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Zhang M, Lin K. Unintended polyhalogenated carbazole production during advanced oxidation of coking wastewater. JOURNAL OF HAZARDOUS MATERIALS 2024; 473:134649. [PMID: 38772108 DOI: 10.1016/j.jhazmat.2024.134649] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/27/2024] [Revised: 05/10/2024] [Accepted: 05/17/2024] [Indexed: 05/23/2024]
Abstract
Polyhalogenated carbazoles (PHCZs) are emerging as dioxin-like global pollutants, yet their environmental origins are not fully understood. This study investigates the application of the Fenton process in coking wastewater treatment, focusing on its dual role in carbazole removal and unintended PHCZ formation. The common halide ions (Cl- and Br-) in coking wastewater, especially Br- ions, exerted a notable impact on carbazole removal. Particularly, the influence of Br- ions was more significant, not only enhancing carbazole removal but also shaping the congener composition of PHCZ formation. Elevated halide ion concentrations were associated with the heightened formation of higher halogenated carbazoles. The Fenton reagent dosage ratio was identified as a crucial factor affecting the congener composition of PHCZs and their toxic equivalency value. The coexisting organic substance (i.e., phenol) in coking wastewater was observed to inhibit PHCZ formation, likely through competitive reactions with carbazole. Intriguingly, ammonium (NH4+) facilitated the generation of higher and mixed halogenated carbazoles, possibly due to the generation of nitrogen-containing brominating agents with stronger bromination capacity. This study underscores the importance of a comprehensive assessment, considering both substrate removal and potential byproduct formation, when employing the Fenton process for saline wastewater treatment.
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Affiliation(s)
- Meng Zhang
- Fujian Provincial Key Laboratory for Coast Ecology and Environmental Studies, College of the Environment and Ecology, Xiamen University, Xiamen 361102, China
| | - Kunde Lin
- Fujian Provincial Key Laboratory for Coast Ecology and Environmental Studies, College of the Environment and Ecology, Xiamen University, Xiamen 361102, China.
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Chen A, Li H, Wu H, Song Z, Chen Y, Zhang H, Pang Z, Qin Z, Wu Y, Guan X, Huang H, Li Z, Qiu G, Wei C. Anaerobic cyanides oxidation with bimetallic modulation of biological toxicity and activity for nitrite reduction. JOURNAL OF HAZARDOUS MATERIALS 2024; 472:134540. [PMID: 38733787 DOI: 10.1016/j.jhazmat.2024.134540] [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: 02/29/2024] [Revised: 04/26/2024] [Accepted: 05/03/2024] [Indexed: 05/13/2024]
Abstract
Cyanide is a typical toxic reducing agent prevailing in wastewater with a well-defined chemical mechanism, whereas its exploitation as an electron donor by microorganisms is currently understudied. Given that conventional denitrification requires additional electron donors, the cyanide and nitrogen can be eliminated simultaneously if the reducing HCN/CN- and its complexes are used as inorganic electron donors. Hence, this paper proposes anaerobic cyanides oxidation for nitrite reduction, whereby the biological toxicity and activity of cyanides are modulated by bimetallics. Performance tests illustrated that low toxicity equivalents of iron-copper composite cyanides provided higher denitrification loads with the release of cyanide ions and electrons from the complex structure by the bimetal. Both isotopic labeling and Density Functional Theory (DFT) demonstrated that CN--N supplied electrons for nitrite reduction. The superposition of chemical processes reduces the biotoxicity and enhances the biological activity of cyanides in the CN-/Fe3+/Cu2+/NO2- coexistence system, including complex detoxification of CN- by Fe3+, CN- release by Cu2+ from [Fe(CN)6]3-, and NO release by nitrite substitution of -CN groups. Cyanide is the smallest structural unit of C/N-containing compounds and serves as a probe to extend the electron-donating principle of anaerobic cyanides oxidation to more electron-donor microbial utilization.
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Affiliation(s)
- Acong Chen
- School of Environment and Energy, South China University of Technology, Guangzhou, Guangdong 510006, PR China
| | - Haoling Li
- School of Biology and Biological Engineering, South China University of Technology, Guangzhou, Guangdong 510006, PR China
| | - Haizhen Wu
- School of Biology and Biological Engineering, South China University of Technology, Guangzhou, Guangdong 510006, PR China.
