Experimental investigation of simultaneous hydrogen production and desalination via electrodialysis process

Abstract

The primary purpose of the electrodialysis (ED) process is to desalinate saline water; besides this, hydrogen, a valuable energy carrier gas, is generated at the cathode side of the ED cell in this study. However, hydrogen gas reacts with oxygen gas and reforms water due to the internal recirculation of the electrolyte solution from the anode to the cathode compartment. This study investigates the potential of hydrogen gas generation in an ED system that desalinates sodium sulfate (Na2SO4) solution. The maximum conductivity removal ratio is 98.1% when ion-exchange resins are placed into the diluate compartment at pH 8, and the ED system's hydrogen production rate is 76.8 mg H2/h·kg Na2SO4. The maximum hydrogen production rate is achieved as 118.8 mg H2/h·kg Na2SO4 solution under 14.06 mA/cm2 current density. The maximum energy and exergy efficiencies are calculated as 25.29% and 28.78%, respectively. The results indicate that the conventional ED process makes hydrogen production possible while desalinating saline water.