TY - JOUR
T1 - Conversion of carbohydrates to carboxylic acids during hydrothermal and oxidative treatment of concentrated kraft black liquor
AU - Maitz, Silvia
AU - Siebenhofer, Matthäus
AU - Kienberger, Marlene
N1 - Funding Information:
The authors wish to give their thanks to Julian Christian and Patrick Harrer for their valuable assistance in the experimental work. Funding: The collaboration and financial support of the KrAcid project (grant number 867068 ) consortium as well as the FFG Austria are gratefully acknowledged.
Publisher Copyright:
© 2022
PY - 2022/9
Y1 - 2022/9
N2 - Black liquor, a side stream of the kraft pulping process, contains valuable low molecular weight carboxylic acids and carbohydrates. Hydrothermal treatment and wet oxidation of black liquor with a dry matter content of 43 % were investigated as an approach to convert these carbohydrates to carboxylic acids to increase their concentration. Wet oxidation with H2O2 or O2 at 115–185 °C led to partial degradation of carbohydrates, but no significant formation of the investigated carboxylic acids, glycolic, lactic, formic and acetic acid, was detected. Treatment under N2 atmosphere at 185 and 220 °C finally led to an increase of the hydroxy acid concentration. After two hours of heat treatment at 220 °C, 90 % of the carbohydrates were degraded, coupled with a high carbon conversion efficiency of 32 % based on the formation of lactic acid and glycolic acid, of which the concentrations increased by 51 and 73 %, respectively.
AB - Black liquor, a side stream of the kraft pulping process, contains valuable low molecular weight carboxylic acids and carbohydrates. Hydrothermal treatment and wet oxidation of black liquor with a dry matter content of 43 % were investigated as an approach to convert these carbohydrates to carboxylic acids to increase their concentration. Wet oxidation with H2O2 or O2 at 115–185 °C led to partial degradation of carbohydrates, but no significant formation of the investigated carboxylic acids, glycolic, lactic, formic and acetic acid, was detected. Treatment under N2 atmosphere at 185 and 220 °C finally led to an increase of the hydroxy acid concentration. After two hours of heat treatment at 220 °C, 90 % of the carbohydrates were degraded, coupled with a high carbon conversion efficiency of 32 % based on the formation of lactic acid and glycolic acid, of which the concentrations increased by 51 and 73 %, respectively.
KW - Biorefinery
KW - Black liquor
KW - Carboxylic acids
KW - Hemicellulose degradation
UR - http://www.scopus.com/inward/record.url?scp=85136595739&partnerID=8YFLogxK
U2 - 10.1016/j.biteb.2022.101148
DO - 10.1016/j.biteb.2022.101148
M3 - Article
AN - SCOPUS:85136595739
SN - 2589-014X
VL - 19
JO - Bioresource Technology Reports
JF - Bioresource Technology Reports
M1 - 101148
ER -
