) optimization show that the influence of reaction conditions on the reduction rate of Cr(VI) by NS is as follows: reaction time > initial pH of solution > reaction temperature > starch to Cr(VI) mass ratio; and on the reduction rate of Cr(VI) by AHS and HOS is as follows: initial pH of solution > reaction time > starch to Cr(VI) mass ratio > reaction temperature.
研究领域:
环境科学
·
材料科学
✓ 已验证
DOI
高影响因子
Journal of Cleaner Production
·
2025
·
IF 10
Jialin Chen,Jingfei Zhou,Shoukai Chen,Haibo Shi,Qingfeng Hu,Yingdong Tang
It is anticipated that this would address the underlying reasons of the disposal challenges and associated safety hazards if Cr-containing tannery waste from the tannery industry could be produced into stabilized sustainable construction materials. In this paper, the geopolymer was prepared employing solid waste furnace slag (FS) and tannery sludge powder (TSP) and evaluated for mass loss rate, appearance, residual compressive strength, pore properties, phase transformation and Cr leaching behavior after different thermal exposure (200 °C, 400 °C, 600 °C, 800 °C, and 1000 °C) for 2 h. The results revealed that the compressive strength increased and then dropped with increasing thermal exposure temperature, with the residual compressive strength of geopolymer being the maximum (63.00 MPa) at 200 °C. Dehydroxylation and phase transition disrupted the pore structure, and the hydration products, mostly C-(A)-S-H, underwent depolymerization and repolymerization to create new crystalline phases including akermanite and gehlenite. Even at 600 °C, which has the greatest impact on the safety of geopolymers, the leaching concentrations of total Cr and Cr (Ⅵ) were only 1.39 mg/L and 0.074 mg/L, respectively, which were still far below the standard requirements. The possible Stabilization-Migration-Restabilization (SMR) route of Cr was identified as follows: Cr was physically encapsulated by C-(A)-S-H at 20 °C–400 °C; C-(A)-S-H was destroyed at 600 °C–800 °C, and Cr migrated and was oxidized to Cr (Ⅵ) by CaO; it was then probably reduced to Cr(V) by heat and Mg-O at 1000 °C and finally immobilized in akermanite by chemical bonding.
研究领域:
材料科学
·
环境科学
✓ 已验证
DOI
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2025
·
IF 13.2
Lv Xi,Xu Xincheng,Peng Yang,Li Bolin,Yang Lie,He Xiaoman
This study introduces a novel modification method for micron-sized zero-valent iron, utilizing Shewanella oneidensis MR-1 to simultaneously colonize its surface, disrupt the passivation layer, and alter the crystal structure of the core. This process yields a composite that retains its reducing activity even in high concentrations of pollutants (500 ppm Cr(VI)) and under neutral to slightly acidic conditions. Our findings indicate that the modified system induces the Kirkendall effect in zero-valent iron, leading to the formation of amorphous zero-valent iron with a non-spherical core structure, in contrast to conventional direct mixing approaches. The modified system achieves complete reduction of 100 ppm Cr(VI) to Cr(III) within 8 h. Notably, within the first 4 h of reaction, the reduction rate is approximately three times higher than that of the conventional direct mixing system. XPS, XRD, SEM, EEM and TEM analyses reveal that the surface passivation layer of the biochemically modified zero-valent iron is disrupted, leading to changes in its crystal structure, the formation of hollow spherical structures, and the development of a biological protective film on its surface. Interestingly, electrochemical and ETSA analyses indicate that the electron transfer rate of the biochemically modified composite is significantly enhanced. This study provides fundamental insights into the removal of Cr(VI) from groundwater using biochemically modified micron-sized zero-valent iron (mZVI).
研究领域:
环境科学
·
微生物学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF RADIOANALYTICAL AND NUCLEAR CHEMISTRY
·
2024
·
IF 1.5
Lu Sen,Yin Yuqiang,Bao Jiacheng,Wang Hongqiang,Lei Zhiwu,Hu Eming,Xin Qi,Quan Yihao,Wang Qingliang
In this study, tin sulphide (SnS 2 ) and nickel–chromium hydrotalcite (NiCr-LDH) complexes (SnS 2 /NiCr-LDH) were used for the simultaneous removal of U(VI) and humic acid (HA) from U(VI)-containing wastewater. The results showed that the adsorption of HA by the SnS 2 /NiCr-LDH was greatly enhanced, which was 4.07 and 2.94 times higher than that of pure SnS 2 and NiCr-LDH, respectively, and the highest U(VI) adsorption quantity over SnS 2 /NiCr-LDH increased from 127.81 to 446.68 mg g −1 when HA was present. Density functional theory (DFT) calculations revealed that the enhanced U(VI) adsorption on SnS 2 /NiCr-LDH was facilitated by the formation of a robust inner-sphere surface complex between U(VI) and HA.
研究领域:
环境科学
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF COLLOID AND INTERFACE SCIENCE
·
2025
·
IF 9.7
Hongwei Xu,Xiaxia Chen,Chao Liu,Mingyang Xu,Chenxi Guo,Yinglong Wang,Zhaoyou Zhu,Fanqing Meng
The presence of hexavalent chromium(Ⅵ) Cr(Ⅵ) and antibiotics in the environment can lead to the formation of combined pollutants that are harmful to ecosystems. To address this problem, we synthesized MoS 2 embedded in the porous super-hydrophilic polyurethane (PU) sponge and used weak water flow to drive the piezoelectric catalytic synergistic degradation of Cr(Ⅵ) and tetracycline (TC). In this study, the piezoelectric properties of MoS 2 /PU were confirmed via piezoresponse force microscopy (PFM) and COMSOL multiphysics calculations. Additionally, dynamics experiments, quenching experiments, electron paramagnetic resonance (EPR) spectroscopy, three-dimensional fluorescence excitation-emission matrix (3D-EEM) spectroscopy, and free radical generation rate analysis were conducted to explore the removal performance and mechanisms of MoS 2 /PU on the TC-Cr(VI) system. The results indicated that the coexistence of the two pollutants promotes the transfer of charge in MoS 2 /PU, further combined with O 2 to produce H 2 O 2 and continued to produce OH. The removal rates of TC and Cr(VI) in the TC-Cr (VI) mixed system at 30 min were 97 % and 94 %, respectively, which were 1.45 and 1.46 times those of the single TC and single Cr(VI) systems, respectively. Finally, potentially vulnerable sites of TC were calculated and analyzed according to density functional theory (DFT). Our results provide a new strategy for improving the degradation efficiency of antibiotics and Cr(VI) metals.
研究领域:
环境科学
·
材料科学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
危险品化学品经营许可证（带存储）