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Chen S, Zhao Z, Li L, Cui F. Comparison of UV/PS and VUV/PS as ultrafiltration pretreatment: Performance, mechanisms, DBPs formation and toxicity assessment. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 946:174457. [PMID: 38969137 DOI: 10.1016/j.scitotenv.2024.174457] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/11/2024] [Revised: 06/03/2024] [Accepted: 07/01/2024] [Indexed: 07/07/2024]
Abstract
Ultrafiltration (UF) is widely used in drinking water plants, nevertheless, it still encounters challenges stemming from inevitable membrane fouling caused by natural organic matter (NOM). Herein, this work applied VUV/PS as UF membrane pretreatment and used UV/PS for comparison. VUV/PS system exhibited superior ability in removing NOM compared to UV/PS system. HO and SO4- played crucial roles in the degradation. [SO4-]ss was notably higher than [HO]ss in the systems, yet HO was of greater significance. [HO]ss and [SO4-]ss in the VUV/PS process were remarkably higher than those in the UV/PS process, due to the function of 185 nm photons. VUV/PS pretreatment basically recovered flux and effectively reduced fouling resistance, with better performance than UV/PS. Fouling mechanism was dominated by multiple mechanisms after UV/PS pretreatment, whereas it was transformed into pore blockage after VUV/PS pretreatment. Moreover, the UF effluent quality after VUV/PS pretreatment outperformed that of UV/PS but fell short of that without pretreatment, possibly due to the generation of abundant low MW substances under the action of HO and SO4-. After chlorine disinfection, UV/PS and VUV/PS pretreatments increased the DBPs production and cytotoxicity. Specifically, oxidant PS affected the membrane surface morphology and fouling behaviors, and had no obvious effect on interception performance and mechanical properties. In actual water treatment, VUV/PS and UV/PS pretreatments exhibited excellent performance in alleviating membrane fouling, improving water quality, and reducing DBPs formation and acute toxicity.
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Affiliation(s)
- Shengnan Chen
- College of Environment and Ecology, Chongqing University, Chongqing 400045, PR China
| | - Zhiwei Zhao
- College of Environment and Ecology, Chongqing University, Chongqing 400045, PR China; School of Civil and Transportation Engineering, Guangdong University of Technology, Guangzhou 510006, PR China.
| | - Li Li
- College of Environment and Ecology, Chongqing University, Chongqing 400045, PR China
| | - Fuyi Cui
- College of Environment and Ecology, Chongqing University, Chongqing 400045, PR China
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Chen S, Zhao Z, Wang C, Cui F. VUV coupled with low-dose H 2O 2 as pretreatment prior to UF: Performance, mechanisms, DBPs formation and toxicity evaluation. JOURNAL OF HAZARDOUS MATERIALS 2024; 476:134966. [PMID: 38901255 DOI: 10.1016/j.jhazmat.2024.134966] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/31/2024] [Revised: 05/17/2024] [Accepted: 06/17/2024] [Indexed: 06/22/2024]
Abstract
Ultrafiltration (UF) is widely used in drinking water plants; however, membrane fouling is unavoidable. Natural organic matter (NOM) is commonly considered as an important pollutant that causes membrane fouling. Herein, we proposed VUV/H2O2 as a UF pretreatment and used UV/H2O2 for comparison. Compared to UV/H2O2, the VUV/H2O2 system presented superior NOM removal. In the VUV/H2O2 system, the steady-state concentration of HO• was approximately twice that in the UV/H2O2 system, which was ascribed to the promoting effect of the 185 nm photons. Specifically, 185 nm photons promoted HO• generation by decomposing mainly H2O at a low H2O2 dose or by decomposing mainly H2O2 at a high H2O2 dose. The VUV/H2O2 pretreatment also demonstrated better membrane fouling mitigation performance than did UV/H2O2. An increase in the H2O2 dose promoted HO• generation, thereby enhancing the performance of NOM degradation and membrane fouling alleviation and shifting the major membrane fouling mechanism from cake filtration to standard blocking. The VUV/H2O2 (0.60 mM) pretreatment effectively reduced disinfection byproducts (DBPs) formation during chlorine disinfection. Additionally, the oxidant H2O2 affected the membrane surface morphology and performance but had no evident effect on the mechanical properties. In actual water treatment, the VUV/H2O2 pretreatment exhibited better performance than the UV/H2O2 pretreatment in easing membrane fouling, ameliorating water quality, and reducing DBPs formation and acute toxicity.
