Hydrogen production from sewage sludge solubilized in hot-compressed water using photocatalyst under light irradiation

Photocatalytic hydrogen production from a digested sewage sludge solubilized in hot-compressed water (573K) was investigated in order to develop a low-cost sacrifice agent for CdS-based photocatalysts from biomass. H2 evolution occurred over a LaMnO3/CdS composite photocatalyst under Xe lamp irradiation from water containing the solubilized sewage sludge and the amount of evolved H2 reached more than 30 mmol/g-catalyst for a 200 h-reaction; on the other hand, no H2 was formed in the absence of the solubilized sewage sludge. The H2 evolution rate was comparable to that when typical Na2S–Na2SO3 sacrifice agents were used, suggesting the applicability of a biomass-derived sacrifice agent for photocatalysis. Organic compounds, such as methanol and formic acid, contained in the solubilized sewage sludge are responsible for the H2 evolution observed.