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Chen T, Mackey E, Andrews S, Hofmann R. Kinetics of chlorine and chloramine reactions in reverse osmosis permeate and their impact on radical formation during UV/chlorine advanced oxidation for potable reuse. WATER RESEARCH 2024; 254:121433. [PMID: 38461603 DOI: 10.1016/j.watres.2024.121433] [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: 12/06/2023] [Revised: 02/06/2024] [Accepted: 03/05/2024] [Indexed: 03/12/2024]
Abstract
Knowledge of the speciation of chlorine and chloramines in reverse osmosis (RO) permeate is needed to estimate the performance (i.e., pollutant log reduction) of subsequent UV/chlorine advanced oxidation processes (AOPs). To accurately predict the speciation, a previously reported breakpoint chlorination kinetic model was experimentally validated for pH 5.5 and reaction times < 3 min and used to predict the kinetics of breakpoint chlorination in RO permeate. The predictions showed that eliminating chloramines by adding chlorine at a dose beyond the chlorine-to-nitrogen (Cl/N) breakpoint ratio is not practical due to the high breakpoint Cl/N ratio for RO permeate (∼3.0 molar ratio) and an estimated > 40 min reaction time. The conversion from monochloramine (NH2Cl) to dichloramine (NHCl2) is the major process involved, and either or both free chlorine and chloramines may be the major species present, depending on the Cl/N ratio. Model simulations showed that increasing the oxidant dose may not always enhance the performance of UV/chlor(am)ine in RO permeate, due to the need for a low free chlorine dose for optimal •OH exposure in RO permeate. Further UV/AOPs modelling showed that it is important to control the NH2Cl concentration to improve the UV/AOP performance in RO permeate, which may be achieved by extending the reaction time after chlorine is added or increasing the applied Cl/N ratio (e.g., increasing chlorine dose). However, these measures only enhance the pollutant percentage removal by about 5 % under the conditions modelled. A simulation tool was developed and is provided to predict the speciation of chlor(am)ine in RO permeate.
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Affiliation(s)
- Tianyi Chen
- Department of Civil and Mineral Engineering, University of Toronto, 35St. George Street, Toronto, Ontario M5S 1A4, Canada
| | - Erin Mackey
- Brown and Caldwell, 201N Civic Dr. #300, Walnut Creek, CA 94596, USA
| | - Susan Andrews
- Department of Civil and Mineral Engineering, University of Toronto, 35St. George Street, Toronto, Ontario M5S 1A4, Canada
| | - Ron Hofmann
- Department of Civil and Mineral Engineering, University of Toronto, 35St. George Street, Toronto, Ontario M5S 1A4, Canada.
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2
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Pimentel A, Linden KG. Optimizing radical yield from free chlorine with tailored UV light emitting diode emission spectra. WATER RESEARCH 2024; 249:120923. [PMID: 38064784 DOI: 10.1016/j.watres.2023.120923] [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: 07/12/2023] [Revised: 09/29/2023] [Accepted: 11/23/2023] [Indexed: 01/03/2024]
Abstract
Novel UV sources, which do not contain mercury, provide the opportunity for enhancement of current oxidation technologies through spectral optimization, minimizing inefficiencies that currently limit conventional technology. Wastewater reuse is the primary full-scale application of UV advanced oxidation processes (AOPs) in practice but any background absorbance and the low molar absorption by conventional radical promoters (hydrogen peroxide) have historically limited their system efficiency, resulting in the underutilization of photons in a reactor. This bench-scale research evaluated use of longer wavelength UV light emitting diodes (265, 280, and 300 nm) matched with free chlorine to optimize the utilization of photons for advanced oxidation. Free chlorine possesses large absorption bands in the 280 to 300 nm range in basic pH waters which are common in carbon-based reuse and was used to experimentally verify quantum yields of hydroxyl radical generation across the UV LED peak emission wavelengths. pH- and wavelength-dependent fluence-based rate constants were experimentally derived using Nitrobenzene and Benzoic acid as probe compounds and evaluated to determine the contribution of the hydroxyl and chlorine radical. Reclaimed water taken from various advanced treatment steps was treated with this UV LED AOP to investigate how background absorbance affects radical generation and contaminant transformation kinetics. In addition, alternative performance metrics to evaluate hydroxyl radical production at different incident fluence rates and different rates of photon absorption at unique wavelengths across varying background UV absorbance levels were assessed.
