Study on the reaction mechanism of the potassium bicarbonate alkali activation process in black liquor
Jeong Han Lee, Young‐Lok Cha, Yong‐Mook Kang, Kwang Chul Roh
Abstract
The alkaline hydrothermal separation of cellulose is a crucial step in biofuel generation, wherein black liquor containing lignin and alkali is produced as a by-product. This study explored the reaction mechanism of the residual alkali during the activation process. In this reaction, the impregnated K reagent exhibited unusual behavior owing to its bonding with the lignin structure, which was confirmed by the K 2p peak shift in x-ray photoelectron spectra. This behavior resulted in the formation of a microporous and mesoporous substance with a high surface area of 2146 m2 g−1 without requiring additional chemical reagents. Furthermore, the activated carbon derived from black liquor possessed outstanding properties, allowing its use in supercapacitors. This study demonstrates that giant miscanthus-derived black liquor can be used as an activated carbon precursor for application in electric double-layer capacitors owing to its superior electrochemical capabilities.