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Rekik H, Arab H, Pichon L, El Khakani MA, Drogui P. Per-and polyfluoroalkyl (PFAS) eternal pollutants: Sources, environmental impacts and treatment processes. CHEMOSPHERE 2024; 358:142044. [PMID: 38648982 DOI: 10.1016/j.chemosphere.2024.142044] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/03/2024] [Revised: 04/03/2024] [Accepted: 04/04/2024] [Indexed: 04/25/2024]
Abstract
Per- and polyfluoroalkyl substances (PFAS) have become a growing environmental concern due to their tangible impacts on human health. However, due to the large number of PFAS compounds and the analytical difficulty to identify all of them, there are still some knowledge gaps not only on their impact on human health, but also on how to manage them and achieve their effective degradation. PFAS compounds originate from man-made chemicals that are resistant to degradation because of the presence of the strong carbon-fluorine bonds in their chemical structure. This review consists of two parts. In the first part, the environmental effects of fluorinated compound contamination in water are covered with the objective to highlight how their presence in the environment adversely impacts the human health. In the second part, the focus is put on the different techniques available for the degradation and/or separation of PFAS compounds in different types of waters. Examples of removal/treatment of PFAS present in either surface or ground water are presented.
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Affiliation(s)
- Hela Rekik
- Institut National de la Recherche Scientifique (INRS) - Centre Eau Terre Environnement (ETE), 490 Rue de la Couronne, Québec (QC), G1K 9A9, Canada
| | - Hamed Arab
- Institut National de la Recherche Scientifique (INRS) - Centre Eau Terre Environnement (ETE), 490 Rue de la Couronne, Québec (QC), G1K 9A9, Canada
| | - Loick Pichon
- Institut National de la Recherche Scientifique, Centre Énergie, Matériaux et Télécommunications, 1650, Blvd, Lionel-Boulet, Varennes, QC, J3X-1P7, Canada
| | - My Ali El Khakani
- Institut National de la Recherche Scientifique, Centre Énergie, Matériaux et Télécommunications, 1650, Blvd, Lionel-Boulet, Varennes, QC, J3X-1P7, Canada
| | - Patrick Drogui
- Institut National de la Recherche Scientifique (INRS) - Centre Eau Terre Environnement (ETE), 490 Rue de la Couronne, Québec (QC), G1K 9A9, Canada.
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2
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Liu Y, Lu MY, Bao J, Shao LX, Yu WJ, Hu XM, Zhao X. Periodically reversing electrocoagulation technique for efficient removal of short-chain perfluoroalkyl substances from contaminated groundwater around a fluorochemical facility. CHEMOSPHERE 2023:138953. [PMID: 37196788 DOI: 10.1016/j.chemosphere.2023.138953] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/14/2022] [Revised: 05/06/2023] [Accepted: 05/14/2023] [Indexed: 05/19/2023]
Abstract
Widespread distributions of short-chain perfluoroalkyl substances (PFASs) has been recognized as a crucial environmental issue. However, multiple treatment techniques were ineffective due to their high polarity and mobility, contributing to a never-ending existence in the aquatic environment ubiquitously. The present study revealed potential technique of periodically reversing electrocoagulation (PREC) to perform efficient removal of short-chain PFASs including experimental factors (in the conditions of 9 V for voltage, 600 r/min of stirring speed, 10 s of reversing period, and 2 g/L of NaCl electrolyte), orthogonal experiments, actual application, and removal mechanism. Accordingly, based upon the orthogonal experiments, the removal efficiencies of perfluorobutane sulfonate (PFBS) in simulated solution could achieve 81.0% with the optimal parameters of Fe-Fe electrode materials, addition of 665 μL H2O2 per 10 min, and pH at 3.0. The PREC was further applied for treating the actual groundwater around a fluorochemical facility, consequently the removal efficiencies for typical short-chain perfluorobutanoic acid (PFBA), perfluoropentanoic acid (PFPeA), perfluorohexanoic acid (PFHxA), PFBS, and perfluoropentane sulfonate (PFPeS) were 62.5%, 89.0%, 96.4%, 90.0%, and 97.5%, respectively. The other long-chain PFASs contaminants had superior removal with the removal efficiencies up to 97%-100%. In addition, a comprehensive removal mechanism related to electric attraction adsorption for short-chain PFASs could be verified through the morphological analysis of ultimate flocs composition. The oxidation degradation was further revealed as the other removal mechanism by suspect and nontarget screening of intermediates formed in simulated solution, as well as density functional theory (DFT) calculation theory. Moreover, the degradation pathways about one CF2O molecule or CO2 eliminated with one C atom removed in PFBS by ·OH generated from the PREC oxidation process were further proposed. As a result, the PREC would be a promising technique for the efficient removal of short-chain PFASs from severely contaminated water bodies.
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Affiliation(s)
- Yang Liu
- School of Environmental and Chemical Engineering, Shenyang University of Technology, Shenyang, 110870, China.
| | - Meng-Yuan Lu
- School of Environmental and Chemical Engineering, Shenyang University of Technology, Shenyang, 110870, China
| | - Jia Bao
- School of Environmental and Chemical Engineering, Shenyang University of Technology, Shenyang, 110870, China.
| | - Li-Xin Shao
- School of Mechanical Engineering, Shenyang University of Technology, Shenyang, 110870, China
| | - Wen-Jing Yu
- School of Water Resources & Environment, China University of Geosciences, Beijing, 100083, China
| | - Xiao-Min Hu
- School of Resources and Civil Engineering, Northeastern University, Shenyang, 110819, China
| | - Xin Zhao
- School of Resources and Civil Engineering, Northeastern University, Shenyang, 110819, China
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Li YF, Fang T, Lee YC, Liu YJ, Hu CY, Lo SL. Cationic surfactants influencing the enhancement of energy efficiency for perfluorooctanoic acid (PFOA) removal in the electrocoagulation-flotation (ECF) system. CHEMOSPHERE 2023; 318:137932. [PMID: 36690258 DOI: 10.1016/j.chemosphere.2023.137932] [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: 09/07/2022] [Revised: 12/24/2022] [Accepted: 01/19/2023] [Indexed: 06/17/2023]
Abstract
From an environmental perspective, approaching sustainability requires a fundamental conceptual shift from the wastewater treatment process toward integrated treatment systems that consider efficient and effective utilization. This study aims to investigate the effects of different surfactants on the removal of perfluorooctanoic acid (PFOA). We used cationic surfactants as both frothers and collectors in the electrocoagulation-flotation (ECF) method to improve the removal efficiency of PFOA. The results showed that, under a monopolar aluminum electrode and with an initial PFOA concentration of 0.25 mM, the ECF method with decyl-trimethyl-ammonium bromide (DTAB) was able to remove over 98% of PFOA within 10 min. Cationic surfactants with a similar linear alkyl chain shape to PFOA, but a longer chain length, are more effective at removing PFOA through the ECF process. The removal mechanism is thought to involve co-precipitation with aluminum hydroxides through Al-F bonding, co-flotation with cationic surfactants, and mixed micelle formation with cationic surfactants. The optimal conditions were tested in both synthetic and realistic wastewater matrices and produced similar results. It has the potential for real wastewater application. The energy yield (G50) of ECF with 5 mM DTAB is 497 g·kWh-1, superior to other treatments, and is an extremely energy-effective method for separating PFOA from wastewater.