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Affiliation(s)
- Anthony Pimentel
- Department of Civil, Environmental, and Architectural Engineering, University of Colorado Boulder, 4001 Discovery Dr, Boulder, CO 80303, USA
| | - Karl G Linden
- Department of Civil, Environmental, and Architectural Engineering, University of Colorado Boulder, 4001 Discovery Dr, Boulder, CO 80303, USA.
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3
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Kundu D, Dutta D, Joseph A, Jana A, Samanta P, Bhakta JN, Alreshidi MA. Safeguarding drinking water: A brief insight on characteristics, treatments and risk assessment of contamination. ENVIRONMENTAL MONITORING AND ASSESSMENT 2024; 196:180. [PMID: 38244090 DOI: 10.1007/s10661-024-12311-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: 08/04/2023] [Accepted: 01/04/2024] [Indexed: 01/22/2024]
Abstract
Water pollution stands as a critical worldwide concern, bearing extensive repercussions that extend to human health and the natural ecosystem. The sources of water pollution can be diverse, arising from natural processes and human activities and the pollutants may range from chemical and biological agents to physical and radiological contaminants. The contamination of water disrupts the natural functioning of the system, leading to both immediate and prolonged health problems. Various technologies and procedures, ranging from conventional to advanced, have been developed to eliminate water impurities, with the choice depending on the type and level of contamination. Assessing risks is a crucial element in guaranteeing the safety of drinking water. Till now, research is continuing the removal of contaminates for the sake of supplying safe drinking water. The study examined physical, inorganic, organic, biological and radiological contaminants in drinking water. It looked at where these contaminants come from, their characteristics, the impact they have and successful methods used in real-world situations to clean the contaminated water. Risk assessment methodologies associated with the use of unsafe drinking water as future directives are also taken into consideration in the present study for the benefit of public concern. The manuscript introduces a comprehensive study on water pollution, focusing on assessing and mitigating risks associated with physical, inorganic, organic, biological and radiological contaminants in drinking water, with a novel emphasis on future directives and sustainable solutions for public safety.
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Affiliation(s)
- Debajyoti Kundu
- Department of Environmental Science and Engineering, School of Engineering and Sciences, SRM University-AP, Amaravati, Andhra Pradesh, 522 240, India.
| | - Deblina Dutta
- Department of Environmental Science and Engineering, School of Engineering and Sciences, SRM University-AP, Amaravati, Andhra Pradesh, 522 240, India.
| | - Anuja Joseph
- School of Environmental Science and Engineering, Indian Institute of Technology Kharagpur, Kharagpur, 721 302, India
| | - Ankan Jana
- Malaviya National Institute of Technology, Jaipur, Rajasthan, 302 017, India
| | - Palas Samanta
- Department of Environmental Science, Sukanta Mahavidyalaya, University of North Bengal, Dhupguri, Jalpaiguri, 735 210, India
| | - Jatindra Nath Bhakta
- Department of Ecological Studies & International Centre for Ecological Engineering, University of Kalyani, Kalyani, West Bengal, 741 235, India
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Li B, Pan H, Chen B. A review of factors affecting the formation and roles of primary and secondary reactive species in UV 254-based advanced treatment processes. WATER RESEARCH 2023; 244:120537. [PMID: 37683496 DOI: 10.1016/j.watres.2023.120537] [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: 04/06/2023] [Revised: 07/10/2023] [Accepted: 08/27/2023] [Indexed: 09/10/2023]
Abstract
The presence of organic micropollutants (OMPs) in water has been threatening human health and aquatic ecosystems worldwide. Ultraviolet-based advanced treatment processes (UV-ATPs) are one of the most effective and promising technologies to transform OMPs in water; therefore, an increasing number of emerging UV-ATPs are proposed. However, appropriate selection of UV-ATPs for practical applications is challenging because each UV-ATP generates different types and concentrations of reactive species (RSs) that may not be sufficient to degrade specific types of OMPs. Furthermore, the concentrations and types of RSs are highly influenced by anions and dissolved organic matter (DOM) coexisting in real waters, making systematic understandings of their interfering mechanisms difficult. To identify and address the knowledge gaps, this review provides a comparison of the generations and variations of various types of RSs in different UV-ATPs. These analyses not only prove the importance of water matrices on formation and consumption of primary and secondary RSs under different conditions, but also highlight the non-negligible roles of optical properties and reactivities of DOM and anions. For example, different UV-ATPs may be applicable to different target OMPs under different conditions; and the concentrations and roles of secondary RSs may outperform those of primary RSs in OMP degradation for real applications. With continuous progress and outstanding achievements in the UV-ATPs, it is hoped that the findings and conclusions of this review could facilitate further research and application of UV-ATPs.
