Bagasse heavy ash-derived Zn-loaded porous silica with tunable mesopores: Effect of monomodal and bimodal pores on VOCs adsorption

This work aimed to utilize bagasse heavy ash for bimodal mesoporous silica (BPS) synthesis through a novel and environmentally-friendly synthesis process using a single–template pH alteration process. The surface functional groups over the BPS products were then modified using Zn precursor, and the obtained samples were examined for the adsorption of methanol, butanol, hexane, and benzene. Effects of hydrolysis–condensation rate controlled by varying sulfuric acid concentrations in the synthesis process on the formation of controllable bimodal mesopores were systematically investigated. The Zn-loaded bagasse ash-derived BPS products exhibited outstanding adsorption performances, especially for methanol and benzene adsorption over the BPS with medium to large pores, of approximately 4.10 and 7.51 times those over the monomodal mesoporous silica (MPS), due to the existence of large pores within the BPS products. The potential application of bagasse heavy ash-derived bimodal mesoporous silica absorbents in adsorption—separation processes are evidently demonstrated.