Electrochemical reduction of nitrate using divided electrolytic cell by proton exchange membrane

Abstract

The electrochemical reduction of nitrate using a divided electrolytic cell in combination with Zn cathode and (Pt)/Ti anode reduced the high concentrations of nitrate (1,000 mg NO3-N/L). A proton exchange membrane (Nafion-117) was used to increase the nitrate reduction efficiency by preventing the re-oxidation of nitrite produced during the reduction process. The current density and anolyte concentration, considered as parameters, were tested to assess the electrochemical reduction of nitrate. The reduction of nitrate shortened the electrolysis time in proportion to the current density, and the time for 90% removal was 5 h at 5 mA/cm2, 3 h at 10 mA/cm2, and 1.8 h at 20 mA/cm2. The yields of ammonia were approximately 50%-55% of the initial nitrate-nitrogen concentration regardless of the current density and was insignificantly related to the anolyte concentration.