ZnO site-occupying effect assisted regulation of nanoporous carbon network to enhance capacitive deionization for copper ions removal

• Published in: Desalination 2025-01, Vol.594, p.118264, Article 118264
• Main Authors: Zhao, Yang, Wang, Fei, Yan, Yufeng, Fang, Shuangfeng, Cai, Baihang, Huang, Jin, Gong, Xinru, Hu, Jian, Liu, Li, Hu, Hengyuan, Zhang, Yudan, Cai, Ziqi, Yan, Qing, Wang, Yong, Qiao, Liang, Yan, Minglei
• Format: Article
• Language: English
• Subjects: Capacitive deionization; Carbon network; Copper ions; Rice husk; Site-occupying effect
• ISSN: 0011-9164
• DOI: 10.1016/j.desal.2024.118264

Capacitive deionization (CDI) technology, based on the electric field ion capture mechanism, holds significant application prospects for purifying copper ions (Cu2+) from industrial wastewater. The development of electrode materials is crucial for enhancing capacitive Cu2+ removal. Herein, the three-dimensional nanoporous carbon network is prepared from agricultural waste rice husk using basic zinc carbonate as the pyrolytic activator. It is found that the ZnO site-occupying effect, stemming from the pyrolysis activator, exerts a pronounced regulatory influence on the porous structure of carbon network. The carbon electrode exhibits a satisfactory specific capacitance of 256.2 F g−1 at 0.5 A g−1. More importantly, the assembled symmetrical CDI cell demonstrates an excellent electrochemical adsorption capacity of 60.5 mg g−1 for Cu2+. Such exceptional capacitive deionization performance can be attributed to the synergistic effect of the electrochemical double-layer and electrochemical reduction during the adsorption process of Cu2+. Thus, this research offers a promising strategy for efficient wastewater treatment. [Display omitted] •ZnO site-occupying effect on pore formation has been thoroughly investigated.•The CDI cell presents a superb Cu2+ adsorption capacity of 60.5 mg g−1.•The electrochemical synergistic effect enhances the ability to purify Cu2+.