Hydrothermal processing of arsenic containing bioremediation biomass: Pteris vittata

Hyperaccumulator biomass harvested after heavy-metal phytoremediation must be considered as hazardous waste that should be contained or treated appropriately before disposal or reuse. As a potential method to detoxify the biomass and to convert this material to a suitable bio-energy resource, the hydrothermal upgrading process was applied to remove heavy metals and upgrading crude bio-oil from Pteris vittata stems and leaves harvest. By using univariate experiment method, parameters such as material granularity, temperature, liquid/solid (L/S, mL/g), pressure, duration and catalysts were examined for their effect on the removal efficiency of heavy metals and upgrading efficiency of crude bio-oil. A heavy metals removal efficiency of >99% and crude bio-oil upgrading efficiency of 83% were attained with a 200 mesh (75 α/4m) granularity, L/S 40:1 and 23 MPa at 380 °C in the presence of 0.1 mol/L K2CO3 for 30 min. GC
• MS analysis results show that the resulting bio-oil mainly consists of benzene 11%, ketone 42%, alcohols 14%, alkene 15% and ester 11%, etc., and the relative molecular weight distribution lies in 94
• 282, carbon number distribution lies in 6
• 18, calorific value is 32 MJ/kg.