Development of a hybrid reaction module linked to liquid-phase plasma and electrolysis for hydrogen production with wastewater decomposition

The development of a hybrid reaction system linking photochemical decomposition with liquid-phase plasma and photocatalyst and electrolysis in a consecutive reaction was attempted for efficient decomposition and hydrogen production from high-concentration ethanolamine-resistant wastewater. A consecutive process was developed in which ethanolamine wastewater was decomposed completely by an electrolysis process after first reducing the concentration of ethanolamine by a decomposition reaction through liquid phase plasma and photocatalyst in the first step. The chemical oxygen demand (COD) and total nitrogen removal performance of wastewater containing ethanolamine were also investigated using the consecutive process. The COD and nitrogen removal efficiency were higher in the photochemical reaction by liquid plasma and bismuth ferrite photocatalyst than by electrolysis in a single reaction. In the hybrid reaction linking the two reactions, the COD and total nitrogen were removed entirely. The hydrogen production rates obtained from the photochemical reaction by liquid plasma and bismuth ferrite photocatalyst were higher than the respective hydrogen production rates obtained by a single electrolysis reaction. The hydrogen production rate obtained from the hybrid reaction system was increased significantly. Hydrogen produced by a photocatalytic reaction using liquid plasma and hydrogen produced by electrolysis could increase the overall hydrogen production rate.