Numerical Analysis of Capacitive Deionization Process Using Activated Carbon Electrodes

• Published in: Water, air, and soil pollution air, and soil pollution, 2021-09, Vol.232 (9), Article 364
• Main Authors: Xiaobing, Wang, Jinqiu, Liu, Yang, Liu, Sen, Li, Dong, Li, Tingting, Ma, An, Jin, Yanshe, Hu, Fengwei, Guan
• Format: Article
• Language: English
• Subjects: Activated carbon; Adsorption; Analysis; Aquatic resources; Atmospheric Protection/Air Quality Control/Air Pollution; Carbon; Cathodes; Climate Change/Climate Change Impacts; Computational fluid dynamics; Convection; Deionization; Desalination; Earth and Environmental Science; Electrodes; Environment; Environmental monitoring; Finite element method; Flow rates; Flow theory; Flow velocity; Hydrogeology; Ion concentration; Ions; Liquid flow; Mass transfer; Mathematical models; Mine drainage; Mine water; Mine waters; Numerical analysis; Oil and gas fields; Oil fields; Porous media; River water; Rivers; Saline water conversion; Salinity; Saturation; Sodium chloride; Soil Science & Conservation; Water desalting; Water Quality/Water Pollution
• ISSN: 0049-6979; 1573-2932
• DOI: 10.1007/s11270-021-05320-y

The discharge of untreated high-salinity mine water will cause harm to the environment, such as the increase of salt content in river water. Capacitive deionization technology has the advantages of low cost, high efficiency, and no pollution . It is an effective means to treat highly mineralized water in the oil field. This paper establishes a simplified mathematical model based on the Nernst Planck equation, combined with porous media flow theory and Langmuir isotherm theory. The capacitive deionization process of NaCl solution by finite element method is simulated. The results show that the convection mass transfer effect of ions in the activated carbon electrodes is weak. When the initial solution ion concentration is equal, the activated carbon cathode can absorb more Cl − . In the solution with an initial concentration of 1.7 mol/m 3 , when the electrode adsorption reaches saturation, the concentration of Cl − is 0.1 mm lower than that of Na + . In the capacitive deionization process using activated carbon electrodes, the desalting efficiency of ions is almost proportional to the voltage and inversely proportional to the liquid flow rate. In a relatively low concentration solution, the desalination effect of using activated carbon as electrodes is better.