SEPARATION AND PURIFICATION TECHNOLOGY
·
2021
·
IF 7.312
Ousmanou Njoya,Shengxin Zhao,Xingyu Kong,Jimin Shen,Jing Kang,Binyuan Wang,Zhonglin Chen
The treatment of industrial wastewater containing Cr(VI)–organic compounds is a long-term concern in the field of environment. In order to realize the high-efficient reduction of Cr(VI) and solve the problem of Cr(III) residue in water environment, a novel catalytic chemical reduction/membrane filtration method was developed for the removal of total Cr (TCr) in a system with coexisting Cr(VI) and oxalate (Ox). The effects of the concentrations of Ox, Fe(III), and Al(III), the dosage of NaBH 4 , and sedimentation time on the removal of Cr(VI) containing Ox by NaBH 4 were investigated. Additionally, the simultaneous removal of turbidity and TCr using a microfiltration membrane was investigated, and the reason for the enhanced TCr removal was clarified. The results of ion chromatography (IC), atomic force microscopy (AFM), and X-ray photoelectron spectroscopy (XPS) suggested that when Cr(VI) and Ox coexist, low concentrations (0.3 mM) of Fe(III) or Al(III) contributed significantly to the high turbidity caused by the formation of suspended solids (SS) following the reduction of Cr(VI) by NaBH 4 . However, almost all the Cr(III) could be removed by a 1-μm microfiltration membrane. The high turbidity system formed by Ox and Cr(III) is unstable, and some Ox will gradually release their binding sites with Cr(III) with the extension of the natural settling time. For 24 h, 53.75% of Ox was involved in the formation of SS, while in the presence of Fe(III) or Al(III), only 11.28% and 6.30% of Ox were involved, respectively. High concentrations of Fe(III) and Al(III) enhanced the reduction of Cr(VI) by NaBH 4 . The removal of TCr was close to 100% after natural sedimentation for 15 min and combined with a microfiltration membrane. This result is caused because Fe(III)–Cr(III) or Al(III)–Cr(III) can form larger SS, which is easily intercepted by the microfiltration membrane. The development of a novel combined method of catalytic chemical reduction and membrane filtration will be beneficial for reducing the retention of TCr in the environment.
研究领域:
环境科学
·
化学工程
✓ 已验证
产品关联
DOI
高影响因子
CHEMOSPHERE
·
2024
·
IF 8.1
Weiting Chen,Bing Li,Weizhao Yin,Weilong Zeng,Ping Li,Jinhua Wu
Zero-valent iron (ZVI), as an effective medium, is widely used to eliminate heavy metal ions in filter tanks. However, it will react with Cr(VI) to generate Fe–Cr precipitates with low conductivity on its surface, resulting in slow iron corrosion and low Cr(VI) removal efficiency. In this study, three oxidants (KMnO 4 , NaClO, and Na 2 S 2 O 8 ) were employed to promote iron corrosion in ZVI systems for enhanced Cr(VI) removal at a concentration of 5 mg/L through batch tests and column experiments. The ZVI/KMnO 4 , ZVI/NaClO, and ZVI/Na 2 S 2 O 8 systems achieved significantly higher Cr(VI) removal rates of 31.5%, 52.8%, and 65.9% than the ZVI system (9.8%). Solid phase characterization confirmed that these improvements were attributed to promoted iron corrosion and secondary mineral formation (e.g., lepidocrocite, ferrihydrite, and magnetite) by oxidants. Those minerals offered more reaction sites for Cr(VI) reduction, adsorption, and sequestration. Cycle experiments indicated that ZVI/oxidant systems could stably remove Cr(VI). In long-term column experiment, the ZVI/NaClO column showed a much longer life-span and exhibited a 34.8 times higher Cr(VI) removal capacity than that of the ZVI column. These findings demonstrated that ZVI in combination with a reasonable amount of oxidants was a promising method for removing Cr(VI) in practical filter tanks and provided a new insight to enhance Cr(VI) removal.
