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Fu R, Zhang PS, Jiang YX, Sun L, Sun XH. Wastewater treatment by anodic oxidation in electrochemical advanced oxidation process: Advance in mechanism, direct and indirect oxidation detection methods. CHEMOSPHERE 2023; 311:136993. [PMID: 36309052 DOI: 10.1016/j.chemosphere.2022.136993] [Citation(s) in RCA: 12] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/05/2022] [Revised: 10/19/2022] [Accepted: 10/21/2022] [Indexed: 06/16/2023]
Abstract
Electrochemical Advanced Oxidation Process (EAOP) has been applied to the degradation of refractory pollutants in wastewater due to its strong oxidation capacity, high degradation efficiency, simple operation, and mild reaction. Among electrochemical processes, anodic oxidation (AO) is the most widely used and its mechanism is mainly divided into direct oxidation and indirect oxidation. Direct oxidation means that pollutants are oxidized at the anode by direct electron transfer. Indirect oxidation refers to the generation of active species during the electrolytic reaction, which acts on pollutants. The mechanism of AO process is controlled by many factors, including electrode type, electrocatalyst material, wastewater composition, pH, applied current and voltage levels. It is very important to explore the reaction mechanism of electrochemical treatment, which determines the efficiency of the reaction, the products of the reaction, and the extent of reaction. This paper firstly reviews the current research progress on the mechanism of AO process, and summarizes in detail the different mechanisms caused by influencing factors under common AO process. Then, strategies and methods to distinguish direct oxidation and indirect oxidation mechanisms are reviewed, such as intermediate product analysis, electrochemical test analysis, active species detection, theoretical calculation, and the limitations of these methods are analyzed. Finally some suggestions are put forward for the study of the mechanism of electrochemical advanced oxidation.
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Affiliation(s)
- Rui Fu
- School of Chemical Engineering, Northeast Electric Power University, 132012, Jilin, PR China.
| | - Peng-Shuang Zhang
- School of Chemical Engineering, Northeast Electric Power University, 132012, Jilin, PR China.
| | - Yuan-Xing Jiang
- School of Chemical Engineering, Northeast Electric Power University, 132012, Jilin, PR China.
| | - Lin Sun
- College of Chemistry, Jilin University, ChangChun, 130012, Jilin, PR China.
| | - Xu-Hui Sun
- School of Chemical Engineering, Northeast Electric Power University, 132012, Jilin, PR China.
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2
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Zheng X, Gao M, Liang C, Wang S, Wang X. Expanded graphite supported TiO2 composites using polyaniline as the anchor: Improved catalytic performance for the electro-Fenton-like reaction. Electrochim Acta 2022. [DOI: 10.1016/j.electacta.2022.140910] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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3
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Qi G, Wang X, Zhao J, Song C, Zhang Y, Ren F, Zhang N. Fabrication and Characterization of the Porous Ti4O7 Reactive Electrochemical Membrane. Front Chem 2022; 9:833024. [PMID: 35237568 PMCID: PMC8882842 DOI: 10.3389/fchem.2021.833024] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2021] [Accepted: 12/20/2021] [Indexed: 11/27/2022] Open
Abstract
Preparation of the Magnéli Ti4O7 reactive electrochemical membrane (REM) with high purity is of great significance for its application in electrochemical advanced oxidation processes (EAOPs) for wastewater treatment. In this study, the Ti4O7 REM with high purity was synthesized by mechanical pressing of TiO2 powders followed by thermal reduction to Ti4O7 using the Ti powder as the reducing reagent, where the TiO2 monolith and Ti powder were separated from each other with the distance of about 5 cm in the vacuum furnace. When the temperature was elevated to 1333 K, the Magnéli phase Ti4O7 REM with the Ti4O7 content of 98.5% was obtained after thermal reduction for 4 h. Noticeably, the surface and interior of the obtained REM bulk sample has a homogeneous Ti4O7 content. Doping carbon black (0wt%-15wt%) could increase the porosity of the Ti4O7 REM (38–59%). Accordingly, the internal resistance of the electrode and electrolyte and the charge-transfer impedance increased slightly with the increasing carbon black content. The optimum electroactive surface area (1.1 m2) was obtained at a carbon black content of 5wt%, which increased by 1.3-fold in comparison with that without carbon black. The as-prepared Ti4O7 REMs show high oxygen evolution potential, approximately 2.7 V/SHE, indicating their appreciable electrocatalytic activity toward the production of •OH.
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Affiliation(s)
- Guangfeng Qi
- Technical Test Center of Sinopec Shengli OilField, Dongying, China
- Testing and Evalution Research Co. Ltd. of Sinopec Shengli OilField, Dongying, China
| | - Xiaohui Wang
- Technical Test Center of Sinopec Shengli OilField, Dongying, China
- Testing and Evalution Research Co. Ltd. of Sinopec Shengli OilField, Dongying, China
- *Correspondence: Xiaohui Wang,
| | - Jingang Zhao
- Technical Test Center of Sinopec Shengli OilField, Dongying, China
- Testing and Evalution Research Co. Ltd. of Sinopec Shengli OilField, Dongying, China
| | - Chunyan Song
- Technical Test Center of Sinopec Shengli OilField, Dongying, China
- Testing and Evalution Research Co. Ltd. of Sinopec Shengli OilField, Dongying, China
| | - Yanbo Zhang
- Technical Test Center of Sinopec Shengli OilField, Dongying, China
- Testing and Evalution Research Co. Ltd. of Sinopec Shengli OilField, Dongying, China
| | - Feizhou Ren
- Technical Test Center of Sinopec Shengli OilField, Dongying, China
- Testing and Evalution Research Co. Ltd. of Sinopec Shengli OilField, Dongying, China
| | - Nan Zhang
- Technical Test Center of Sinopec Shengli OilField, Dongying, China
- Testing and Evalution Research Co. Ltd. of Sinopec Shengli OilField, Dongying, China
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Long Y, Li H, Jin H, Ni J. Interpretation of high perchlorate generated during electrochemical disinfection in presence of chloride at BDD anodes. CHEMOSPHERE 2021; 284:131418. [PMID: 34323797 DOI: 10.1016/j.chemosphere.2021.131418] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/21/2021] [Revised: 05/31/2021] [Accepted: 06/30/2021] [Indexed: 06/13/2023]
Abstract
Perchlorate is a disinfection by-product (DBP) of serious health concern. Herein, the long sought mechanism of high perchlorate production during electrochemical disinfection at boron-doped diamond (BDD) anode in the presence of chloride was elucidated. The generated perchlorate at BDD during electrochemical disinfection (in 10 mM NaCl) in 60 min reached 0.125 mM, which was 830 times higher than the EPA standard. In contrast, perchlorate at PbO2 and SnO2 anodes was below the detection limit. Further experiments employing NaClO3 revealed that the conversion ratio from ClO3- to ClO4- in 10 h at BDD (98%) was considerably higher than PbO2 (13%) and SnO2 (12%). Such significant difference among anodes was fully interpreted with a two-step mechanism. The first step is essential to produce ·ClO3 by oxidizing ClO3- at electrodes. Otherwise, the conversion to perchlorate would be impossible even with excessive ·OH, which was verified with the photocatalysis process. The second step is the perchlorate generation with radical reaction between ·ClO3 and ·OH, where the primary role of ·OH was substantiated by scavenging test. Interestingly, the capability of perchlorate production was correlated with free ·OH instead of the total amount of ·OH. Despite the similar abilities of electron transfer between anodes and ClO3-, much higher free ·OH exists at BDD anode than at PbO2 and SnO2 anodes through chronoamperometry experiments and work function characterization, which reasonably provides interpretation of high perchlorate production at BDD anode.
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Affiliation(s)
- Yujiao Long
- Institute of Agricultural Resources and Environment, Jiangsu Academy of Agricultural Sciences, Nanjing, 210014, China; College of Environmental Sciences and Engineering, Peking University, The Key Laboratory of Water and Sediment Sciences, Ministry of Education, Beijing, 100871, China
| | - Hongna Li
- Agricultural Clean Watershed Research Group, Institute of Environment and Sustainable Development in Agriculture, Chinese Academy of Agricultural Sciences, Beijing, 100081, China
| | - Hongmei Jin
- Institute of Agricultural Resources and Environment, Jiangsu Academy of Agricultural Sciences, Nanjing, 210014, China
| | - Jinren Ni
- College of Environmental Sciences and Engineering, Peking University, The Key Laboratory of Water and Sediment Sciences, Ministry of Education, Beijing, 100871, China.