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Affiliation(s)
- Yueh-Feng Li
- Graduate Institute of Environmental Engineering, National Taiwan University, 71 Chuo-Shan Rd., Taipei, 10673, Taiwan
| | - Ting Fang
- Graduate Institute of Environmental Engineering, National Taiwan University, 71 Chuo-Shan Rd., Taipei, 10673, Taiwan
| | - Yu-Chi Lee
- Graduate Institute of Environmental Engineering, National Taiwan University, 71 Chuo-Shan Rd., Taipei, 10673, Taiwan
| | - Yu-Jung Liu
- Graduate Institute of Environmental Engineering, National Taiwan University, 71 Chuo-Shan Rd., Taipei, 10673, Taiwan
| | - Ching-Yao Hu
- School of Public Health, Taipei Medical University, 250 Wu-Xing Street, Taipei, 11031, Taiwan.
| | - Shang-Lien Lo
- Graduate Institute of Environmental Engineering, National Taiwan University, 71 Chuo-Shan Rd., Taipei, 10673, Taiwan; Water Innovation, Low Carbon and Environmental Sustainability Research Center, National Taiwan University, Taipei, 10617, Taiwan.
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Wang Z, An X, Wang P, Du X, Hao X, Hao X, Ma X. Removal of high concentration of chloride ions by electrocoagulation using aluminium electrode. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2023; 30:50567-50581. [PMID: 36795207 DOI: 10.1007/s11356-023-25792-1] [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: 08/08/2022] [Accepted: 02/03/2023] [Indexed: 02/17/2023]
Abstract
Wastewater containing a high concentration of chloride ions (Cl- ions) generated in industrial production will corrode equipment and pipelines and cause environmental problems. At present, systematic research on Cl- removal by electrocoagulation is scarce. To study the Cl- removal mechanism, process parameters (current density and plate spacing), and the influence of coexisting ions on the removal of Cl- in electrocoagulation, we use aluminum (Al) as the sacrificial anode, combined with physical characterization and density functional theory (DFT) to study Cl- removal by electrocoagulation. The result showed that the use of electrocoagulation technology to remove Cl- can reduce the concentration of Cl- in an aqueous solution below 250 ppm, meeting the Cl- emission standard. The mechanism of Cl- removal is mainly co-precipitation and electrostatic adsorption by forming chlorine-containing metal hydroxyl complexes. The current density and plate spacing affect the Cl- removal effect and operation cost. As a coexisting cation, magnesium ion (Mg2+) promotes the removal of Cl-, while calcium ion (Ca2+) inhibits it. Fluoride ion (F-), sulfate (SO42-), and nitrate (NO3-) as coexisting anions affect the removal of Cl- ions through competitive reaction. This work provides a theoretical basis for the industrialization of Cl- removal by electrocoagulation.
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Affiliation(s)
- Zirui Wang
- Department of Environmental Science and Engineering, Taiyuan University of Technology, Taiyuan, 030024, China
| | - Xiaowei An
- Department of Environmental Science and Engineering, Taiyuan University of Technology, Taiyuan, 030024, China
| | - Peifen Wang
- Department of Environmental Science and Engineering, Taiyuan University of Technology, Taiyuan, 030024, China
| | - Xiao Du
- Department of Chemical Engineering, Taiyuan University of Technology, Taiyuan, 030024, China
| | - Xiaogang Hao
- Department of Chemical Engineering, Taiyuan University of Technology, Taiyuan, 030024, China
| | - Xiaoqiong Hao
- Department of Petroleum and Chemical Engineering, Jiangsu Key Lab Advanced Catalytic Materials and Technology, Changzhou University, Changzhou, 213164, China
| | - Xuli Ma
- Department of Environmental Science and Engineering, Taiyuan University of Technology, Taiyuan, 030024, China.
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Laouameur K, Flilissa A, Lemaoui CE, Ferkous H, Benguerba Y. Study of the effect of current intensity on the structural performance of electrogenerated mesoporous aluminum phosphate: application for adsorption. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2023; 30:27510-27524. [PMID: 36385339 DOI: 10.1007/s11356-022-23578-5] [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: 08/02/2022] [Accepted: 10/07/2022] [Indexed: 06/16/2023]
Abstract
To keep up with the development of contaminants in the water supply, it is required to create new adsorbents or improve current ones. The adsorption capacity of AlPO4 electrocoagulated with varying current intensities was examined. AlPO4 was produced by electrolysis in a NaCl solution using aluminum electrodes and a 0.1 M phosphate buffer at varying current intensities. Current efficiency was enhanced. X-ray diffraction (XRD), scanning electron microscopy (SEM), and Fourier transform infrared spectroscopy were used to analyze the adsorbents (FTIR). The specific surface area was estimated by the quantity of methylene blue adsorbed by particles in an aqueous solution. Numerous operating factors must be addressed, including pH, starting concentration, adsorbent dose, and contact duration. The electrostatic interaction between positively charged MB molecules and negatively charged adsorbents drives adsorption at alkaline pH. When describing equilibrium adsorption, the Langmuir model is more accurate. Modeling using an adsorption isotherm may further improve the predicted specific surface area. At 0.2 amperes, the observed specific surface area was 2.86 m2/g.
