Synthesis of improved hydrochar by microwave hydrothermal carbonization of green waste

Abstract Green waste (GW), a typical biomass waste, was used to produce hydrochar using microwave hydrothermal carbonization (MHTC). The results indicate that MHTC promotes the dehydration of GW to a greater extent than traditional oven or oil bath heating under the same hydrothermal conditions. The hydrochar obtained from the MHTC process showed an energy densification factor of 1.27 and a fuel ratio of 0.19, both of which exceeded those produced by traditional hydrothermal processes. Thermogravimetric data also demonstrated that hydrochar obtained using MHTC had better incineration properties. Moreover, the material possessed a high specific surface area and a more porous structure, resulting in improved adsorption properties. The result of value and potential evaluation demonstrated that the MHTC process also displays the lower energy consumption of operation. Hydrochar generated from GW is a potential environmentally friendly functional material, and MHTC appears to be a suitable means of producing this substance.