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Wang H, Li Z, Zhang F, Wang Y, Zhang X, Wang J, He X. Comparison of Ti/Ti4O7, Ti/Ti4O7-PbO2-Ce, and Ti/Ti4O7 nanotube array anodes for electro-oxidation of p-nitrophenol and real wastewater. Sep Purif Technol 2021. [DOI: 10.1016/j.seppur.2021.118600] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
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6
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Ouarda Y, Trellu C, Lesage G, Rivallin M, Drogui P, Cretin M. Electro-oxidation of secondary effluents from various wastewater plants for the removal of acetaminophen and dissolved organic matter. THE SCIENCE OF THE TOTAL ENVIRONMENT 2020; 738:140352. [PMID: 32806341 DOI: 10.1016/j.scitotenv.2020.140352] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/10/2020] [Revised: 06/03/2020] [Accepted: 06/17/2020] [Indexed: 05/03/2023]
Abstract
Electro-oxidation of acetaminophen (ACT) in three different doped secondary effluents collected from a conventional Municipal Waste Water Treatment Plant (MWWTP), a MWWTP using a membrane bioreactor (WWTP MBR) and a lab-scale MBR treating source-separated urine (Urine MBR) was investigated by electro-Fenton (EF) coupled with anodic oxidation (AO) using sub-stoichiometric titanium oxide anode (Ti4O7). After 8 h of treatment, 90 ± 15%, 76 ± 3.8% and 46 ± 1.3% of total organic carbon removal was obtained for MWWTP, MWWTP-MBR and Urine-MBR respectively, at a current intensity of 250 mA, pH of 3 and [Fe2+] = 0.2 mM. Faster degradation of ACT was observed in the WWTP MBR because of the lower amount of competitive organic matter, however, >99% degradation of ACT was obtained after 20 min for all effluents. The acute toxicity of the treated effluent was measured using Microtox® tests. Results showed an initial increase in toxicity, which could be assigned to formation of more toxic by-products than parent compounds. From 3D excitation and emission matrix fluorescence (3DEEM), different reactivity was observed according to the nature of the organic matter. Particularly, an increase of low molecular weight organic compounds fluorescence was observed during Urine MBR treatment. This could be linked to the slow decrease of the acute toxicity during Urine MBR treatment and ascribed to the formation and recalcitrance of toxic organic nitrogen and chlorinated organic by-products. By comparison, the acute toxicity of other effluents decreased much more rapidly. Finally, energy consumption was calculated according to the objective to achieve (degradation, absence of toxicity, mineralization).
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Affiliation(s)
- Yassine Ouarda
- Institut National de la Recherche Scientifique Eau Terre et Environnement (INRS-ETE), Université du Quebec, 490 rue de la Couronne, Quebec, QC G1K 9A9, Canada; Institut Européen des Membranes, IEM, Université Montpellier, CNRS, ENSCM, Place Eugène Bataillon, 34095 Montpellier cedex 5, France
| | - Clément Trellu
- Institut Européen des Membranes, IEM, Université Montpellier, CNRS, ENSCM, Place Eugène Bataillon, 34095 Montpellier cedex 5, France; Laboratoire Géomatériaux et Environnement, LGE - Université Paris-Est, EA 4508, UPEM, 77454 Marne-la-Vallée, France
| | - Geoffroy Lesage
- Institut Européen des Membranes, IEM, Université Montpellier, CNRS, ENSCM, Place Eugène Bataillon, 34095 Montpellier cedex 5, France
| | - Matthieu Rivallin
- Institut Européen des Membranes, IEM, Université Montpellier, CNRS, ENSCM, Place Eugène Bataillon, 34095 Montpellier cedex 5, France
| | - Patrick Drogui
- Institut National de la Recherche Scientifique Eau Terre et Environnement (INRS-ETE), Université du Quebec, 490 rue de la Couronne, Quebec, QC G1K 9A9, Canada
| | - Marc Cretin
- Institut Européen des Membranes, IEM, Université Montpellier, CNRS, ENSCM, Place Eugène Bataillon, 34095 Montpellier cedex 5, France.
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7
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Moradi M, Vasseghian Y, Khataee A, Kobya M, Arabzade H, Dragoi EN. Service life and stability of electrodes applied in electrochemical advanced oxidation processes: A comprehensive review. J IND ENG CHEM 2020. [DOI: 10.1016/j.jiec.2020.03.038] [Citation(s) in RCA: 63] [Impact Index Per Article: 15.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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8
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Mora-Gómez J, García-Gabaldón M, Carrillo-Abad J, Montañés M, Mestre S, Pérez-Herranz V. Influence of the reactor configuration and the supporting electrolyte concentration on the electrochemical oxidation of Atenolol using BDD and SnO2 ceramic electrodes. Sep Purif Technol 2020. [DOI: 10.1016/j.seppur.2020.116684] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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9
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Silva Barni MF, Doumic LI, Procaccini RA, Ayude MA, Romeo HE. Layered platforms of Ti 4O 7 as flow-through anodes for intensifying the electro-oxidation of bentazon. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2020; 263:110403. [PMID: 32883479 DOI: 10.1016/j.jenvman.2020.110403] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/06/2019] [Revised: 02/11/2020] [Accepted: 03/03/2020] [Indexed: 05/03/2023]
Abstract
In this study, we prepared Ti4O7 porous electrodes with continuous layered structures characterized by different layer-to-layer distance (from 2 to 10 μm) but the same total void fraction (88-90%), to modulate the electrodes' permeability and the volumetric electrochemical surface area (from 90 to 840 cm2 cm-3). These platforms were evaluated as anodes in the electro-oxidation (EO) of bentazon in a three-electrode cell under galvanostatic conditions, operated both in traditional batch (TB) or batch recycle flow-through (BRFT) modes. The performance was significantly enhanced when the liquid was recirculated through the lamellar structure of the electrodes. In BRFT mode, the electrode interlayer gap was found to be a key factor to control the bentazon and total organic carbon (TOC) conversions. For the best conditions evaluated (BRFT, 10 μm-interlayered Ti4O7 electrodes with a volumetric surface area of 90 cm2 cm-3), the effect of the applied current (1 or 3 mA) and liquid flow rate (10, 12 or 14 mL. min-1) was investigated. Specific energy consumption (SEC) values were estimated to reveal the performance of each of the EO treatments from an energetic point of view. The use of 10 μm-interlayered Ti4O7 electrodes at 1 mA in BRFT mode at a flow rate of 14 mL min-1 showed the best results, yielding 85% bentazon removal, 57% mineralization and SEC values of 0.006 kWh.gTOC-1 after 6 h of treatment. This contribution highlights the use of layered Ti4O7 electrodes as a promising strategy for intensifying EO processes, pointing to a trade-off between the accessibility to the internal electrode structure and the volumetric electrode surface area to enhance the contact between the target molecules and the hydroxyl radicals physisorbed on the electrode surface, while minimizing simultaneously the energy requirements.
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Affiliation(s)
- María F Silva Barni
- División Polímeros Nanoestructurados, INTEMA-CONICET, Facultad de Ingeniería, UNMdP, Av. Juan B. Justo, 4302, B7608FDQ, Mar del Plata, Argentina
| | - Lucila I Doumic
- División Catalizadores y Superficies, INTEMA-CONICET, Departamento de Ingeniería Química, Facultad de Ingeniería, UNMdP, Av. Juan B. Justo, 4302, B7608FDQ, Mar del Plata, Argentina
| | - Raúl A Procaccini
- División Electroquímica Aplicada, INTEMA-CONICET, Facultad de Ingeniería, UNMdP, Av. Juan B. Justo, 4302, B7608FDQ, Mar del Plata, Argentina
| | - María A Ayude
- División Catalizadores y Superficies, INTEMA-CONICET, Departamento de Ingeniería Química, Facultad de Ingeniería, UNMdP, Av. Juan B. Justo, 4302, B7608FDQ, Mar del Plata, Argentina.
| | - Hernán E Romeo
- División Polímeros Nanoestructurados, INTEMA-CONICET, Facultad de Ingeniería, UNMdP, Av. Juan B. Justo, 4302, B7608FDQ, Mar del Plata, Argentina.
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Skolotneva E, Trellu C, Cretin M, Mareev S. A 2D Convection-Diffusion Model of Anodic Oxidation of Organic Compounds Mediated by Hydroxyl Radicals Using Porous Reactive Electrochemical Membrane. MEMBRANES 2020; 10:membranes10050102. [PMID: 32429328 PMCID: PMC7280982 DOI: 10.3390/membranes10050102] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/27/2020] [Revised: 05/11/2020] [Accepted: 05/13/2020] [Indexed: 11/16/2022]
Abstract
In recent years, electrochemical methods utilizing reactive electrochemical membranes (REM) have been considered as a promising technology for efficient degradation and mineralization of organic compounds in natural, industrial and municipal wastewaters. In this paper, we propose a two-dimensional (2D) convection-diffusion-reaction model concerning the transport and reaction of organic species with hydroxyl radicals generated at a TiOx REM operated in flow-through mode. It allows the determination of unknown parameters of the system by treatment of experimental data and predicts the behavior of the electrolysis setup. There is a good agreement in the calculated and experimental degradation rate of a model pollutant at different permeate fluxes and current densities. The model also provides an understanding of the current density distribution over an electrically heterogeneous surface and its effect on the distribution profile of hydroxyl radicals and diluted species. It was shown that the percentage of the removal of paracetamol increases with decreasing the pore radius and/or increasing the porosity. The effect becomes more pronounced as the current density increases. The model highlights how convection, diffusion and reaction limitations have to be taken into consideration for understanding the effectiveness of the process.
