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Parsa Z, Dhib R, Mehrvar M. Dynamic Modelling, Process Control, and Monitoring of Selected Biological and Advanced Oxidation Processes for Wastewater Treatment: A Review of Recent Developments. Bioengineering (Basel) 2024; 11:189. [PMID: 38391675 PMCID: PMC10886268 DOI: 10.3390/bioengineering11020189] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2024] [Revised: 02/02/2024] [Accepted: 02/09/2024] [Indexed: 02/24/2024] Open
Abstract
This review emphasizes the significance of formulating control strategies for biological and advanced oxidation process (AOP)-based wastewater treatment systems. The aim is to guarantee that the effluent quality continuously aligns with environmental regulations while operating costs are minimized. It highlights the significance of understanding the dynamic behaviour of the process in developing effective control schemes. The most common process control strategies in wastewater treatment plants (WWTPs) are explained and listed. It is emphasized that the proper control scheme should be selected based on the process dynamic behaviour and control goal. This study further discusses the challenges associated with the control of wastewater treatment processes, including inadequacies in developed models, the limitations of most control strategies to the simulation stage, the imperative requirement for real-time data, and the financial and technical intricacies associated with implementing advanced controller hardware. It is discussed that the necessity of the availability of real-time data to achieve reliable control can be achieved by implementing proper, accurate hardware sensors in suitable locations of the process or by developing and implementing soft sensors. This study recommends further investigation on available actuators and the criteria for choosing the most appropriate one to achieve robust and reliable control in WWTPs, especially for biological and AOP-based treatment approaches.
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Affiliation(s)
- Zahra Parsa
- Department of Chemical Engineering, Toronto Metropolitan University, 350 Victoria Street, Toronto, ON M5B 2K3, Canada
| | - Ramdhane Dhib
- Department of Chemical Engineering, Toronto Metropolitan University, 350 Victoria Street, Toronto, ON M5B 2K3, Canada
| | - Mehrab Mehrvar
- Department of Chemical Engineering, Toronto Metropolitan University, 350 Victoria Street, Toronto, ON M5B 2K3, Canada
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Han Q, Sun T, Zhang X, Li S, Zhu Y. Degradation of polyvinyl alcohol (PVA) in neutral conditions based on copper-manganese bimetallic catalyst. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2023; 30:97990-98003. [PMID: 37603237 DOI: 10.1007/s11356-023-29366-z] [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: 06/26/2023] [Accepted: 08/12/2023] [Indexed: 08/22/2023]
Abstract
There have been many studies on the degradation of polyvinyl alcohol (PVA) by the Fenton-like method, but the narrow acid-base (pH) range, poor degradation effect, and time-consuming of the Fenton-like method limit its development. Therefore, to improve the shortcomings of the Fenton-like method, the study aimed to synthesize copper-manganese bimetal oxide loaded catalysts (MnCuO@γ-Al2O3) through the impregnation calcination method, and its potential to activate hydrogen peroxide (H2O2) for the degradation of PVA was evaluated. The X-ray diffraction (XRD), scanning electron microscopy (SEM), Brunauer Emmett Teller (BET), energy dispersive spectroscopy (EDS), and X-ray photoelectron spectroscopy (XPS) characterizations revealed the chemical composition, structure and morphology of the prepared MnCuO@γ-Al2O3, furthermore the synergistic mechanism was proposed. Results indicated that copper and manganese could successfully attach to γ-Al2O3 and reduce the specific surface area of γ-Al2O3, promoting the transformation of multivalent metals and the generation of oxygen vacancies. In addition, comparative experiments demonstrated that the PVA removal efficiency was significantly improved at the catalyst calcination temperature of 500 °C, reaction temperature of 70 °C, H2O2 dosage of 125 [Formula: see text], and catalyst dosage of 625 [Formula: see text] and more than 96% of PVA was removed within 20 min in neutral conditions. Lastly, four catalyst cycle degradation experiments of PVA were carried out, and the degradation effect could reach more than 96% in a certain time.
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Affiliation(s)
- Qinghe Han
- School of Textile Science and Engineering, Jiangnan University, Wuxi, 214122, Jiangsu, China
| | - Tongming Sun
- National Innovation Center of Advanced Dyeing & Finishing Technology, Tai'an, Shandong, 271000, People's Republic of China
| | - Xinyu Zhang
- National Innovation Center of Advanced Dyeing & Finishing Technology, Tai'an, Shandong, 271000, People's Republic of China
| | - Shen Li
- Sichuan Province Fiber Inspection Bureau, Chengdu, 610015, Sichuan, China
| | - Yanan Zhu
- School of Textile Science and Engineering, Jiangnan University, Wuxi, 214122, Jiangsu, China.