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Affiliation(s)
- Khaoula Laouameur
- Laboratoire Des Maladies Cardiovasculaires Génétiques Et Nutritionnelles, Faculté de Médecine Département de Pharmacie, Ferhat ABBAS University of Setif-1, Sétif, Algeria
| | - Abdenacer Flilissa
- Laboratoire Des Maladies Cardiovasculaires Génétiques Et Nutritionnelles, Faculté de Médecine Département de Pharmacie, Ferhat ABBAS University of Setif-1, Sétif, Algeria
| | - Charaf Eddine Lemaoui
- Laboratoire Des Maladies Cardiovasculaires Génétiques Et Nutritionnelles, Faculté de Médecine Département de Pharmacie, Ferhat ABBAS University of Setif-1, Sétif, Algeria
| | - Hana Ferkous
- Laboratoire de Génie Mécanique Et Matériaux, Faculté de Technologie, Université de 20 Août 1955, 21000, Skikda, Algeria
- Département de Technologie, Université 20 août 1955 de Skikda, 21000, Skikda, Algeria
| | - Yacine Benguerba
- Laboratoire de Biopharmacie Et Pharmacotechnie (LBPT), Ferhat Abbas Setif 1 University, Setif, Algeria.
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Leung SCE, Shukla P, Chen D, Eftekhari E, An H, Zare F, Ghasemi N, Zhang D, Nguyen NT, Li Q. Emerging technologies for PFOS/PFOA degradation and removal: A review. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 827:153669. [PMID: 35217058 DOI: 10.1016/j.scitotenv.2022.153669] [Citation(s) in RCA: 66] [Impact Index Per Article: 33.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/26/2021] [Revised: 01/31/2022] [Accepted: 01/31/2022] [Indexed: 05/20/2023]
Abstract
Perfluorooctane sulfonate (PFOS) and perfluorooctanoic acid (PFOA) are highly recalcitrant anthropogenic chemicals that are ubiquitously present in the environment and are harmful to humans. Typical water and wastewater treatment processes (coagulation, flocculation, sedimentation, and filtration) are proven to be largely ineffective, while adsorption with granular activated carbon (GAC) has been the chief option to capture them from aqueous sources followed by incineration. However, this process is time-consuming, and produces additional solid waste and air pollution. Treatment methods for PFOS and PFOA generally follow two routes: (1) removal from source and reduce the risk; (2) degradation. Emerging technologies focusing on degradation are critically reviewed in this contribution. Various processes such as bioremediation, electrocoagulation, foam fractionation, sonolysis, photocatalysis, mechanochemical, electrochemical degradation, beams of electron and plasma have been developed and studied in the past decade to address PFAS crisis. The underlying mechanisms of these PFAS degradation methods have been categorized. Two main challenges have been identified, namely complexity in large scale operation and the release of toxic byproducts. Based on the literature survey, we have provided a strength-weakness-opportunity-threat (SWOT) analysis and quantitative rating on their efficiency, environmental impact and technology readiness.
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Affiliation(s)
- Shui Cheung Edgar Leung
- Queensland Micro- and Nanotechnology Centre, Griffith University, Brisbane, QLD 4111, Australia; School of Engineering and Built Environment, Griffith University, Brisbane, QLD 4111, Australia
| | - Pradeep Shukla
- Queensland Alliance for Environmental Health Sciences, Department of Chemical Engineering, The University of Queensland, St. Lucia, QLD 4072, Australia
| | - Dechao Chen
- Queensland Micro- and Nanotechnology Centre, Griffith University, Brisbane, QLD 4111, Australia
| | - Ehsan Eftekhari
- School of Engineering and Built Environment, Griffith University, Brisbane, QLD 4111, Australia; Golder Associates Pty Ltd, Level 4, 45 Francis Street, Northbridge, Western Australia 6003, Australia
| | - Hongjie An
- Queensland Micro- and Nanotechnology Centre, Griffith University, Brisbane, QLD 4111, Australia
| | - Firuz Zare
- School of Electrical Engineering and Robotics, Faculty of Engineering, Queensland University of Technology, Garden Point, QLD 4000, Australia
| | - Negareh Ghasemi
- School of Information Technology and Electrical Engineering, The University of Queensland, St. Lucia, QLD 4072, Australia
| | - Dongke Zhang
- Centre for Energy (M473), The University of Western Australia, 35 Stirling Highway, Crawley, WA 6009, Australia
| | - Nam-Trung Nguyen
- Queensland Micro- and Nanotechnology Centre, Griffith University, Brisbane, QLD 4111, Australia
| | - Qin Li
- Queensland Micro- and Nanotechnology Centre, Griffith University, Brisbane, QLD 4111, Australia; School of Engineering and Built Environment, Griffith University, Brisbane, QLD 4111, Australia.
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Shokri A, Fard MS. A critical review in electrocoagulation technology applied for oil removal in industrial wastewater. CHEMOSPHERE 2022; 288:132355. [PMID: 34582927 DOI: 10.1016/j.chemosphere.2021.132355] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/05/2021] [Revised: 09/20/2021] [Accepted: 09/22/2021] [Indexed: 06/13/2023]
Abstract
EC process, which stands for Electrocoagulation, is considered a widespread wastewater remediation method that is investigated widely for an extensive variety of wastewater resources, based on its flexibility, easy setup, eco-friendly nature, and low footprint. The critical operative factors in the EC process and the crucial relation between EC and the typical chemical coagulation approach had been thoroughly evaluated because they are the main variables that govern the process of contaminant elimination. As a result, the EC process requires further investigations for scale-up simulations in the manufacturing scopes and optimization of operational parameters. Furthermore, the current paper studies the novel integrated separation methods with the combined EC process and also their limitations for improved wastewater remediation process for cleaner wastes, recycling processes, and water recovery. In this paper, the EC enhancement processes toward oil removal from wastewater have been reviewed which includes a concise representation of the source and features of oily wastewater. Additionally, the advanced remediation methods for oil-contained wastewater and the electrocoagulation process are presented. This review summarized the present utilization of electrocoagulation to eliminate oil from wastewater. Besides the process optimization and modeling investigations, the parameters that significantly affect the electrocoagulation remediation effectiveness are evaluated. Finally, the cutting-edge and sophisticated methods of electrocoagulation process for oil removal are presented.
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Affiliation(s)
- Aref Shokri
- Jundi-Shapur Research Institute, Dezful, Iran.
| | - Mahdi Sanavi Fard
- Department of Chemical Engineering, Tafresh University, Tafresh, Iran
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Li YF, Hu CY, Lee YC, Lo SL. Effects of zinc salt addition on perfluorooctanoic acid (PFOA) removal by electrocoagulation with aluminum electrodes. CHEMOSPHERE 2022; 288:132665. [PMID: 34710459 DOI: 10.1016/j.chemosphere.2021.132665] [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: 08/15/2021] [Revised: 10/22/2021] [Accepted: 10/23/2021] [Indexed: 06/13/2023]
Abstract
In this study, the electrocoagulation (EC) of perfluorooctanoic acid (PFOA) by an aluminum electrode with the addition of zinc salt was investigated. Adding ZnCl2 successfully prevented a rise in pH during EC and increased the efficiency from 73.7% to over 99%. In addition, the longer the carbon chain of a PFA was, the better the removal of that PFA by electrocoagulation. The main functions of ZnCl2 were to prevent the rise in pH and improve flotation because the flocs with added ZnCl2 were easy to gather together and had a faster floating speed. The XPS results demonstrated the occurrence of bonding between aluminum and fluoride. This finding indicates that complexation between aluminum and fluoride may be the main mechanism for removal when aluminum electrodes are used to remove perfluoroalkyl (PFA) compounds.