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Affiliation(s)
- Ekaterina Skolotneva
- Physical Chemistry Department, Kuban State University, 149 Stavropolskaya str., 350040 Krasnodar, Russia;
| | - Clement Trellu
- Laboratoire Géomatériaux et Environnement (EA 4508), Université Gustave Eiffel, 77454 Marne la Vallée, France;
| | - Marc Cretin
- Institut Europeen des Membranes, IEM-UMR 5635, ENSCM, CNRS, Univ Montpellier, 34095 Montpellier, France;
| | - Semyon Mareev
- Physical Chemistry Department, Kuban State University, 149 Stavropolskaya str., 350040 Krasnodar, Russia;
- Correspondence: ; Tel.: +7-861-519-9573
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11
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Electrochemical Degradation of Reactive Black 5 using two-different reactor configuration. Sci Rep 2020; 10:4482. [PMID: 32161357 PMCID: PMC7066175 DOI: 10.1038/s41598-020-61501-5] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2019] [Accepted: 02/18/2020] [Indexed: 11/27/2022] Open
Abstract
Novel Sb-doped SnO2 ceramic electrodes sintered at different temperatures, are applied to the degradation of Reactive Black 5 in both divided and undivided electrochemical reactors. In the undivided reactor the discoloration of the solution took place via the oxidation of RB5 dye, without the corresponding reduction in the chemical oxygen demand for the ceramic electrodes. However, in the divided one, it was possible to achieve the discoloration of the solution while at the same time decreasing the chemical oxygen demand through the ·OH-mediated oxidation, although the chemical oxygen demand degradation took place at a slower rate.
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12
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Yang K, Xu J, Lin H, Xie R, Wang K, Lv S, Liao J, Liu X, Chen J, Yang Z. Developing a low-pressure and super stable electrochemical tubular reactive filter: Outstanding efficiency for wastewater purification. Electrochim Acta 2020. [DOI: 10.1016/j.electacta.2020.135634] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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13
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Hua L, Cao H, Ma Q, Shi X, Zhang X, Zhang W. Microalgae Filtration Using an Electrochemically Reactive Ceramic Membrane: Filtration Performances, Fouling Kinetics, and Foulant Layer Characteristics. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2020; 54:2012-2021. [PMID: 31916753 DOI: 10.1021/acs.est.9b07022] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Electrochemical membrane filtration has proven to be successful for microbial removal and separation from water. In addition, membrane fouling could be mitigated by electrochemical reactions and electrostatic repulsion on a reactive membrane surface. This study assessed the filtration performances and fouling characteristics of electrochemically reactive ceramic membranes (a Magneli phase suboxide of TiO2) when filtering algal suspension under different dc currents to achieve anodic or cathodic polarization. The critical flux results indicate that when applying positive or negative dc currents (e.g., 1.25-2.5 mA·cm-2) to the membrane, both significantly mitigated membrane fouling and thus maintained higher critical fluxes (up to 14.6 × 10-5·m3·m-2·s-1 or 526 LMH) compared to the critical flux without dc currents. Moreover, applying dc currents also enhanced membrane defouling processes and recovered high permeate flux better than hydraulic and chemical backwash methods. Moreover, fouling kinetics and the cake layer formation were further analyzed with a resistance-in-series model that revealed many important but underexamined parameters (e.g., cake layer resistance and cake layer thickness). The cake layer structures (e.g., compressibility) were shown to vary with the electrochemical activity, which provide new insight into the biofouling mechanisms. Finally, the algogenic odor, geosmin, was shown to be effectively removed by this reactive membrane under positive dc currents (2.5 mA·cm-2), which highlights the multifunctional capabilities of electrochemically reactive membrane filtration in biomass separation, fouling prevention, and pollutant degradation.
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Affiliation(s)
- Likun Hua
- John A. Reif, Jr. Department of Civil and Environmental Engineering , New Jersey Institute of Technology , Newark , New Jersey 07102 , United States
| | - Han Cao
- John A. Reif, Jr. Department of Civil and Environmental Engineering , New Jersey Institute of Technology , Newark , New Jersey 07102 , United States
| | - Qingquan Ma
- John A. Reif, Jr. Department of Civil and Environmental Engineering , New Jersey Institute of Technology , Newark , New Jersey 07102 , United States
| | - Xiaonan Shi
- John A. Reif, Jr. Department of Civil and Environmental Engineering , New Jersey Institute of Technology , Newark , New Jersey 07102 , United States
| | - Xuezhi Zhang
- Center for Algal Biology and Applied Research, Institute of Hydrobiology , Chinese Academy of Sciences , South Donghu Road , Wuchang District, Wuhan , Hubei 430072 , China
| | - Wen Zhang
- John A. Reif, Jr. Department of Civil and Environmental Engineering , New Jersey Institute of Technology , Newark , New Jersey 07102 , United States
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14
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dos Santos AJ, Garcia-Segura S, Dosta S, Cano IG, Martínez-Huitle CA, Brillas E. A ceramic electrode of ZrO2-Y2O3 for the generation of oxidant species in anodic oxidation. Assessment of the treatment of Acid Blue 29 dye in sulfate and chloride media. Sep Purif Technol 2019. [DOI: 10.1016/j.seppur.2019.115747] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
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15
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Chaplin BP. The Prospect of Electrochemical Technologies Advancing Worldwide Water Treatment. Acc Chem Res 2019; 52:596-604. [PMID: 30768240 DOI: 10.1021/acs.accounts.8b00611] [Citation(s) in RCA: 141] [Impact Index Per Article: 28.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Growing worldwide population, climate change, and decaying water infrastructure have all contributed to a need for a better water treatment and conveyance model. Distributed water treatment is one possible solution, which relies on the local treatment of water from various sources to a degree dependent on its intended use and, finally, distribution to local consumers. This distributed, fit-for-purpose water treatment strategy requires the development of new modular point-of-use and point-of-entry technologies to bring this idea to fruition. Electrochemical technologies have the potential to contribute to this vision, as they have several advantages over established water treatment technologies. Electrochemical technologies have the ability to simultaneously treat multiple classes of contaminants through the in situ production of chemicals at the electrode surfaces with low power and energy demands, thereby allowing the construction of compact, modular water treatment technologies that require little maintenance and can be easily automated or remotely controlled. In addition, these technologies offer the opportunity for energy recovery through production of fuels at the cathode, which can further reduce their energy footprint. In spite of these advantages, there are several challenges that need to be overcome before widespread adoption of electrochemical water treatment technologies is possible. This Account will focus primarily on destructive electrolytic technologies that allow for removal of water contaminants without the need for residual treatment or management. Most important to the development of destructive electrochemical technologies is a need to fabricate nontoxic, inexpensive, high-surface-area electrodes that have a long operational life and can operate without the production of unwanted toxic byproducts. Overcoming these barriers will decrease the capital costs of water treatment and allow the development of the point-of-use and point-of-entry technologies that are necessary to promote more sustainable water treatment solutions. However, to accomplish this goal, a reprioritization of research is needed. Current research is primarily focused on investigating individual contaminant transformation pathways and mechanisms. While this research is important for understanding these technologies, additional work is needed in developing inexpensive, high-surface-area, stable electrode materials, minimizing toxic byproduct formation, and determining the life cycle and technoeconomic analyses necessary for commercialization. Better understanding of these critical research areas will allow for strategic deployment of electrochemical water treatment technologies to promote a more sustainable future.