研究领域:
环境科学
·
化学工程
✓ 已验证
产品关联
DOI
PubMed
高影响因子
JOURNAL OF HAZARDOUS MATERIALS
·
2017
·
IF 6.065
Weizhao Yin,Yongtao Li,Jinhua Wu,Guocai Chen,Gangbiao Jiang,Ping Li,Jingjing Gu,Hao Liang,Chuansheng Liu
A one-pot bio-iron system was established to investigate synergetic abiotic and biotic effects between iron and microorganisms on Cr(VI) removal. More diverse iron corrosion and reactive solids, such as green rusts, lepidocrocite and magnetite were found in the bio-iron system than in the Fe 0 -H 2 O system, leading to 4.3 times higher Cr(VI) removal efficiency in the bio-iron system than in the Fe 0 -H 2 O system. The cycling experiment also showed that the Cr(VI) removal capacity of Fe 0 in the bio-iron system was 12.4 times higher than that in the Fe 0 -H 2 O system. A 62 days of life-span could be achieved in the bio-iron system, while the Fe 0 -H 2 O system lost its efficacy after 30 days. Enhanced effects of extra Fe 2+ on Cr(VI) removal was observed, largely contributed to the adsorbed Fe 2+ on iron surface, which could function as an extra reductant for Cr(VI) and promote the electron transfer on the solid phase. The results also showed that the reduction of Cr(VI) by microorganisms was insignificant, indicating the adsorption/co-precipitation of Cr by iron oxides on iron surface was responsible for the overall Cr(VI) removal. Our study demonstrated that the bio-amended iron corrosion could improve the performance of Fe 0 for Cr(VI) removal from groundwater.
研究领域:
环境科学
·
微生物学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2024
·
IF 13.3
Tong Hu,Wenjun Zhou,Haijiao Xie
Lattice engineering of Fe 0 based on heteroatom doping holds great promise in water purification owing to their tunable geometric and electronic structure. However, there is limited understanding of how nitrogen atom in Fe 0 lattice structure affects its local microenvironment and corresponding reactivity toward target contaminants. Herein, microscale zero-valent iron with interstitial N doping (N-mZVI) was successfully prepared by a facile mechanochemical method for heavy metal pollution control. N-mZVI exhibited excellent reactivity for Cr(VI) elimination, and both removal efficiency and conversion rate could reach 100 %, which was 8.06 and 2.73 times higher than that of pristine ball milled mZVI, respectively. Besides, the rate constant of various heavy metals sequestration (Cr(VI), Ni(II), Pb(II), Cu(II), and Cd(II)) over N-mZVI was 61.3 ∼ 115.6-fold faster than that of pristine ball milled mZVI. N-mZVI was also demonstrated to be pH-universal, long-term stability, and environmental applicability. Experimental results and theoretical calculations indicated that tensile strain induced by interstitial N doping expanded Fe 0 lattice and weakened the lattice Fe-Fe interaction, thus significantly accelerating electron transport dynamics in Fe 0 core. Meanwhile, iron nitride species on the surface of N-mZVI promoted electron transfer from iron shell layer to heavy metals. This work comprehensively investigates the structure–property relationships of lattice engineering-based N-mZVI, and provides a new insight into rational design of modified mZVI with high reactivity.
研究领域:
环境科学
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材料科学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF HAZARDOUS MATERIALS
·
2025
·
IF 11.3
Cuili Xing,Xinyi Yao,Kaiwei Zheng,Yang Liu,Yuankui Sun,Xiaohong Guan
Efficient removal of recalcitrant Cr(III)-organic complexes is always challenged by slow decomplexation process and the possible accumulation of highly toxic Cr(VI). Herein, a sulfidated zero-valent iron coupled ozonation strategy (S-ZVI/O 3 ) was proposed to achieve efficient decomplexation and simultaneous abatement of Cr(III)-EDTA without Cr(VI) accumulation. Results revealed that S-ZVI could catalyze O 3 to enhance removal of Cr(III)-EDTA and total organic carbon. Moreover, 88.3 % of total Cr was sequestrated by S-ZVI/O 3 and the corresponding kinetic constant was 3.1 times higher than that of ZVI/O 3 . Mechanistically, electron paramagnetic resonance and probing tests verified HO • was the dominant reactive oxidation species for decomplexation of Cr(III)-EDTA in both S-ZVI/O 3 and ZVI/O 3 . More attractively, it was found that structural Fe(II) was the major O 3 activator in S-ZVI/O 3 , whereas dissolved Fe 2+ accounted for O 3 catalyzation in ZVI/O 3 . The X-ray absorption spectroscopy analysis revealed that sulfidation treatment could enhance corrosion of ZVI with the formation of sufficient Fe(II) species. The in-situ formed Fe(II) could not only transform undesired Cr(VI) back to Cr(III) but also co-precipitate with Cr(III) to form solid Fe-Cr hydroxides. Besides Cr(III)-EDTA, S-ZVI/O 3 is also applicable to other EDTA complexed heavy metals. This work would provide a new method for the heavy metal complexes removal from water.
