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Xie J, Latif J, Yang K, Wang Z, Zhu L, Yang H, Qin J, Ni Z, Jia H, Xin W, Li X. A state-of-art review on the redox activity of persistent free radicals in biochar. WATER RESEARCH 2024; 255:121516. [PMID: 38552490 DOI: 10.1016/j.watres.2024.121516] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/11/2023] [Revised: 03/04/2024] [Accepted: 03/23/2024] [Indexed: 04/24/2024]
Abstract
Biochar-bound persistent free radicals (biochar-PFRs) attract much attention because they can directly or indirectly mediate the transformation of contaminants in large-scale wastewater treatment processes. Despite this, a comprehensive top-down understanding of the redox activity of biochar-PFRs, particularly consumption and regeneration mechanisms, as well as challenges in redox activity assessment, is still lacking. To tackle this challenge, this review outlines the identification and determination methods of biochar-PFRs, which serve as a prerequisite for assessing the redox activity of biochar-PFRs. Recent developments concerning biochar-PFRs are discussed, with a main emphasis on the reaction mechanisms (both non-free radical and free radical pathways) and their effectiveness in removing contaminants. Importantly, the review delves into the mechanism of biochar-PFRs regeneration, triggered by metal cations, reactive oxygen species, and ultraviolet radiations. Furthermore, this review thoroughly explores the dilemma in appraising the redox activity of biochar-PFRs. Components with unpaired electrons (particular defects and metal ions) interfere with biochar-PFRs signals in electron paramagnetic resonance spectra. Scavengers and extractants of biochar-PFRs also inevitably modify the active ingredients of biochar. Based on these analyses, a practical strategy is proposed to precisely determine the redox activity of biochar-PFRs. Finally, the review concludes by presenting current gaps in knowledge and offering suggestions for future research. This comprehensive examination aims to provide new and significant insights into the redox activity of biochar-PFRs.
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Affiliation(s)
- Jia Xie
- Key Laboratory of Low-carbon Green Agriculture in Northwestern China, Ministry of Agriculture and Rural Affairs, College of Natural Resources and Environment, Northwest A & F University, Yangling 712100, China
| | - Junaid Latif
- Key Laboratory of Low-carbon Green Agriculture in Northwestern China, Ministry of Agriculture and Rural Affairs, College of Natural Resources and Environment, Northwest A & F University, Yangling 712100, China
| | - Kangjie Yang
- Key Laboratory of Low-carbon Green Agriculture in Northwestern China, Ministry of Agriculture and Rural Affairs, College of Natural Resources and Environment, Northwest A & F University, Yangling 712100, China
| | - Zhiqiang Wang
- Key Laboratory of Low-carbon Green Agriculture in Northwestern China, Ministry of Agriculture and Rural Affairs, College of Natural Resources and Environment, Northwest A & F University, Yangling 712100, China
| | - Lang Zhu
- Key Laboratory of Low-carbon Green Agriculture in Northwestern China, Ministry of Agriculture and Rural Affairs, College of Natural Resources and Environment, Northwest A & F University, Yangling 712100, China
| | - Huiqiang Yang
- Key Laboratory of Low-carbon Green Agriculture in Northwestern China, Ministry of Agriculture and Rural Affairs, College of Natural Resources and Environment, Northwest A & F University, Yangling 712100, China
| | - Jianjun Qin
- Key Laboratory of Low-carbon Green Agriculture in Northwestern China, Ministry of Agriculture and Rural Affairs, College of Natural Resources and Environment, Northwest A & F University, Yangling 712100, China
| | - Zheng Ni
- Key Laboratory of Low-carbon Green Agriculture in Northwestern China, Ministry of Agriculture and Rural Affairs, College of Natural Resources and Environment, Northwest A & F University, Yangling 712100, China
| | - Hanzhong Jia
- Key Laboratory of Low-carbon Green Agriculture in Northwestern China, Ministry of Agriculture and Rural Affairs, College of Natural Resources and Environment, Northwest A & F University, Yangling 712100, China.
