Dielectric Barrier Plasma Discharge Assisted Electrolysis for Sustainable Hydrogen Production from Desalination Reject

Abstract

The technology for producing hydrogen from water through the direct dissociation of water molecules using microwave dielectric barrier plasma discharge in an electrolytic solution using at different pressures has been studied and found to be a viable process for hydrogen generation. In general, higher electron temperature raises the fraction of high energy electrons above 5 eV  (where 5 eV is the bonding energy between hydrogen and oxygen). It is difficult for water to be split (direct dissociation) by an atmospheric pressure thermal plasma since a high electron collision rate above a pressure of 10–50 Torr causes a very strong decrease in electron temperature due to radiative cooling, which is photon loss from the excited atoms and molecules produced by collisions with high energy electrons. Therefore to better understand the process a simulation study using MATLAB and COMSOL was conducted and validated at the lab scale.  microwave dielectric barrier plasma discharge assisted hydrolysis of desalinated seawater (200 mg/l) to desalination reject (70 g/l) were tried with different electrolysis voltages from 6 V to 20 V at atmospheric pressure. The results indicated that hydrogen production is directly proportional to the electrolysis voltage and total dissolved solids in the electrolytic solution. Transmutation of the atomic nuclei of alkaline metals and the atomic nuclei of the cathode material increases the content of gases in the gas-vapor mixture and additional thermal energy is generated from the destroyed molecules of water in plasma. Desalination reject is an ideal substrate for microwave plasma-assisted hydrogen production.