Enhanced Desalination Performance of Battery Electrode Deionization Based on the Optimized Design of Flow Channel Structure and Channel Section Reconstruction

Abstract

Battery electrode deionization is an emerging technology for water desalination that cuts down on energy costs when desalinating different water streams. It uses electrochemical reactions under the action of an electric field to achieve salt removal. The removal of salt from water is achieved through an electrochemical reaction between ions and active compounds in this process. Traditional desalination cells typically employ a flat flow channel structure, which unfortunately results in a significant dead zone of flow. This paper proposes a new optimized design of a leaf-shaped flow field (FF). The development of a three-dimensional numerical model of the capacitive deionization and investigation of mass transfer behavior and cell performance for different channel cross sections is carried out. A uniformity factor has been introduced to describe the uniformity of Na + ion concentration distribution and the desalination performance of the system is evaluated by salt adsorption capacity, average salt adsorption rate, and volumetric energy consumption (E d ). The results show that the FF design scheme can effectively reduce the dead zones in the flow channel, resulting in a more uniform and full utilization of the electrodes. The mass transfer behavior and cell performance of porous electrodes are affected by the channel cross-section. The use of a semicircular channel cross-section is the optimal design form. In addition, decreasing the charging current density and increasing the inlet flow rate can optimize the uniformity of the ion distribution in the flow channel and the uniform utilization of the electrodes, and reduce the volumetric energy consumption.