Reverse Electrodialysis For Perchlorate Abatement In Salt Water

Perchlorate (ClO4-) is a toxic anion that inhibits iodine uptake by the thyroid gland and subsequently disrupts thyroid hormone production. In this study, the feasibility of using reverse electrodialysis (RED) was examined for the treatment of perchlorate in salt (5% NaCl; w/v) water. RED uses direct electricity, produced by salinity gradients in a membrane stack, to drive the electrochemical treatment of wastewater. Operational conditions such as salinity gradient (S.G.), number of membrane pairs, and stack solution flowrates were varied and their effects on electricity generation and perchlorate reduction were investigated. Experimental batch results showed that a higher number of membrane pairs and salinity gradient gave higher values of power density, which also resulted in higher abatement of perchlorate. In contrast, the reduction of perchlorate was lowered upon increasing the stack solution flowrate. The maximum abatement of perchlorate (38.76%) was achieved using 15 pairs of cation and anion exchange membranes and 5 M/0.005 M salinity ratio (S.G. 1,000) of high and low concentrated NaCl solutions at 1.5 mL/min stack solution flowrate. This study successfully demonstrated that RED can be a sustainable alternative method for the abatement of perchlorate in salt waters.