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Affiliation(s)
- Yueh-Feng Li
- Graduate Institute of Environmental Engineering, National Taiwan University, 71 Chou-Shan Rd., Taipei, 10673, Taiwan, ROC
| | - Ching-Yao Hu
- School of Public Health, Taipei Medical University, 250 Wu-Xing Street, Taipei, 11031, Taiwan, ROC
| | - Yu-Chi Lee
- Graduate Institute of Environmental Engineering, National Taiwan University, 71 Chou-Shan Rd., Taipei, 10673, Taiwan, ROC
| | - Shang-Lien Lo
- Graduate Institute of Environmental Engineering, National Taiwan University, 71 Chou-Shan Rd., Taipei, 10673, Taiwan, ROC; Water Innovation, Low Carbon and Environmental Sustainability Research Center, National Taiwan University, Taipei, 10617, Taiwan, ROC.
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Song P, Sun C, Wang J, Ai S, Dong S, Sun J, Sun S. Efficient removal of Cu-EDTA complexes from wastewater by combined electrooxidation and electrocoagulation process: Performance and mechanism study. CHEMOSPHERE 2022; 287:131971. [PMID: 34438208 DOI: 10.1016/j.chemosphere.2021.131971] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/19/2021] [Revised: 08/18/2021] [Accepted: 08/19/2021] [Indexed: 06/13/2023]
Abstract
In this study, combined electrooxidation and electrocoagulation (EO-EC) reactor using RuO2-IrO2/Ti and Al electrodes has been built for treatment of Cu-EDTA wastewater. Effects of current density, electrolyte, NaCl concentration, pH and initial concentration on EO-EC performance were investigated. In this study, Cu-EDTA removal efficiency increased with a higher current density. The electrolyte type exerted a significant role in EO-EC process, compared with Na2SO4 and NaNO3, NaCl was a superior supporting electrolyte because the oxidation of Cl- into Cl2 provided additional highly reactive oxidant ClO- for Cu-EDTA oxidation or mineralization. In neutral or alkaline solution, EO-EC reactor performed better than when it was acid. At the condition of current density 10.29 mA cm-2, C0(NaCl) 1 g L-1, C0(Cu) 50 mg L-1 and pH 7, the Cu and COD removal efficiency reached 99.85% and 85.01%, respectively within 60 min. The possible mechanism of Cu-EDTA removal was proposed based on SEM, EDS, XRD, FTIR and XPS analysis of the products. Cu-EDTA chelates were degraded or mineralized by direct charge transfer, chemisorbed M(·OH) and active chorine species produced on anode surface, in which degradation intermediates and mineralization products of Cu-EDTA were generated. Meanwhile, residual degradation intermediates and mineralization products were removed by electrocoagulation. In this study, EO-EC process has been proved to be an effective way for the treatment of Cu-EDTA contaminated wastewater.
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Affiliation(s)
- Peipei Song
- College of Resources and Environment, Key Laboratory of Agricultural Environment, Shandong Agricultural University, Tai'an, 271018, PR China.
| | - Chengye Sun
- College of Resources and Environment, Key Laboratory of Agricultural Environment, Shandong Agricultural University, Tai'an, 271018, PR China
| | - Jun Wang
- College of Resources and Environment, Key Laboratory of Agricultural Environment, Shandong Agricultural University, Tai'an, 271018, PR China
| | - Shiyun Ai
- College of Chemistry and Material Science, Shandong Agricultural University, Tai'an, 271018, PR China
| | - Shujun Dong
- Hunan University of Arts and Sciences, Changde, 415000, PR China
| | - Jie Sun
- College of Resources and Environment, Key Laboratory of Agricultural Environment, Shandong Agricultural University, Tai'an, 271018, PR China
| | - Shuai Sun
- College of Resources and Environment, Key Laboratory of Agricultural Environment, Shandong Agricultural University, Tai'an, 271018, PR China
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Lu J, Zhang P, Li J. Electrocoagulation technology for water purification: An update review on reactor design and some newly concerned pollutants removal. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2021; 296:113259. [PMID: 34256295 DOI: 10.1016/j.jenvman.2021.113259] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/02/2021] [Revised: 06/30/2021] [Accepted: 07/08/2021] [Indexed: 06/13/2023]
Abstract
Water shortage and quality deterioration are plaguing people all over the world. Providing sustainable and affordable treatment solutions to these problems is a need of the hour. Electrocoagulation (EC) technology is a burgeoning alternative for effective water treatment, which offers the virtues such as compact equipment, easy operation, and low sludge production. Compared to other water purification technologies, EC shows excellent removal efficacy for a wide range of contaminants in water and has great potential for addressing limitations of conventional water purification technologies. This review summarizes the latest development of principle, characteristics, and reactor design of EC. The design of key parameters including reactor shape, power supply type, current density, as well as electrode configuration is further elaborated. In particular, typical water treatment systems powered by renewable energy (solar photovoltaic and wind turbine systems) are proposed. Further, this review provides an overview on expanded application of EC in the removal of some newly concerned pollutants in recent years, including arsenite, perfluorinated compounds, pharmaceuticals, oil, bacteria, and viruses. The removal efficiency and mechanisms of these pollutants are also discussed. Finally, future research trend and focus are further recommended. This review can bridge the large knowledge gap for the EC application that is beneficial for environmental researchers and engineers.