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Affiliation(s)
- Boqiang Li
- State Key Laboratory of Urban Water Resource and Environment, Shenzhen Key Laboratory of Organic Pollution Prevention and Control, Harbin Institute of Technology, Shenzhen 518055, China
| | - Huimei Pan
- State Key Laboratory of Urban Water Resource and Environment, Shenzhen Key Laboratory of Organic Pollution Prevention and Control, Harbin Institute of Technology, Shenzhen 518055, China
| | - Baiyang Chen
- State Key Laboratory of Urban Water Resource and Environment, Shenzhen Key Laboratory of Organic Pollution Prevention and Control, Harbin Institute of Technology, Shenzhen 518055, China.
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5
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Vaidyanathan VK, Alanazi AK, Senthil Kumar P, Rajendran DS, Chidambaram A, Venkataraman S, Kumar VV, Rangasamy G, Cabana H, Abo-Dief HM. Cost-effective, scalable production of glucose oxidase using Casuarina equisetifolia biomass and its application in the bio-Fenton oxidation process for the removal of trace organic contaminants from wastewater. BIORESOURCE TECHNOLOGY 2023; 377:128958. [PMID: 36965584 DOI: 10.1016/j.biortech.2023.128958] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/04/2023] [Revised: 03/19/2023] [Accepted: 03/22/2023] [Indexed: 06/18/2023]
Abstract
This study focuses on using Casuarina equisetifolia biomass for pilot-scale glucose oxidase production from Aspergillus niger and its application in the removal of trace organic contaminants (TrOCs) from municipal wastewater through the bio-Fenton oxidation. The cost of glucose oxidase was 0.005 $/U, including the optimum production parameters, 10% biomass, 7% sucrose, 1% peptone, and 3% CaCO3 at 96 h with an enzyme activity of 670 U/mL. Optimized conditions for H2O2 were 1 M glucose, 100 U/mL glucose oxidase, and 120 mins of incubation, resulting in 544.3 mg/L H2O2. Thus, H2O2 produced under these conditions lead to bio-Fenton oxidation resulting in the removal of 36-92% of nine TrOCs in municipal wastewater at pH 7.0 in 360 mins. Therefore, this work establishes the cost-effective glucose oxidase-producing H2O2 as an attractive bioremediating agent to enhance the removal of TrOCs in wastewater at neutral pH.
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Affiliation(s)
- Vinoth Kumar Vaidyanathan
- Integrated Bioprocessing Laboratory, Department of Biotechnology, SRM Institute of Science and Technology, Chennai, Tamil Nadu 603203, India; Environmental Engineering Laboratory, Faculty of Engineering, Université de Sherbrooke, 2500 boul. de l'Université, Sherbrooke, Quebec J1K 2R1, Canada
| | - Abdullah K Alanazi
- Department of Chemistry, College of Science, Taif University, P.O. Box 11099, Taif 21944, Saudi Arabia
| | - P Senthil Kumar
- Department of Chemistry, College of Science, Taif University, P.O. Box 11099, Taif 21944, Saudi Arabia; Department of Chemical Engineering, Sri Sivasubramaniya Nadar College of Engineering, Kalavakkam 603110, Tamil Nadu, India; Centre of Excellence in Water Research (CEWAR), Sri Sivasubramaniya Nadar College of Engineering, Kalavakkam 603 110, Tamil Nadu, India.
