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Su R, Fu H, Ding L, Fu B, He S, Ma H, Hu H, Ren H. Long-term impact of nano zero-valent iron on methanogenic activity, microbial community structure, and transcription activity in anaerobic wastewater treatment system. BIORESOURCE TECHNOLOGY 2024; 393:130028. [PMID: 37977494 DOI: 10.1016/j.biortech.2023.130028] [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: 07/28/2023] [Revised: 11/14/2023] [Accepted: 11/14/2023] [Indexed: 11/19/2023]
Abstract
Nano zero-valent iron (NZVI) is commonly used in industrial wastewater treatment. However, its long-term impact mechanisms of metabolization in anaerobic systems are not well understood. This study investigated the effects of long-term and continuous addition of NZVI on methanogenic activity, microbial community, and transcription activity. The results demonstrated that low levels of NZVI (1000 mg/L) induced inhibition of methanogenesis after 80 days, while high levels of NZVI (5000 mg/L) immediately led to a sharp decrease of cumulative methane production and chemical oxygen demand removal, which arrived at a steady state (14.4 % of control and 17 %) after 30 days. NZVI adversely affected cell viability, adenosine triphosphate production, and fatty acid evolution of cell membranes played a crucial role in resisting chronic NZVI toxicity. Moreover, high NZVI levels hindered the transcription of key enzymes CoM and mcrA, while low NZVI levels maintained its high CoM and mcrA activity, but down-regulated the transcription of cdh and hdr. Besides, amino-utilizing bacteria was reduced under the high NZVI concentration, while low NZVI changed dominant genus with potential protein hydrolysis function from Candidatus Cloacamonas to Sedimentibacter. These results provide a guideline for proper NZVI utilization in wastewater treatment.
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Affiliation(s)
- Runhua Su
- State Key Laboratory of Pollution Control and Resource Reuse, School of Environment, Nanjing University, Nanjing 210023, China
| | - Huimin Fu
- State Key Laboratory of Pollution Control and Resource Reuse, School of Environment, Nanjing University, Nanjing 210023, China; National Research Base of Intelligent Manufacturing Service, Chongqing Technology and Business University, Chongqing 400067, China
| | - Lili Ding
- State Key Laboratory of Pollution Control and Resource Reuse, School of Environment, Nanjing University, Nanjing 210023, China.
| | - Bo Fu
- School of Environmental and Civil Engineering, Jiangsu Key Laboratory of Anaerobic Biotechnology, Jiangnan University, Wuxi 214122, China
| | - Su He
- State Key Laboratory of Pollution Control and Resource Reuse, School of Environment, Nanjing University, Nanjing 210023, China
| | - Haijun Ma
- State Key Laboratory of Pollution Control and Resource Reuse, School of Environment, Nanjing University, Nanjing 210023, China
| | - Haidong Hu
- State Key Laboratory of Pollution Control and Resource Reuse, School of Environment, Nanjing University, Nanjing 210023, China
| | - Hongqiang Ren
- State Key Laboratory of Pollution Control and Resource Reuse, School of Environment, Nanjing University, Nanjing 210023, China
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Yao B, Liu M, Tang T, Hu X, Yang C, Chen Y. Enhancement of anaerobic digestion of ciprofloxacin wastewater by nano zero-valent iron immobilized onto biochar. BIORESOURCE TECHNOLOGY 2023; 385:129462. [PMID: 37429552 DOI: 10.1016/j.biortech.2023.129462] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/15/2023] [Revised: 07/02/2023] [Accepted: 07/04/2023] [Indexed: 07/12/2023]
Abstract
The commonly used antibiotic ciprofloxacin (CIP) can significantly inhibit and interfere with the anaerobic digestion (AD) performance. This work was developed to explore the effectiveness and feasibility of nano iron-carbon composites to simultaneously enhance methane production and CIP removal during AD under CIP stress. The results demonstrated that when the nano-zero-valent iron (nZVI) content immobilized on biochar (BC) was 33% (nZVI/BC-33), the CIP degradation efficiency reached 87% and the methanogenesis reached 143 mL/g COD, both higher than Control, respectively. Reactive oxygen species analysis demonstrated that nZVI/BC-33 could effectively mitigate microorganisms subjected to the dual redox pressure from CIP and nZVI, and reduce a series of oxidative stress reactions. The microbial community depicted that nZVI/BC-33 enriched functional microorganisms related to CIP degradation and methane production and facilitated direct electron transfer processes. Nano iron-carbon composites can effectively alleviate the stress of CIP on AD and enhance methanogenesis.
