Visible-light-assisted ionic liquid system for fractionating corn stalk at low temperature

Photothermal pretreatment of corn stalk at low temperature was developed. • 84.68% cellulose retention and 83.03% lignin removal were achieved at 80 ℃, 4 h. • Photothermal synergistic strategy enhanced the separation of cellulose and lignin in corn stalk pretreatment. Efficient fractionation of lignocellulosic components is essential for sustainable biomass valorization. Herein, a visible-light-assisted ionic liquid (IL) composite system composed of 30% 2-hydroxy-N-(2-hydroxyethyl)- N -methylethanaminium methanesulfonate ([BHEM]mesy) and 70% ethylene glycol, containing 0.1 wt% photocatalyst g-C 3 N 4 , was developed to achieve low temperature photothermal fractionation of corn stalk. The IL provides protonic sites and hydrogen-bonding capability for lignin solubilization, while the dispersed photocatalyst absorbs light energy to accelerate mass transfer and enhance solvation selectivity between lignin and cellulose. Under the optimized conditions (80 ℃, 4 h), 83.03% of lignin is removed while 84.68% of cellulose is retained. The regenerated lignin exhibits reduced molecular weight, while the purified cellulose phase enables aerogel fabrication. Compared to conventional hydrothermal pretreatment, visible-light coupling enhances the pretreatment process. Reduces the reaction temperature and maintains cellulose crystallinity, confirming its superior pretreatment efficiency. This study establishes an integrated photothermal biomass fractionation strategy that offers a novel and highly efficient method for biomass utilization. Download: Download high-res image (124KB) Download: Download full-size image