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Yao L, Hu Y, Zou Y, Ji Z, Hu S, Wang C, Zhang P, Yang H, Shen Z, Tang D, Zhang S, Zhao G, Wang X. Selective and Efficient Photoextraction of Aqueous Cr(VI) as a Solid-State Polyhydroxy Cr(V) Complex for Environmental Remediation and Resource Recovery. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2022; 56:14030-14037. [DOI: doi.org/10.1021/acs.est.2c03994] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/25/2023]
Affiliation(s)
- Ling Yao
- College of Environmental Science and Engineering, North China Electric Power University, 102206 Beijing, P. R. China
| | - Yezi Hu
- College of Environmental Science and Engineering, North China Electric Power University, 102206 Beijing, P. R. China
| | - Yingtong Zou
- College of Environmental Science and Engineering, North China Electric Power University, 102206 Beijing, P. R. China
| | - Zhuoyu Ji
- College of Environmental Science and Engineering, North China Electric Power University, 102206 Beijing, P. R. China
| | - Shuxian Hu
- Beijing Computational Science Research Center, 100193 Beijing, China
| | - Cong Wang
- Institute of Applied Physics and Computational Mathematics, 100088 Beijing, China
| | - Ping Zhang
- Institute of Applied Physics and Computational Mathematics, 100088 Beijing, China
| | - Hui Yang
- College of Environmental Science and Engineering, North China Electric Power University, 102206 Beijing, P. R. China
| | - Zewen Shen
- College of Environmental Science and Engineering, North China Electric Power University, 102206 Beijing, P. R. China
| | - Duoyue Tang
- College of Environmental Science and Engineering, North China Electric Power University, 102206 Beijing, P. R. China
| | - Sai Zhang
- College of Environmental Science and Engineering, North China Electric Power University, 102206 Beijing, P. R. China
| | - Guixia Zhao
- College of Environmental Science and Engineering, North China Electric Power University, 102206 Beijing, P. R. China
| | - Xiangke Wang
- College of Environmental Science and Engineering, North China Electric Power University, 102206 Beijing, P. R. China
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Yao L, Hu Y, Zou Y, Ji Z, Hu S, Wang C, Zhang P, Yang H, Shen Z, Tang D, Zhang S, Zhao G, Wang X. Selective and Efficient Photoextraction of Aqueous Cr(VI) as a Solid-State Polyhydroxy Cr(V) Complex for Environmental Remediation and Resource Recovery. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2022; 56:14030-14037. [PMID: 36130076 DOI: 10.1021/acs.est.2c03994] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Aqueous hexavalent chromium (Cr(VI)) treatment and chromium resource recovery toward Cr-containing wastes are of significant importance and necessity to both wastewater remediation and resource recovery. Herein, via mild photoreaction conditions with isopropanol (IPA) as an electron donor, a catalyst-free strategy for aqueous Cr(VI) extraction to form an insoluble polyhydroxy Cr(V) complex is developed for the first time. Aqueous Cr(VI) with concentration from 5 to 150 ppm can be efficiently extracted with high selectivity even in the presence of coexisting ions, and the total Cr concentration in residue solution can be as low as 0.5 ppm. The Cr resource could be efficiently recovered as pure Cr2O3 by calcinating the resulting Cr(V) precipitate. Outstanding extraction efficiency could be realized with various IPA concentrations (1.3-12.0 mol/L) by coordinately tuning the pH value to promote the formation of Cr(VI)-IPA ester. The formed ester undergoes intramolecular electron transition under visible light irradiation, resulting in a polyhydroxy solid-state Cr(V) intermediate complex. The controlled pH value blocks further reduction of Cr(V) to soluble Cr(III); thus the insoluble Cr(V) intermediate complex is stabilized thermodynamically under ambient conditions. Because of its electric neutrality property and the strong intermolecule interaction via hydrogen bonds, a dioxo-bridged di-nuclear Cr(V) complex {Cr2(μ-O)2(OH)4[OCH(CH3)2]2} is finally precipitated as the main product. Satisfactory extraction and recovery of Cr from chromium-plating wastewater and discarded stainless steel verify that this approach is ideal for both one-step purification of Cr(VI)-containing wastewater and selective resource recovery from Cr-containing solid wastes in practical application.
