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Mahajan R, Sharma G, Chadha P, Saini HS. Evaluating efficacy of Pseudomonas sp. EN-4 to lower the toxic potential of 4-bromophenol and assessing its competency in simulated microcosm. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2024; 349:123990. [PMID: 38631447 DOI: 10.1016/j.envpol.2024.123990] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/18/2023] [Revised: 03/18/2024] [Accepted: 04/14/2024] [Indexed: 04/19/2024]
Abstract
An indigenous bacterium Pseudomonas sp. EN-4 had been reported earlier for its ability to co-metabolise 4-bromophenol (4-BP), in presence of phenol (100 mg/L) as co-substrate. The present study was undertaken to validate the efficacy of biotransformation by comparing the toxicity profiles of untreated and EN-4 transformed samples of 4-BP, using both plant and animal model. The toxicity studies in Allium cepa (A. cepa) indicated to lowering of mitotic index (MI) from 12.77% (water) to 3.33% in A. cepa bulbs exposed to 4-BP + phenol, which reflects the cytotoxic nature of these compounds. However, the MI value significantly improves to 11.36% in its biologically treated counterpart, indicating normal cell growth. This was further supported by significant reduction in chromosomal aberrations in A. cepa root cells exposed to biologically treated samples of 4-BP as compared to untreated controls. The oxidative stress assessed by comparing the activity profiles of different marker enzymes showed that the activities of superoxide dismutase (SOD), ascorbate peroxidase (APX) and guaiacol peroxidase (GPX) were reduced by 56%, 72%, and 37% respectively, in EN-4 transformed samples of 4-BP + phenol compared to its untreated counterpart. Similar trends were evident in the comet assay of fish (Channa punctatus) blood cells exposed to untreated and biologically treated samples of 4-BP. The comparative studies showed significant reduction in tail length (72.70%) and % tail intensity (56.15%) in fish blood cells exposed to EN-4 treated 4-BP + phenol, compared to its untreated counterpart. The soil microcosm studies validated the competency of the EN-4 cells to establish and transform 4-BP in soil polluted with 4-BP (20 mg/kg) and 4-BP + phenol (20 + 100 mg/kg). The isolate EN-4 achieved 98.08% transformation of 4-BP in non-sterile microcosm supplemented with phenol, indicating to potential of EN-4 cells to establish along with indigenous microflora.
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Affiliation(s)
- Rohit Mahajan
- Department of Microbiology, Guru Nanak Dev University, Amritsar, Punjab-143005 India.
| | - Geetika Sharma
- Department of Zoology, Guru Nanak Dev University, Amritsar, Punjab-143005 India.
| | - Pooja Chadha
- Department of Zoology, Guru Nanak Dev University, Amritsar, Punjab-143005 India.
| | - Harvinder Singh Saini
- Department of Microbiology, Guru Nanak Dev University, Amritsar, Punjab-143005 India.