| | - Devi Sri Rajendran
- Integrated Bioprocessing Laboratory, Department of Biotechnology, SRM Institute of Science and Technology, Chennai, Tamil Nadu 603203, India
| | - Ashok Chidambaram
- Integrated Bioprocessing Laboratory, Department of Biotechnology, SRM Institute of Science and Technology, Chennai, Tamil Nadu 603203, India
| | - Swethaa Venkataraman
- Integrated Bioprocessing Laboratory, Department of Biotechnology, SRM Institute of Science and Technology, Chennai, Tamil Nadu 603203, India
| | - Vaithyanathan Vasanth Kumar
- Environmental Engineering Laboratory, Faculty of Engineering, Université de Sherbrooke, 2500 boul. de l'Université, Sherbrooke, Quebec J1K 2R1, Canada; Department of Electronics and Communication Engineering, Hindustan Institute of Technology and Science, Chennai, India
| | - Gayathri Rangasamy
- School of Engineering, Lebanese American University, Byblos, Lebanon; University Centre for Research and Development & Department of Civil Engineering, Chandigarh University, Gharuan, Mohali, Punjab 140413, India
| | - Hubert Cabana
- Environmental Engineering Laboratory, Faculty of Engineering, Université de Sherbrooke, 2500 boul. de l'Université, Sherbrooke, Quebec J1K 2R1, Canada
| | - Hala M Abo-Dief
- Department of Science and Technology, University College-Ranyah, Taif University, P.O. Box 11099, Taif 21944, Saudi Arabia
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6
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Dong S, Ding Y, Feng H, Xu J, Han J, Jiang W, Xia Y, Wang A. Source preventing mechanism of florfenicol resistance risk in water by VUV/UV/sulfite advanced reduction pretreatment. WATER RESEARCH 2023; 235:119876. [PMID: 36931185 DOI: 10.1016/j.watres.2023.119876] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/02/2022] [Revised: 02/13/2023] [Accepted: 03/12/2023] [Indexed: 06/18/2023]
Abstract
To avoid the inhibition of microbial activity and the emergence of bacterial resistance, effective abiotic pretreatment methods to eliminate the antibacterial activity of target antibiotics before the biotreatment system for antibiotic-containing wastewater are necessary. In this study, the VUV/UV/sulfite system was developed as a pretreatment technique for the source elimination of florfenicol (FLO) resistance risk. Compared with the VUV/UV/persulfate and sole VUV photolysis, the VUV/UV/sulfite system had the highest decomposition rate (0.33 min‒1) and the highest defluorination (83.0%), resulting in the efficient elimination of FLO antibacterial activity with less than 2.0% mineralization, which would effectively retain the carbon sources for the sludge microorganisms in the subsequent biotreatment process. Furthermore, H• was confirmed to play a more important role in the elimination of FLO antibacterial activity by controlling the environmental conditions for the formation and transformation of reactive species and adding their scavengers. Based on the theoretical calculation and proposed photolytic intermediates, the elimination of FLO antibacterial activity was achieved by dechlorination, defluorination and removal of sulfomethyl groups. When the pretreated FLO-containing wastewater entered the biological treatment unit, the abundance of associated antibiotic resistance genes (ARGs) and the relative abundance of integrons were efficiently prevented by approximately 55.4% and 22.9%, respectively. These results demonstrated that the VUV/UV/sulfite system could be adopted as a promising pretreatment option for the source elimination of FLO resistance risk by target decomposition of its responsible structures before the subsequent biotreatment process.
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Affiliation(s)
- Shuangjing Dong
- School of Environmental Science and Engineering, Zhejiang Gongshang University, Hangzhou 310018, P. R. China; International Science and Technology Cooperation Platform for Low-Carbon Recycling of Waste and Green Development, Zhejiang Gongshang University, Hangzhou, 310018, P. R. China
| | - Yangcheng Ding
- School of Environmental Science and Engineering, Zhejiang Gongshang University, Hangzhou 310018, P. R. China; International Science and Technology Cooperation Platform for Low-Carbon Recycling of Waste and Green Development, Zhejiang Gongshang University, Hangzhou, 310018, P. R. China; School of Statistics and Mathematics, Zhejiang Gongshang University, Hangzhou 310018, P. R. China.