研究领域:
环境科学
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化学工程
✓ 已验证
产品关联
DOI
PubMed
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2019
·
IF 8.355
Lian Zhang,Yue Zhang,Xuyan Gao,Chunhua Xu
Recent studies showed that Fe(II) acts as the major electron donor when sulfidated zero-valent iron (S-ZVI) is used for reductive removal of pollutants. However, few studies have focused on the utilization efficiency and regeneration rate of Fe(II). In this work, the dynamic interaction between pH and S-ZVI for Cr(VI) removal and Fe(II) production was investigated at several pH levels. It was found that the maximum utilization efficiency and regeneration rate of Fe(II) was obtained at pH 5, which is consistent with the Cr(VI) removal by S-ZVI. To further study the role of Fe(II) in Cr(VI) reduction, an innovative binary correlation analysis between aqueous Cr(VI) and Fe(II) was applied with the addition of 1,10-phenanthroline as a way to control Fe(II) availability for Cr(VI) reduction. The analysis revealed that the Cr(VI) sequestration was initially controlled by Fe 0 /FeS and then by Fe(II), which accounts for the majority of the Cr(VI) sequestration. Additionally, the effects of several operational parameters (e.g., S/Fe ratio, S-ZVI dosage and initial concentration of Cr(VI)) on Cr(VI) removal were also evaluated and the results indicated that the removal of Cr(VI) exhibited a bimodal pattern with increasing S/Fe ratio, but followed a unimodal pattern with increase of S-ZVI dosage and chromium concentration. This study sheds additional insight into the dynamic interaction between pH and Fe(II), which is significant for further improving the efficiency of Fe(II) on contaminants.
研究领域:
环境科学
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化学工程
✓ 已验证
产品关联
DOI
高影响因子
WATER AIR AND SOIL POLLUTION
·
2022
·Vol. 233
·期 12
·1-14
·
IF 2.984
Li Weiquan,Li Mingxi,Yin Weizhao,Zhang Weinan,Zhong Jiawei,Li Ping,Deng Hong,Wu Jinhua
The removal of Cr(VI) from groundwater by zero-valent iron (Fe 0 ) and microorganisms under different nutrients and electron-accepting conditions was investigated using continuously-flowed column reactors with an abiotic Fe 0 column as the control. Both abiotic and biotic Fe 0 columns were operated at low and relatively high concentrations of organic substrates (sodium acetate and humic acid) and electron acceptors (nitrate and sulfate). Sodium acetate and humic acid were found to be effective substrates for the biotic Fe 0 system to remove Cr(VI) since microorganisms were able to gain extra reducing capacity from two nutrients and simultaneously avoid the passivation effect of humic acid on Fe 0 by metabolizing it. For nitrate and sulfate, varied influences were observed in the biotic Fe 0 system. The former showed apparent inhibition on Cr(VI) removal as it competed with Cr(VI) for electrons, and the inhibition became more severe while nitrate concentrations increased. Differently, highly reactive minerals such as green rusts and iron sulfide could be generated on the biotic Fe 0 surface under sulfate-reducing condition. They significantly enhanced Cr(VI) removal by providing more adsorptive and reductive sites. Overall, though the biotic Fe 0 column exhibited a longer life-span and higher Cr(VI) removal capacity than the abiotic Fe 0 column, the effects of organic substrates and electron acceptors should still be taken into account when applying biotic Fe 0 systems for Cr(VI)-contaminated groundwater remediation.