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Affiliation(s)
- Brian P. Chaplin
- Department of Chemical Engineering, University of Illinois at Chicago, 810 S. Clinton Street, Chicago, Illinois 60607, United States
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16
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Ganiyu SO, Oturan N, Trellu C, Raffy S, Cretin M, Causserand C, Oturan MA. Electrochemical Abatement of Analgesic Antipyretic 4‐Aminophenazone using Conductive Boron‐Doped Diamond and Sub‐Stoichiometric Titanium Oxide Anodes: Kinetics, Mineralization and Toxicity Assessment. ChemElectroChem 2019. [DOI: 10.1002/celc.201801741] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Soliu O. Ganiyu
- Université Paris-Est Laboratoire Géomatériaux et Environnement (EA 4508), UPEM 77454 Marne-la-Vallée France
| | - Nihal Oturan
- Université Paris-Est Laboratoire Géomatériaux et Environnement (EA 4508), UPEM 77454 Marne-la-Vallée France
| | - Clément Trellu
- Université Paris-Est Laboratoire Géomatériaux et Environnement (EA 4508), UPEM 77454 Marne-la-Vallée France
| | - Stéphane Raffy
- Saint-Gobain C.R.E.E. 550 avenue Alphonse Jauffret 84300 Cavaillon France
| | - Marc Cretin
- IEM (Institut Européen des Membranes) UMR 5635 (CNRS-ENSCM-UM)Université de Montpellier Place E. Bataillon F-34095 Montpellier, Cedex 5 France
| | - Christel Causserand
- Laboratoire de Génie ChimiqueUniversité de Toulouse, CNRS, INPT, UPS Toulouse France
| | - Mehmet A. Oturan
- Université Paris-Est Laboratoire Géomatériaux et Environnement (EA 4508), UPEM 77454 Marne-la-Vallée France
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Ganiyu SO, Oturan N, Raffy S, Cretin M, Causserand C, Oturan MA. Efficiency of plasma elaborated sub-stoichiometric titanium oxide (Ti4O7) ceramic electrode for advanced electrochemical degradation of paracetamol in different electrolyte media. Sep Purif Technol 2019. [DOI: 10.1016/j.seppur.2018.03.076] [Citation(s) in RCA: 58] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
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18
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Electrochemical degradation of norfloxacin using BDD and new Sb-doped SnO2 ceramic anodes in an electrochemical reactor in the presence and absence of a cation-exchange membrane. Sep Purif Technol 2019. [DOI: 10.1016/j.seppur.2018.05.017] [Citation(s) in RCA: 53] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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19
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Trellu C, Chaplin BP, Coetsier C, Esmilaire R, Cerneaux S, Causserand C, Cretin M. Electro-oxidation of organic pollutants by reactive electrochemical membranes. CHEMOSPHERE 2018; 208:159-175. [PMID: 29864707 DOI: 10.1016/j.chemosphere.2018.05.026] [Citation(s) in RCA: 103] [Impact Index Per Article: 17.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/31/2018] [Revised: 04/18/2018] [Accepted: 05/02/2018] [Indexed: 06/08/2023]
Abstract
Electro-oxidation processes are promising options for the removal of organic pollutants from water. The major appeal of these technologies is the possibility to avoid the addition of chemical reagents. However, a major limitation is associated with slow mass transfer that reduces the efficiency and hinders the potential for large-scale application of these technologies. Therefore, improving the reactor configuration is currently one of the most important areas for research and development. The recent development of a reactive electrochemical membrane (REM) as a flow-through electrode has proven to be a breakthrough innovation, leading to both high electrochemically active surface area and convection-enhanced mass transport of pollutants. This review summarizes the current state of the art on REMs for the electro-oxidation of organic compounds by anodic oxidation. Specific focuses on the electroactive surface area, mass transport, reactivity, fouling and stability of REMs are included. Recent advances in the development of sub-stoichiometric titanium oxide REMs as anodes have been made. These electrodes possess high electrical conductivity, reactivity (generation of •OH), chemical/electrochemical stability, and suitable pore structure that allows for efficient mass transport. Further development of REMs strongly relies on the development of materials with suitable physico-chemical characteristics that produce electrodes with efficient mass transport properties, high electroactive surface area, high reactivity and long-term stability.
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Affiliation(s)
- Clément Trellu
- Institut Européen des Membranes, IEM - UMR 5635, ENSCM, CNRS, Univ Montpellier, Montpellier, France; Laboratoire de Génie Chimique, Université de Toulouse, CNRS, INPT, UPS, Toulouse, France.
| | - Brian P Chaplin
- Department of Chemical Engineering, University of Illinois at Chicago, 810 S. Clinton Street, Chicago, IL 60607, USA
| | - Clémence Coetsier
- Laboratoire de Génie Chimique, Université de Toulouse, CNRS, INPT, UPS, Toulouse, France
| | - Roseline Esmilaire
- Institut Européen des Membranes, IEM - UMR 5635, ENSCM, CNRS, Univ Montpellier, Montpellier, France
| | - Sophie Cerneaux
- Institut Européen des Membranes, IEM - UMR 5635, ENSCM, CNRS, Univ Montpellier, Montpellier, France
| | - Christel Causserand
- Laboratoire de Génie Chimique, Université de Toulouse, CNRS, INPT, UPS, Toulouse, France
| | - Marc Cretin
- Institut Européen des Membranes, IEM - UMR 5635, ENSCM, CNRS, Univ Montpellier, Montpellier, France
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20
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Comparative Degradation of Atrazine by Anodic Oxidation at Graphite and Platinum Electrodes and Insights into Electrochemical Behavior of Graphite Anode. Electrocatalysis (N Y) 2018. [DOI: 10.1007/s12678-018-0493-z] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
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21
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Miklos DB, Remy C, Jekel M, Linden KG, Drewes JE, Hübner U. Evaluation of advanced oxidation processes for water and wastewater treatment - A critical review. WATER RESEARCH 2018; 139:118-131. [PMID: 29631187 DOI: 10.1016/j.watres.2018.03.042] [Citation(s) in RCA: 979] [Impact Index Per Article: 163.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/19/2018] [Revised: 03/13/2018] [Accepted: 03/15/2018] [Indexed: 05/05/2023]
Abstract
This study provides an overview of established processes as well as recent progress in emerging technologies for advanced oxidation processes (AOPs). In addition to a discussion of major reaction mechanisms and formation of by-products, data on energy efficiency were collected in an extensive analysis of studies reported in the peer-reviewed literature enabling a critical comparison of various established and emerging AOPs based on electrical energy per order (EEO) values. Despite strong variations within reviewed EEO values, significant differences could be observed between three groups of AOPs: (1) O3 (often considered as AOP-like process), O3/H2O2, O3/UV, UV/H2O2, UV/persulfate, UV/chlorine, and electron beam represent median EEO values of <1 kWh/m3, while median energy consumption by (2) photo-Fenton, plasma, and electrolytic AOPs were significantly higher (EEO values in the range of 1-100 kWh/m3). (3) UV-based photocatalysis, ultrasound, and microwave-based AOPs are characterized by median values of >100 kWh/m3 and were therefore considered as not (yet) energy efficient AOPs. Specific evaluation of 147 data points for the UV/H2O2 process revealed strong effects of operational conditions on reported EEO values. Besides water type and quality, a major influence was observed for process capacity (lab-vs. pilot-vs. full-scale applications) and, in case of UV-based processes, of the lamp type. However, due to the contribution of other factors, correlation of EEO values with specific water quality parameters such as UV absorbance and dissolved organic carbon were not substantial. Also, correlations between EEO and compound reactivity with OH-radicals were not significant (photolytically active compounds were not considered). Based on these findings, recommendations regarding the use of the EEO concept, including the upscaling of laboratory results, were derived.
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Affiliation(s)
- David B Miklos
- Chair of Urban Water Systems Engineering, Technical University of Munich, Am Coulombwall 3, D-85748 Garching, Germany.
| | - Christian Remy
- Kompetenzzentrum Wasser Berlin gGmbH, Cicerostrasse 24, D-10709 Berlin, Germany.
| | - Martin Jekel
- Technische Universität Berlin, Chair of Water Quality Control, KF4, Str. des 17. Juni 135, D-10623, Berlin, Germany.
| | - Karl G Linden
- Department of Civil, Environmental, and Architectural Engineering, University of Colorado Boulder, UCB 607, Boulder, CO 80303, USA.
| | - Jörg E Drewes
- Chair of Urban Water Systems Engineering, Technical University of Munich, Am Coulombwall 3, D-85748 Garching, Germany.
| | - Uwe Hübner
- Chair of Urban Water Systems Engineering, Technical University of Munich, Am Coulombwall 3, D-85748 Garching, Germany.