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Affiliation(s)
- Bing Yao
- College of Architecture and Environment, Sichuan University, Chengdu 610065, China
| | - Min Liu
- College of Architecture and Environment, Sichuan University, Chengdu 610065, China
| | - Taotao Tang
- College of Architecture and Environment, Sichuan University, Chengdu 610065, China
| | - Xuan Hu
- College of Architecture and Environment, Sichuan University, Chengdu 610065, China
| | - Chengyu Yang
- College of Architecture and Environment, Sichuan University, Chengdu 610065, China
| | - Ying Chen
- College of Architecture and Environment, Sichuan University, Chengdu 610065, China
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Li L, Dong H, Lu Y, Zhang H, Li Y, Xiao J, Xiao S, Jin Z. In-depth exploration of toxicity mechanism of nanoscale zero-valent iron and its aging products toward Escherichia coli under aerobic and anaerobic conditions. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2022; 313:120118. [PMID: 36087891 DOI: 10.1016/j.envpol.2022.120118] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/12/2022] [Revised: 08/22/2022] [Accepted: 09/02/2022] [Indexed: 06/15/2023]
Abstract
The bacteria toxicity of nanoscale zero-valent iron (nZVI) can be changed during its application in water treatment but the toxicity mechanism is still not well understood, particularly under anaerobic conditions. Here, the toxicity of nZVI and its aging products towards Escherichia coli (E. coli) and the mechanisms of extracellular and intracellular reactive oxygen species (ROS) damage were deeply probed in the presence and absence of oxygen in ultrapure water. Under aerobic conditions, the ROS damage primarily caused by the generation of extracellular free •OH can be a major contributor to the toxicity of nZVI to E. coli. By contrast, in anaerobic nZVI treatment system, the intracellular •OH can be quenched by benzoic acid which is a cell permeable quencher and the electron spin resonance (ESR) signals of 5,5-dimethy-1-pyrroline (DMPO)- •OH were evidently observed in system with the addition of F- which could desorb the surface •OH into solution. It indicated that the intracellular •OH adsorbed on the particle surface can also play an indispensable role in inactivating cells under anaerobic conditions. Moreover, nZVI can steeply decline the membrane potential, causing severe membrane disruption and therefore resulting in the stronger toxicity in anaerobic conditions. Furthermore, the chemical composition transformation of nZVI and generation of benign iron corrosion products (e.g., Fe3O4, γ-Fe2O3, γ-FeOOH) are mainly responsible for the reduced toxicity with the increasing aging time. These results provide insights into the extracellular and intracellular ROS damage occurred in aerobic and anaerobic nZVI treatment systems, offering more perspective to the risk assessment of nZVI application.
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Affiliation(s)
- Long Li
- College of Environmental Science and Engineering, Hunan University, Changsha, Hunan, 410082, China; Key Laboratory of Environmental Biology and Pollution Control (Hunan University), Ministry of Education, Changsha, Hunan, 410082, China
| | - Haoran Dong
- College of Environmental Science and Engineering, Hunan University, Changsha, Hunan, 410082, China; Key Laboratory of Environmental Biology and Pollution Control (Hunan University), Ministry of Education, Changsha, Hunan, 410082, China.
| | - Yue Lu
- College of Environmental Science and Engineering, Hunan University, Changsha, Hunan, 410082, China; Key Laboratory of Environmental Biology and Pollution Control (Hunan University), Ministry of Education, Changsha, Hunan, 410082, China
| | - Haoxuan Zhang
- College of Environmental Science and Engineering, Hunan University, Changsha, Hunan, 410082, China; Key Laboratory of Environmental Biology and Pollution Control (Hunan University), Ministry of Education, Changsha, Hunan, 410082, China
| | - Yangju Li
- College of Environmental Science and Engineering, Hunan University, Changsha, Hunan, 410082, China; Key Laboratory of Environmental Biology and Pollution Control (Hunan University), Ministry of Education, Changsha, Hunan, 410082, China
| | - Junyang Xiao
- College of Environmental Science and Engineering, Hunan University, Changsha, Hunan, 410082, China; Key Laboratory of Environmental Biology and Pollution Control (Hunan University), Ministry of Education, Changsha, Hunan, 410082, China
| | - Shuangjie Xiao
- College of Environmental Science and Engineering, Hunan University, Changsha, Hunan, 410082, China; Key Laboratory of Environmental Biology and Pollution Control (Hunan University), Ministry of Education, Changsha, Hunan, 410082, China
| | - Zilan Jin
- College of Environmental Science and Engineering, Hunan University, Changsha, Hunan, 410082, China; Key Laboratory of Environmental Biology and Pollution Control (Hunan University), Ministry of Education, Changsha, Hunan, 410082, China
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Jing P, Peng L, Xu N, Feng Y, Liu X. Escherichia coli and phosphate interplay mediates transport of nanoscale zero-valent iron synthesized by green tea in water-saturated porous media. Colloids Surf B Biointerfaces 2022; 219:112783. [PMID: 36049251 DOI: 10.1016/j.colsurfb.2022.112783] [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: 05/13/2022] [Revised: 08/04/2022] [Accepted: 08/18/2022] [Indexed: 10/31/2022]
Abstract
Green synthesized nano-zero-valent iron (GT-nZVI) has been considered an excellent material for in-situ soil remediation due to its high stability and environmental benignity. However, sufficient transportability of GT-nZVI downstream towards the contaminated sites, likely affected by the physicochemical properties of soil-groundwater, is required for improved in-situ remediation. Thus, the effect of soil components (i.e., bacteria and phosphate) on GT-nZVI transportability is significant. Hence, we studied the transport of GT-nZVI (Fe0 core wrapped by green tea polyphenols) with the existence of E. coli and phosphate in water-saturated porous sand media in NaCl and CaCl2 solutions at pHs 6.0 and 8.0. Also studied were the stability, surface characteristics, and two-site kinetics attachment modeling (TKAM) with Escherichia coli or/and phosphate. The results showed that phosphate could further enhance GT-nZVI co-transport with E. coli by increasing the negative charge on GT-nZVI at pH 6.0. However, E. coli reduced GT-nZVI mobility at pH 8.0 because the cell-cell interactions could mask the negative charges of pre-deposited GT-nZVI on E. coli, forming the large clusters between GT-nZVI and E. coli. Then, phosphate occurrence diminished E. coli inhibition by detaching GT-nZVI from nZVI-E. coli-phosphate polymers due to the stronger phosphate adsorption on E. coli than GT-nZVI at pH 8.0. Overall, TKAM describes the transport and retention of GT-nZVI adequately under various conditions, indicating the deposition order with k2str value as follows: GT-nZVI alone > with (w.) E. coli > w. phosphate > w. combined E. coli & phosphate at pH 6.0. By contrast, w. phosphate > w. E. coli > w. combined E. coli & phosphate > GT-nZVI alone ensued at pH 8.0. This investigation highlights the transport behavior of GT-nZVI associated with surface property changes in complex environments for effective in-situ remediation.
