Utilization of sub and supercritical water reactions in resource recovery of biomass wastes

Abstract

Recently, the utilization of sub and supercritical water has been proposed to recover waste substances from biomass. This is important not only for prevention of environmental issues, but also for rational utilization of natural resources. Sub and supercritical water treatment is one of the most effective methods for this, because water at high temperature and high pressure behaves as a reaction medium with remarkable properties. This sub and supercritical water treatment process can promote various reactions such as oxidation, hydrolysis, and dehydration. Therefore, sub and supercritical water can be used for the conversion of organic wastes to useful chemical compounds, as well as for oxidizing hazardous waste into CO2 or harmless compounds. This paper presents the concepts of sub and supercritical water and their application in organic waste recycling at temperatures of 423 - 673 K for substances such as lignin and its derived compounds.