Development of a highly efficient electrochemical flow-through anode based on inner in-site enhanced TiO2-nanotubes array

This paper reports on the development of macroporous flow-through anodes. The anodes comprised an enhanced TiO2 nanotube array (ENTA) that was grown on three macroporous titanium substrates (MP-Ti) with nominal pore sizes of 10, 20, and 50 µm. The ENTA was then covered with SnO2-Sb2O3. We refer to t...

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Main Authors: Min Chen, Can Wang, Xin Zhao, Yingcai Wang, Weiqiu Zhang, Zefang Chen, Xiaoyang Meng, Jinming Luo, John Crittenden
Format: Article
Language:English
Published: Elsevier 2020-07-01
Series:Environment International
Subjects:
Online Access:http://www.sciencedirect.com/science/article/pii/S0160412020317682
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author Min Chen
Can Wang
Xin Zhao
Yingcai Wang
Weiqiu Zhang
Zefang Chen
Xiaoyang Meng
Jinming Luo
John Crittenden
author_facet Min Chen
Can Wang
Xin Zhao
Yingcai Wang
Weiqiu Zhang
Zefang Chen
Xiaoyang Meng
Jinming Luo
John Crittenden
author_sort Min Chen
collection DOAJ
description This paper reports on the development of macroporous flow-through anodes. The anodes comprised an enhanced TiO2 nanotube array (ENTA) that was grown on three macroporous titanium substrates (MP-Ti) with nominal pore sizes of 10, 20, and 50 µm. The ENTA was then covered with SnO2-Sb2O3. We refer to this anode as the MP-Ti-ENTA/SnO2-Sb2O3 anode. The morphology, pore structure, and electrochemical properties of the anode were characterized. Compared with the traditional NTA layer, we found that the MP-Ti-ENTA/SnO2-Sb2O3 anode has a service lifetime that was 1.56 times larger than that of MP-Ti-NTA/SnO2-Sb2O3. We used 2-methyl-4-isothiazolin-3-one (MIT), a common biocide, as the target pollutant. We evaluated the impact of the operating parameters on energy efficiency and the oxidation rate of MIT. Furthermore, the apparent rate constants were 0.38, 1.63, and 1.24 min−1 for the 10, 20, and 50 μm nominal pore sizes of the MP-Ti substrates, respectively, demonstrating the different coating–loading mechanisms for the porous substrate. We found that hydroxyl radicals were the dominant species in the MIT oxidation in the HO· radical scavenging experiments. The radical and nonradical oxidation contributions to the MIT degradation for different current densities were quantitatively determined as 72.1%–74.8% and 25.2%–27.9%, respectively. Finally, we summarized the oxidation performance for MIT destruction for (1) the published literature on various advanced oxidation technologies, (2) the published literature on various anodes, and (3) our flow-by and -through anodes. Accordingly, we found that our flow-through anode has a much lower electrical efficiency per order value (0.58 kWh m−3) than the flow-by anodes (6.85 kWh m−3).
