An experimental study on integrated power-free shock electrodialysis for desalination

Abstract

The removal of TDS and other solids from the saltwater was experimentally investigated by using shock electrodialysis by supplying a direct current (DC). Shock electrodialysis (SED) is a newly developed technique for water desalination. In the case of saltwater, the effect of reaction time or electrolysis time, EC, and current density were examined. The TDS which contributed to the EC in the aqueous phase was removed by silica gel which acts as microporous voids under the application of voltage through an aluminum electrode. The initial characteristics of saltwater such as pH, electrical conductivity, TDS, turbidity, and salinity were examined. The removal of dissolved solids in the aqueous phase was done by using aluminum electrodes. The performance of the process evaluated in terms of total solids, electrical conductivity, salinity reduction, and power consumption was also monitored. The results show that around 68.72% of TDS removal took place at a maximum removal condition of 20 V and at a reaction time of 5 min. Electrical conductivity was reduced from 55 to 18.19 mS/cm. An optimum voltage was found to be 13.64 V at a reaction time 15.40 min. Electrical conductivity was reduced to 26.9 mS/cm from 55 mS/cm, TDS was reduced to 16,490 mg/L from 33,550 mg/L, and power consumption was 14.90 W. Brine water was rejected having an electrical conductivity of 73.66 mS/cm and the power generated was 14.67 mW from 924 cm2 of electrode area for an optimized reaction time of 20 min.