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Nasr Esfahani K, Pérez-Moya M, Graells M. Modelling of the photo-Fenton process with flexible hydrogen peroxide dosage: Sensitivity analysis and experimental validation. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 839:155941. [PMID: 35577083 DOI: 10.1016/j.scitotenv.2022.155941] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/23/2022] [Revised: 05/06/2022] [Accepted: 05/10/2022] [Indexed: 06/15/2023]
Abstract
The supply of hydrogen peroxide (H2O2) controlling the amount of highly oxidant hydroxyl radicals is the most critical operational issue for the photo-Fenton process. Accordingly, this study addresses the development of a model for photo-Fenton processes including a flexible H2O2 supply given as a function of time. The model is aimed at its future exploitation in treatment optimization and the determination of the optimal profile for H2O2 supply. The work has adopted a photo Fenton model previously reported that includes the inlet flow (fed-batch) and describes the system dynamics under a flexible dosage. Thus, model global sensitivity analysis (GSA) and parameter estimation were performed using Simulink® to examine the behavior of the model under flexible H2O2 dosage. GSA was carried out using partial rank correlation methods and the Latin hypercube sampling to assess to which extent variations of the model parameters affect each measured response (H2O2, total organic carbon, TOC, and dissolved oxygen, O2 -the experimentally available information). Hence, the model is discussed in regard of its hypothesis and chances for reducing its complexity. This resulted in the rejection of two reactions of the initial model. Next, a set of 12 kinetic, stoichiometric and operative parameters was estimated through the fitting of H2O2, TOC, and O2 profiles. Discussion on model fitting includes computational issues, the role of initial values for the estimation process, the goodness of fit criteria, and the sampling method. The model was fit to experimental data with assorted H2O2 supply profiles and validated, and Root Mean Square Error (RMSE) below 0.009 mM, 0.42 mM, and 0.127 mM were obtained for TOC, H2O2 and O2, respectively. Therefore, this work contributes a practical model aimed at providing model-based optimization for the H2O2 dosage profile of the photo-Fenton process.
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Affiliation(s)
- Kourosh Nasr Esfahani
- Chemical Engineering Department, EEBE, Universitat Politècnica de Catalunya, Av. Eduard Maristany, 16, 08019 Barcelona, Spain
| | - Montserrat Pérez-Moya
- Chemical Engineering Department, EEBE, Universitat Politècnica de Catalunya, Av. Eduard Maristany, 16, 08019 Barcelona, Spain.
| | - Moisès Graells
- Chemical Engineering Department, EEBE, Universitat Politècnica de Catalunya, Av. Eduard Maristany, 16, 08019 Barcelona, Spain
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Recent Advances in Dynamic Modeling and Process Control of PVA Degradation by Biological and Advanced Oxidation Processes: A Review on Trends and Advances. ENVIRONMENTS 2021. [DOI: 10.3390/environments8110116] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Polyvinyl alcohol (PVA) is an emerging pollutant commonly found in industrial wastewater, owing to its extensive usage as an additive in the manufacturing industry. PVA’s popularity has made wastewater treatment technologies for PVA degradation a popular research topic in industrial wastewater treatment. Although many PVA degradation technologies are studied in bench-scale processes, recent advancements in process optimization and control of wastewater treatment technologies such as advanced oxidation processes (AOPs) show the feasibility of these processes by monitoring and controlling processes to meet desired regulatory standards. These wastewater treatment technologies exhibit complex reaction mechanisms leading to nonlinear and nonstationary behavior related to variability in operational conditions. Thus, black-box dynamic modeling is a promising tool for designing control schemes since dynamic modeling is more complicated in terms of first principles and reaction mechanisms. This study seeks to provide a survey of process control methods via a comprehensive review focusing on PVA degradation methods, including biological and advanced oxidation processes, along with their reaction mechanisms, control-oriented dynamic modeling (i.e., state-space, transfer function, and artificial neural network modeling), and control strategies (i.e., proportional-integral-derivative control and predictive control) associated with wastewater treatment technologies utilized for PVA degradation.
