Synthesis and xylene isomers adsorption of silicalite-1 crystals with intracrystalline mesopores aided by 3-glycidoxypropyl-trimethoxysilane and polyethene glycol

Well-defined silicalite-1 crystals with intracrystalline mesopores were successfully synthesized in the presence of 3-glycidoxypropyl-trimethoxysilane (GPTMS) and polyethylene glycol (PEG) from a hydrothermal synthetic system. Various techniques, such as XRD, SEM, TEM, TGA, and Ar adsorption, were used to characterize the textural properties of the obtained hierarchical silicalite-1. The results indicated that the addition of GPTMS to the silicalite-1 synthesis system could bring some mesopores in the silicate-1 crystals. While PEG, as a mesoporogen, was added along with GPTMS, silicalite-1 crystals with abundant intramesoporosity were obtained. The liquid-phase absorption of xylene isomers (p/o) on the hierarchical silicalite-1 indicated that the hierarchical silicalite-1 showed better absorption properties in terms of both adsorption rate and capacity for p-xylene, compared to silicalite-1 crystals synthesized in the absence of GPTMS and PEG.