Enhancement of electrocatalytic activity for micropollutant removal by CeO2@CNT-based membranes: The influences of the structure and morphology of CeO2

• Published in: Journal of cleaner production Vol. 425; p. 139005
• Main Authors: Chu, Yongbao, Ma, Qingfeng, Hou, Xuan, Zhang, Yunxin, Zhang, Jingyi, Ni, Xiaoyu, Wang, Yan
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01.11.2023
• Subjects: Cerium oxide; Electrified membrane; Micropollutant; Transformation of ROS; Micropollutant; Cerium oxide; Electrified membrane; Transformation of ROS
• ISSN: 0959-6526; 1879-1786
• DOI: 10.1016/j.jclepro.2023.139005

It is important to develop novel electrocatalytic membranes for efficiently remove micropollutants from water and wastewater. In this study, two CeO2 samples (denoted as CeO2-N and CeO2-O, respectively) were synthesized to modify the carbon nanotube (CNT)-based membrane. CeO2-N exhibited a higher proportion of Oad and Olat to the formation of Ov. In contrast, CeO2-O possessed a cubic cerianite structure with less Ov. As a result, the CeO2-N@CNT-based membrane displayed a smaller equivalent polarization resistance of 5.6 Ω/cm2 and lower potential differences of 0.19 V compared to the CeO2-O@CNT-based membrane, which had an equivalent polarization resistance of 6.9 Ω/cm2 and potential differences of 0.51V. Consequently, the CeO2-N@CNT-based membrane demonstrated superior performance in diclofenac (DCF) removal compared to the CeO2-O@CNT-based membrane. Due to its planes with lower apparent activation energy and higher single electron transfer rate, the CeO2-N@CNT-based membrane generated a greater amount of 1O2. Conversely, the CeO2-O@CNT-based membrane generated more ·OH. Therefore, DCF mainly underwent degradation via C-N bond cleavage and decarboxylation through direct attack of 1O2 for the CeO2-N@CNT-based membrane, while ·OH played a significant role in removing DCF via hydrogen loss, chlorine loss and C-N cleavage for the CeO2-O@CNT-based membrane. [Display omitted] •The structure and morphology of CeO2 determine ROS species generated by CeO2@CNT-based membrane.•CeO2-N@CNT-based membrane generated a greater amount of 1O2.•CeO2-O@CNT-based membrane showed a preference for generating ·OH.•DCF was removed mainly by 1O2 for CeO2-N@CNT membrane.•CeO2-O@CNT membrane removed DCF mainly through ·OH.