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Affiliation(s)
- Shengnan Chen
- College of Environment and Ecology, Chongqing University, Chongqing 400045, PR China
| | - Zhiwei Zhao
- College of Environment and Ecology, Chongqing University, Chongqing 400045, PR China; School of Civil and Transportation Engineering, Guangdong University of Technology, Guangzhou 510006, PR China.
| | - Chuang Wang
- School of Civil Engineering, Hunan University of Science and Technology, Xiangtan, Hunan 411201, PR China
| | - Fuyi Cui
- College of Environment and Ecology, Chongqing University, Chongqing 400045, PR China
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Tian J, Qi Y, Wei J, Rady A, Maodaa S, Allam AA, Wang Z, Qu R. Enhanced removal of bisphenol S in ozone/peroxymonosulfate system: Kinetics, intermediates and reaction mechanism. CHEMOSPHERE 2024; 349:140952. [PMID: 38101481 DOI: 10.1016/j.chemosphere.2023.140952] [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: 09/17/2023] [Revised: 11/28/2023] [Accepted: 12/11/2023] [Indexed: 12/17/2023]
Abstract
The degradation process of bisphenol S (BPS) in ozone/peroxymonosulfate (O3/PMS) system was systematically explored. The results showed that the removal efficiency of BPS by O3 could be significantly improved with addition of PMS. Compared with ozonation alone, the pseudo-first-order constant (kobs) was increased by 2-5 times after adding 400 μM PMS. In O3/PMS system, accelerated removal of BPS was observed under neutral and alkaline conditions. The removal efficiency of BPS reached 100% after 40 s of reaction at pH 7.0, with the kobs of 0.098 s-1. Moreover, Cu2+ had a catalytic effect on the O3/PMS system, because it could catalyze the decomposition of ozone and PMS to produce •OH and SO4•-, respectively. Electron paramagnetic resonance illustrated that •OH and SO4•- were the reactive species in O3/PMS system. Twelve intermediates were identified by mass spectrometry, and the degradation reactions in O3/PMS system mainly included hydroxylation, sulfate addition, polymerization and β-scission. Finally, the toxicity of the products was evaluated by the EOCSAR program. Our results introduce an efficient method for BPS removal and would provide some guidance for the development of O3-based advanced oxidation technology.
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Affiliation(s)
- Jie Tian
- State Key Laboratory of Pollution Control and Resources Reuse, School of the Environment, Nanjing University, Nanjing, 210023, Jiangsu, PR China
| | - Yumeng Qi
- State Key Laboratory of Pollution Control and Resources Reuse, School of the Environment, Nanjing University, Nanjing, 210023, Jiangsu, PR China
| | - Junyan Wei
- State Key Laboratory of Pollution Control and Resources Reuse, School of the Environment, Nanjing University, Nanjing, 210023, Jiangsu, PR China
| | - Ahmed Rady
- Department of Zoology, College of Science, King Saud University, P.O. Box 2455, Riyadh, 11451, Saudi Arabia
| | - Saleh Maodaa
- Department of Zoology, College of Science, King Saud University, P.O. Box 2455, Riyadh, 11451, Saudi Arabia
| | - Ahmed A Allam
- Department of Zoology, Beni-suef University, Beni-suef, 65211, Egypt
| | - Zunyao Wang
- State Key Laboratory of Pollution Control and Resources Reuse, School of the Environment, Nanjing University, Nanjing, 210023, Jiangsu, PR China.
| | - Ruijuan Qu
- State Key Laboratory of Pollution Control and Resources Reuse, School of the Environment, Nanjing University, Nanjing, 210023, Jiangsu, PR China
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