The basic electrophysical and technological parameters of a CDI desalination plant designed for long-term operation, based on the principle of salt solution deionization on electrodes with a developed surface, have been studied. The proposed equipment for water demineralization uses a simplified design with pumping the solution through electrodes (“flow through electrodes”), which allows bypassing without relatively expensive ion-exchange membranes. Non-woven felt “Karbopon-V-Aktiv-200-65A” was used as the electrode material, the estimated value of the specific surface of the material of which, according to the results of measurements by the method with the deposition of acetone, amounted to ~ 1000 m2/g or more. Also, the advantages of the proposed CDI desalination plant are the absence of highly loaded power elements, the use of corrosion-resistant materials and the reliability of the electrode stacking scheme, which makes it possible to count on its long-term and reliable operation. Various possibilities of operational adjustment of the desalination plant modes are demonstrated – reduction of the discharge period due to the application of voltage pulses of reverse polarity, increasing efficiency by organizing a procedure for taking into account the real voltage at the working electrodes inside the CDI cell. The high-energy efficiency of demineralization is determined by the relatively low operating voltage of ~ 1 V. It is established that with increasing amperage, salt removal is more efficient, respectively, the degree of desalination is higher at a higher current: the working period of 30 minutes corresponds to the degree of desalination of ~ 20 % at a voltage of 1.4 V and ~ 30 % in the 1.6 V mode. The possibility of increasing the desalination capacity to ~ 100 g of salt over a half-hour period was noted. Possible ways to further improvement of the performance of the equipment presented in the article are identified.
Surface-treated carbon electrodes with modified potential of zero charge for capacitive deionization