| | - Zhaohui Song
- School of Environment and Energy, South China University of Technology, Guangzhou, Guangdong 510006, PR China
| | - Yao Chen
- School of Environment and Energy, South China University of Technology, Guangzhou, Guangdong 510006, PR China
| | - Heng Zhang
- School of Environment and Energy, South China University of Technology, Guangzhou, Guangdong 510006, PR China
| | - Zijun Pang
- School of Environment and Energy, South China University of Technology, Guangzhou, Guangdong 510006, PR China
| | - Zhi Qin
- School of Environment and Energy, South China University of Technology, Guangzhou, Guangdong 510006, PR China
| | - Yulun Wu
- School of Environment and Energy, South China University of Technology, Guangzhou, Guangdong 510006, PR China
| | - Xianghong Guan
- School of Environment and Energy, South China University of Technology, Guangzhou, Guangdong 510006, PR China
| | - Hua Huang
- School of Environment and Energy, South China University of Technology, Guangzhou, Guangdong 510006, PR China
| | - Zemin Li
- School of Environment and Energy, South China University of Technology, Guangzhou, Guangdong 510006, PR China; School of Environment, South China Normal University, Guangzhou, Guangdong 510006, PR China
| | - Guanglei Qiu
- School of Environment and Energy, South China University of Technology, Guangzhou, Guangdong 510006, PR China
| | - Chaohai Wei
- School of Environment and Energy, South China University of Technology, Guangzhou, Guangdong 510006, PR China; School of Environment and Energy, Guangdong Provincial Key Laboratory of Solid Wastes Pollution Control and Recycling, South China University of Technology, Guangzhou, Guangdong 510006, PR China.
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Wei T, Ban Z, Ke X, Chen A, Guan X, Gan H, Pan J, Li Z, Wei C, Qiu G, Wu H, Wei C. A combined process model for wastewater treatment based on hydraulic retention time and toxicity inhibition. CHEMOSPHERE 2023; 329:138660. [PMID: 37044138 DOI: 10.1016/j.chemosphere.2023.138660] [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: 12/07/2022] [Revised: 03/25/2023] [Accepted: 04/08/2023] [Indexed: 05/03/2023]
Abstract
Hydraulic retention time (HRT), as an important parameter in the wastewater treatment process, has a great impact on water quality and energy consumption. With the rapid advances in computer technology and deepened understanding of in microbial metabolism, a series of activated sludge models (ASMs) have been developed and applied in wastewater treatment. However, ASMs simulation based on the nexus of HRT, water treatment process, water quality and energy consumption has yet to be verified. In this study, HRT was creatively linked to water treatment process variation. And a novel combined process model (CPM) was developed based on the operational data and treatment performance data from 4 full-scale coking wastewater treatment processes. In the CPM, an array of biological treatment processes were represented by setting the HRT in respective treatment units of the anaerobic-oxic-hydrolytic & denitrification-oxic (A/O/H/O) process. The relationships between HRT, effluent quality and energy consumption were systematically analyzed. Results showed that: (i) for A/O/H/O process, the HRT of first oxic (O1) reactor has a key effect on the effluent water quality and energy consumption, while the impact of the anaerobic (A) reactor HRT was limited; (ii) the O/H/O process has a clear advantage in treating coking wastewater due to the carbon removal and detoxification function of O1 reactor; (iii) the lowest energy consumption (with the total system HRT below 210 h) to meet the biological effluent quality requirements (COD = 200 mg/L, TN = 50 mg/L) is 4.429 kWh/m3. Since the CPM could effectively work out the optimal process configuration and break the boundaries between HRT and process variation, it has enormous potential to be extended to the design of other wastewater treatment processes.
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Affiliation(s)
- Tuo Wei
- School of Environment and Energy, South China University of Technology, Guangdong, Guangzhou, 510006, PR China
| | - Zixin Ban
- School of Environment and Energy, South China University of Technology, Guangdong, Guangzhou, 510006, PR China
| | - Xiong Ke
- School of Environment and Energy, South China University of Technology, Guangdong, Guangzhou, 510006, PR China
| | - Acong Chen
- School of Environment and Energy, South China University of Technology, Guangdong, Guangzhou, 510006, PR China
| | - Xianghong Guan
- School of Environment and Energy, South China University of Technology, Guangdong, Guangzhou, 510006, PR China
| | - Haibo Gan
- China State Key Laboratory of Fine Chemicals, School of Chemical Engineering, Dalian University of Technology, Dalian, 116024, PR China
| | - Jiamin Pan
- School of Environment and Energy, South China University of Technology, Guangdong, Guangzhou, 510006, PR China
| | - Zemin Li
- School of Environment and Energy, South China University of Technology, Guangdong, Guangzhou, 510006, PR China
| | - Cong Wei
- School of Environment and Energy, South China University of Technology, Guangdong, Guangzhou, 510006, PR China
| | - Guanglei Qiu
- School of Environment and Energy, South China University of Technology, Guangdong, Guangzhou, 510006, PR China
| | - Haizhen Wu
- School of Biology and Biological Engineering, South China University of Technology, Guangzhou, 510006, PR China
| | - Chaohai Wei
- School of Environment and Energy, South China University of Technology, Guangdong, Guangzhou, 510006, PR China; School of Environment and Energy, Guangdong Provincial Key Laboratory of Solid Wastes Pollution Control and Recycling, South China University of Technology, Guangzhou, Guangdong, 510006, PR China.
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