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Affiliation(s)
- Jianbo Lu
- School of Civil Engineering, Yantai University, Yantai, Shandong, 264005, China.
| | - Peng Zhang
- School of Civil Engineering, Yantai University, Yantai, Shandong, 264005, China
| | - Jie Li
- School of Economics and Management, Yantai University, Yantai, Shandong, 264005, China
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Mu T, Park M, Kim KY. Energy-efficient removal of PFOA and PFOS in water using electrocoagulation with an air-cathode. CHEMOSPHERE 2021; 281:130956. [PMID: 34289618 DOI: 10.1016/j.chemosphere.2021.130956] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/21/2021] [Revised: 05/06/2021] [Accepted: 05/17/2021] [Indexed: 06/13/2023]
Abstract
Electrocoagulation (EC) with a zinc anode demonstrated promising results to remove perfluorooctanoic acid (PFOA) and perfluorooctane sulfonate (PFOS) from an aqueous solution. However, the energy requirement for EC is usually very high due to water electrolysis or aeration. This study aims to reduce energy consumption using an air-cathode in EC (ACEC) to supply oxygen electron acceptor without aeration for attenuating PFOA/PFOS in this new configuration. For the high PFOA concentration (0.25 mM), ACEC with 45 min of the reaction time exhibited an excellent PFOA removal (99.8 ± 0.3% removal) comparable to an EC with aeration (EC-aeration, 100% removal) while achieving much less energy consumption (0.14 kWh/m3). For the low PFOA concentration (0.1 μM), only 41.1 ± 11.6% was removed by the ACEC due to the low concentration gradient for adsorption. EC-aeration achieved higher PFOA removal (81.9 ± 15.1%) for the low PFOA concentration, possibly because air bubbles floated PFOA to the water surface, thereby concentrating PFOA. The PFOS removals in the ACEC and EC-aeration (76.4-88.5%) at the high concentration (0.25 mM) were lower than PFOA due tentatively to its micelle formation. However, PFOS was removed better than PFOA at the low concentration (0.1 μM) due to its higher hydrophobicity.
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Affiliation(s)
- Tianhong Mu
- Department of Environmental and Sustainable Engineering, University at Albany, State University of New York, 1400 Washington Avenue, Albany, NY, 12222, USA
| | - Minkyu Park
- Department of Chemical & Environmental Engineering, University of Arizona, 1133 E James E Rogers Way, Harshbarger 108, Tucson, AZ, 85721-0011, USA
| | - Kyoung-Yeol Kim
- Department of Environmental and Sustainable Engineering, University at Albany, State University of New York, 1400 Washington Avenue, Albany, NY, 12222, USA.
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Shi H, Chiang SYD, Wang Y, Wang Y, Liang S, Zhou J, Fontanez R, Gao S, Huang Q. An electrocoagulation and electrooxidation treatment train to remove and degrade per- and polyfluoroalkyl substances in aqueous solution. THE SCIENCE OF THE TOTAL ENVIRONMENT 2021; 788:147723. [PMID: 34034184 DOI: 10.1016/j.scitotenv.2021.147723] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/10/2021] [Revised: 05/06/2021] [Accepted: 05/08/2021] [Indexed: 06/12/2023]
Abstract
This study examined the feasibility of a novel treatment train that combines electrocoagulation (EC) with electrooxidation (EO) treatment to remove and degrade per- and polyfluoroalkyl substances (PFASs) from water. Electrocoagulation with a zinc anode could effectively remove PFASs from water, and long-chain PFASs (C7-C10) tended to have a higher removal rate. Foam was generated when a relatively high current density (>1 mA cm-2) was applied to a relatively high PFAS concentration (each PFAS > 0.1 μM) during EC, which promoted the separation of PFASs from the bulk solution, especially for long-chain PFASs. Isotherm-like adsorption results indicated that competitive adsorption on floc occurred between PFASs when no foam was produced in a solution containing 10 different PFASs. Acid dissolution methods could recover and concentrate 10 PFASs in controlled volumes from both the floc and the foam, and it was also successfully applied in groundwater collected from a contaminated site. The concentrated PFASs in the acid solutions were efficiently destructed using EO treatment with a Ti4O7 anode at 10 mA cm-2, and no supplement of electrolyte was needed for the floc dissolved solution. This electrochemical-based process can economically separate, concentrate and destroy PFASs in groundwater and wastewater.
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Affiliation(s)
- Huanhuan Shi
- School of Ecology and Environment, Zhengzhou University, Zhengzhou 450001, China; College of Agricultural and Environmental Sciences, Department of Crop and Soil Sciences, University of Georgia, Griffin, GA 30223, United States
| | | | - Yaye Wang
- College of Agricultural and Environmental Sciences, Department of Crop and Soil Sciences, University of Georgia, Griffin, GA 30223, United States
| | - Yifei Wang
- College of Agricultural and Environmental Sciences, Department of Crop and Soil Sciences, University of Georgia, Griffin, GA 30223, United States
| | - Shangtao Liang
- AECOM Technical Services, Inc., Atlanta, GA 30309, United States
| | - Jing Zhou
- AECOM Technical Services, Inc., Atlanta, GA 30309, United States
| | - Raymond Fontanez
- College of Agricultural and Environmental Sciences, Department of Crop and Soil Sciences, University of Georgia, Griffin, GA 30223, United States
| | - Shixiang Gao
- State Key Laboratory of Pollution Control and Resources Reuse, School of the Environment, Nanjing University, Nanjing 210023, China
| | - Qingguo Huang
- College of Agricultural and Environmental Sciences, Department of Crop and Soil Sciences, University of Georgia, Griffin, GA 30223, United States.
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13
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Xu B, Liu S, Zhou JL, Zheng C, Weifeng J, Chen B, Zhang T, Qiu W. PFAS and their substitutes in groundwater: Occurrence, transformation and remediation. JOURNAL OF HAZARDOUS MATERIALS 2021; 412:125159. [PMID: 33951855 DOI: 10.1016/j.jhazmat.2021.125159] [Citation(s) in RCA: 92] [Impact Index Per Article: 30.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/20/2020] [Revised: 12/29/2020] [Accepted: 01/13/2021] [Indexed: 05/27/2023]
Abstract
Poly- and perfluoroalkyl substances (PFAS) are increasingly investigated due to their global occurrence and potential human health risk. The ban on PFOA and PFOS has led to the use of novel substitutes such as GenX, F-53B and OBS. This paper reviews the studies on the occurrence, transformation and remediation of major PFAS i.e. PFOA, PFNA, PFBA, PFOS, PFHxS, PFBS and the three substitutes in groundwater. The data indicated that PFOA, PFBA, PFOS and PFBS were present at high concentrations up to 21,200 ng L-1 while GenX and F-53B were found up to 30,000 ng L-1 and 0.18-0.59 ng L-1, respectively. PFAS in groundwater are from direct sources e.g. surface water and soil. PFAS remediation methods based on membrane, redox, sorption, electrochemical and photocatalysis are analyzed. Overall, photocatalysis is considered to be an ideal technology with low cost and high degradation efficacy for PFAS removal. Photocatalysis could be combined with electrochemical or membrane filtration to become more advantageous. GenX, F-53B and OBS in groundwater treatment by UV/sulfite system and electrochemical oxidation proved effective. The review identified gaps such as the immobilization and recycling of materials in groundwater treatment, and recommended visible light photocatalysis for future studies.