| | - Huajun Feng
- School of Environmental Science and Engineering, Zhejiang Gongshang University, Hangzhou 310018, P. R. China; International Science and Technology Cooperation Platform for Low-Carbon Recycling of Waste and Green Development, Zhejiang Gongshang University, Hangzhou, 310018, P. R. China
| | - Jixiao Xu
- School of Environmental Science and Engineering, Zhejiang Gongshang University, Hangzhou 310018, P. R. China; International Science and Technology Cooperation Platform for Low-Carbon Recycling of Waste and Green Development, Zhejiang Gongshang University, Hangzhou, 310018, P. R. China
| | - Jinglong Han
- State Key Lab of Urban Water Resource and Environment, School of Civil and Environmental Engineering, Harbin Institute of Technology Shenzhen, Shenzhen 518055, P. R. China
| | - Wenli Jiang
- Department of Civil and Environmental Engineering, University of California, Berkeley, California 94720, United States
| | - Yijing Xia
- School of Environmental Science and Engineering, Zhejiang Gongshang University, Hangzhou 310018, P. R. China; International Science and Technology Cooperation Platform for Low-Carbon Recycling of Waste and Green Development, Zhejiang Gongshang University, Hangzhou, 310018, P. R. China
| | - Aijie Wang
- State Key Lab of Urban Water Resource and Environment, School of Civil and Environmental Engineering, Harbin Institute of Technology Shenzhen, Shenzhen 518055, P. R. China; Key Laboratory of Environmental Biotechnology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, P. R. China
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7
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Enhanced activation of peroxymonosulfate by abundant Co-Nx sites onto hollow N-doped carbon polyhedron for bisphenol A degradation via a nonradical mechanism. Sep Purif Technol 2023. [DOI: 10.1016/j.seppur.2022.122773] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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8
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Parra-Marfil A, López-Ramón MV, Aguilar-Aguilar A, García-Silva IA, Rosales-Mendoza S, Romero-Cano LA, Bailón-García E, Ocampo-Pérez R. An efficient removal approach for degradation of metformin from aqueous solutions with sulfate radicals. ENVIRONMENTAL RESEARCH 2023; 217:114852. [PMID: 36457238 DOI: 10.1016/j.envres.2022.114852] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/14/2022] [Revised: 10/18/2022] [Accepted: 11/16/2022] [Indexed: 06/17/2023]
Abstract
Metformin consumption for diabetes treatment is increasing, leading to its presence in wastewater treatment plants where conventional methods cannot remove it. Therefore, this work aims to analyze the performance of advanced oxidation processes using sulfate radicals in the degradation of metformin from water. Experiments were performed in a photoreactor provided with a low-pressure Hg lamp, using K2S2O8 as oxidant and varying the initial metformin concentration (CA0), oxidant concentration (Cox), temperature (T), and pH in a response surface experimental design. The degradation percentages ranged from 26.1 to 87.3%, while the mineralization percentages varied between 15.1 and 64%. Analysis of variance (ANOVA) showed that the output variables were more significantly affected by CA0, Cox, and T. Besides, a reduction of CA0 and an increase of Cox up to 5000 μM maximizes the metformin degradation since the generation of radicals and their interaction with metformin molecules are favored. For the greatest degradation percentage, the first order apparent rate constant achieved was 0.084 min-1. Furthermore, while in acidic pH, temperature benefits metformin degradation, an opposite behavior is obtained in a basic medium because of recombination and inhibition reactions. Moreover, three degradation pathways were suggested based on the six products detected by HPLC-MS: N-cyanoguanidine m/z = 85; N,N-dimethylurea m/z = 89; N,N-dimethyl-cyanamide m/z = 71 N,N-dimethyl-formamide m/z = 74; glicolonitrilo m/z = 58; and guanidine m/z = 60. Finally, it was shown that in general the toxicity of the degradation byproducts was lower than the toxicity of metformin toward Chlamydomonas reinhardtii.