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Wang J, Chi Q, Pan L, Zhang R, Mu Y, Shen J. New insights into enhanced biodegradation of 4-bromphenol in a nitrate-reducing system: Process performance and mechanism. WATER RESEARCH 2023; 242:120200. [PMID: 37336182 DOI: 10.1016/j.watres.2023.120200] [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: 05/10/2023] [Revised: 06/06/2023] [Accepted: 06/08/2023] [Indexed: 06/21/2023]
Abstract
Due to the recalcitrant nature of halogenated phenol, conventional anaerobic bioprocess is often limited by low removal efficiency and poor process stability. At the presence of electron acceptors such as nitrate, 4-bromophenol (4-BP) removal efficiency is significantly higher than that in the anaerobic control system, but the mechanism involved is still unclear. Therefore, an up-flow nitrate-reducing bioreactor (NRBR) was designed and consecutively performed for 215 days to explore the synergistic mechanism for BPs biodegradation and nitrate reduction. Complete 4-BP biodegradation could be obtained in NRBR at HRT and 4-BP loading rate of 24 h and 0.29 mol m - 3d - 1, while the TOC removal and nitrate reduction efficiencies were as high as 91.33±2.11% and 98.31±1.33%, respectively. Population evolution analyses revealed that the microorganisms involved in 4-BP debromination and biodegradation (Candidatus Peregrinibacteria, Denitratisoma, Anaerolineaceae and Ignavibacterium) as well as nitrate reduction (Denitratisoma, Anaerolineaceae, Limnobacter and Ignavibacterium) were significantly enriched in NRBR. Major intermediates during 4-BP biodegradation, including 4-bromocatechol, 4‑bromo-6-oxo-hexanoic acid and succinic acid were identified, while a distinct 4-BP biodegradation pathway via hydration, aromatic-ring cleavage, hydrolysis debromination and oxidation was expounded. Metagenomic analysis indicated that oxidation (had, pht4, boh, butA), hydrolysis debromination ((S)-2-haloacid dehalogenase) and bio-mineralization (gabD, sdhA) of 4-BP were largely enhanced in NRBR. Moreover, carbon, nitrogen, energy and amino acid metabolisms were significantly facilitated with the injection of nitrate in order to provide energy and electron, thus enhanced microbial activities and enzymatic reactions in NRBR. The proposed mechanism provides new insights into our mechanistic understanding of halogenated phenol biodegradation and the development of sustainable bioremediation strategies.
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Affiliation(s)
- Jing Wang
- Key Laboratory of Environmental Remediation and Ecological Health, Ministry of Industry and Information Technology, School of Environmental and Biological Engineering, Nanjing University of Science and Technology, Nanjing 210094, China
| | - Qiang Chi
- Key Laboratory of Environmental Remediation and Ecological Health, Ministry of Industry and Information Technology, School of Environmental and Biological Engineering, Nanjing University of Science and Technology, Nanjing 210094, China
| | - Ling Pan
- Key Laboratory of Environmental Remediation and Ecological Health, Ministry of Industry and Information Technology, School of Environmental and Biological Engineering, Nanjing University of Science and Technology, Nanjing 210094, China
| | - Ranran Zhang
- Key Laboratory of Environmental Remediation and Ecological Health, Ministry of Industry and Information Technology, School of Environmental and Biological Engineering, Nanjing University of Science and Technology, Nanjing 210094, China
| | - Yang Mu
- CAS Key Laboratory of Urban Pollutant Conversion, Department of Environmental Science and Engineering, University of Science and Technology of China, Hefei 230026, China
| | - Jinyou Shen
- Key Laboratory of Environmental Remediation and Ecological Health, Ministry of Industry and Information Technology, School of Environmental and Biological Engineering, Nanjing University of Science and Technology, Nanjing 210094, China.
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Xiang Y, Li S, Rene ER, Lun X, Zhang P, Ma W. Detoxification of fluoroglucocorticoid by Acinetobacter pittii C3 via a novel defluorination pathway with hydrolysis, oxidation and reduction: Performance, genomic characteristics, and mechanism. JOURNAL OF HAZARDOUS MATERIALS 2023; 452:131302. [PMID: 37031670 DOI: 10.1016/j.jhazmat.2023.131302] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/15/2023] [Revised: 03/10/2023] [Accepted: 03/24/2023] [Indexed: 05/03/2023]
Abstract
Biological dehalogenation degradation was an important detoxification method for the ecotoxicity and teratogenic toxicity of fluorocorticosteroids (FGCs). The functional strain Acinetobacter pittii C3 can effectively biodegrade and defluorinate to 1 mg/L Triamcinolone acetonide (TA), a representative FGCs, with 86 % and 79 % removal proportion in 168 h with the biodegradation and detoxification kinetic constant of 0.031/h and 0.016/h. The dehalogenation and degradation ability of strain C3 was related to its dehalogenation genomic characteristics, which manifested in the functional gene expression of dehalogenation, degradation, and toxicity tolerance. Three detoxification mechanisms were positively correlated with defluorination pathways through hydrolysis, oxidation, and reduction, which were regulated by the expression of the haloacid dehalogenase (HAD) gene (mupP, yrfG, and gph), oxygenase gene (dmpA and catA), and reductase gene (nrdAB and TgnAB). Hydrolysis defluorination was the most critical way for TA detoxification metabolism, which could rapidly generate low-toxicity metabolites and reduce toxic bioaccumulation due to hydrolytic dehalogenase-induced defluorination. The mechanism of hydrolytic defluorination was that the active pocket of hydrolytic dehalogenase was matched well with the spatial structure of TA under the adjustment of the hydrogen bond, and thus induced molecular recognition to promote the catalytic hydrolytic degradation of various amino acid residues. This work provided an effective bioremediation method and mechanism for improving defluorination and detoxification performance.
