A reactive electrochemical filter system with an excellent penetration flux porous Ti/SnO2-Sb filter for efficient contaminant removal from water

Kui Yang; Hui Lin; Shangtao Liang; Ruzhen Xie; Sihao Lv; Junfeng Niu; Jie Chen; Yongyou Hu

doi:10.1039/c8ra00603b

A reactive electrochemical filter system with an excellent penetration flux porous Ti/SnO₂-Sb filter for efficient contaminant removal from water

RSC Adv. 2018 Apr 16;8(25):13933-13944. doi: 10.1039/c8ra00603b. eCollection 2018 Apr 11.

Authors

Kui Yang^{1

2}, Hui Lin², Shangtao Liang³, Ruzhen Xie⁴, Sihao Lv², Junfeng Niu², Jie Chen², Yongyou Hu^{1

5}

Affiliations

¹ School of Environment and Energy, South China University of Technology Guangzhou 510006 P. R. China 201520132411@mail.scut.edu.cn ppyyhu@scut.edu.cn +86-20-3938-0508 +86-136-0274-6125.
² School of Environment and Civil Engineering, Dongguan University of Technology Dongguan 523808 P. R. China linhui@bnu.edu.cn 23817001@qq.com junfengn@bnu.edu.cn 1875898657@qq.com +86-769-3901-8706 +86-769-3901-8706.
³ AECOM Inc., Environment Atlanta Georgia 30309 USA sliang@uga.edu.
⁴ College of Architecture and Environment, Sichuan University Chengdu 610065 P. R. China xieruzhen@scu.edu.cn.
⁵ The Key Lab of Pollution Control and Ecosystem Restoration in Industry Clusters, Ministry of Education, South China University of Technology, Guangzhou Higher Education Mega Centre Guangzhou 510006 PR China.

Abstract

Tubular porous Ti/SnO₂-Sb filters with excellent penetration flux (∼61.94 m³ m^-2 h^-1 bar^-1) and electrochemical activity were prepared by a sol-gel method using low-cost porous titanium filters as the substrates. The porous Ti/SnO₂-Sb filters were used as anodic reactive electrochemical membranes to develop reactive electrochemical filter systems, by combining membrane filtration technology with the electrooxidation process, for water treatment. A convection-enhanced rate constant of 4.35 × 10^-4 m s^-1 was achieved for Fe(CN)₆ ^4- oxidation, which approached the kinetic limit and is the highest reported in an electrochemical system. The electrooxidative performance of the reactive electrochemical filter system was evaluated with 50 mg L^-1 rhodamine B (RhB). The results showed that the reactive electrochemical filter system in flow-through mode resulted in an 8.6-fold enhancement in RhB oxidation as compared to those in flow-by mode under the same experimental conditions. A normalized rate constant of 5.76 × 10^-4 m s^-1 for RhB oxidation was observed at an anode potential of 3.04 V vs. SCE, which is much higher than that observed in a reactive electrochemical filter system with carbon nanotubes and/or Ti₄O₇ (1.7 × 10^-5-1.4 × 10^-4 m s^-1). The electrical energy per order degradation (EE/O) for RhB was as low as 0.28 kW h m^-3 in flow-through mode, with a relatively short residence time of 9.8 min. The overall mineralization current efficiency (MCE) was calculated to be 83.6% with ∼99% RhB removal and ∼51% TOC removal. These results illustrate that this reactive electrochemical filter system is expected to be a promising method for water treatment.