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Li D, Wang S, Tian Y, Ma H, Ma C, Fu Y, Dong X. Preparation and Photoelectrocatalytic Performance of Ti/PbO
2
Electrodes Modified with Ti
4
O
7. ChemistrySelect 2018. [DOI: 10.1002/slct.201703181] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Affiliation(s)
- Dunchao Li
- School of light industry&chemical engineeringDalian Polytechnic University, No.1 Qinggongyuan, Ganjinzi District, Dalian, P.R. China
| | - Shuai Wang
- The 18th Research Institute of China Electronics Technology Group Corporation, Tianjin, P.R. China
| | - Yihua Tian
- School of light industry&chemical engineeringDalian Polytechnic University, No.1 Qinggongyuan, Ganjinzi District, Dalian, P.R. China
| | - Hongchao Ma
- School of light industry&chemical engineeringDalian Polytechnic University, No.1 Qinggongyuan, Ganjinzi District, Dalian, P.R. China
| | - Chun Ma
- School of light industry&chemical engineeringDalian Polytechnic University, No.1 Qinggongyuan, Ganjinzi District, Dalian, P.R. China
| | - Yinghuan Fu
- School of light industry&chemical engineeringDalian Polytechnic University, No.1 Qinggongyuan, Ganjinzi District, Dalian, P.R. China
| | - Xiaoli Dong
- School of light industry&chemical engineeringDalian Polytechnic University, No.1 Qinggongyuan, Ganjinzi District, Dalian, P.R. China
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23
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Yang X, Jiuji G, Zhaowu Z, Zhang H, Qi T. Doping effects on the electro-degradation of phenol on doped titanium suboxide anodes. Chin J Chem Eng 2018. [DOI: 10.1016/j.cjche.2017.12.007] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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24
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Nayak S, Chaplin BP. Fabrication and characterization of porous, conductive, monolithic Ti4O7 electrodes. Electrochim Acta 2018. [DOI: 10.1016/j.electacta.2018.01.034] [Citation(s) in RCA: 68] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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25
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Ganiyu SO, Oturan N, Raffy S, Esposito G, van Hullebusch ED, Cretin M, Oturan MA. Use of Sub-stoichiometric Titanium Oxide as a Ceramic Electrode in Anodic Oxidation and Electro-Fenton Degradation of the Beta-blocker Propranolol: Degradation Kinetics and Mineralization Pathway. Electrochim Acta 2017. [DOI: 10.1016/j.electacta.2017.05.047] [Citation(s) in RCA: 72] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
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26
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Jing Y, Chaplin BP. Mechanistic Study of the Validity of Using Hydroxyl Radical Probes To Characterize Electrochemical Advanced Oxidation Processes. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2017; 51:2355-2365. [PMID: 28072535 DOI: 10.1021/acs.est.6b05513] [Citation(s) in RCA: 106] [Impact Index Per Article: 15.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
The detection of hydroxyl radicals (OH•) is typically accomplished by using reactive probe molecules, but prior studies have not thoroughly investigated the suitability of these probes for use in electrochemical advanced oxidation processes (EAOPs), due to the neglect of alternative reaction mechanisms. In this study, we investigated the suitability of four OH• probes (coumarin, p-chlorobenzoic acid, terephthalic acid, and p-benzoquinone) for use in EAOPs. Experimental results indicated that both coumarin and p-chlorobenzoic acid are oxidized via direct electron transfer reactions, while p-benzoquinone and terephthalic acid are not. Coumarin oxidation to form the OH• adduct product 7-hydroxycoumarin was found at anodic potentials lower than that necessary for OH• formation. Density functional theory (DFT) simulations found a thermodynamically favorable and non-OH• mediated pathway for 7-hydroxycoumarin formation, which is activationless at anodic potentials > 2.10 V/SHE. DFT simulations also provided estimates of E° values for a series of OH• probe compounds, which agreed with voltammetry results. Results from this study indicated that terephthalic acid is the most appropriate OH• probe compound for the characterization of electrochemical and catalytic systems.
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Affiliation(s)
- Yin Jing
- Department of Chemical Engineering, University of Illinois at Chicago , 810 South Clinton Street, Chicago, Illinois 60607, United States
| | - Brian P Chaplin
- Department of Chemical Engineering, University of Illinois at Chicago , 810 South Clinton Street, Chicago, Illinois 60607, United States
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27
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Guo L, Ding K, Rockne K, Duran M, Chaplin BP. Bacteria inactivation at a sub-stoichiometric titanium dioxide reactive electrochemical membrane. JOURNAL OF HAZARDOUS MATERIALS 2016; 319:137-146. [PMID: 27283345 DOI: 10.1016/j.jhazmat.2016.05.051] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/15/2015] [Revised: 04/27/2016] [Accepted: 05/15/2016] [Indexed: 06/06/2023]
Abstract
This study investigated the use of a sub-stoichiometric TiO2 reactive electrochemical membrane (REM) for the inactivation of a model Escherichia coli (E. coli) pathogen in chloride-free solutions. The filtration system was operated in dead-end, outside-in filtration model, using the REM as anode and a stainless steel mesh as cathode. A 1-log removal of E. coli was achieved when the electrochemical cell was operated at the open circuit potential, due to a simple bacteria-sieving mechanism. At applied cell potentials of 1.3 and 3.5V neither live nor dead E. coli cells were detected in the permeate stream (detection limit of 1.0 cell mL(-1)), which was attributed to enhanced electrostatic bacteria adsorption at the REM anode. Bacteria inactivation in the retentate solution increased as a function of the applied cell potential, which was attributed to transport of E. coli to the REM and stainless steel cathode surfaces, and direct contact with the local acidic and alkaline environment produced by water oxidation at the anode and cathode, respectively. Clear evidence for an E. coli inactivation mechanism mediated by either direct or indirect oxidation was not found. The low energy requirement of the process (2.0-88Whm(-3)) makes the REM an attractive method for potable water disinfection.
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Affiliation(s)
- Lun Guo
- Department of Chemical Engineering, University of Illinois at Chicago, 810 South Clinton Street, Chicago, IL 60607, United States
| | - Kai Ding
- Department of Civil and Environmental Engineering, Villanova University, 800 Lancaster Ave., Villanova, PA, 19085 United States
| | - Karl Rockne
- Department of Civil and Materials Engineering, University of Illinois at Chicago, 842 W. Taylor St., Chicago, IL 60607, United States
| | - Metin Duran
- Department of Civil and Environmental Engineering, Villanova University, 800 Lancaster Ave., Villanova, PA, 19085 United States
| | - Brian P Chaplin
- Department of Chemical Engineering, University of Illinois at Chicago, 810 South Clinton Street, Chicago, IL 60607, United States.
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28
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Ganiyu SO, Oturan N, Raffy S, Cretin M, Esmilaire R, van Hullebusch E, Esposito G, Oturan MA. Sub-stoichiometric titanium oxide (Ti 4O 7) as a suitable ceramic anode for electrooxidation of organic pollutants: A case study of kinetics, mineralization and toxicity assessment of amoxicillin. WATER RESEARCH 2016; 106:171-182. [PMID: 27716467 DOI: 10.1016/j.watres.2016.09.056] [Citation(s) in RCA: 118] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/21/2016] [Revised: 09/25/2016] [Accepted: 09/27/2016] [Indexed: 05/03/2023]
Abstract
Electrochemical degradation of aqueous solutions containing antibiotic amoxicillin (AMX) has been extensively studied in an undivided electrolytic cell using a sub-stoichiometric titanium oxide (Ti4O7) anode, elaborated by plasma deposition. Oxidative degradation of AMX by hydroxyl radicals was assessed as a function of applied current and was found to follow pseudo-first order kinetics. The use of carbon-felt cathode enhanced oxidation capacity of the process due to the generation of H2O2. Comparative studies at low current intensity using dimensional stable anode (DSA) and Pt anodes led to the lower mineralization efficiencies compared to Ti4O7 anode: 36 and 41% TOC removal for DSA and Pt respectively compared to 69% for Ti4O7 anode. Besides, the use of boron doped diamond (BDD) anode under similar operating conditions allowed reaching higher mineralization (94%) efficiency. Although Ti4O7 anode provides a lesser mineralization rate compared to BDD, it exhibits better performance compared to the classical anodes Pt and DSA and can constitutes an alternative to BDD anode for a cost effective electro-oxidation process. Moreover several aromatic and aliphatic oxidation reaction intermediates and inorganic end-products were identified and a plausible mineralization pathway of AMX involving these intermediates was proposed.
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Affiliation(s)
- Soliu O Ganiyu
- Université Paris-Est, Laboratoire Géomatériaux et Environnement (EA 4508), UPEM, 77454, Marne-la-Vallée, France
| | - Nihal Oturan
- Université Paris-Est, Laboratoire Géomatériaux et Environnement (EA 4508), UPEM, 77454, Marne-la-Vallée, France
| | - Stéphane Raffy
- SAINT-GOBAIN CREE, 550 Avenue Alphonse Jauffret, 84300, Cavaillon, France
| | - Marc Cretin
- IEM (Institut Européen des Membranes), UMR 5635 (CNRS-ENSCM-UM), Université de Montpellier, Place E. Bataillon, F-34095, Montpellier, Cedex 5, France
| | - Roseline Esmilaire
- IEM (Institut Européen des Membranes), UMR 5635 (CNRS-ENSCM-UM), Université de Montpellier, Place E. Bataillon, F-34095, Montpellier, Cedex 5, France
| | - Eric van Hullebusch
- Université Paris-Est, Laboratoire Géomatériaux et Environnement (EA 4508), UPEM, 77454, Marne-la-Vallée, France
| | - Giovanni Esposito
- Department of Civil and Mechanical Engineering, University of Cassino and Southern Lazio, Via Di Biasio 43, 03043, Cassino, FR, Italy
| | - Mehmet A Oturan
- Université Paris-Est, Laboratoire Géomatériaux et Environnement (EA 4508), UPEM, 77454, Marne-la-Vallée, France.
