Parameter optimization based on capacitive deionization for highly efficient desalination of domestic wastewater biotreated effluent and the fouled electrode regeneration

Capacitive deionization (CDI) has gradually become an alternative desalination technique due to its many merits in comparison to conventional approaches. A novel optimized CDI device based on common carbon electrode has been developed successfully considering economics and efficiencies of CDI for the practical application. The optimized parameters of CDI have been obtained by adjusting the experimental conditions. The proposed results are 1.8V of applied potential, 2mm of plate distance and 15mL/min of flow rate. Besides, the adsorption process was in accordance with Lagergren equation and Langmuir isothermal equation. Moreover, the carbon electrode exhibited the excellent regeneration performance by desalting the domestic wastewater biotreated effluent, which would permit the recycling of CDI device. It is notable that some dissolved organic matters (DOMs) existing in waste water, such as humic acid, would decrease its desalination and regeneration performances. Fortunately, the generation and mechanism of electrode pollution were analyzed by advanced detecting instruments, such as three-dimensional fluorescence and Gel Permeation Chromatograph. During the treating process of regeneration, we found that the fouled carbon electrodes could be cleaned up by alkali washing instead of water or acid. The results provided in this paper would guide the practical application of CDI effectively. [Display omitted] •Finding the main reason of fouled electrode by analyzing the wash solution•Proposition and comparison of two kinds of wash method effect on the fouled electrode•Developing a CDI device based on common carbon electrode for desalination•Research treating domestic wastewater biotreated effluent by CDI