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Affiliation(s)
- Yayun Xiang
- College of Environmental Science and Engineering, Beijing Forestry University, Beijing 100083, China
| | - Sinuo Li
- Beijing No. 80 High School, Beijing 100102, China
| | - Eldon R Rene
- IHE-Delft, Institute for Water Education, Department of Environmental Engineering and Water Technology, Westvest 7, 2611AX Delft, the Netherlands
| | - Xiaoxiu Lun
- College of Environmental Science and Engineering, Beijing Forestry University, Beijing 100083, China
| | - Panyue Zhang
- College of Environmental Science and Engineering, Beijing Forestry University, Beijing 100083, China
| | - Weifang Ma
- College of Environmental Science and Engineering, Beijing Forestry University, Beijing 100083, China.
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Wang G, Guo P, Liu Y, Li C, Wang X, Wang H. Mechanistic characterization of anaerobic microbial degradation of BTBPE in coastal wetland soils: Implication by compound-specific stable isotope analysis. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2023; 335:117622. [PMID: 36867899 DOI: 10.1016/j.jenvman.2023.117622] [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: 12/24/2022] [Revised: 02/06/2023] [Accepted: 02/26/2023] [Indexed: 06/18/2023]
Abstract
As a novel brominate flame retardants, 1,2-bis(2,4,6-tribromophenoxy)ethane (BTBPE) has been extensively used in various consumer products, and frequently detected in various environmental matrices. However, the microbial degradation of BTBPE remains unclear in the environment. This study comprehensively investigated the anaerobic microbial degradation of BTBPE and therein stable carbon isotope effect in the wetland soils. BTBPE degradation followed the pseudo-first-order kinetic, with degradation rate of 0.0085 ± 0.0008 day-1. Based on identification of degradation products, stepwise reductive debromination was the main transformation pathway of BTBPE, and tended to keep the stable of 2,4,6-tribromophenoxy group during the microbial degradation. The pronounced carbon isotope fractionation was observed for BTBPE microbial degradation, and carbon isotope enrichment factor (εC) was determined to be -4.81 ± 0.37‰, indicating cleavage of C-Br bond as the rate-limiting step. Compared to previously reported isotope effects, carbon apparent kinetic isotope effect (AKIEC = 1.072 ± 0.004) suggested that the nucleophilic substitution (SN2 reaction) was the potential reaction mechanism for reductive debromination of BTBPE in the anaerobic microbial degradation. These findings demonstrated that BTBPE could be degraded by the anaerobic microbes in wetland soils, and the compound-specific stable isotope analysis was a robust method to discover the underlying reaction mechanisms.