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29
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Jasmann JR, Borch T, Sale TC, Blotevogel J. Advanced Electrochemical Oxidation of 1,4-Dioxane via Dark Catalysis by Novel Titanium Dioxide (TiO2) Pellets. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2016; 50:8817-8826. [PMID: 27420906 DOI: 10.1021/acs.est.6b02183] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
1,4-dioxane is an emerging groundwater contaminant with significant regulatory implications. Because it is resistant to traditional groundwater treatments, remediation of 1,4-dioxane is often limited to costly ex situ UV-based advanced oxidation. By varying applied voltage, electrical conductivity, seepage velocity, and influent contaminant concentration in flow-through reactors, we show that electrochemical oxidation is a viable technology for in situ and ex situ treatment of 1,4-dioxane under a wide range of environmental conditions. Using novel titanium dioxide (TiO2) pellets, we demonstrate for the first time that this prominent catalyst can be activated in the dark even when electrically insulated from the electrodes. TiO2-catalyzed reactors achieved efficiencies of greater than 97% degradation of 1,4-dioxane, up to 4.6 times higher than noncatalyzed electrolytic reactors. However, the greatest catalytic enhancement (70% degradation versus no degradation without catalysis) was observed in low-ionic-strength water, where conventional electrochemical approaches notoriously fail. The TiO2 pellet's dark-catalytic oxidation activity was confirmed on the pharmaceutical lamotrigine and the industrial solvent chlorobenzene, signifying that electrocatalytic treatment has tremendous potential as a transformative remediation technology for persistent organic pollutants in groundwater and other aqueous environments.
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Affiliation(s)
- Jeramy R Jasmann
- Department of Chemistry, ‡Department of Soil and Crop Sciences and §Department of Civil and Environmental Engineering, Colorado State University , Fort Collins, Colorado 80523, United States
| | - Thomas Borch
- Department of Chemistry, ‡Department of Soil and Crop Sciences and §Department of Civil and Environmental Engineering, Colorado State University , Fort Collins, Colorado 80523, United States
| | - Tom C Sale
- Department of Chemistry, ‡Department of Soil and Crop Sciences and §Department of Civil and Environmental Engineering, Colorado State University , Fort Collins, Colorado 80523, United States
| | - Jens Blotevogel
- Department of Chemistry, ‡Department of Soil and Crop Sciences and §Department of Civil and Environmental Engineering, Colorado State University , Fort Collins, Colorado 80523, United States
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30
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Deen M, Shamshoom C, Gamble A, Bejan D, Bunce NJ. Electrodeposition of metal cations from the wet ionic liquid [EMIM][TFSI]. CAN J CHEM 2016. [DOI: 10.1139/cjc-2015-0308] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
We investigated the deposition of silver, copper, and lead from the ionic liquid 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide [EMIM][TFSI] under potentiostatic conditions in the presence of water. This was part of a larger project involving the extraction of metal ions from mining waste into an ionic liquid followed by electrodeposition so that the ionic liquid could be recycled. All three elements were deposited in metallic form by electrolysis in the ionic liquid, and the process was enhanced rather than hindered by the presence of water. The deposited metals did not adhere strongly to the cathode of the electrochemical cell, especially when Ebonex® was used as the cathode. The deposition of silver showed little temperature dependence, and at temperatures close to ambient, the ionic liquid was not adversely affected. The deposits of copper and lead gradually re-dissolved after electrodeposition, suggesting that chemical re-oxidation of these metals by air is more facile in the ionic liquid than in water. Copper showed strong evidence of formation of a Cu+ species upon reduction of Cu2+ (not seen in water); lead (Pb2+) showed evidence of a time-dependent complexation with the anions of the ionic liquid.
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Affiliation(s)
- Matthew Deen
- Electrochemical Technology Centre, Chemistry Department, University of Guelph, 50 Stone Road East, Guelph, ON N1G 2W1, Canada
- Electrochemical Technology Centre, Chemistry Department, University of Guelph, 50 Stone Road East, Guelph, ON N1G 2W1, Canada
| | - Christina Shamshoom
- Electrochemical Technology Centre, Chemistry Department, University of Guelph, 50 Stone Road East, Guelph, ON N1G 2W1, Canada
- Electrochemical Technology Centre, Chemistry Department, University of Guelph, 50 Stone Road East, Guelph, ON N1G 2W1, Canada
| | - Alison Gamble
- Electrochemical Technology Centre, Chemistry Department, University of Guelph, 50 Stone Road East, Guelph, ON N1G 2W1, Canada
- Electrochemical Technology Centre, Chemistry Department, University of Guelph, 50 Stone Road East, Guelph, ON N1G 2W1, Canada
| | - Dorin Bejan
- Electrochemical Technology Centre, Chemistry Department, University of Guelph, 50 Stone Road East, Guelph, ON N1G 2W1, Canada
- Electrochemical Technology Centre, Chemistry Department, University of Guelph, 50 Stone Road East, Guelph, ON N1G 2W1, Canada
| | - Nigel J. Bunce
- Electrochemical Technology Centre, Chemistry Department, University of Guelph, 50 Stone Road East, Guelph, ON N1G 2W1, Canada
- Electrochemical Technology Centre, Chemistry Department, University of Guelph, 50 Stone Road East, Guelph, ON N1G 2W1, Canada
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31
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Santos MC, Elabd YA, Jing Y, Chaplin BP, Fang L. Highly porous Ti4
O7
reactive electrochemical water filtration membranes fabricated via electrospinning/electrospraying. AIChE J 2015. [DOI: 10.1002/aic.15093] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Melissa C. Santos
- Dept. of Chemical Engineering; Texas A&M University; College Station TX 77843
| | - Yossef A. Elabd
- Dept. of Chemical Engineering; Texas A&M University; College Station TX 77843
| | - Yin Jing
- Dept. of Chemical Engineering; University of Illinois at Chicago; IL 60607
| | - Brian P. Chaplin
- Dept. of Chemical Engineering; University of Illinois at Chicago; IL 60607
| | - Lei Fang
- Dept. of Chemical Engineering; University of Illinois at Chicago; IL 60607
- College of Civil Engineering and Architecture; Zhejiang University; Hangzhou 310058 P.R. China
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32
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Highly-Ordered Magnéli Ti4O7 Nanotube Arrays as Effective Anodic Material for Electro-oxidation. Electrochim Acta 2015. [DOI: 10.1016/j.electacta.2014.11.178] [Citation(s) in RCA: 78] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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33
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Zaky AM, Chaplin BP. Mechanism of p-substituted phenol oxidation at a Ti4O7 reactive electrochemical membrane. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2014; 48:5857-5867. [PMID: 24766505 DOI: 10.1021/es5010472] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
This research investigated the removal mechanisms of p-nitrophenol, p-methoxyphenol, and p-benzoquinone at a porous Ti4O7 reactive electrochemical membrane (REM) under anodic polarization. Cross-flow filtration experiments and density functional theory (DFT) calculations indicated that p-benzoquinone removal was primarily due to reaction with electrochemically formed OH(•), while the dominant removal mechanism of p-nitrophenol and p-methoxyphenol was a function of the anodic potential. At low anodic potentials (1.7-1.8 V/SHE), p-nitrophenol and p-methoxyphenol were removed primarily by an electrochemical adsorption/polymerization mechanism on the REM. Increasing anodic potentials (1.9-3.2 V/SHE) resulted in the electroassisted adsorption mechanism contributing far less to p-methoxyphenol removal compared to p-nitrophenol. DFT calculations indicated that an increase in anodic potential resulted in a shift in p-methoxyphenol removal from a 1e(-) direct electron transfer (DET) reaction that resulted in radical formation and significant adsorption/polymerization, to a 2e(-) DET reaction that formed nonadsorbing products (i.e., p-benzoquinone). However, the anodic potentials were too low for the 2e(-) DET reaction to be thermodynamically favorable for p-nitrophenol. The decreased COD adsorption for p-nitrophenol at higher anodic potentials was attributed to reaction of soluble/adsorbed organics with OH(•). These results provide the first mechanistic explanation for p-substituted phenolic compound removal during advanced electrochemical oxidation processes.
