LAUSR

Abstract Frequency spectra of electrochemical impedance and current-overvoltage characteristics of an MB-2m bipolar membrane containing ion-polymer with catalytically active phosphoric acid groups in water dissociation reaction, and industrial MB-1, MB-2, and MB-3 bipolar membranes were studied in a system containing nitric acid and sodium hydroxide solutions. It is shown that the electrical resistance and overvoltage of bipolar region in the modified MB-2m and industrial MB-3 membranes are close and significantly lower than in industrial MB-1 and MB-2membranes. The effective rate constants of catalytic reaction of water dissociation are determined in the studied membranes. The process of producing nitric acid and sodium hydroxide from sodium nitrate with the modified MB-2m bipolar membrane and industrial MB-1 and MB-3 bipolar membranes was studied. It is shown that the use of the MB-2m bipolar membrane allows producing nitric acid and sodium hydroxide with higher concentrations, current efficiencies, specific productivity, lower specific energy consumption, and degree of sodium nitrate contamination than in the case when using industrial MB-1 and MB-3 membranes.