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Affiliation(s)
- Ling Yao
- College of Environmental Science and Engineering, North China Electric Power University, 102206 Beijing, P. R. China
| | - Yezi Hu
- College of Environmental Science and Engineering, North China Electric Power University, 102206 Beijing, P. R. China
| | - Yingtong Zou
- College of Environmental Science and Engineering, North China Electric Power University, 102206 Beijing, P. R. China
| | - Zhuoyu Ji
- College of Environmental Science and Engineering, North China Electric Power University, 102206 Beijing, P. R. China
| | - Shuxian Hu
- Beijing Computational Science Research Center, 100193 Beijing, China
| | - Cong Wang
- Institute of Applied Physics and Computational Mathematics, 100088 Beijing, China
| | - Ping Zhang
- Institute of Applied Physics and Computational Mathematics, 100088 Beijing, China
| | - Hui Yang
- College of Environmental Science and Engineering, North China Electric Power University, 102206 Beijing, P. R. China
| | - Zewen Shen
- College of Environmental Science and Engineering, North China Electric Power University, 102206 Beijing, P. R. China
| | - Duoyue Tang
- College of Environmental Science and Engineering, North China Electric Power University, 102206 Beijing, P. R. China
| | - Sai Zhang
- College of Environmental Science and Engineering, North China Electric Power University, 102206 Beijing, P. R. China
| | - Guixia Zhao
- College of Environmental Science and Engineering, North China Electric Power University, 102206 Beijing, P. R. China
| | - Xiangke Wang
- College of Environmental Science and Engineering, North China Electric Power University, 102206 Beijing, P. R. China
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Zheng Y, Li H, Yu Q, Yu L, Jiao B, Li D. Application of UV radiation for in-situ Cr(VI) reduction from contaminated soil with electrokinetic remediation. JOURNAL OF HAZARDOUS MATERIALS 2021; 416:125806. [PMID: 33873035 DOI: 10.1016/j.jhazmat.2021.125806] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/26/2020] [Revised: 03/03/2021] [Accepted: 03/31/2021] [Indexed: 06/12/2023]
Abstract
Restoring hexavalent chromium (Cr(VI)) to trivalent chromium (Cr(III)) from contaminated soil is a cost-effective alternative for attenuating Cr(VI) toxicity to the ecosystem. A new electrokinetic remediation (EKR) system with UV light was explored to overcome an energy barrier to catalyze Cr(VI) reduction from the surface soil near the anodic reservoir. Natural organic matters and minerals from the contaminated soil acted as electron donors and catalysts for Cr(VI) photo-reduction and no additional chemical reagent. There was almost no residual Cr(VI) in anolyte after UV/EKR compared with the conventional EKR. The reduction improved the efficiency of EKR in the soil near the anodic reservoir by dropped the Cr(VI) negative mass flux caused by electroosmosis advection and concentration diffusion. The pathways of Cr(VI) photo-reduction are possibly dominated by ligand-to-metal charge transfer, i.e., photocatalytic cyclic reduction by Fe(III)/Fe(II) complexes on the surface of the minerals and in soil pore fluid and the photo-induced decomposition of chromate ester. It is concluded that UV/EKR is a clean, efficient, and low-cost method for remediation of Cr(VI)-contaminated soil.
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Affiliation(s)
- Yi Zheng
- State Key Laboratory of Coal Mine Disaster Dynamics and Control, Chongqing University, Chongqing 400044, China; College of Resource and Safety Engineering, Chongqing University, Chongqing, 400044, China
| | - Huilin Li
- State Key Laboratory of Coal Mine Disaster Dynamics and Control, Chongqing University, Chongqing 400044, China; College of Resource and Safety Engineering, Chongqing University, Chongqing, 400044, China
| | - Qiu Yu
- State Key Laboratory of Coal Mine Disaster Dynamics and Control, Chongqing University, Chongqing 400044, China; College of Resource and Safety Engineering, Chongqing University, Chongqing, 400044, China
| | - Lin Yu
- State Key Laboratory of Coal Mine Disaster Dynamics and Control, Chongqing University, Chongqing 400044, China; College of Resource and Safety Engineering, Chongqing University, Chongqing, 400044, China
| | - Binquan Jiao
- State Key Laboratory of Coal Mine Disaster Dynamics and Control, Chongqing University, Chongqing 400044, China; College of Resource and Safety Engineering, Chongqing University, Chongqing, 400044, China
| | - Dongwei Li
- State Key Laboratory of Coal Mine Disaster Dynamics and Control, Chongqing University, Chongqing 400044, China; College of Resource and Safety Engineering, Chongqing University, Chongqing, 400044, China.
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Wu B, Yu S, Zhang G, Zhang S, Shen P, Tratnyek PG. Role of complexation in the photochemical reduction of chromate by acetylacetone. JOURNAL OF HAZARDOUS MATERIALS 2020; 400:123306. [PMID: 32947710 DOI: 10.1016/j.jhazmat.2020.123306] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/10/2020] [Revised: 06/15/2020] [Accepted: 06/22/2020] [Indexed: 06/11/2023]
Abstract
Organic ligands can alter the redox behavior of metal species through the generation of metal-ligand complexes. Photo-induced complexation between ligands and metals is an important, but under-appreciated, aspect of process. Acetylacetone (AA) is a good chelating agent due to keto-enol tautomerization. In the presence of AA, photoreduction of Cr(VI) is accelerated; however, it is unclear exactly how complexation is involved in UV/AA mediated Cr(VI) reduction. On the basis of spectral and kinetic analyses, this study shows that the formation of {Cr(VI)-AA}* complexes is the main mechanism of Cr(VI) reduction by UV/AA. Evidence for this includes (1) the formation rate constant of Cr(III)-AA complexes in the UV system was 2-3 orders of magnitude greater than that in the thermal system; (2) there was a linear relationship between the photons absorbed by AA and the reduction rate constants of Cr(VI); and (3) the reaction appeared initially zero-order in Cr(VI) and turned to first-order as the pool of available Cr(VI) ran out. The results presented here are not only important for the better understanding of the complexation effects in the reduction of Cr(VI), but also crucial for the possible application of the UV/AA process in many other scenarios.
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Affiliation(s)
- Bingdang Wu
- State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing, 210023, China
| | - Shouyun Yu
- State Key Laboratory of Analytical Chemistry for Life Science, Jiangsu Key Laboratory of Advanced Organic Materials, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, 210023, China
| | - Guoyang Zhang
- State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing, 210023, China
| | - Shujuan Zhang
- State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing, 210023, China.
| | - Pengfei Shen
- State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing, 210023, China
| | - Paul G Tratnyek
- OHSU-PSU School of Public Health, Oregon Health & Science University, 3181 SW Sam Jackson Park Road, Portland, OR, 97239, USA
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