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
Nanomaterials
·
2021
·Vol. 11
·期 10
·2580
·
IF 5.076
Jien Ye,Yating Luo,Jiacong Sun,Jiyan Shi
The aggregation of nanoscale zero-valent iron (nZVI) particles and their limited transport ability in environmental media hinder their application in environmental remediation. In this study, the Cr(VI) removal efficiency, transport performance, and toxicity of nZVI and bentonite-modified nZVI (B-nZVI) were investigated. Compared with nZVI, B-nZVI improved the removal efficiency of Cr(VI) by 10%, and also significantly increased the transport in quartz sand and soil. Increasing the flow rate can enhance the transport of nZVI and B-nZVI in the quartz sand columns. The transport of the two materials in different soils was negatively correlated with the clay composition. Besides, modification of nZVI by bentonite could reduce toxicity to luminous bacteria (Photobacterium phosphereumT3) and ryegrass (Lolium perenneL.). Compared with Fe-EDTA, the transfer factors of nZVI and B-nZVI were 65.0% and 66.4% lower, respectively. This indicated that although iron nanoparticles accumulated in the roots of ryegrass, they were difficult to be transported to the shoots. The results of this study indicate that B-nZVI has a strong application potential in in situ environmental remediation.Keywords:nanoscale zerovalent iron (nZVI);hexavalent chromium;bentonite;toxicity
研究领域:
环境科学
·
化学
·
纳米技术
✓ 已验证
DOI
PubMed
高影响因子
Nanomaterials
·
2022
·Vol. 12
·期 11
·1846
·
IF 5.719
Zhuang Tong,Qin Deng,Shengxu Luo,Jinying Li,Yong Liu
Heavy metal ions such as Cr(VI) pose great hazards to the environment, which requests materials and methods for decontamination. Nano zero-valent iron (nZVI) has emerged as a promising candidate for Cr(VI) removal. Herein, harnessing the merits of marine biomass, a heterogeneous water treatment system for the decontamination of Cr(VI) is developed based on the in situ immobilization of nZVI on the seashell powder (SP)-derived porous support. A response surface methodology (RSM) study involving three independent factors is designed and conducted to direct material synthesis and reaction design for products with optimal performances. Under optimal synthetic conditions, the nZVI-loaded seashell powder (SP@nZVI), which is characterized in detail by scanning electron microscope (SEM), X-ray diffraction (XRD), and Fourier-transform infrared spectroscopy (FTIR), results in a 79% increase in the removal efficiency of Cr(VI) compared to free nZVI. Mechanism studies show that the removal of Cr(VI) by SP@nZVI conforms to the Langmuir adsorption model with a quasi-second order kinetic equation, in which redox reactions between nZVI and Cr(VI) occurred at the SP surface. The results of this work are expected to benefit the reuse of bioresource waste in developing environmental remediation materials.Keywords:seashell resource utilization;pyrolysis;zero-valent iron;response surface methodology;chromium removal
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
SEPARATION AND PURIFICATION TECHNOLOGY
·
2024
·
IF 8.1
Yixin Pan,Leilei Sun,Zhixin Yu,Xiahui Guo,Lujia Chen,Man Huang
In this study, a composite material (FeS-Mor) of nano ferrous sulfide (FeS) and mordenite was prepared by coprecipitation method using mordenite as a stabilizer to prevent the aggregation of FeS to achieve the purpose of efficient removal of chromium from water. Experimental results revealed that the optimum pH for Cr(VI) removal was ∼ 2 with a removal capacity of 199.0 mg/g and efficiency of 99.5 % at 303 K. Common co-existing cations of Na + , Ca 2+ and K + promoted the removal efficiency, while Mg 2+ inhibited the removal of Cr(VI). While Common anions of SO 4 2− , CO 3 2− , Cl − and NO 3 − inhibited chromium removal. The pseudo-second-order kinetics model fitted the kinetic removal of Cr(VI) onto FeS-Mor composites best under absent/present co-existing cations, indicating that chemical reduction and complexation dominated the removal process. The thermodynamic results were best described with the Freundlich model and showed an endothermic process of Cr(VI) removal. The FeS-Mor composites with FeS:Mor mass ratio in the range of 1:1–1:2 exhibited the best performance in removal efficiency and reusability. These results reveal that introducing mordenite to develop an efficient FeS-based nanocomposite system can significantly improve the performance of chromium remediation from aqueous solutions.