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Affiliation(s)
- Guoguang Wang
- College of Environmental Science and Engineering, Dalian Maritime University, Dalian, 116026, China.
| | - Pengxu Guo
- College of Environmental Science and Engineering, Dalian Maritime University, Dalian, 116026, China
| | - Yu Liu
- College of Environmental Science and Engineering, Dalian Maritime University, Dalian, 116026, China; Environmental Information Institute, Dalian Maritime University, Dalian, 116026, China
| | - Chuanyuan Li
- College of Environmental Science and Engineering, Dalian Maritime University, Dalian, 116026, China
| | - Xu Wang
- College of Environmental Science and Engineering, Dalian Maritime University, Dalian, 116026, China
| | - Haixia Wang
- Navigation College, Dalian Maritime University, Dalian, 116026, China
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Sahoo MM, Sahoo NK, Daverey A, Raut S. Co-metabolic biodegradation of 4-bromophenol in a mixture of pollutants system by Arthrobacter chlorophenolicus A6. ECOTOXICOLOGY (LONDON, ENGLAND) 2022; 31:602-614. [PMID: 35059927 DOI: 10.1007/s10646-021-02508-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 11/19/2021] [Indexed: 06/14/2023]
Abstract
Brominated phenols are listed as priority pollutants together with nitrophenol and chlorophenol are the key components of paper pulp wastewater. However, the biodegradation of bromophenol in a mixed substrate system is very scanty. In the present investigation, simultaneous biodegradation kinetics of three substituted phenols 4-bromophenol (4-BP), 4-nitrophenol (4-NP), and 4-chlorophenol (4-CP) were investigated using Arthrobacter chlorophenolicus A6. A 23 full factorial design was applied with varying 4-BP and 4-CP from 75-125 mg/L and 4-NP from 50-100 mg/L. Almost complete degradation of this mixture of substituted phenols was achieved at initial concentration combinations of 125, 125, and 100 mg/L of 4-CP, 4-BP, and 4-NP, respectively, in 68 h. Statistical analysis of the results revealed that, among the three variables, 4-NP had the most prominent influence on the degradation of both 4-CP and 4-BP, while the concentration of 4-CP had a strong negative interaction effect on the biodegradation of 4-NP. Irrespective of the concentration levels of these three substrates, 4-NP was preferentially biodegraded over 4-CP and 4-BP. Furthermore, 4-BP biodegradation rates were found to be higher than those of 4-CP, followed by 4-NP. Besides, the variation of the biomass yield coefficient of the culture was investigated at different initial concentration combinations of these substituted phenols. Although the actinomycetes consumed 4-NP at a faster rate, the biomass yield was very poor. This revealed that the microbial cells were more stressed when grown on 4-NP compared to 4-BP and 4-CP. Overall, this study revealed the potential of A. chlorophenolicus A6 for the degradation of 4-BP in mixed substrate systems.
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Affiliation(s)
- Mitali Madhusmita Sahoo
- Centre for Biotechnology, Siksha 'O'Anusandhan, Deemed to be University, Bhubaneswar, 751 030, Odisha, India
| | - Naresh Kumar Sahoo
- Department of Chemistry, Environmental Science and Technology Program, Institute of Technical Education and Research, Siksha'O'Anusandhan, Deemed to be University, Bhubaneswar, 751 030, Odisha, India.
