Preparation of High-Strength Sustainable Lignocellulose Gels and Their Applications for Antiultraviolet Weathering and Dye Removal

The synthesis of functional lignocellulose-based gels from sustainable biomass has received considerable attention in material chemistry. In this study, robust, porous, and lignin-containing lignocellulose hydrogels were prepared based on the sol–gel process. The lignin-containing lignocellulose materials were dissolved (or dispersed) in N-methylmorpholine-N-oxide (NMMO) and cross-linked with a silane coupling agent 3-aminopropyltriethoxysilane (APTES), followed by coagulation and solvent exchange to form gel structures. The formation of Si–O–C cross-links among the lignocellulosic fibrils as a result of the addition of APTES was mainly responsible for the strength improvement. Furthermore, the presence of lignin also contributed to the enhancement of strength properties. The as-prepared lignocellulose gels were further characterized using rheological and compression tests. The dynamic storage modulus of APTES-reinforced lignocellulose gel (LCGA) can reach up to 1391 kPa and the compressive modulus up to 96 kPa, which shows a 3-fold increase in viscoelastic properties and a 2-fold increase in compressive strength compared with unmodified gel. In addition, the obtained LCGA gel exhibits unique properties, such as antiultraviolet weathering and dye removal via adsorption, and their potential applications were explored.