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Li Y, Zhang Y, Yang W, Lin Y. The reaction pathway and mechanism of 2,4-dichlorophenol removal by modified fly ash-loaded nZVI/Ni particles. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2023:10.1007/s11356-023-27770-z. [PMID: 37256401 DOI: 10.1007/s11356-023-27770-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 01/20/2023] [Accepted: 05/16/2023] [Indexed: 06/01/2023]
Abstract
Nanoscale zero-valent iron (nZVI) is more valuable in environmental restoration than other materials. Chemical treatment of fly ash (CFA) was employed as a support material to disperse iron nickel bimetal nanoparticles (CFA-nZVI/Ni) to remove 2,4-dichlorophenol (2,4-DCP). Batch experiments showed that 2,4-DCP was completely removed by CFA-nZVI/Ni, and an optimal loading ratio was 8:1. The degradation of 2,4-DCP by CFA-nZVI/Ni was a chemical control reaction with an activation energy of 95.6 kJ mol-1 and followed pseudo-first-order kinetics. The addition of Cl- increased the removal rate of 2,4-DCP by 4%, while the addition of CO32- and SO42- decreased the removal rate of 2,4-DCP by 32% and 72.3%, respectively. The removal process of 2,4-DCP by CFA-nZVI/Ni included adsorption and reduction. The 2-CP (7.1 mg/L) and 4-CP (11.6 mg/L) could be converted to phenol using the CFA-nZVI/Ni system. Cl on the para-position of 2,4-DCP was simpler to remove than on the ortho-position. The following steps were taken in the electrophilic substitution reaction between substituted phenols and hydrogen radicals: 2,4-DCP > 2-CP > 4-CP > phenol. This research provides a novel concept to effectively remove 2,4-DCP and mechanism analysis.
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Affiliation(s)
- Yajun Li
- Faculty of Architecture, Civil and Transportation Engineering, Beijing University of Technology, 100 Pingleyuan, Beijing, 100124, China
| | - Yongxiang Zhang
- Faculty of Architecture, Civil and Transportation Engineering, Beijing University of Technology, 100 Pingleyuan, Beijing, 100124, China.
| | - Wenjing Yang
- Faculty of Architecture, Civil and Transportation Engineering, Beijing University of Technology, 100 Pingleyuan, Beijing, 100124, China
| | - Yuhui Lin
- Faculty of Architecture, Civil and Transportation Engineering, Beijing University of Technology, 100 Pingleyuan, Beijing, 100124, China
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Removal of Nitrate Nitrogen in Groundwater by Attapulgite Loaded with Nano-Zero-Valent Iron. ADSORPT SCI TECHNOL 2023. [DOI: 10.1155/2023/5594717] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/17/2023] Open
Abstract
Nano-zero-valent iron (nZVI) can be used to remove nitrate nitrogen (NO3-N) from groundwater. However, it has low reduction efficiency owing to its oxidation and aggregation characteristics. Thus, nZVI-loaded material is used to alleviate these drawbacks. In this study, nZVI-coated attapulgite (ATP) was prepared for the removal of NO3-N from groundwater. ATP-nZVI was prepared using the chemical liquid deposition-coreduction method. The prepared materials were characterized by SEM, XRD, and XPS analyses, which confirmed that the aluminum silicate particles in the ATP structure are effective carriers of nZVI and effectively inhibit self-consumption caused by the oxidation and aggregation of nZVI. The batch experiments examined experimental samples containing 30 mg/L nitrate and analyzed the effects of various parameters, including the material, mass ratio, initial pH, initial temperature, and coexisting anions on the NO3-N removal efficiency. The results showed that the optimal removal rate of the composite was 78.61%, which is higher than that using the same amount of ATP, iron powder, and nZVI. When the mass ratio of ATP to nZVI was 1 : 1, the NO3-N removal efficiency was the highest. When the pH value increased from 3 to 9, the NO3-N removal rate decreased, while an increase in the reaction temperature promoted NO3-N removal. The order of the inhibitory effect of coexisting anions on NO3-N removal by various nanoions was PO43–>CO32–>SO42–>Cl–. The adsorption kinetic model fitting results indicated that the chemisorption of electron exchange between ATP and nZVI in NO3-N removal was the main rate-limiting step in the reaction. This study demonstrates the potential of the prepared ATP-nZVI composite for NO3-N removal from groundwater.