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Affiliation(s)
- Amr M Zaky
- Department of Chemical Engineering, University of Illinois at Chicago , 810 South Clinton Avenue, Chicago, Illinois 60607, United States
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34
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Chaplin BP. Critical review of electrochemical advanced oxidation processes for water treatment applications. ENVIRONMENTAL SCIENCE. PROCESSES & IMPACTS 2014; 16:1182-203. [PMID: 24549240 DOI: 10.1039/c3em00679d] [Citation(s) in RCA: 250] [Impact Index Per Article: 25.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
Electrochemical advanced oxidation processes (EAOPs) have emerged as novel water treatment technologies for the elimination of a broad-range of organic contaminants. Considerable validation of this technology has been performed at both the bench-scale and pilot-scale, which has been facilitated by the development of stable electrode materials that efficiently generate high yields of hydroxyl radicals (OH˙) (e.g., boron-doped diamond (BDD), doped-SnO2, PbO2, and substoichiometic- and doped-TiO2). Although a promising new technology, the mechanisms involved in the oxidation of organic compounds during EAOPs and the corresponding environmental impacts of their use have not been fully addressed. In order to unify the state of knowledge, identify research gaps, and stimulate new research in these areas, this review critically analyses published research pertaining to EAOPs. Specific topics covered in this review include (1) EAOP electrode types, (2) oxidation pathways of select classes of contaminants, (3) rate limitations in applied settings, and (4) long-term sustainability. Key challenges facing EAOP technologies are related to toxic byproduct formation (e.g., ClO4(-) and halogenated organic compounds) and low electro-active surface areas. These challenges must be addressed in future research in order for EAOPs to realize their full potential for water treatment.
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Affiliation(s)
- Brian P Chaplin
- Department of Chemical Engineering, University of Illinois at Chicago, 810 S. Clinton Ave., Chicago, IL 60607, USA.
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Hu Z, Zhou M, Zhou L, Li Y, Zhang C. Effect of matrix on the electrochemical characteristics of TiO₂ nanotube array-based PbO₂ electrode for pollutant degradation. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2014; 21:8476-8484. [PMID: 24687791 DOI: 10.1007/s11356-014-2792-0] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/19/2014] [Accepted: 03/10/2014] [Indexed: 06/03/2023]
Abstract
A series of lead dioxide electrodes developed on titania nanotube arrays with different matrix were fabricated by electrodeposition. Before the deposition of PbO₂, the matrix of this anode was electrochemically reduced in (NH₄)₂SO₄ solution and/or pre-deposited with certain amounts of copper. To gain insight into these pretreatments, the PbO₂ electrodes were characterized by SEM, LSV, and XRD, and their electrocatalytic activities for pollutant degradation were compared using p-nitrophenol (p-NP) as a model. It was confirmed that the electrochemical reduction with (NH4)₂SO₄ resulted in the partial conversion of TiO₂ into Ti₄O₇ and Ti₅O₉, which increased the conductivity of PbO₂ anode, but decreased its electrochemical activity, while the Ti/TNTs*-Cu/PbO₂ electrode with both pretreatments possessed the highest oxygen evolution overpotential of 2.5 V (vs. SCE) and low substrate resistance. After a 180-min treatment on this electrode, the removal efficiency of p-NP reached 82.5% and the COD removal achieved 42.5% with the energy consumption of 9.45 kWh m(-3), demonstrating the best performance among these electrodes with different matrices. Therefore, this titania nanotube array-based PbO₂ electrode has a promising application in the industrial wastewater treatment.
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Affiliation(s)
- Zhongxin Hu
- Key Laboratory of Pollution Process and Environmental Criteria, Ministry of Education, Tianjin Key Laboratory of Urban Ecology Environmental Remediation and Pollution Control, College of Environmental Science and Engineering, Nankai University, Tianjin, 300071, China
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Donaghue A, Chaplin BP. Effect of select organic compounds on perchlorate formation at boron-doped diamond film anodes. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2013; 47:12391-12399. [PMID: 24066803 DOI: 10.1021/es4031672] [Citation(s) in RCA: 71] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
Rates of ClO4(-) formation from ClO3(-) oxidation were investigated in batch experiments as a function of organic compounds (p-nitrophenol, p-benzoquinone, p-methoxyphenol, and oxalic acid) and current density using boron-doped diamond film anodes. Excluding organics, ClO4(-) formation rates ranged from 359 to 687 μmoles m(-2) min(-1) for current densities of 1-10 mA cm(-2). The presence of p-substituted phenols inhibited ClO4(-) formation rates between 13.0 and 99.6%. Results from a reactive-transport model of the diffuse layer adjacent to the anode surface indicate that competition between organics and ClO3(•) for OH(•) within a reaction zone (0.02-0.96 μm) adjacent to the anode controls ClO4(-) formation. Under kinetic-limited conditions (1.0 mA cm(-2)), organics reach the anode surface and substrates with higher OH(•) reaction rates demonstrate greater inhibition of perchlorate formation (IPF). At higher current densities (10 mA cm(-2)), organic compound oxidation becomes mass transfer-limited and compounds degrade a small distance from the anode surface (∼ 0.26 μm for p-methoxyphenol). Therefore, OH(•) scavenging does not occur at the anode surface and IPF values decrease. Results provide evidence for the existence of desorbed OH(•) near the anode surface and highlight the importance of controlling reactor operating conditions to limit ClO4(-) production during anodic treatment of organic compounds.
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Affiliation(s)
- Adrienne Donaghue
- Department of Civil and Environmental Engineering and Villanova Center for the Advancement of Sustainable Engineering (VCASE), Villanova University , Villanova, Pennsylvania 19085, United States
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Kasian O, Luk’yanenko T, Demchenko P, Gladyshevskii R, Amadelli R, Velichenko A. Electrochemical properties of thermally treated platinized Ebonex® with low content of Pt. Electrochim Acta 2013. [DOI: 10.1016/j.electacta.2013.07.162] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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Zaky AM, Chaplin BP. Porous substoichiometric TiO2 anodes as reactive electrochemical membranes for water treatment. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2013; 47:6554-6563. [PMID: 23688192 DOI: 10.1021/es401287e] [Citation(s) in RCA: 169] [Impact Index Per Article: 15.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
This research investigates the characterization and testing of an anodic reactive electrochemical membrane (REM) for water treatment. The REM consists of a porous substoichiometric titanium dioxide (Ti4O7) tubular, ceramic electrode operated in cross-flow filtration mode. Advection-enhanced mass transfer rates, on the order of a 10-fold increase, are obtained when the REM is operated in filtration-mode, relative to a traditional flow-through mode. Oxidation experiments with model organic compounds showed that the REM was active for both direct oxidation reactions and formation of hydroxyl radicals (OH(•)). Electrochemical impedance spectroscopy data interpreted by transmission line modeling determined that the electro-active surface area was 619 times the nominal geometric surface area. Results from filtration-mode experiments with p-methoxyphenol indicate that compound removal occurred by electro-assisted adsorption and subsequent oxidation. Electro-assisted adsorption was the primary removal mechanism at potentials where OH(•) did not form. At higher potentials (>2.0 V), where OH(•) concentrations were significant, p-methoxyphenol removal occurred by a combination of electro-assisted adsorption and OH(•) oxidation. These removal mechanisms resulted in 99.9% p-methoxyphenol removal in the permeate, with calculated current efficiencies >73% at applied current densities of 0.5-1.0 mA cm(-2). These results illustrate the extreme promise of the REM for water treatment.
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Affiliation(s)
- Amr M Zaky
- Department of Civil and Environmental Engineering and Villanova Center for the Advancement of Sustainable Engineering, Villanova University, Villanova, Pennsylvania 19085, United States
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Kasian OI, Luk’yanenko TV, Amadelli R, Velichenko AB. Electrochemical properties of Ebonex®/Pt anodes. RUSS J ELECTROCHEM+ 2013. [DOI: 10.1134/s1023193513060062] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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Canillas M, Chinarro E, Carballo-Vila M, Jurado JR, Moreno B. Physico-chemical properties of the Ti5O9 Magneli phase with potential application as a neural stimulation electrode. J Mater Chem B 2013; 1:6459-6468. [DOI: 10.1039/c3tb20751j] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Kearney D, Bejan D, Bunce NJ. The use of Ebonex electrodes for the electrochemical removal of nitrate ion from water. CAN J CHEM 2012. [DOI: 10.1139/v2012-048] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
This work addresses the remediation of nitrate-contaminated water using electrodes made of Ebonex (a titanium oxide ceramic with a wide range of potential stability). The objective was the complete denitrification of solutions containing nitrate ion. Denitrification was achieved in about 50% yield with unreactive supporting electrolytes when Ebonex was used as both cathode and anode, the remaining product being ammonia. Ammonia could be re-oxidized at the Ebonex anode, but this was much less efficient than the reduction step. A more efficient electrolytic denitrification was possible for solutions containing chloride; this is oxidized anodically to hypochlorite, which then oxidizes ammonia chemically to N2. The overall rate of denitrification was highest at moderate concentrations of chloride ion, because hypochlorite also re-oxidizes reduction intermediates such as nitrite back to nitrate. Complete denitrification was achieved at all stages of the reaction using Ebonex cathode and a dimensionally stable anode based on Ti/IrO2 or Ti/RuO2, because the DSA oxidizes chloride ion more efficiently than Ebonex. Cathode fouling by water sources that are high in hardness cations can be prevented by using one DSA and a pair of Ebonex electrodes that undergo periodic polarity reversal.