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Lin YP, Dhib R, Mehrvar M. Nonlinear System Identification for Aqueous PVA Degradation in a Continuous UV/H2O2 Tubular Photoreactor. Ind Eng Chem Res 2020. [DOI: 10.1021/acs.iecr.0c04637] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Yi Ping Lin
- Department of Chemical Engineering, Ryerson University, 350 Victoria Street, Toronto, Ontario M5B 2K3, Canada
| | - Ramdhane Dhib
- Department of Chemical Engineering, Ryerson University, 350 Victoria Street, Toronto, Ontario M5B 2K3, Canada
| | - Mehrab Mehrvar
- Department of Chemical Engineering, Ryerson University, 350 Victoria Street, Toronto, Ontario M5B 2K3, Canada
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Additive manufacturing of the core template for the fabrication of an artificial blood vessel: the relationship between the extruded deposition diameter and the filament/nozzle transition ratio. MATERIALS SCIENCE & ENGINEERING. C, MATERIALS FOR BIOLOGICAL APPLICATIONS 2020; 118:111406. [PMID: 33255009 DOI: 10.1016/j.msec.2020.111406] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/20/2020] [Revised: 07/22/2020] [Accepted: 08/19/2020] [Indexed: 12/14/2022]
Abstract
An artificial blood vessel with a tubular structure was additively manufactured via fused deposition modeling (FDM) starting from a single strand of polyvinyl alcohol (PVA) filament coated with a specific thickness of biocompatible polydimethylsiloxane (PDMS), followed by removal of the inner core via hydrogen peroxide leaching under sonication. In particular, we examined the relationship between the extruded deposition diameter and the filament migration speed/nozzle control speed (referred to as the filament/nozzle transition ratio), which is almost independent of the extruded deposition flow rate due to the weak die-swelling and memory effects of the extruded PVA arising from its intrinsically low viscoelasticity. The chemical stability of the PDMS during sonication in the hydrogen peroxide solution was then determined by spectroscopic techniques. The PDMS displayed no mechanical degradation in the hydrogen peroxide solution, resulting in similar fracture elongation and yield strength to those of the pristine specimen without the leaching treatment. As a further advantage, the inside surface of the PDMS was smooth regardless of the hydrogen peroxide leaching under sonication. The potential application of the as-developed scaffold in soft tissue engineering (particularly that involving vascular tissue regeneration) was demonstrated by the successful transplantation of the artificial blood vessel in a right-hand surgical replica used in a clinical simulation.
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Okonogi S, Kaewpinta A, Rades T, Müllertz A, Yang M, Khongkhunthian S, Chaijareenont P. Enhancing Stability and Tooth Bleaching Activity of Carbamide Peroxide by Electrospun Nanofibrous Film. Pharmaceuticals (Basel) 2020; 13:E381. [PMID: 33187352 PMCID: PMC7698251 DOI: 10.3390/ph13110381] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2020] [Revised: 11/08/2020] [Accepted: 11/09/2020] [Indexed: 12/27/2022] Open
Abstract
Carbamide peroxide (CP) possesses a strong tooth bleaching activity, however, its clinical application is limited because of its instability in aqueous formulations. This study explores the improvement of CP stability and bleaching activity by loading CP in electrospun nanofibrous film (ENF). Polyvinylalcohol, polyvinylpyrrolidone, and silica were used as components for core-based nanofibers of ENF. Electrospinning feed aqueous solutions (EFASs) were developed for preparing CP loaded ENF (CP-ENF). Stability of CP in EFASs is significantly higher than in pure water. The highest stability of CP is found in PPS-CP3, composed of 0.5% CP, 5.5% polyvinylalcohol, 3% polyvinylpyrrolidone, and 1% silica. The results from X-ray diffraction indicate that CP is dispersed as a non-crystalline form in CP-ENFs. CP and the compositions of EFASs play a major role on characteristics and bleaching efficiency of CP-ENFs. Drug release of CP-ENFs is the first order kinetics. CP-ENF obtained from PPS-CP3 shows the highest drug entrapment efficiency, high adhesion, and suitable sustained release. Drug release mechanism is along with anomalous transport according to Korsmeyer-Peppas model. In an ex vivo study using human teeth, it shows the highest bleaching efficiency among the others. Therefore, CP-ENF obtained from PPS-CP3 is a promising ENF for clinical use.