研究领域:
环境科学
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材料科学
✓ 已验证
产品关联
DOI
高影响因子
RSC Advances
·
2018
·Vol. 8
·期 58
·33217-33227
·
IF 2.936
Wenjie Tang,Yue Wu,Tingting Gao,Yingqin Wei,Guowei Zhou
In the present work, leucoemeraldine-based hybrid porous polyanilines (LHPPs) have been synthesized by the Friedel–Crafts reaction of leucoemeraldine and octavinylsilsesquioxane (OVS) for Cr(VI) removal. The resulting LHPPs were characterized by Fourier transform infrared spectroscopy, powder X-ray diffraction, thermogravimetric analysis, scanning electron microscopy and N2 adsorption–desorption. The findings indiated that the LHPPs were amorphous, with apparent surface areas (SBET) in the range of 147 to 388 m2 g−1 and total volumes in the range of 0.13 to 0.44 cm3 g−1. Cr(VI) removal experiments displayed that the LHPPs exhibited highly efficient Cr(VI) removal performance. The maximum Cr(VI) removal capacity of LHPP-1 was 990.1 mg g−1 at 308 K and pH 1, which is higher than those of other reported polyaniline-based adsorbents. The adsorption process was a spontaneous, endothermic and chemical adsorption process. The adsorption behavior agreed well with Langmuir models and pseudo second-order equations. X-ray photoelectron spectroscopy and Fourier transformed infrared (FTIR) spectroscopy analysis revealed that the highly efficient Cr(VI) removal performance can be mainly attributed to the existence of numerous amine and imine groups on the surface of the LHPPs; these can function as adsorption active sites for Cr(VI) removal through electrostatic adsorption and reduction to Cr(III) under acidic conditions. Moreover, the LHPPs exhibited excellent adsorption selectivity for Cr(VI) despite the presence of other metal ions (K+, Cu2+, Mn2+) and anions (NO3−, SO42−). Therefore, the LHPPs have potential applications for Cr(VI) removal in industrial wastewater.
研究领域:
环境科学
·
材料科学
✓ 已验证
DOI
高影响因子
SEPARATION AND PURIFICATION TECHNOLOGY
·
2020
·
IF 5.774
Yujun Cheng,Haoran Dong,Tianwei Hao
In this study, calcium carbonate (CaCO 3 ) coated nanoscale zero-valent iron (referred to as C-nZVI) was successfully synthesized and used for the removal of Cr(VI) in aqueous solution. The obtained C-nZVI particles were observed to be chain-like structure of spherical particles with a smooth surface by Transmission Electron Microscope (TEM). The magnetic hysteresis loop manifested that C-nZVI (CaCO 3 /Fe = 1:4, mass ratio) was ferromagnetic and the saturation magnetization (Ms) was 115.48 emu/g, revealing that C-nZVI had favorable properties of separation, recovery and reuse. Regarding the Cr(VI) removal, no positive correlation between the removal efficiencies and CaCO 3 /Fe mass ratio increasing from CaCO 3 /Fe = 0.5:4 to 4:4. Meanwhile, complete removal of Cr(VI) was observed at initial pH = 3.0 and initial Cr(VI) concentration of 5 mg/L, and the removal efficiency gradually decreased with increasing the initial pH and initial Cr(VI) concentration. The water chemistry had a more or less influence on the reactivity of C-nZVI. Specifically, the presence of Ca 2+ and Mg 2+ facilitated the Cr(VI) removal by C-nZVI, but the PO 4 3− and humic acid (HA) impeded the reactivity of C-nZVI. NO 3 − is generally considered to have an adverse influence on nZVI, but it displayed a positive effect on C-nZVI, which should be ascribed to the promotion of C-nZVI corrosion. Additionally, C-nZVI aged for 2 d and 30 d in air had a similar removal efficiency (83.2% and 82.6%) of Cr(VI) as fresh C-nZVI (85%), whereas the Cr(VI) removal efficiency by C-nZVI aged for the same aging times in aqueous solution were approximate 65.9% and 46.6%, respectively.
研究领域:
环境科学
·
材料科学
✓ 已验证
DOI
高影响因子
危险品化学品经营许可证（带存储）