Photo-catalytic reforming of aqueous phase derived from hydrothermal liquefaction of Nostoc ellipsosporum for bio-hydrogen production

In this study, green fuel (hydrogen energy) was produced from the aqueous phase obtained from the hydrothermally liquefied Nostoc ellipsosporum biomass via photo-catalytic reforming. Initially, algae were cultivated in municipal wastewater and fog medium (80:20) in photo bio-reactor for biomass production. Later the algae biomass was liquefied under varying temperature of 220 degrees C to 320 degrees C at 5Mpa for 60 min. From the results, it was seen that the maximum bio-oil yield was 31 wt% for biomass to solvent ratio of 0.05 g/mL at 300 degrees C. Gas Chromatography-Mass Spectroscopy (GC-MS) analysis of bio-oil showed the presence of hydrocarbons like octadecane, heptadecane, etc. Aqueous phase comprised of hydrogen generating low molecular weight compounds. Photo-catalytic reforming process with 0.1 g of TiO2 catalyst at time of 2 h resulted in hydrogen yield of 27 wt%. Catalyst reusability study resulted in cumulative hydrogen yield of 76 wt% from five consecutive cycles.