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Affiliation(s)
- Siriporn Okonogi
- Department of Pharmaceutical Sciences, Faculty of Pharmacy, Chiang Mai University, Chiang Mai 50200, Thailand
- Research Center of Pharmaceutical Nanotechnology, Chiang Mai University, Chiang Mai 50200, Thailand; (S.K.); (P.C.)
| | - Adchareeya Kaewpinta
- Interdisciplinary Program in Nanoscience and Nanotechnology, Faculty of Science, Chiang Mai University, Chiang Mai 50200, Thailand;
| | - Thomas Rades
- Department of Pharmacy, Faculty of Health and Medical Sciences, University of Copenhagen, 2100 Copenhagen, Denmark; (T.R.); (A.M.); (M.Y.)
| | - Anette Müllertz
- Department of Pharmacy, Faculty of Health and Medical Sciences, University of Copenhagen, 2100 Copenhagen, Denmark; (T.R.); (A.M.); (M.Y.)
| | - Mingshi Yang
- Department of Pharmacy, Faculty of Health and Medical Sciences, University of Copenhagen, 2100 Copenhagen, Denmark; (T.R.); (A.M.); (M.Y.)
- Wuya College of Innovation, Shenyang Pharmaceutical University, Shenyang 110016, China
| | - Sakornrat Khongkhunthian
- Research Center of Pharmaceutical Nanotechnology, Chiang Mai University, Chiang Mai 50200, Thailand; (S.K.); (P.C.)
- Department of Restorative Dentistry and Periodontology, Faculty of Dentistry, Chiang Mai University, Chiang Mai 50200, Thailand
| | - Pisaisit Chaijareenont
- Research Center of Pharmaceutical Nanotechnology, Chiang Mai University, Chiang Mai 50200, Thailand; (S.K.); (P.C.)
- Department of Prosthodontics, Faculty of Dentistry, Chiang Mai University, Chiang Mai 50200, Thailand
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Wang Z, Teng X, Xie M, Cheng X, Li J. Pretreatment of polyvinyl alcohol by electrocoagulation coupling with catalytic oxidation: Performance, mechanism and pathway. CHINESE CHEM LETT 2020. [DOI: 10.1016/j.cclet.2020.03.051] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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Wang K, Li Y, Huang J, Xu L, Yin L, Ji Y, Wang C, Xu Z, Niu J. Insights into electrochemical decomposition mechanism of lipopolysaccharide using TiO 2 nanotubes arrays electrode. JOURNAL OF HAZARDOUS MATERIALS 2020; 391:122259. [PMID: 32062543 DOI: 10.1016/j.jhazmat.2020.122259] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/12/2019] [Revised: 02/03/2020] [Accepted: 02/07/2020] [Indexed: 06/10/2023]
Abstract
Electrochemical decomposition of lipopolysaccharide (LPS) was firstly investigated over titania nanotubes (TNTs) arrays electrode. The TNTs layer of this electrode consisted of numerous tubular structures which arranged tightly, and the average diameter of each nanotube is 100 ± 5 nm. The degradation of LPS and polysaccharides followed pseudo-first-order kinetics. The optimal LPS removal ratio was nearly 80 %. The endotoxin toxicity of LPS steadily decreased during the electrolysis process. The acute toxicity of the intermediates increased suddenly at the beginning of electrochemical degradation process (< 5 min), then maintained high inhibition ratio (> 95 %) for about 150 min, and decreased significantly (< 10 %) after electrolysis for 240 min. After 20 min of electrolysis, LPS with molecular weight of 116,854 Da was transformed into small molecular compounds with molecular weights of 59,312 - 12,209 Da. Possible degradation and detoxification mechanisms of LPS including electric-field-force-driving accumulation, adsorption and direct electron transfer on TNTs arrays electrode, and •OH oxidation were proposed. This study underscores that electrochemical technique can be applied to eliminate and decrease the toxicity of LPS from contaminated water.
