Towards furfural and biomass char production from Camellia oleifera husks using dilute hydrochloric acid pretreatment: a comprehensive investigation on adsorption performance

Abstract

This study aimed to revolutionize the conventional lignocellulose refinery approach by capitalizing on the unique composition of Camellia oleifera husks, renowned for a high hemicellulose content compared to cellulose and lignin. The complete removal of hemicellulose was successfully achieved using dilute hydrochloric acid (HA) under optimized conditions (130 °C, 500 rpm, 40% solids, and 1 h). The resulting xylose solution, derived from the hemicellulose, served as a valuable resource for furfural production. Remarkably, S-8 macroporous resin exhibited exceptional adsorption properties for furfural, with an impressive maximum adsorption capacity of 335.68 mg g⁻¹, adhering to the Langmuir model; furthermore, the residual husk material was converted into biomass char (BC), which underwent characterization using FTIR, SEM, and BET techniques. The BC displayed remarkable adsorption capabilities for methylene blue dye, with a maximum theoretical adsorption capacity of 250.63 mg g⁻¹. Notably, the dilute HA solution and S-8 macroporous resin could be successfully recycled up to five cycles, as the furfural yields consistently exceeded 70%, and the S-8 resin fully regained its initial adsorption capacity after the regeneration process. Mass balance analysis showed that 100 g of C. oleifera husks had the potential to yield 11.3 g of furfural and 35.7 g of BC. These findings unlock promising avenues for sustainable biomass valorization, representing a significant step forward in utilizing C. oleifera husks efficiently.