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Affiliation(s)
- David Kearney
- Electrochemical Technology Centre, Chemistry Department, University of Guelph, Guelph, ON N1G 2W1, Canada
| | - Dorin Bejan
- Electrochemical Technology Centre, Chemistry Department, University of Guelph, Guelph, ON N1G 2W1, Canada
| | - Nigel J. Bunce
- Electrochemical Technology Centre, Chemistry Department, University of Guelph, Guelph, ON N1G 2W1, Canada
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Bejan D, Guinea E, Bunce NJ. On the nature of the hydroxyl radicals produced at boron-doped diamond and Ebonex® anodes. Electrochim Acta 2012. [DOI: 10.1016/j.electacta.2012.02.097] [Citation(s) in RCA: 120] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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Portehault D, Maneeratana V, Candolfi C, Oeschler N, Veremchuk I, Grin Y, Sanchez C, Antonietti M. Facile general route toward tunable Magnéli nanostructures and their use as thermoelectric metal oxide/carbon nanocomposites. ACS NANO 2011; 5:9052-9061. [PMID: 21978378 DOI: 10.1021/nn203265u] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Engineering nanoscale interfaces is a requisite for harnessing electrical and thermal transports within nanostructured materials, especially those destined for thermoelectric applications requiring an unusual combination of low thermal conductivity and electrical resistivity. Nanocomposites open up possibilities in this area, but are still bound to a very narrow range of materials. Here, we report a new approach combining the sol-gel process toward hybrid materials with spark plasma sintering (SPS) to yield functional nanocomposites based on substoichiometric titanium oxides Ti(n)O(2n-1), so-called Magnéli phases. The potential of this new approach is demonstrated by three results. First, multiple Ti(n)O(2n-1) compounds (n = 3, 4, 5, 6, 8) are obtained for the first time as sole nano-Magnéli crystalline phases with controlled specific surface areas from 55 to 300 m(2)·g(-1), classified as potential thermoelectric n-type metal oxides and paving the way toward advanced systems for energy-harvesting devices and optoelectronics. Second, this work combines the use of sol-gel and SPS processes to yield percolated nanocomposites based on metal oxide nanoparticles embedded in a carbon matrix with low electrical resistivity (2 × 10(-4) Ω·m for a Ti(4)O(7) compound) and reduced thermal conductivity (1 W·m(-1)·K(-1)) with respect to bulk phases. Finally, the discovered materials are reliable with thermoelectric figures of merit (ZT = 0.08) relatively high for n-type Ti-O-based systems and metal oxides. Thereby this study represents a proof of concept for the development of promising, cheaper, and more efficient thermoelectric conversion devices.
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Affiliation(s)
- David Portehault
- UPMC Univ Paris 06, UMR 7574, Chimie de la Matière Condensée de Paris, Collège de France, 11 place Marcelin Berthelot, 75231 Paris Cedex 05, France.
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El-Sherif S, Bejan D, Bunce NJ. Electrochemical oxidation of sulfide ion in synthetic sour brines using periodic polarity reversal at Ebonex® electrodes. CAN J CHEM 2010. [DOI: 10.1139/v10-081] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The Magneli phase Ti4O7 (Ebonex®) was used as both anode and cathode in the electrochemical oxidation of sulfide ion in alkaline solution in the absence and presence of chloride and naphthenate ions. Ebonex anodes gradually lost their activity through the formation of an over-oxidized surface layer, but their activity could be maintained by periodic polarity reversal. In the context of the current paradigm for the mechanistic behaviour of oxide-based anodes, Ti4O7 has properties that combine those of “inactive” anodes (formation of hydroxyl radicals) and “active” anodes (formation of a higher oxide at the surface), with the exception that the higher oxide in the case of Ti4O7 is TiO2, which is incapable of substrate oxidation. Sulfate is the major oxidation product, especially in the presence of chloride, an ubiquitous component of sour brines, via mediated electro-oxidation to hypochlorite. Unlike at boron-doped diamond anodes, at which sulfide is oxidized with near-quantitative current efficiency, significant parasitic oxidation of water to O2 occurs at Ebonex, and oxidation of sulfide requires ~16 F mol–1, corresponding to a 50% current efficiency.
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Affiliation(s)
- Shaimaa El-Sherif
- Electrochemical Technology Centre, Chemistry Department, University of Guelph, 50 Stone Road East, Guelph, ON N1G 2W1, Canada
| | - Dorin Bejan
- Electrochemical Technology Centre, Chemistry Department, University of Guelph, 50 Stone Road East, Guelph, ON N1G 2W1, Canada
| | - Nigel J. Bunce
- Electrochemical Technology Centre, Chemistry Department, University of Guelph, 50 Stone Road East, Guelph, ON N1G 2W1, Canada
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Boudreau J, Bejan D, Bunce NJ. Competition between electrochemical advanced oxidation and electrochemical hypochlorination of acetaminophen at boron-doped diamond and ruthenium dioxide based anodes. CAN J CHEM 2010. [DOI: 10.1139/v10-017] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
This work was undertaken to distinguish four pathways for the electrochemical oxidation of acetaminophen as a model organic substrate: (i) direct electron transfer from the substrate to the anode, (ii) reaction of the substrate with HO• at boron-doped diamond anodes, (iii) non-radical (two-electron) oxidation of the substrate at Ti/RuO2 anodes, and (iv) electrochemical hypochlorination if Cl– is present. Pathway (i) was isolated as a slow reaction when boron-doped diamond (BDD) was used as the anode in the range of water stability, whereas in the corresponding reaction with Ti/RuO2 only pathway (iii) could be detected. Pathway (ii) predominated for BDD in the potential range of water oxidation, and was the only mechanism leading to mineralization of the substrate. Comparison between chemical hypochlorination and electrochemical oxidation at Ti/RuO2 in the presence of chloride ion indicated that the latter process principally involves mediated hypochlorination. Oxidation at boron-doped diamond anodes in the presence of chloride was the most complex mechanistically, with competition between hypochlorination and the electrochemical “advanced oxidation process”; this led to the formation of chlorinated byproducts. The observation of mineralization under these conditions demonstrated cross-over between reaction pathways (ii) and (iv), even though hypochlorination appeared to be the initial pathway for loss of acetaminophen. The presence of chloride ion did not significantly retard mineralization of acetaminophen in the initial stages of oxidation, but significantly increased the energy requirement for complete mineralization. The results are discussed in the context of the use of electrochemical oxidation in waste management.
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Affiliation(s)
- Jordache Boudreau
- Electrochemical Technology Centre, Chemistry Department, University of Guelph, 50 Stone Road East, Guelph, ON N1G 2W1, Canada
| | - Dorin Bejan
- Electrochemical Technology Centre, Chemistry Department, University of Guelph, 50 Stone Road East, Guelph, ON N1G 2W1, Canada
| | - Nigel J. Bunce
- Electrochemical Technology Centre, Chemistry Department, University of Guelph, 50 Stone Road East, Guelph, ON N1G 2W1, Canada
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Carter KE, Farrell J. Electrochemical oxidation of trichloroethylene using boron-doped diamond film electrodes. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2009; 43:8350-8354. [PMID: 19924968 DOI: 10.1021/es9017738] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
This research investigated the oxidation of trichloroethene (TCE) at boron-doped diamond film electrodes. Flow-through experiments in gastight reactors were performed to determine trichloroethene oxidation products, and rotating disk electrode (RDE) experiments were used to determine TCE oxidation kinetics. RDE experiments were performed over a range in current densities and temperatures in order to elucidate the rate-limiting mechanisms for TCE oxidation. Density functional theory (DFT) simulations were used to investigate the activation barriers for oxidation by direct electron transfer and hydroxyl radicals. Oxidation of TCE produced formate, carbon dioxide, chlorate, and chloride. DFT simulations, experimentally measured apparent activation energies, and linear sweep voltammetry scans indicated that TCE oxidation occurred via direct electron transfer at electrode potentials <2.0 V/SHE, while at higher electrode potentials TCE oxidation also occurred via hydroxyl radicals produced from water oxidation.
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Affiliation(s)
- Kimberly E Carter
- Department of Chemical and Environmental Engineering, The University of Arizona, Tucson, Arizona 85721, USA
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