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Affiliation(s)
- Kaixuan Wang
- Research Center for Eco-environmental Engineering, Dongguan University of Technology, Dongguan, Guangdong 523808, PR China; Key Laboratory of Water and Sediment Sciences of Ministry of Education, State Key Laboratory of Water Environment Simulation, School of Environment, Beijing Normal University, Beijing 100875, PR China
| | - Yang Li
- Key Laboratory of Water and Sediment Sciences of Ministry of Education, State Key Laboratory of Water Environment Simulation, School of Environment, Beijing Normal University, Beijing 100875, PR China
| | - Junxiong Huang
- Key Laboratory of Water and Sediment Sciences of Ministry of Education, State Key Laboratory of Water Environment Simulation, School of Environment, Beijing Normal University, Beijing 100875, PR China
| | - Lei Xu
- Research Center for Eco-environmental Engineering, Dongguan University of Technology, Dongguan, Guangdong 523808, PR China
| | - Lifeng Yin
- Key Laboratory of Water and Sediment Sciences of Ministry of Education, State Key Laboratory of Water Environment Simulation, School of Environment, Beijing Normal University, Beijing 100875, PR China
| | - Yangyuan Ji
- Key Laboratory of Water and Sediment Sciences of Ministry of Education, State Key Laboratory of Water Environment Simulation, School of Environment, Beijing Normal University, Beijing 100875, PR China
| | - Chong Wang
- Key Laboratory of Water and Sediment Sciences of Ministry of Education, State Key Laboratory of Water Environment Simulation, School of Environment, Beijing Normal University, Beijing 100875, PR China
| | - Zesheng Xu
- Chinese Academy for Environmental Planning, Beijing 100012, PR China
| | - Junfeng Niu
- Research Center for Eco-environmental Engineering, Dongguan University of Technology, Dongguan, Guangdong 523808, PR China.
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Lamponi S, Leone G, Consumi M, Nelli N, Magnani A. Porous multi-layered composite hydrogel as cell substrate for in vitro culture of chondrocytes. INT J POLYM MATER PO 2020. [DOI: 10.1080/00914037.2020.1765351] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Affiliation(s)
- Stefania Lamponi
- Department of Biotechnology, Chemistry and Pharmacy, University of Siena, Siena, Italy
| | - Gemma Leone
- Department of Biotechnology, Chemistry and Pharmacy, University of Siena, Siena, Italy
| | - Marco Consumi
- Department of Biotechnology, Chemistry and Pharmacy, University of Siena, Siena, Italy
| | - Nicola Nelli
- Department of Biotechnology, Chemistry and Pharmacy, University of Siena, Siena, Italy
| | - Agnese Magnani
- Department of Biotechnology, Chemistry and Pharmacy, University of Siena, Siena, Italy
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Ullah M, Weng CH, Li H, Sun SW, Zhang H, Song AH, Zhu H. Degradation of polyvinyl alcohol by a novel bacterial strain Stenotrophomonas sp. SA21. ENVIRONMENTAL TECHNOLOGY 2018; 39:2056-2061. [PMID: 28669293 DOI: 10.1080/09593330.2017.1349189] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
UNLABELLED In this study, polyvinyl alcohol (PVA)-degrading bacteria were screened from oil sludge using PVA as a sole source of carbon in the culture medium. A novel strain, SA21, was obtained and identified as a member of the Stenotrophomonas genus based on the analysis of a partial 16S rDNA nucleotide sequence, morphological and biochemical characteristics, and phylogenetic analysis. This Stenotrophomonas isolate had not previously been reported as a PVA-degrading bacterium. Stenotrophomonas sp. strain SA21 degraded 90% of the PVA present in the culture medium after 4 days. The effect of nitrogen sources on the production of PVA-degrading enzyme involved in the biodegradation process was significant, and the enzymatic activity reached 82 U/ml when ammonium nitrate or urea was used in the optimized medium. The information obtained in this study will provide a foundation for improving industrial wastewater treatment. ABBREVIATIONS DCW: dry cell weight; FTIR: Fourier Transform Infrared Spectroscopy; NCBI: National Center for Biotechnology Information; PCR: polymerase chain reaction; PVA: polyvinyl alcohol; SEM: scanning electron microscope.
