Delignification of Wheat Straw Using DES-like Mixtures

Abstract

Wheat straw, an agricultural residue, is emerging as a viable alternative to wood biomass alongside other annual plants. The exploration of novel methods, particularly those involving ecofriendly solvents, is at the forefront of harnessing the potential of these annual crops. This study focuses on the delignification of wheat straw using DES-like mixtures composed of choline chloride and lactic acid in a molar ratio of 1:5. We closely monitored three critical factors influencing delignification: temperature, time, and the ratio of biomass to the DES-like mixtures. Temperature ranged from 80 to 160 °C, time varied from 60 to 240 min, and the ratio spanned from 1:10 to 1:60. The percentage of lignin remaining in the samples after delignification varied between 16.13% and 35.49%, while the cellulose content fell within the range of 43.77% to 69.53%. To pinpoint optimal conditions for delignification, we performed calculations. The ideal lignin content of 16.44% was achieved at a temperature of 111 °C, a duration of 60 min, and a biomass-to-solvent ratio of 1:27. For maximum delignification efficiency, reaching 37.32%, the optimal conditions were determined as a temperature of 120 °C, a duration of 150 min, and a ratio of 1:34.