Preparation of polydimethylsiloxane/poly (styrene-butadiene-styrene) blend membrane by in-situ reactive compatibilizer γ-methacryloxy propyl trimethoxyl silane for efficient recovery of n-butanol from aqueous solution

Abstract

For commercial use, separating membranes need to have outstanding chemical, thermal, and mechanical stability. Moreover, striking a compromise between selectivity and permeability is essential for commercialization. Motivated by the robust and extensible properties of plant cell walls， we develop a strategy to build a cavity cell structure on the surface of the polydimethylsiloxane (PDMS) membrane utilizing a styrene-butadiene-styrene block copolymer (SBS) phase as the “cell wall" to enhance mechanical properties and prevent water permeation to achieve high selectivity. To obtain a controlled split-phase structure, γ-methacryloxy propyl trimethoxyl silane (WD-70) was selected for in situ accommodation of PDMS and SBS. The best results were achieved during the pervaporation separation of 1 wt % n-butanol aqueous solution at 70 °C, with 67.86 μm•kg/(m2•h) flux and an ultra-high separation factor of 73.6, as well as long-term operating stability. All the raw ingredients are affordable and readily available. The synergistic effect of PDMS and SBS mitigated the trade-off effect of the polymer membrane and improved the separation performance.