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Affiliation(s)
- Munzer Ullah
- a Centre for Bioengineering and Biotechnology , China University of Petroleum (East China) , Qingdao , People's Republic of China
| | - Cai-Hong Weng
- a Centre for Bioengineering and Biotechnology , China University of Petroleum (East China) , Qingdao , People's Republic of China
| | - Hui Li
- a Centre for Bioengineering and Biotechnology , China University of Petroleum (East China) , Qingdao , People's Republic of China
| | - Shi-Wei Sun
- a Centre for Bioengineering and Biotechnology , China University of Petroleum (East China) , Qingdao , People's Republic of China
| | - Hong Zhang
- a Centre for Bioengineering and Biotechnology , China University of Petroleum (East China) , Qingdao , People's Republic of China
| | - Ai-Huan Song
- b Marine Biology Institute of Shandong Province , Qingdao , People's Republic of China
| | - Hu Zhu
- a Centre for Bioengineering and Biotechnology , China University of Petroleum (East China) , Qingdao , People's Republic of China
- c College of Chemistry and Chemical Engineering , Fujian Normal University , Fuzhou , People's Republic of China
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Ye B, Li Y, Chen Z, Wu QY, Wang WL, Wang T, Hu HY. Degradation of polyvinyl alcohol (PVA) by UV/chlorine oxidation: Radical roles, influencing factors, and degradation pathway. WATER RESEARCH 2017; 124:381-387. [PMID: 28783494 DOI: 10.1016/j.watres.2017.05.059] [Citation(s) in RCA: 58] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/06/2017] [Revised: 05/15/2017] [Accepted: 05/28/2017] [Indexed: 05/28/2023]
Abstract
Polyvinyl alcohol (PVA) is widely used in industry but is difficult to degrade. In this study, the synergistic effect of UV irradiation and chlorination on degradation of PVA was investigated. UV irradiation or chlorination alone did not degrade PVA. By contrast, UV/chlorine oxidation showed good efficiency for PVA degradation via generation of active free radicals, such as OH and Cl. The relative importance of these two free radicals in the oxidation process was evaluated, and it was shown that OH contributed more to PVA degradation than Cl did. The degradation of PVA followed pseudo first order kinetics. The rate constant k increased linearly from 0 min-1 to 0.3 min-1 with increasing chlorine dosage in range of 0 mg/L to 20 mg/L. However, when the chlorine dosage was increased above 20 mg/L, scavenging effect of free radicals occurred, and the degradation efficiency of PVA did not increase much more. Acidic media increased the degradation efficiency of PVA by UV/chlorine oxidation more than basic or neutral media because of the higher ratio of [HOCl]/[OCl-], higher free radical quantum yields, and the lower free radical quenching effect under acidic conditions. Results of Fourier Transform Infrared Spectroscopy showed that carbonyl groups in degradation products were formed during UV/chlorine oxidation, and a possible degradation pathway via alcohol to carbonyl was proposed.
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Affiliation(s)
- Bei Ye
- Shenzhen Environmental Science and New Energy Technology Engineering Laboratory, Tsinghua-Berkeley Shenzhen Institute, Shenzhen 518055, PR China
| | - Yue Li
- Key Laboratory of Microorganism Application and Risk Control of Shenzhen, Graduate School at Shenzhen, Tsinghua University, Shenzhen 518055, PR China; Environmental Simulation and Pollution Control State Key Joint Laboratory and State Environmental Protection Key Laboratory of Microorganism Application and Risk Control (SMARC), School of Environment, Tsinghua University, Beijing 100084, PR China
| | - Zhuo Chen
- Key Laboratory of Microorganism Application and Risk Control of Shenzhen, Graduate School at Shenzhen, Tsinghua University, Shenzhen 518055, PR China; Environmental Simulation and Pollution Control State Key Joint Laboratory and State Environmental Protection Key Laboratory of Microorganism Application and Risk Control (SMARC), School of Environment, Tsinghua University, Beijing 100084, PR China
| | - Qian-Yuan Wu
- Key Laboratory of Microorganism Application and Risk Control of Shenzhen, Graduate School at Shenzhen, Tsinghua University, Shenzhen 518055, PR China.
| | - Wen-Long Wang
- Key Laboratory of Microorganism Application and Risk Control of Shenzhen, Graduate School at Shenzhen, Tsinghua University, Shenzhen 518055, PR China; Environmental Simulation and Pollution Control State Key Joint Laboratory and State Environmental Protection Key Laboratory of Microorganism Application and Risk Control (SMARC), School of Environment, Tsinghua University, Beijing 100084, PR China
| | - Ting Wang
- Key Laboratory of Microorganism Application and Risk Control of Shenzhen, Graduate School at Shenzhen, Tsinghua University, Shenzhen 518055, PR China; Environmental Simulation and Pollution Control State Key Joint Laboratory and State Environmental Protection Key Laboratory of Microorganism Application and Risk Control (SMARC), School of Environment, Tsinghua University, Beijing 100084, PR China
| | - Hong-Ying Hu
- Shenzhen Environmental Science and New Energy Technology Engineering Laboratory, Tsinghua-Berkeley Shenzhen Institute, Shenzhen 518055, PR China; Environmental Simulation and Pollution Control State Key Joint Laboratory and State Environmental Protection Key Laboratory of Microorganism Application and Risk Control (SMARC), School of Environment, Tsinghua University, Beijing 100084, PR China.
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