Preparation of high-performance adsorption carbon materials via hydrothermal carbonization of agricultural solid waste-grapevines

This study uses grapevine agricultural waste to prepare grapevine-derived biobased activated carbon (AGV) through chemical activation with NaOH after hydrothermal carbonization. A comprehensive analysis of the adsorption performance and mechanisms of AGV for methylene blue (MB) was conducted. The results demonstrated that AGV possesses a highly developed reticular pore structure, with a specific surface area of 3230.57 m² g⁻¹ and is rich in oxygen functional groups (OFGs). At pH 7.0, AGV achieved a removal rate of 90 % within 30 min, with a maximum adsorption capacity of 661.7 mg g⁻¹, surpassing that of most previously reported activated carbons. Adsorption followed the Langmuir isotherm and pseudo-second-order kinetics, with thermodynamics confirming endothermic and spontaneous MB adsorption. The adsorption mechanism primarily involves chemical adsorption, including electrostatic interactions, pore filling, hydrogen bonding, acid-base interactions, and π-π stacking. The AGV maintained 86.7 % adsorption efficiency after 5 cycles, demonstrating excellent recyclability. This study provides a novel approach for preparing high-performance adsorption materials from waste biomass.