Performance enhancement of a polydimethylsiloxane membrane for effective n-butanol pervaporation by bonding multi-silyl-functional MCM-41

Preparation of modified MFI-type/PDMS composite membranes for the separation of dichlorobenzene isomers via pervaporation

Zeolite-polymer composite membranes have become promising and effective materials for the pervaporative separation of liquids, especially for isomeric mixtures. In this paper, silicalite-1/PDMS composite membranes have been used to investigate the separation of dichlorobenzene (DCB) isomers via pervaporation for the first time. Silicalite-1 zeolites modified by the silane coupling agent, NH3-C3H6-Si(OC2H5)3, have been incorporated into polydimethylsiloxane (PDMS). Then, the silicalite-1/PDMS composite membranes have been successfully prepared on porous polyvinylidene fluoride (PVDF) supports. The morphology and structure of the silicalite-1 zeolites and silicalite-1/PDMS composite membranes have been characterized by XRD, FTIR, SEM and BET techniques. The results show that the modified silicalite-1 zeolite particles have smaller pore sizes dispersed more uniformly in the active layers of the silicalite-1/PDMS composite membranes and present fewer aggregation and pinholes formed by the accumulation of zeolite particles. The silicalite-1/PDMS composite membranes are all dense and continuous with good homogeneity. To evaluate the pervaporative separation performance of the DCB isomers, the unmodified and modified silicalite-1/PDMS composite membranes have been further tested in single-isomer and binary-isomer systems at 60 °C. The modified silicalite-1/PDMS composite membranes present higher DCB isomer separation factors. The separation factors of the modified silicalite-1/PDMS composite membranes in the binary-isomer systems for p-/o-DCB and p-/m-DCB are 3.53 and 5.63, respectively. The permeate flux of p-DCB through the modified silicalite-1/PDMS composite membranes in the p-/o-DCB binary-isomer system is 116.7 g m-2 h-1 and in the p-/m-DCB binary-isomer system, it is 93.5 g m-2 h-1. The result provides a new approach towards the pervaporative separation of DCB isomers from their mixture for future industrialization applications.

Organic Hollow Mesoporous Silica as a Promising Sandalwood Essential Oil Carrier

As film-forming agents, fillers and adsorbents, microplastics are often added to daily personal care products. Because of their chemical stability, they remain in the environment for thousands of years, endangering the safety of the environment and human health. Therefore, it is urgent to find an environmentally friendly substitute for microplastics. Using n-octyltrimethoxysilane (OTMS) and tetraethoxysilane (TEOS) as silicon sources, a novel, environmentally friendly, organic hollow mesoporous silica system is designed with a high loading capacity and excellent adsorption characteristics in this work. In our methodology, sandalwood essential oil (SEO) was successfully loaded into the nanoparticle cavities, and was involved in the formation of Pickering emulsion as well, with a content of up to 40% (w/w). The developed system was a stable carrier for the dispersion of SEO in water. This system can not only overcome the shortcomings of poor water solubility and volatility of sandalwood essential oil, but also act as a microplastic substitute with broad prospects in the cosmetics and personal care industry, laying a foundation for the preparation and applications of high loading capacity microcapsules in aqueous media.