Camellia sinensis leaf-assisted green synthesis of SO3H-functionalized ZnS/biochar nanocatalyst for highly selective solketal production and improved reusability in methylene blue dye adsorption

This study reports the successful synthesis of an acid-functionalized ZnS/Biochar (ZBC-SO3H) nanocatalyst through a co-precipitation method utilizing Camellia sinensis leaf extract. The ZBC-SO3H nanocatalyst was employed for the microwave-assisted acetalization reaction of glycerol with acetone for selective solketal synthesis (biofuel derivative). Through systematic optimization of multiple reaction parameters, the most favorable conditions for solketal synthesis were identified. The ideal reaction conditions involved an 8:1 M ratio of acetone to glycerol (AC to GL), a 6 wt% catalyst loading, an 8-min reaction time, and a temperature of 60 °C. A significantly high surface area of 326.21 m2/g for the ZBC-SO3H nanocatalyst demonstrates its exceptional potential for catalytic applications. In addition, the plausible reaction pathway for selective solketal synthesis was suggested. The catalyst was reusable up to 6 reaction runs in the solketal synthesis, which remarks the high stability of the ZBC-SO3H. Further, the reusability of the ZBC-SO3H (remaining catalyst after 6 runs) was examined in the adsorption of methylene blue (MB) dye. This groundbreaking study showcases the exceptional performance of the ZBC-SO3H nanocatalyst in selective solketal production and its remarkable reusability in the adsorption of methylene blue dye. The outstanding results underscore the novelty and significance of this research endeavor.