Effects of hydrothermal treatment and surfactant modification on the surface properties and methyl violet adsorption capacity of sugarcane bagasse-derived biochar

Abstract

In this study, than sinh học (BC) derived from sugarcane bagasse by pyrolysis was sequentially modified by hydrothermal treatment at 200°C for 4 h (BC-HT), chemical modification with the surfactant sodium dodecyl sulfate (BC-SDS), and by both processes (BC-HT-SDS). Hydrothermal treatment increased the specific surface area of BC while shifting the zeta potential toward more negative values. In contrast, SDS modification decreased the specific surface area but increased the negative magnitude of the zeta potential, indicating substantial changes in the surface properties of the material. At an SDS concentration of 6 g/l, the modified materials exhibited high adsorption capacity for methyl violet (MV). The adsorption equilibrium data were better described by the Langmuir model, with maximum adsorption capacities (q_max) of 25.25 and 26.60 mg/g for BC-SDS and BC-HT-SDS, respectively, which were significantly higher than those of BC (17.67 mg/g) and BC-HT (19.16 mg/g). Compared to hydrothermal treatment, surface modification of BC with SDS played a more important role in enhancing the adsorption capacity of the material. The improvement in MV adsorption performance was not solely dependent on the specific surface area but was also associated with the modification of surface chemistry and surface charge by SDS.