Bridged organosilica membranes with precisely tailored microstructure for efficient pervaporation purification of organic solvents

Dimethyl carbonate (DMC), as an environmentally friendly green chemical, has been widely used in industrial, pharmaceutical, and food applications. However, the utilization of methanol (MeOH) in its production process leads to the formation of azeotropic mixtures that are difficult to be separated. Similarly, this problem also presents a critical challenge in toluene (TOL) production process. Pervaporation technology has emerged as an effective solution to this challenge, due to its characteristics of energy-efficient and high-performance. Nevertheless, the development of membrane materials that simultaneously exhibit high flux and excellent selectivity remains a significant challenge. In this study, bis(triethoxysilyl)ethane (BTESE) was employed as a precursor to fabricate organosilica membranes by adjusting the H 2 O/BTESE molar ratio, and their separation performance for MeOH/DMC and MeOH/TOL systems was systematically investigated. The results illustrated that the optimized BTESE membrane exhibits outstanding pervaporation performance, achieving separation factor of 1868/113 and high fluxes of 2.12/1.55 kg m −2  h −1 for MeOH/TOL and MeOH/DMC mixtures, respectively. Further studies reveal that membrane performance is closely correlated with the H 2 O/BTESE ratios, and tuning the molecular sieving properties effectively balances flux and separation factor. Additionally, gas permeation experiments elucidate the mass transfer mechanisms of organic solvent molecules in the membranes, providing theoretical guidance for the design of high-performance organosilica membranes. This study offers an energy-efficient membrane-based solution for methanol separation in MeOH/DMC and MeOH/TOL mixtures.