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Affiliation(s)
- Pengcheng Jing
- School of Environmental Science and Engineering, Suzhou University of Science and Technology, Suzhou 215009, China; School of Chemistry and Life Sciences, Suzhou University of Science and Technology, Suzhou 215009, China
| | - Lei Peng
- School of Environmental Science and Engineering, Suzhou University of Science and Technology, Suzhou 215009, China; School of Chemistry and Life Sciences, Suzhou University of Science and Technology, Suzhou 215009, China
| | - Nan Xu
- School of Environmental Science and Engineering, Suzhou University of Science and Technology, Suzhou 215009, China.
| | - Yifei Feng
- School of Environmental Science and Engineering, Suzhou University of Science and Technology, Suzhou 215009, China; School of Chemistry and Life Sciences, Suzhou University of Science and Technology, Suzhou 215009, China
| | - Xia Liu
- School of Environmental Science and Engineering, Suzhou University of Science and Technology, Suzhou 215009, China
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Wang J, Liu C, Sun H, Wang S, Liao X, Zhang L. Membrane disruption boosts iron overload and endogenous oxidative stress to inactivate Escherichia coli by nanoscale zero-valent iron. JOURNAL OF HAZARDOUS MATERIALS 2022; 435:128951. [PMID: 35472538 DOI: 10.1016/j.jhazmat.2022.128951] [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: 03/06/2022] [Revised: 04/07/2022] [Accepted: 04/15/2022] [Indexed: 06/14/2023]
Abstract
The inactivation of microorganisms by nanoscale zero-valent iron (nZVI) was extensively reported, but what happens inside the cells is rarely explored. Herein, we revealed that nZVI caused the drastic increase of intracellular iron concentrations, which subsequently catalyzed the Haber-Weiss reaction to produce high levels of endogenous reactive oxygen species (ROSs) and inactivated E. coli cells by oxidative damage of DNA, evidenced by the significantly higher inactivation efficiencies of E. coli mutant strains deficient in iron uptake regulation and DNA repair than the parental strain. The intracellular iron levels, endogenous ROSs levels and the inactivation efficiencies of E. coli were positively correlated. The permeabilized cytomembrane due to the close contact between nZVI and E. coli was responsible for the iron overload. This work demonstrates experimentally for the first time that nZVI causes iron overload and endogenous oxidative stress to inactivate E. coli, thus deepening our knowledge of the nZVI antimicrobial mechanism.
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Affiliation(s)
- Jian Wang
- Hubei Key Lab of Genetic Regulation and Integrative Biology, School of Life Sciences, Central China Normal University, Wuhan 430079, PR China
| | - Congcong Liu
- Hubei Key Lab of Genetic Regulation and Integrative Biology, School of Life Sciences, Central China Normal University, Wuhan 430079, PR China
| | - Hongwei Sun
- Key Laboratory of Pesticide & Chemical Biology of Ministry of Education, Institute of Environmental & Applied Chemistry, College of Chemistry, Central China Normal University, Wuhan 430079, PR China.
| | - Shaohui Wang
- Hubei Key Lab of Genetic Regulation and Integrative Biology, School of Life Sciences, Central China Normal University, Wuhan 430079, PR China
| | - Xiaomei Liao
- Hubei Key Lab of Genetic Regulation and Integrative Biology, School of Life Sciences, Central China Normal University, Wuhan 430079, PR China.
| | - Lizhi Zhang
- Key Laboratory of Pesticide & Chemical Biology of Ministry of Education, Institute of Environmental & Applied Chemistry, College of Chemistry, Central China Normal University, Wuhan 430079, PR China
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