J. Mater. Sci. Technol. ›› 2023, Vol. 148: 10-18.DOI: 10.1016/j.jmst.2022.11.016

• Research article • Previous Articles     Next Articles

Efficient removal and recovery of Cd2+ from aqueous solutions by capacitive deionization (CDI) method using biochars

Zhao Songa, Lingyu Lia, Yidi Chena,*, Xiaoguang Duanb,*, Nanqi Rena   

  1. aState Key Laboratory of Urban Water Resource and Environment, Shenzhen Key Laboratory of Organic Pollution Prevention and Control, School of Civil and Environmental Engineering, Harbin Institute of Technology (Shenzhen), Shenzhen 518055, China;
    bSchool of Chemical Engineering and Advanced Materials, The University of Adelaide, Adelaide, SA 5005, Australia
  • Received:2022-07-30 Revised:2022-11-07 Accepted:2022-11-08 Published:2023-06-10 Online:2023-06-05
  • Contact: *E-mail addresses:. chenyidi@hit.edu.cn (Y. Chen), xiaoguang.duan@adelaide.edu.au (X. Duan)

Abstract: Biochars are low-cost and sustainable materials for environmental technologies. In this work, we prepared three biochars using pomelo peel (P-BC), algae (A-BC), and corncob (C-BC) to recover Cd2+ from wastewater via capacitive deionisation (CDI). A-BC possesses the highest amount of mesopores and nitrogen functionality and attains the highest removal of Cd2+ via physical adsorption. For the electro-sorption capacity, C-BC and A-BC perform better capacitive removal of Cd2+ than P-BC due to the smaller charge-transfer and mass-transfer resistances. Also, this work investigated the impacts of surface morphology, cell voltage, NaCl, initial pH, and Cd2+ concentrations on Cd2+ capacitive removal and electrode regeneration performances. The results indicated that A-BC and C-BC may be prospective materials for Cd2+ removal from wastewater by CDI. However, the presence of competing cations at high concentrations may influence the removal of Cd2+ at a low level, requiring the modification of A-BC and C-BC in future work.

Key words: Biochar, Cd removal, Capacitive deionisation, Heavy metals, Selectivity