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Affiliation(s)
- Bentuo Xu
- National and Local Joint Engineering Research Center of Ecological Treatment Technology for Urban Water Pollution, School of Life and Environmental Science, Wenzhou University, Wenzhou 325035, China
| | - Shuai Liu
- Research Institute of Poyang Lake, Jiangxi Academy of Sciences, Nanchang 330012, China
| | - John L Zhou
- Centre for Green Technology, School of Civil and Environmental Engineering, University of Technology Sydney, 15 Broadway, NSW 2007, Australia
| | - Chunmiao Zheng
- Guangdong Provincial Key Laboratory of Soil and Groundwater Pollution Control, State Environmental Protection Key Laboratory of Integrated Surface Water-Groundwater Pollution Control, School of Environmental Science and Engineering, Southern University of Science and Technology, Shenzhen 518055, China
| | - Jin Weifeng
- National and Local Joint Engineering Research Center of Ecological Treatment Technology for Urban Water Pollution, School of Life and Environmental Science, Wenzhou University, Wenzhou 325035, China
| | - Bei Chen
- Fisheries Research Institute of Fujian, Xiamen 361013, China
| | - Ting Zhang
- Guangdong Provincial Key Laboratory of Soil and Groundwater Pollution Control, State Environmental Protection Key Laboratory of Integrated Surface Water-Groundwater Pollution Control, School of Environmental Science and Engineering, Southern University of Science and Technology, Shenzhen 518055, China
| | - Wenhui Qiu
- Guangdong Provincial Key Laboratory of Soil and Groundwater Pollution Control, State Environmental Protection Key Laboratory of Integrated Surface Water-Groundwater Pollution Control, School of Environmental Science and Engineering, Southern University of Science and Technology, Shenzhen 518055, China.
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14
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Mineralization of perfluorooctanoic acid by combined aerated electrocoagulation and Modified peroxi-coagulation methods. J Taiwan Inst Chem Eng 2021. [DOI: 10.1016/j.jtice.2021.01.006] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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15
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Degradation mechanism of perfluorooctanoic acid (PFOA) during electrocoagulation using Fe electrode. Sep Purif Technol 2020. [DOI: 10.1016/j.seppur.2020.116911] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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16
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Ji B, Kang P, Wei T, Zhao Y. Challenges of aqueous per- and polyfluoroalkyl substances (PFASs) and their foreseeable removal strategies. CHEMOSPHERE 2020; 250:126316. [PMID: 32120153 DOI: 10.1016/j.chemosphere.2020.126316] [Citation(s) in RCA: 32] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/31/2019] [Revised: 02/21/2020] [Accepted: 02/22/2020] [Indexed: 06/10/2023]
Abstract
Per- and polyfluoroalkyl substances (PFASs) are artificial refractory organic pollutants which are widely presented in aqueous environment. Due to the unquiet strength of the highly polarized carbon-fluorine bond (C-F) and their hydrophobic/lipophobic feature as well as biological persistence properties, the remediation and treatment of PFASs is a big challenge. Preliminary studies indicate that a few kinds of technical approaches could remove or transfer PFASs, but the effectiveness is not high as expected or limited while most of the techniques are only tested at laboratory scale. A review of existing treatment technologies was thus conducted for the purpose to outlook these technologies, and more importantly, to propose the foreseeable technique. As such, a constructed wetland-microbial fuel cell (CW-MFC) technology was recommended, which is a newly emerged technology by integrating physical, chemical and enhanced biological processes plus the wetland plants function with strong eco-friendly feature for a comprehensive removal of PFASs. It is expected that the review can strengthen our understanding on PFASs' research and thus can help selecting reasonable technical means of aqueous PFASs control.
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Affiliation(s)
- Bin Ji
- State Key Laboratory of Eco-Hydraulics in Northwest Arid Region, Xi'an University of Technology, Xi'an, China
| | - Peiying Kang
- State Key Laboratory of Eco-Hydraulics in Northwest Arid Region, Xi'an University of Technology, Xi'an, China
| | - Ting Wei
- State Key Laboratory of Eco-Hydraulics in Northwest Arid Region, Xi'an University of Technology, Xi'an, China
| | - Yaqian Zhao
- State Key Laboratory of Eco-Hydraulics in Northwest Arid Region, Xi'an University of Technology, Xi'an, China.
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17
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Li P, Zhi D, Zhang X, Zhu H, Li Z, Peng Y, He Y, Luo L, Rong X, Zhou Y. Research progress on the removal of hazardous perfluorochemicals: A review. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2019; 250:109488. [PMID: 31499465 DOI: 10.1016/j.jenvman.2019.109488] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/13/2019] [Revised: 08/21/2019] [Accepted: 08/27/2019] [Indexed: 05/27/2023]
Abstract
Perfluorinated substances are global and ubiquitous pollutants. The persistent organic pollution of perfluorochemicals (PFCs) have drawn attentions worldwide. In view of the current need for sustainable development, many researchers began to study the remediation techniques for PFCs. Due to its unique hydrophobic and oil-phobic characteristics, the requirements for the PFCs removal process are different, so that their remediation techniques are still under continuous exploration. Hence, this review summarized the removal behaviors of various PFCs on different materials which supply a good foundation for future investigations in this field. It is evident from previous literature that every remediation techniques for PFCs has its own advantages. Among various currently evaluated removal methods, adsorption seems to be one of the most commonly used and recognized techniques for PFCs pollution control. Other innovative and promising techniques, such as physical and/or chemical methods, have also been tested for their effectiveness in removing perfluorinated compounds.
