(513bn) A New Route for Enhanced Production of Humic Acids from Heavy Residual Feedstocks

The increased local and global demand for humic acids (HA) materials offers great opportunities to explore new alternate routes for high yield production of HA from naturally sourced materials to meet the needs for today and tomorrow. This is because HA has extensively used in various fields, like agriculture, concrete industry, medicine, and environment protection. As a kind of potential organic resource that was developed and utilized, humic acids are drawing more and more attention from the world. In this study, a new process for a high yield production of humic acids is introduced. The proposed process is focused on creating economic value from heavy feedstocks by converting them into value-added products, like humic acids, under subcritical water saturated with oxygen medium.

Different operating conditions have been investigated to maximize the yield and selectivity of humic acids, such as temperature, reaction time, type and dosage of alkaline solution. The results indicate that the optimal processing conditions can be achieved when using potassium hydroxide solution as the extraction agents, at a temperature of 50 ^oC, and the rate of humic acids production can reach to 94%. The isolated humic acids were characterized by FTIR, UV-vis spectrophotometer and elemental analysis. The produced humic acids were found to have functionalities of carboxylic, carbonyl, and phenolic compounds. The results also showed that the operating conditions for the extraction of humic acids have a significant effect on improving the product quantity without impacting its quality.