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Zhao Z, Ren D, Zhuang M, Wang Z, Zhang X, Zhang S, Chen W. Degradation of 2,4-DCP by the immobilized laccase on the carrier of sodium alginate-sodium carboxymethyl cellulose. Bioprocess Biosyst Eng 2022; 45:1739-1751. [PMID: 36121508 DOI: 10.1007/s00449-022-02783-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2022] [Accepted: 09/08/2022] [Indexed: 12/07/2022]
Abstract
In this paper, sodium alginate-sodium carboxymethyl cellulose (SA-CMC) composite material was used as a carrier, and sodium alginate-embedded laccase (Lac@SC) was prepared by traditional embedding method. After that, ethylene glycol diglycidyl ether (EGDE) and glutaraldehyde (GLU) were used as cross-linking agents, two different cross-linking-embedded co-immobilized laccases (Lac@SCG and Lac@SCE) were innovatively prepared, respectively, and then these immobilized laccases were characterized by SEM, FT-IR and XRD, and the stability of the three immobilized laccases was explored. In addition, the effects of different factors on the removal of 2,4-DCP by immobilized laccase were studied, and the degradation kinetic models of three immobilized laccases on 2,4-DCP were summarized, the possible degradation pathways of pollutants were also given. Experimental results showed that compared to free laccase, the pH stability, thermal stability and storage stability of immobilized laccase were greatly improved. These immobilized laccases could maintain high activity at pH3~6, 45~55 °C. Lac@SCG had the best storage stability. After 30 days of storage, the relative enzyme activity was still more than 40%. Lac@SC had good reusability, the relative enzyme activity was still more than 50% after 5 uses. In the degradation of 2,4-DCP, all three immobilized laccases showed good performance, when Lac@SCE was at pH5, 35 °C, 25 h, the removal rate of 2,4-DCP could reach 95.2%; When at 45 °C, Lac@SC had the highest degradation rate which reach to 94%; At 45 °C, the degradation rate of Lac@SCG reached 83.2%.
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Affiliation(s)
- Zhe Zhao
- College of Resource and Environmental Engineering, Wuhan University of Science and Technology, Wuhan, 430081, China.,Hubei Key Laboratory for Efficient Utilization and Agglomeration of Metallurgic Mineral Resources, Wuhan University of Science and Technology, Wuhan, 430081, Hubei, China
| | - Dajun Ren
- College of Resource and Environmental Engineering, Wuhan University of Science and Technology, Wuhan, 430081, China. .,Hubei Key Laboratory for Efficient Utilization and Agglomeration of Metallurgic Mineral Resources, Wuhan University of Science and Technology, Wuhan, 430081, Hubei, China.
| | - Mengjuan Zhuang
- College of Resource and Environmental Engineering, Wuhan University of Science and Technology, Wuhan, 430081, China.,Hubei Key Laboratory for Efficient Utilization and Agglomeration of Metallurgic Mineral Resources, Wuhan University of Science and Technology, Wuhan, 430081, Hubei, China
| | - Zhaobo Wang
- College of Resource and Environmental Engineering, Wuhan University of Science and Technology, Wuhan, 430081, China.,Hubei Key Laboratory for Efficient Utilization and Agglomeration of Metallurgic Mineral Resources, Wuhan University of Science and Technology, Wuhan, 430081, Hubei, China
| | - Xiaoqing Zhang
- College of Resource and Environmental Engineering, Wuhan University of Science and Technology, Wuhan, 430081, China.,Hubei Key Laboratory for Efficient Utilization and Agglomeration of Metallurgic Mineral Resources, Wuhan University of Science and Technology, Wuhan, 430081, Hubei, China
| | - Shuqin Zhang
- College of Resource and Environmental Engineering, Wuhan University of Science and Technology, Wuhan, 430081, China.,Hubei Key Laboratory for Efficient Utilization and Agglomeration of Metallurgic Mineral Resources, Wuhan University of Science and Technology, Wuhan, 430081, Hubei, China
| | - Wangsheng Chen
- College of Resource and Environmental Engineering, Wuhan University of Science and Technology, Wuhan, 430081, China.,Hubei Key Laboratory for Efficient Utilization and Agglomeration of Metallurgic Mineral Resources, Wuhan University of Science and Technology, Wuhan, 430081, Hubei, China
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