Catalytic transformation of cellulose into short rod-like cellulose nanofibers and platform chemicals over lignin-based solid acid

Robust environmental regulations are driving the chemical industries to develop low-cost, eco-friendly, and efficient solid acid catalysts for catalytic transformation of cellulose into high-value products. In our work, lignin separated from enzymatic hydrolyzed residues was used as the carbon source to synthesize lignin-based solid acid (LC-SO3H) via facile carbonization-sulfonation process. Cellulose nanofibers (CNFs) and platform chemicals (mainly glucose and formic acid) were efficiently transformed from cellulose through LC-SO3H catalytic hydrolysis pretreatment combined with microfluidization. Short rod-like CNFs were obtained with large crystallinity index of 82 % and small aspect ratio of 10-28. Furthermore, LC-SO3H can be recycled and reused. After five successive cycles, the yield of CNFs, glucose, and formic acid reached up to 90.8 %, 3.9 %, and 2.1 %, respectively. This work provides a novel, low-cost, and environmental benign approach to prepare CNFs and platform chemicals, and it holds great potential for green and sustainable production of high value-added biomass products.