| | - Achlesh Daverey
- School of Environment & Natural Resources, Doon University, Dehradun, 248012, Uttarakhand, India
| | - Sangeeta Raut
- Centre for Biotechnology, Siksha 'O'Anusandhan, Deemed to be University, Bhubaneswar, 751 030, Odisha, India
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Min J, Fang S, Peng J, Lv X, Xu L, Li Y, Hu X. Microbial detoxification of 2,4,6-tribromophenol via a novel process with consecutive oxidative and hydrolytic debromination: Biochemical, genetic and evolutionary characterization. ENVIRONMENTAL RESEARCH 2022; 205:112494. [PMID: 34890595 DOI: 10.1016/j.envres.2021.112494] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/23/2021] [Revised: 11/26/2021] [Accepted: 12/01/2021] [Indexed: 06/13/2023]
Abstract
As a typical brominated flame retardants (BFRs), 2,4,6-tribromophenol (TBP) has serious hazard to the environmental health and its environmental fate has attracted considerable attention. Dehalogenation reaction plays key role in microbial TBP degradation and detoxification. So far, several halophenols-degrading enzymes have been reported to transform their substrate by oxidative dehalogenation; however, the molecular and biochemistry characterization of microbial hydrolytic dehalogenation is limited. In this study, Cupriavidus sp. CNP-8 with high TBP degradation activity was found to degrade TBP via an obviously differnet pathway as compared to other reported TBP-degraders. The transcription of hnp genes were significantly upregulated with TBP stimulation, indicating their involvment in TBP degradation. Enzymatic assays with 18O-labeling experiments showed that HnpAB, a two-component FAD-dependent monooxygenase, transformed TBP via consecutive oxidative and hydrolytic debromination reactions with the formation of 6-bromo-1,2,4-benzenetriol (BBT) as the ring-cleavage substrate. The function of the BBT ring-cleavage enzyme (HnpC) was also characterized both in vitro and in vivo. This finding provides new molecular mechanism of microbial detoxification of TBP and novel information of the environmental fate of this BFRs. Furthermore, to investigate the frequency of this novel dehalogenation mechanism in microbes, we also analyzed the distribution as well as the genetic structure of the hnpABC cluster by comparative genomics. Although hnpA homolog is distributed in several bacterial genera including Cupriavidus, Paraburkholderia, Variovorax and Streptomyces, the complete hnpABC cluster is only retrieved from Cupriavidus and strictly conservative in the genomes. This indicated that Cupriavidus have unique evolutionary pattern in acquiring the hnpABC to degrade TBP and its analogs, enhancing our understanding of the microbial adaptive evolution in halophenols-contaminated environment.
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Affiliation(s)
- Jun Min
- Key Laboratory of Coastal Biology and Bioresource Utilization, Yantai Institute of Coastal Zone Research, Chinese Academy of Sciences, Yantai, 264003, China; Laboratory for Marine Biology and Biotechnology, Qingdao National Laboratory for Marine Science and Technology, Qingdao, China; Center for Ocean Mega-Science, Chinese Academy of Sciences, Qingdao, China
| | - Suyun Fang
- Key Laboratory of Coastal Biology and Bioresource Utilization, Yantai Institute of Coastal Zone Research, Chinese Academy of Sciences, Yantai, 264003, China
| | - Jian Peng
- Key Laboratory of Coastal Biology and Bioresource Utilization, Yantai Institute of Coastal Zone Research, Chinese Academy of Sciences, Yantai, 264003, China
| | - Xin Lv
- Key Laboratory of Coastal Biology and Bioresource Utilization, Yantai Institute of Coastal Zone Research, Chinese Academy of Sciences, Yantai, 264003, China
| | - Lingxue Xu
- Key Laboratory of Coastal Biology and Bioresource Utilization, Yantai Institute of Coastal Zone Research, Chinese Academy of Sciences, Yantai, 264003, China
| | - Yan Li
- College of Life Science of Yantai University, Yantai, China
| | - Xiaoke Hu
- Key Laboratory of Coastal Biology and Bioresource Utilization, Yantai Institute of Coastal Zone Research, Chinese Academy of Sciences, Yantai, 264003, China; Laboratory for Marine Biology and Biotechnology, Qingdao National Laboratory for Marine Science and Technology, Qingdao, China; Center for Ocean Mega-Science, Chinese Academy of Sciences, Qingdao, China.