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spelling doaj.art-daa69b3f913a40b69f1563b1e653c4482022-12-21T23:57:49ZengElsevierEnvironment International0160-41202020-07-01140Development of a highly efficient electrochemical flow-through anode based on inner in-site enhanced TiO2-nanotubes arrayMin Chen0Can Wang1Xin Zhao2Yingcai Wang3Weiqiu Zhang4Zefang Chen5Xiaoyang Meng6Jinming Luo7John Crittenden8School of Environmental Science and Engineering, Tianjin University, Tianjin 300350, PR ChinaSchool of Environmental Science and Engineering, Tianjin University, Tianjin 300350, PR China; Brook Byers Institute of Sustainable Systems, School of Civil and Environmental Engineering, Georgia Institute of Technology, Atlanta, GA 30332, United States; Corresponding authors at: School of Environmental Science and Engineering, Tianjin University, Tianjin 300350, PR China (Can Wang).School of Environmental Science and Engineering, Tianjin University, Tianjin 300350, PR China; Corresponding authors at: School of Environmental Science and Engineering, Tianjin University, Tianjin 300350, PR China (Can Wang).School of Environmental Science and Engineering, Tianjin University, Tianjin 300350, PR ChinaBrook Byers Institute of Sustainable Systems, School of Civil and Environmental Engineering, Georgia Institute of Technology, Atlanta, GA 30332, United StatesBrook Byers Institute of Sustainable Systems, School of Civil and Environmental Engineering, Georgia Institute of Technology, Atlanta, GA 30332, United StatesBrook Byers Institute of Sustainable Systems, School of Civil and Environmental Engineering, Georgia Institute of Technology, Atlanta, GA 30332, United StatesBrook Byers Institute of Sustainable Systems, School of Civil and Environmental Engineering, Georgia Institute of Technology, Atlanta, GA 30332, United StatesBrook Byers Institute of Sustainable Systems, School of Civil and Environmental Engineering, Georgia Institute of Technology, Atlanta, GA 30332, United States; Corresponding authors at: School of Environmental Science and Engineering, Tianjin University, Tianjin 300350, PR China (Can Wang).This paper reports on the development of macroporous flow-through anodes. The anodes comprised an enhanced TiO2 nanotube array (ENTA) that was grown on three macroporous titanium substrates (MP-Ti) with nominal pore sizes of 10, 20, and 50 µm. The ENTA was then covered with SnO2-Sb2O3. We refer to this anode as the MP-Ti-ENTA/SnO2-Sb2O3 anode. The morphology, pore structure, and electrochemical properties of the anode were characterized. Compared with the traditional NTA layer, we found that the MP-Ti-ENTA/SnO2-Sb2O3 anode has a service lifetime that was 1.56 times larger than that of MP-Ti-NTA/SnO2-Sb2O3. We used 2-methyl-4-isothiazolin-3-one (MIT), a common biocide, as the target pollutant. We evaluated the impact of the operating parameters on energy efficiency and the oxidation rate of MIT. Furthermore, the apparent rate constants were 0.38, 1.63, and 1.24 min−1 for the 10, 20, and 50 μm nominal pore sizes of the MP-Ti substrates, respectively, demonstrating the different coating–loading mechanisms for the porous substrate. We found that hydroxyl radicals were the dominant species in the MIT oxidation in the HO· radical scavenging experiments. The radical and nonradical oxidation contributions to the MIT degradation for different current densities were quantitatively determined as 72.1%–74.8% and 25.2%–27.9%, respectively. Finally, we summarized the oxidation performance for MIT destruction for (1) the published literature on various advanced oxidation technologies, (2) the published literature on various anodes, and (3) our flow-by and -through anodes. Accordingly, we found that our flow-through anode has a much lower electrical efficiency per order value (0.58 kWh m−3) than the flow-by anodes (6.85 kWh m−3).http://www.sciencedirect.com/science/article/pii/S0160412020317682MethylisothiazoloneFlow-through anodesElectrochemical oxidationEnhanced TiO2 nanotube arrayOxidation mechanismEnergy efficiency
spellingShingle Min Chen
Can Wang
Xin Zhao
Yingcai Wang
Weiqiu Zhang
Zefang Chen
Xiaoyang Meng
Jinming Luo
John Crittenden
Development of a highly efficient electrochemical flow-through anode based on inner in-site enhanced TiO2-nanotubes array
Environment International
Methylisothiazolone
Flow-through anodes
Electrochemical oxidation
Enhanced TiO2 nanotube array
Oxidation mechanism
Energy efficiency
title Development of a highly efficient electrochemical flow-through anode based on inner in-site enhanced TiO2-nanotubes array
title_full Development of a highly efficient electrochemical flow-through anode based on inner in-site enhanced TiO2-nanotubes array
title_fullStr Development of a highly efficient electrochemical flow-through anode based on inner in-site enhanced TiO2-nanotubes array
title_full_unstemmed Development of a highly efficient electrochemical flow-through anode based on inner in-site enhanced TiO2-nanotubes array
title_short Development of a highly efficient electrochemical flow-through anode based on inner in-site enhanced TiO2-nanotubes array
title_sort development of a highly efficient electrochemical flow through anode based on inner in site enhanced tio2 nanotubes array
topic Methylisothiazolone
Flow-through anodes
Electrochemical oxidation
Enhanced TiO2 nanotube array
Oxidation mechanism
Energy efficiency
url http://www.sciencedirect.com/science/article/pii/S0160412020317682
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