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Affiliation(s)
- Peipei Li
- Hunan International Scientific and Technological Cooperation Base of Agricultural Typical Pollution Remediation and Wetland Protection, College of Resources and Environment, Hunan Agricultural University, Changsha, 410128, China
| | - Dan Zhi
- Hunan International Scientific and Technological Cooperation Base of Agricultural Typical Pollution Remediation and Wetland Protection, College of Resources and Environment, Hunan Agricultural University, Changsha, 410128, China
| | - Xiaoxiao Zhang
- State Key Laboratory of Urban Water Resources and Environment, School of Environment, Harbin Institute of Technology, Harbin, 150090, PR China
| | - Hongmei Zhu
- Hunan International Scientific and Technological Cooperation Base of Agricultural Typical Pollution Remediation and Wetland Protection, College of Resources and Environment, Hunan Agricultural University, Changsha, 410128, China.
| | - Zhiyong Li
- Hunan International Scientific and Technological Cooperation Base of Agricultural Typical Pollution Remediation and Wetland Protection, College of Resources and Environment, Hunan Agricultural University, Changsha, 410128, China
| | - Yutao Peng
- College of Resources and Environmental Sciences, China Agricultural University, Beijing, 100193, China
| | - Yangzhou He
- Hunan International Scientific and Technological Cooperation Base of Agricultural Typical Pollution Remediation and Wetland Protection, College of Resources and Environment, Hunan Agricultural University, Changsha, 410128, China
| | - Lin Luo
- Hunan International Scientific and Technological Cooperation Base of Agricultural Typical Pollution Remediation and Wetland Protection, College of Resources and Environment, Hunan Agricultural University, Changsha, 410128, China
| | - Xiangmin Rong
- Hunan International Scientific and Technological Cooperation Base of Agricultural Typical Pollution Remediation and Wetland Protection, College of Resources and Environment, Hunan Agricultural University, Changsha, 410128, China
| | - Yaoyu Zhou
- Hunan International Scientific and Technological Cooperation Base of Agricultural Typical Pollution Remediation and Wetland Protection, College of Resources and Environment, Hunan Agricultural University, Changsha, 410128, China.
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18
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Safwat SM, Matta ME. Performance evaluation of electrocoagulation process using zinc electrodes for removal of urea. SEP SCI TECHNOL 2019. [DOI: 10.1080/01496395.2019.1636067] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/07/2022]
Affiliation(s)
- Safwat M. Safwat
- Sanitary Environmental Engineering Division, Faculty of Engineering,Cairo University,Giza, Egypt
| | - Minerva E. Matta
- Sanitary Environmental Engineering Division, Faculty of Engineering,Cairo University,Giza, Egypt
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19
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Xu L, Wu D, Liu W, Xu X, Cao G. Comparative performance of green rusts generated in Fe 0-electrocoagulation for Cd 2+ removal from high salinity wastewater: Mechanisms and optimization. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2019; 237:495-503. [PMID: 30825782 DOI: 10.1016/j.jenvman.2019.02.025] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/31/2018] [Revised: 01/08/2019] [Accepted: 02/04/2019] [Indexed: 06/09/2023]
Abstract
The treatment of wastewater containing high concentration of inorganic salts has always been one of the focuses of environmental researchers. In this work, the effect of Cl- and SO42- on the removal of Cd2+ from wastewater using Fe0-electrocoagulation (Fe0-EC) were investigated by evaluating the transformation of Fe mineral. The experimental results indicated that the removal of Cd2+ from wastewater was depended on the property of Fe minerals. The generation of sulfate green rust (GRSO4) produced in the presence of SO42- showed stronger adsorption than the chloride green rust (GRCl) for Cd2+, and GRSO4 was obtained even in the mixture Cl- and SO42- solutions, because Fe(II)-Fe(III) GRs (layered double hydroxides, LDHs) showed stronger affinity for divalent SO42- than monovalent Cl-. High concentration of inorganic anions in wastewater resulted in the negative charged Fe flocs. High concentration of Cl- promoted the oxidation of Fe(II) to Fe(III) by chlorine-containing oxidants, and increased the proportion of Fe(III)/Fe(II) in Fe flocs, secondary Fe mineral magnetite (Fe3O4) was formed because of the increase of pH. Therefore, the presence of GRSO4 intermediate increased the Cd2+ removal by adsorption (coagulation and coprecipitation), and then the generated GRSO4 were gradually transformed into lepidocrocite (γ-FeOOH) by oxygen from air. Finally, the parameter optimization were conducted by adjusting the ratio of Cl- and SO42- (RC:S), current density (j), initial pH (pHi), initial Cd2+ concentration (C0), and temperature (T0). The removal efficiency of Cd2+ reached 99.5% after 10 min Fe0-EC under the optimal parameters: RC:S = 25:50 mmoL/mmol, j = 6 mA/cm2, pHi = 7-9, and T0 = 40 °C.
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Affiliation(s)
- Longqian Xu
- Faculty of Environmental Science and Engineering, Kunming University of Science and Technology, Kunming, 650500, PR China; State Key Laboratory of Pollution Control and Resources Reuse, College of Environmental Science & Engineering, Tongji University, Shanghai, 200092, PR China
| | - Deli Wu
- State Key Laboratory of Pollution Control and Resources Reuse, College of Environmental Science & Engineering, Tongji University, Shanghai, 200092, PR China
| | - Wei Liu
- Faculty of Environmental Science and Engineering, Kunming University of Science and Technology, Kunming, 650500, PR China
| | - Xiaojun Xu
- Faculty of Environmental Science and Engineering, Kunming University of Science and Technology, Kunming, 650500, PR China.
| | - Guangzhu Cao
- Faculty of Land Resource Engineering, Kunming University of Science and Technology, 650500, Kunming, PR China
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20
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Faraji Yaychi R, Manteghian M. Investigation of effect of electric field on silver nanoparticles in order to separation of them from aqueous medium using electrocoagulation process. Sep Purif Technol 2018. [DOI: 10.1016/j.seppur.2017.10.033] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/07/2022]
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21
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Xu L, Cao G, Xu X, Liu S, Duan Z, He C, Wang Y, Huang Q. Simultaneous removal of cadmium, zinc and manganese using electrocoagulation: Influence of operating parameters and electrolyte nature. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2017; 204:394-403. [PMID: 28915474 DOI: 10.1016/j.jenvman.2017.09.020] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/03/2017] [Revised: 08/31/2017] [Accepted: 09/06/2017] [Indexed: 06/07/2023]
Abstract
In the present study, the influence of operating parameters and electrolyte nature on the simultaneous removal of toxic metals (cadmium, zinc and manganese) from synthetic smelting wastewater by batch electrocoagulation was investigated. This wastewater contained high concentrations of anion-cation electrolytes. Results indicated that the efficiency of heavy metals removal can be enhanced by increasing the solution pH and current density. The Fe-Fe electrode combination is more effective than the other combinations (Al-Al, Al-Fe and Fe-Al). The interaction of heavy metal ions showed that the increase of initial Zn2+ concentration adversely affects on Cd2+ removal. In addition, the single chloride system exhibits the optimum removal efficiency on Mn2+. Single sulfate and binary anion systems exert a more positive effect on Cd2+ and Zn2+ removal because of the stronger charge neutralization and destabilization of iron hydroxide flocs. Increases of Ca2+ and Mg2+ ions exert a significant negative effect on metal removal. However, the addition of a small amount of sodium chloride into a high sulfate and hardness solution can accelerate the removal of heavy metals. Finally, the sludge samples generated from electrocoagulation were characterized by XRD and SEM-EDS analyses.