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Yang Y, Zhang ZW, Liu RX, Ju HY, Bian XK, Zhang WZ, Zhang CB, Yang T, Guo B, Xiao CL, Bai H, Lu WY. Research progress in bioremediation of petroleum pollution. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2021; 28:46877-46893. [PMID: 34254241 DOI: 10.1007/s11356-021-15310-6] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/18/2021] [Accepted: 07/01/2021] [Indexed: 06/13/2023]
Abstract
With the enhancement of environmental protection awareness, research on the bioremediation of petroleum hydrocarbon environmental pollution has intensified. Bioremediation has received more attention due to its high efficiency, environmentally friendly by-products, and low cost compared with the commonly used physical and chemical restoration methods. In recent years, bacterium engineered by systems biology strategies have achieved biodegrading of many types of petroleum pollutants. Those successful cases show that systems biology has great potential in strengthening petroleum pollutant degradation bacterium and accelerating bioremediation. Systems biology represented by metabolic engineering, enzyme engineering, omics technology, etc., developed rapidly in the twentieth century. Optimizing the metabolic network of petroleum hydrocarbon degrading bacterium could achieve more concise and precise bioremediation by metabolic engineering strategies; biocatalysts with more stable and excellent catalytic activity could accelerate the process of biodegradation by enzyme engineering; omics technology not only could provide more optional components for constructions of engineered bacterium, but also could obtain the structure and composition of the microbial community in polluted environments. Comprehensive microbial community information lays a certain theoretical foundation for the construction of artificial mixed microbial communities for bioremediation of petroleum pollution. This article reviews the application of systems biology in the enforce of petroleum hydrocarbon degradation bacteria and the construction of a hybrid-microbial degradation system. Then the challenges encountered in the process and the application prospects of bioremediation are discussed. Finally, we provide certain guidance for the bioremediation of petroleum hydrocarbon-polluted environment.
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Affiliation(s)
- Yong Yang
- School of Chemical Engineering and Technology, Tianjin University, No.135, Ya Guan Rd, Jinnan District, Tianjin, 300350, China
- CNOOC EnerTech-Safety & Environmental Protection Co., Tianwei Industrial Park, No. 75 Taihua Rd, TEDA, Tianjin, 300457, China
| | - Zhan-Wei Zhang
- School of Chemical Engineering and Technology, Tianjin University, No.135, Ya Guan Rd, Jinnan District, Tianjin, 300350, China
| | - Rui-Xia Liu
- School of Chemical Engineering and Technology, Tianjin University, No.135, Ya Guan Rd, Jinnan District, Tianjin, 300350, China
| | - Hai-Yan Ju
- School of Chemical Engineering and Technology, Tianjin University, No.135, Ya Guan Rd, Jinnan District, Tianjin, 300350, China
| | - Xue-Ke Bian
- School of Chemical Engineering and Technology, Tianjin University, No.135, Ya Guan Rd, Jinnan District, Tianjin, 300350, China
| | - Wan-Ze Zhang
- School of Chemical Engineering and Technology, Tianjin University, No.135, Ya Guan Rd, Jinnan District, Tianjin, 300350, China
| | - Chuan-Bo Zhang
- School of Chemical Engineering and Technology, Tianjin University, No.135, Ya Guan Rd, Jinnan District, Tianjin, 300350, China
| | - Ting Yang
- CNOOC EnerTech-Safety & Environmental Protection Co., Tianwei Industrial Park, No. 75 Taihua Rd, TEDA, Tianjin, 300457, China
| | - Bing Guo
- CNOOC EnerTech-Safety & Environmental Protection Co., Tianwei Industrial Park, No. 75 Taihua Rd, TEDA, Tianjin, 300457, China
| | - Chen-Lei Xiao
- CNOOC EnerTech-Safety & Environmental Protection Co., Tianwei Industrial Park, No. 75 Taihua Rd, TEDA, Tianjin, 300457, China
| | - He Bai
- China Offshore Environmental Service Ltd., Tianwei Industrial Park, No. 75 Taihua Rd, TEDA, Tianjin, 300457, China.
- Tianjin Huakan Environmental Protection Technology Co. Ltd., No. 67 Guangrui West Rd, Hedong District, Tianjin, 300170, China.
| | - Wen-Yu Lu
- School of Chemical Engineering and Technology, Tianjin University, No.135, Ya Guan Rd, Jinnan District, Tianjin, 300350, China.
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