A novel CNTs/QCS/BiOBr composite membrane with electron-ion transfer channel for Br- recovery in ESIX process

Liang Zhang; Zhen Ma; Haidong Sun; Rongzi Zhang; Zilong Zhao; Jie Wang; Zhonglin Zhang; Zhong Liu; Jun Li; Xiao Du; Xiaogang Hao

doi:10.1016/j.jcis.2023.05.098

A novel CNTs/QCS/BiOBr composite membrane with electron-ion transfer channel for Br^- recovery in ESIX process

J Colloid Interface Sci. 2023 Sep 15:646:784-793. doi: 10.1016/j.jcis.2023.05.098. Epub 2023 May 19.

Authors

Liang Zhang¹, Zhen Ma², Haidong Sun², Rongzi Zhang², Zilong Zhao², Jie Wang¹, Zhonglin Zhang¹, Zhong Liu³, Jun Li³, Xiao Du⁴, Xiaogang Hao⁵

Affiliations

¹ College of Chemical Engineering and Technology, Taiyuan University of Technology, Taiyuan 030024, China.
² Academia Sinica, Qinghai Salt Lake Industry Group Company Limited, Geermu 816000, China.
³ Qinghai Institute of Salt Lakes Chinese Academy of Sciences, Xining 810008, China.
⁴ College of Chemical Engineering and Technology, Taiyuan University of Technology, Taiyuan 030024, China. Electronic address: duxiao@tyut.edu.cn.
⁵ College of Chemical Engineering and Technology, Taiyuan University of Technology, Taiyuan 030024, China. Electronic address: xghao@tyut.edu.cn.

PMID: 37229996
DOI: 10.1016/j.jcis.2023.05.098

Abstract

Based on the superior selectivity of bismuth oxybromide (BiOBr) for Br^-, the excellent electrical conductivity of carbon nanotubes (CNTs), and the ion exchange capacity of quaternized chitosan (QCS), a three-dimensional network composite membrane electrode CNTs/QCS/BiOBr was constructed, in which BiOBr served as the storage space for Br^-, CNTs provided the electron transfer pathway, and QCS cross-linked by glutaraldehyde (GA) was used for ion transfer. The CNTs/QCS/BiOBr composite membrane exhibits superior conductivity after the introduction of the polymer electrolyte, which is seven orders of magnitude higher than that of conventional ion-exchange membranes. Furthermore, the addition of the electroactive material BiOBr improved the adsorption capacity for Br^- by a factor of 2.7 in electrochemically switched ion exchange (ESIX) system. Meanwhile, the CNTs/QCS/BiOBr composite membrane displays excellent Br^- selectivity in mixed solutions of Br^-, Cl^-, SO₄^2- and NO₃^-. Therein, the covalent bond cross-linking within the CNTs/QCS/BiOBr composite membrane endows it great electrochemical stability. The synergistic adsorption mechanism of the CNTs/QCS/BiOBr composite membrane provides a new direction for achieving more efficient ion separation.

Keywords: Bromide ion; CNTs/QCS/BiOBr composite membrane; Electrochemically switched ion exchange; Electron-ion transfer; Synergistic effect.