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Affiliation(s)
- Longqian Xu
- Faculty of Environmental Science and Engineering, Kunming University of Science and Technology, Kunming 650500, China
| | - Guangzhu Cao
- Faculty of Land Resource Engineering, Kunming University of Science and Technology, 650500 Kunming, China.
| | - Xiaojun Xu
- Faculty of Environmental Science and Engineering, Kunming University of Science and Technology, Kunming 650500, China
| | - Shuli Liu
- Faculty of Environmental Science and Engineering, Kunming University of Science and Technology, Kunming 650500, China
| | - Zhengyang Duan
- Faculty of Environmental Science and Engineering, Kunming University of Science and Technology, Kunming 650500, China
| | - Changhua He
- Faculty of Environmental Science and Engineering, Kunming University of Science and Technology, Kunming 650500, China
| | - Yao Wang
- Faculty of Environmental Science and Engineering, Kunming University of Science and Technology, Kunming 650500, China
| | - Qihua Huang
- Faculty of Environmental Science and Engineering, Kunming University of Science and Technology, Kunming 650500, China
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22
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Mudumbi JBN, Ntwampe SKO, Matsha T, Mekuto L, Itoba-Tombo EF. Recent developments in polyfluoroalkyl compounds research: a focus on human/environmental health impact, suggested substitutes and removal strategies. ENVIRONMENTAL MONITORING AND ASSESSMENT 2017; 189:402. [PMID: 28721589 DOI: 10.1007/s10661-017-6084-2] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/02/2016] [Accepted: 06/20/2017] [Indexed: 06/07/2023]
Abstract
Between the late 1940s and early 1950s, humans manufactured polyfluoroalkyl compounds (PFCs) using electrochemical fluorination and telomerisation technologies, whereby hydrogen atoms are substituted by fluorine atoms, thus conferring unnatural and unique physicochemical properties to these compounds. Presently, there are wide ranges of PFCs, and owing to their bioaccumulative properties, they have been detected in various environmental matrices and in human sera. It has thus been suggested that they are hazardous. Hence, this review aims at highlighting the recent development in PFC research, with a particular focus on perfluorooctanoate (PFOA) and perfluorooctane sulfonate (PFOS), the most studied and predominantly found PFCs in various environmental matrices, although recent reports have included perfluorobutane sulfonate (PFBS), which was previously regarded as innocuously harmless, when compared to its counterparts, PFOA and PFOS. As such, proper investigations are thus required for a better understanding of short-chain PFC substitutes, which have been suggested as suitable replacements to long-chained PFCs, although these substitutes have also been suggested to pose various health risks comparable to those associated with long-chain PFCs. Similarly, several novel technologies, such as PFC reduction using zero-valent iron, including removal at point of use, adsorption and coagulation, have been proposed. However, regardless of how efficient removers some of these techniques have proven to be, short-chain PFCs remain a challenge to overcome for scientists, in this regard.
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Affiliation(s)
- John Baptist Nzukizi Mudumbi
- Bioresource Engineering Research Group (BioERG), Department of Biotechnology, Cape Peninsula University of Technology, PO Box 652, Cape Town, 8000, South Africa.
| | - Seteno Karabo Obed Ntwampe
- Bioresource Engineering Research Group (BioERG), Department of Biotechnology, Cape Peninsula University of Technology, PO Box 652, Cape Town, 8000, South Africa
| | - Tandi Matsha
- Department of Bio-Medical Sciences, Faculty of Health and Wellness Science, Cape Peninsula University of Technology, PO Box 1906, Bellville, 7535, South Africa
| | - Lukhanyo Mekuto
- Bioresource Engineering Research Group (BioERG), Department of Biotechnology, Cape Peninsula University of Technology, PO Box 652, Cape Town, 8000, South Africa
| | - Elie Fereche Itoba-Tombo
- Bioresource Engineering Research Group (BioERG), Department of Biotechnology, Cape Peninsula University of Technology, PO Box 652, Cape Town, 8000, South Africa
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An C, Huang G, Yao Y, Zhao S. Emerging usage of electrocoagulation technology for oil removal from wastewater: A review. THE SCIENCE OF THE TOTAL ENVIRONMENT 2017; 579:537-556. [PMID: 27865526 DOI: 10.1016/j.scitotenv.2016.11.062] [Citation(s) in RCA: 151] [Impact Index Per Article: 21.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/03/2016] [Revised: 11/08/2016] [Accepted: 11/09/2016] [Indexed: 06/06/2023]
Abstract
Electrocoagulation is a simple and efficient treatment method involving the electrodissolution of sacrificial anodes and formation of hydroxo-metal products as coagulants, while the simultaneous production of hydrogen at the cathode facilitates the pollutant removal by flotation. Oil is one of the most important hydrocarbon products in the modern world. It can cause environmental pollution during various stages of production, transportation, refining and use. Electrocoagulation treatment is particularly effective for destabilization of oil-in-water emulsions by neutralizing charges and bonding oil pollutants to generated flocs and hydrogen bubbles. The development of electrocoagulation technologies provided a promising alternative for oil removal from wastewater. This paper presents a review of emerging electrochemical technologies used for treating oil-containing wastewater. It includes a brief description of the oily wastewater origin and characteristics. The treatment processes developed so far for oily wastewater and the electrocoagulation mechanisms are also introduced. This paper summarizes the current applications of electrocoagulation for oil removal from wastewater. The factors that influence the electrocoagulation treatment efficiencies as well as the process optimization and modeling studies are discussed. The state-of-the-art and development trends of electrocoagulation process for oil removal are further introduced.
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Affiliation(s)
- Chunjiang An
- Faculty of Engineering and Applied Science, University of Regina, Regina S4S 0A2, Canada; Institute for Energy, Environment and Sustainable Communities, University of Regina, Regina S4S 0A2, Canada
| | - Gordon Huang
- Faculty of Engineering and Applied Science, University of Regina, Regina S4S 0A2, Canada; Institute for Energy, Environment and Sustainable Communities, University of Regina, Regina S4S 0A2, Canada.
| | - Yao Yao
- Faculty of Engineering and Applied Science, University of Regina, Regina S4S 0A2, Canada
| | - Shan Zhao
- Institute for Energy, Environment and Sustainable Communities, University of Regina, Regina S4S 0A2, Canada
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