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Affiliation(s)
- A Parra-Marfil
- Centro de Investigación y Estudios de Posgrado, Facultad de Ciencias Químicas, Universidad Autónoma de San Luis Potosí, San Luis Potosí, 78260, Mexico; Grupo de Investigación en Materiales del Carbón, Facultad de Ciencias, Universidad de Granada, Campus Fuente Nueva s/n., 18071, Granada, Spain.
| | - M V López-Ramón
- Grupo de Investigación en Materiales de Carbón y Medio Ambiente, Facultad de Ciencias Experimentales, Campus Las Lagunillas s/n, 23071, Jaén, Spain.
| | - A Aguilar-Aguilar
- Centro de Investigación y Estudios de Posgrado, Facultad de Ciencias Químicas, Universidad Autónoma de San Luis Potosí, San Luis Potosí, 78260, Mexico.
| | - I A García-Silva
- Centro de Investigación y Estudios de Posgrado, Facultad de Ciencias Químicas, Universidad Autónoma de San Luis Potosí, San Luis Potosí, 78260, Mexico
| | - S Rosales-Mendoza
- Centro de Investigación y Estudios de Posgrado, Facultad de Ciencias Químicas, Universidad Autónoma de San Luis Potosí, San Luis Potosí, 78260, Mexico.
| | - L A Romero-Cano
- Grupo de Investigación en Materiales y Fenómenos de Superficie, Departamento de Ciencias Biotecnológicas y Ambientales, Universidad Autónoma de Guadalajara, Av. Patria 1201, C.P. 45129, Zapopan, Jalisco, Mexico.
| | - E Bailón-García
- Grupo de Investigación en Materiales del Carbón, Facultad de Ciencias, Universidad de Granada, Campus Fuente Nueva s/n., 18071, Granada, Spain.
| | - R Ocampo-Pérez
- Centro de Investigación y Estudios de Posgrado, Facultad de Ciencias Químicas, Universidad Autónoma de San Luis Potosí, San Luis Potosí, 78260, Mexico.
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Liu J, Wei L, Zhang D, Tang L, Liu Y, Jing L, Liu J, Yang S. The effects of inorganic anions on degradation kinetics and isotope fractionation during the transformation of tris(2-chloroethyl) phosphate (TCEP) by UV/persulfate. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 846:157462. [PMID: 35868383 DOI: 10.1016/j.scitotenv.2022.157462] [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: 03/21/2022] [Revised: 07/13/2022] [Accepted: 07/14/2022] [Indexed: 06/15/2023]
Abstract
Tris(2-chloroethyl) phosphate (TCEP), as a typical chlorinated flame retardant, is attracting more attention as a carcinogen. Although persulfate-based oxidation exhibits good performance in removing refractory organic pollutants, the kinetics of persulfate-based remediation are affected by inorganic anions, which causes inaccurate remediation efficiency. This study combines steady-state radical concentration modelling with isotope fractionation to investigate the effects of inorganic anions on TCEP degradation by UV/persulfate (UV/PS). In the absence of anions during UV/PS system, the observed degradation rate was (9.7 ± 0.1) × 10-5 s-1, which was approximately 93 % attributed to sulfate radical (SO4-•) oxidation based on radical modelling. Carbon isotope fractionation, coupled with the identification of transformation products by mass spectrometry, suggests a carbon bond split during TCEP degradation with a carbon isotopic fractionation value (ε) of -1.6 ± 0.2 ‰ (± 95 % confidence intervals). With respect to co-existing anions in UV/PS system, the addition of chloride (Cl-) had a negligible effect on degradation rates, while the addition of hydrogencarbonate (HCO3-) caused them to decrease, and the addition of hydrogenphosphate (HPO42-) caused them to increase. Radical modelling suggested that SO4-• was transformed to chlorine radicals (Cl•/Cl2-•), phosphate radicals (HPO4-•), and carbonate radicals (CO3-•). Furthermore, the overlapping 95 % confidence intervals (C.I.) and the statistical tests (p > 0.05) both agree that Cl- and HPO42- gain identical ε values. Nevertheless, when HCO3- coexisted in the UV/PS system, the ε values were distinct. The addition of HCO3- would result in ε variation of TCEP in the UV activated PS process, which should receive more attention when applying remediation.