| | - Wang Xin
- College of Chemistry and Environmental Science, Inner Mongolia Normal University, Huhhot 010022, China
| | - Xing Li
- College of Chemistry and Environmental Science, Inner Mongolia Normal University, Huhhot 010022, China
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Lv Z, Liu S, Liu Y, Liu P, Fang M, Tan X, Xu W, Kong M, Wang X. Construction of Ni-based N-doped mesoporous carbon sphere for efficiently catalytic dichromate reduction with HCOOH at room temperature. Sep Purif Technol 2022. [DOI: 10.1016/j.seppur.2022.121289] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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The photo-redox of chromium regulated by microplastics (MPs) and MPs-derived dissolved organic matter (MPs-DOM) and the CO2 emission of MPs-DOM. FUNDAMENTAL RESEARCH 2022. [DOI: 10.1016/j.fmre.2022.08.009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
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Ye M, Li G, Liang J, Liao X, Ren J, Fen X, Qian W, Li L, Sun S. A high-efficiency process for the separation of chromium and aluminum from waste aluminum sludge with a high chromium content using a combined oxidation and dispersion process. Sep Purif Technol 2021. [DOI: 10.1016/j.seppur.2020.118083] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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Huang T, Zhang SW, Liu LF, Zhou L. Green rust functionalized geopolymer of composite cementitious materials and its application on treating chromate in a holistic system. CHEMOSPHERE 2021; 263:128319. [PMID: 33297252 DOI: 10.1016/j.chemosphere.2020.128319] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/19/2020] [Revised: 09/03/2020] [Accepted: 09/09/2020] [Indexed: 06/12/2023]
Abstract
Green rust functionalized geopolymer of composite cementitious materials (GR-CCM) was synthesized to improve the adsorption and subsequent stabilization/solidification of chromate in a holistic operating system. The initial pH in solution exhibited the most significant effect on the chromate removal by GR-CCM among three adsorption factors. The maximum monolayer adsorption capacity and theoretical saturation capacity of GR-CCM for Cr(VI) in the acidic condition were 55.01 mg/g and 41.70 mg/g, respectively. Amorphousness brought by loading GR weakened the crystallinity of composite cementitious materials (CCM), which enhanced the adsorption capacity of CCM and boosted the solidification process. The mixed-valent iron species in the GR-CCM not only directly engaged in the adsorption and reduction of chromate also positively strengthened the solidification of Cr species during the whole treatment. This study facilitates the application of GRs on the geopolymer materials and demonstrates the combination of adsorption and immobilization for the treatment of other potential heavy metal contamination.
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Affiliation(s)
- Tao Huang
- School of Materials Engineering, Changshu Institute of Technology, 215500, China; Suzhou Key Laboratory of Functional Ceramic Materials, Changshu Institute of Technology, Changshu, 215500, China; School of Chemical Engineering & Technology, China University of Mining and Technology, Xuzhou, Jiangsu, 221116, China.
| | - Shu-Wen Zhang
- Nuclear Resources Engineering College, University of South China, 421001, China
| | - Long-Fei Liu
- School of Materials Engineering, Changshu Institute of Technology, 215500, China
| | - Lulu Zhou
- School of Materials Engineering, Changshu Institute of Technology, 215500, China
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Yuan F, Sun Z, Li C, Tan Y, Zhang X, Zheng S. Multi-component design and in-situ synthesis of visible-light-driven SnO 2/g-C 3N 4/diatomite composite for high-efficient photoreduction of Cr(VI) with the aid of citric acid. JOURNAL OF HAZARDOUS MATERIALS 2020; 396:122694. [PMID: 32339876 DOI: 10.1016/j.jhazmat.2020.122694] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/29/2020] [Revised: 03/31/2020] [Accepted: 04/09/2020] [Indexed: 06/11/2023]
Abstract
A novel ternary SnO2/g-C3N4/diatomite (SCN/DE) nanocomposite was rationally designed and successfully synthesized via a two-step method with in-situ polymerization and self-assembling. Under visible light illumination, the resulting SCN/DE composite exhibited superior photocatalytic performance and good reusability for the photoreduction of Cr(VI) to Cr(III) in the presence of citric acid, the apparent rate constant of SCN/DE composite was up to around 22.68 times, 13.53 times and 8.65 times as much as those of g-C3N4 (CN), g-C3N4/diatomite (CN/DE) and SnO2/g-C3N4 (SCN) composites, respectively. The citric acid is a co-catalyst (chelating agent) rather than a reactant during the reactive process. Besides, the intimate interface contact and ternary heterogeneous structure were established among the SnO2, g-C3N4 and diatomite. The induced positive charged surface of diatomite should be the key factor in enhancing photoactivity of the resultant SCN/DE composite, which significantly accelerated the charge separation of photogenerated electron-hole pairs as well as improved the adsorption performance towards Cr (VI). In particular, a possible reduction pathway of Cr(VI) to Cr(III) by SCN/DE composite with the assistance of citric acid was first investigated and proposed. This work provides a novel strategy for synthesizing highly efficient mineral-based photocatalysts with great promising application foreground for Cr(VI)-containing wastewater treatment.
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Affiliation(s)
- Fang Yuan
- School of Chemical and Environmental Engineering, China University of Mining and Technology (Beijing), Beijing, 100083, China
| | - Zhiming Sun
- School of Chemical and Environmental Engineering, China University of Mining and Technology (Beijing), Beijing, 100083, China.
| | - Chunquan Li
- School of Chemical and Environmental Engineering, China University of Mining and Technology (Beijing), Beijing, 100083, China.
| | - Ye Tan
- School of Chemical and Environmental Engineering, China University of Mining and Technology (Beijing), Beijing, 100083, China
| | - Xiangwei Zhang
- School of Chemical and Environmental Engineering, China University of Mining and Technology (Beijing), Beijing, 100083, China
| | - Shuilin Zheng
- School of Chemical and Environmental Engineering, China University of Mining and Technology (Beijing), Beijing, 100083, China
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