Enhanced nitrate removal from groundwater using a conductive spacer in flow-electrode capacitive deionization  

作　　者：Hongjie Guo Qiang Wei Yangyang Wu Wei Qiu Hongliang Li Changyong Zhang 

机构地区：[1]College of Mining Engineering,Taiyuan University of Technology,Taiyuan 030024,China [2]CAS Key Laboratory of Urban Pollutant Conversion,Department of Environmental Science and Engineering,University of Science and Technology of China,Hefei 230026,China [3]CAS Key Laboratory of Mechanical Behavior and Design of Materials,Department of Modern Mechanics,University of Science and Technology of China,Hefei 230026,China

出　　处：《Chinese Chemical Letters》2024年第8期379-382,共4页中国化学快报（英文版）

基　　金：supported by Shanxi Province Basic Research Program(Free Exploration Category)(No.202203021221041);National Natural Science Foundation of China(No.52300016);China Postdoctoral Science Foundation(No.2023M733379);Students Innovation and Entrepreneurship Foundation of USTC(No.CY2022G12).

摘　　要：Flow-electrode capacitive deionization(FCDI)represents a promising approach for ion separation from aqueous solutions.However,the optimization of spacer,particularly for nitrate-contaminated groundwa-ter systems,has often been overlooked.This research comprehensively investigates the influence of using a conductive(carbon cloth,CC)spacer on nitrate removal performance within FCDI system,comparing it to a non-conductive(nylon net,NN)spacer.In both CC and NN FCDI systems,it is unsurprisingly that nitrate removal efficiency improved notably with the increasing current density and hydraulic retention time(HRT).Interestingly,the specific energy consumption(SEC)for nitrate removal did not show obvious fluctuations when the current density and HRT varied in both systems.Under the auspiciously optimized process parameters,CC-FCDI attained a 20%superior nitrate removal efficiency relative to NN-FCDI,ac-companied by a notably diminished SEC for CC-FCDI,registering at a mere 28%of NN-FCDI.This great improvement can be primarily attributed to the decrement in FCDI internal resistance after using con-ductive spacer,which further confirmed by electrochemical tests such as linear sweep voltammetry(LSV)and electrochemical impedance spectroscopy(EIS).Upon prolonged continuous nitrate removal at the optimized conditions,the CC-FCDI system achieved a consistent 90%nitrate removal efficiency with a low SEC of 2.7-7.8 kWh/kg NO_(3)-N,underscoring its steady performance.Overall,this study highlights the pivotal importance of careful spacer design and optimization in realizing energy-efficient groundwater treatment via FCDI.

关 键 词：Flow-electrode capacitive deionization Carbon cloth NITRATE Underground water Ions transport 

分 类 号：TQ028[化学工程] X523[环境科学与工程—环境工程]