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Affiliation(s)
- Jia Liu
- Key Laboratory of Pollution Control Chemistry and Environmental Functional Materials for Qinghai-Tibet Plateau of the National Ethnic Affairs Commission, School of Chemistry and Environment, Southwest Minzu University, Chengdu 610041, China; Key Laboratory of General Chemistry of the National Ethnic Affairs Commission, School of Chemistry and Environment, Southwest Minzu University, Chengdu 610041, China.
| | - Liuqing Wei
- Key Laboratory of Pollution Control Chemistry and Environmental Functional Materials for Qinghai-Tibet Plateau of the National Ethnic Affairs Commission, School of Chemistry and Environment, Southwest Minzu University, Chengdu 610041, China; Key Laboratory of General Chemistry of the National Ethnic Affairs Commission, School of Chemistry and Environment, Southwest Minzu University, Chengdu 610041, China
| | - Dan Zhang
- School of Energy & Environment, Zhongyuan University of Technology, Zhengzhou 450007, China
| | - Liang Tang
- Key Laboratory of Pollution Control Chemistry and Environmental Functional Materials for Qinghai-Tibet Plateau of the National Ethnic Affairs Commission, School of Chemistry and Environment, Southwest Minzu University, Chengdu 610041, China; Key Laboratory of General Chemistry of the National Ethnic Affairs Commission, School of Chemistry and Environment, Southwest Minzu University, Chengdu 610041, China
| | - Yaqing Liu
- College of light industry and food engineering, Guangxi University, Nanning 530004, China
| | - Liandong Jing
- Key Laboratory of Pollution Control Chemistry and Environmental Functional Materials for Qinghai-Tibet Plateau of the National Ethnic Affairs Commission, School of Chemistry and Environment, Southwest Minzu University, Chengdu 610041, China; Key Laboratory of General Chemistry of the National Ethnic Affairs Commission, School of Chemistry and Environment, Southwest Minzu University, Chengdu 610041, China
| | - Junfei Liu
- School of Energy and Environmental Engineering, University of Science and Technology Beijing, Beijing 100083, China
| | - Shengtao Yang
- Key Laboratory of Pollution Control Chemistry and Environmental Functional Materials for Qinghai-Tibet Plateau of the National Ethnic Affairs Commission, School of Chemistry and Environment, Southwest Minzu University, Chengdu 610041, China; Key Laboratory of General Chemistry of the National Ethnic Affairs Commission, School of Chemistry and Environment, Southwest Minzu University, Chengdu 610041, China
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10
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Key Points of Advanced Oxidation Processes (AOPs) for Wastewater, Organic Pollutants and Pharmaceutical Waste Treatment: A Mini Review. CHEMENGINEERING 2022. [DOI: 10.3390/chemengineering6010008] [Citation(s) in RCA: 41] [Impact Index Per Article: 20.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Advanced oxidation procedures (AOPs) refer to a variety of technical procedures that produce OH radicals to sufficiently oxidize wastewater, organic pollutant streams, and toxic effluents from industrial, hospital, pharmaceutical and municipal wastes. Through the implementation of such procedures, the (post) treatment of such waste effluents leads to products that are more susceptible to bioremediation, are less toxic and possess less pollutant load. The basic mechanism produces free OH radicals and other reactive species such as superoxide anions, hydrogen peroxide, etc. A basic classification of AOPs is presented in this short review, analyzing the processes of UV/H2O2, Fenton and photo-Fenton, ozone-based (O3) processes, photocatalysis and sonolysis from chemical and equipment points of view to clarify the nature of the reactive species in each AOP and their advantages. Finally, combined AOP implementations are favored through the literature as an efficient solution in addressing the issue of global environmental waste management.
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11
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Stanbury DM. Misconceptions about the Chemistry of Aqueous Chlorine Atoms and HClOH •(aq), and a Revised Mechanism for the Photochemical Peroxydisulfate/Chloride Reaction. Phys Chem Chem Phys 2022; 24:12541-12549. [DOI: 10.1039/d2cp00914e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
It is widely considered that aqueous chlorine atoms (Cl•) convert to the species HClOH• with a half life of about 3 µs and that this species plays an important role...
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