Cation-exchange fibers and silver nanoparticles-modified carbon electrodes for selective removal of hardness ions and simultaneous deactivation of microorganisms in capacitive deionization

Zhonghao Zhu; Can He; Jia Sha; Kaijun Xiao; Liang Zhu

doi:10.1016/j.scitotenv.2024.171318

Cation-exchange fibers and silver nanoparticles-modified carbon electrodes for selective removal of hardness ions and simultaneous deactivation of microorganisms in capacitive deionization

Sci Total Environ. 2024 May 1:923:171318. doi: 10.1016/j.scitotenv.2024.171318. Epub 2024 Feb 27.

Authors

Zhonghao Zhu¹, Can He¹, Jia Sha¹, Kaijun Xiao², Liang Zhu¹

Affiliations

¹ School of Food Science and Engineering, South China University of Technology, Guangzhou 510640, China.
² School of Food Science and Engineering, South China University of Technology, Guangzhou 510640, China. Electronic address: fekjxiao@scut.edu.cn.

PMID: 38423341
DOI: 10.1016/j.scitotenv.2024.171318

Abstract

The hardness and microorganism contamination are common problems of water quality around the world. Capacitive deionization (CDI) is a much-discussed solution to help solve the water crisis by providing efficient water softening while killing microorganism. Carboxylic (Na) cation-exchange fiber (CCEF) is an adsorbent material with good affinity for hardness ions. Silver nanoparticles (AgNPs) is a broad-spectrum microbicide. In this paper, the CCEF modified activated carbon (CCEF-AC) was used as cathode and showed excellent hardness ion adsorption selectivity at the optimum CCEF doping level (αCa²⁺/Na of 15.0, αMg²⁺/Na of 13.5). Its electrosorption capacity of Ca²⁺ reached 311 μmol/g, much higher than that of the AC cathode (188 μmol/g). It also showed good regenerable performance, retaining over 85 % of Ca²⁺ electrosorption capacity after 50 cycles stability test. The activated carbon modified with AgNPs (AC-Ag) was used as anode. When enhanced by an electric field, it could kill bacteria and microalgae with over 99 % and 90 % inhibition rates, respectively. This work has opened up a new way to simultaneously remove multiple pollutants (organic or inorganic) from water.

Keywords: Ion exchange fiber; Killing microorganism; Selective adsorption; Water softening.