Coupling the solvent-based CO2 capture processes to the metal water-splitting for hydrogen generation in a semi-continuous system

Abstract

Hydrogen is considered as the future energy vector. Due to scarceness in materials, obtaining hydrogen from common metals and metallic residues is gaining interest. The present work aims at coupling for the first time solvent-based CO2 capture processes with the hydrogen generation from the metal-water splitting reaction, using common elements such as Al, Zn, Mn and Fe. To do so, a novel semicontinuous facility is developed. In the process, both the CO2-Rich stream (CO2RS) and CO2 Capture-Solvent Lean stream (CO2LS) are considered. The production of H2 increased in the order Al < Mn < Fe < Zn. For pure Al, aqueous NaOH (CO2LS) showed the highest H2 yield, up to 85.5%, while Al chips (residue) showed outstanding performance. The experimental study showed that small particle sizes improve the H2 yield. This technology represents an opportunity for bringing about value-added to CO2 capture by generating at the same time green hydrogen.