Efficient and Cost Effective Way for the Conversion of Potassium Nitrate from Potassium Chloride Using Electrodialysis

A metathesis electrodialysis (MED) system for the conversion of potassium nitrate from potassium chloride is developed. The experiments are carried out in recirculation mode using a four compartment electro-conversion unit of 200 cm2 effective membrane area with 10 cell pairs. The cation exchange membrane and anion exchange membrane used for the present study are converted from a styrene divinylbenzene based interpolymer film by sulfonation and chloromethylation followed by amination, respectively. Membranes are characterized by means of chemical, mechanical, and thermal properties. Membranes show excellent electrochemical properties with adequate thermal and mechanical stability. About 97% conversion of potassium nitrate is achieved during the sets of experiments with high product purity (99%). Four different applied potentials (1.5, 2, 2.5, and 3 V/cell pair) are used during different sets of experiments in metathesis electrodialysis, out of which 2 V/cell pair is found to be more efficient potential with lower energy consumption of 0.82 kwh·kg–1 for the production of potassium nitrate with 83% current efficiency.