Preparation and benchmarking of thin film supported PTMSP-silica pervaporation membranes

• Published in: Journal of membrane science 2012-02, Vol.389, p.265-271
• Main Authors: Claes, Stan, Vandezande, Pieter, Mullens, Steven, De Sitter, Kristien, Peeters, Roos, Van Bael, Marlies K.
• Format: Article
• Language: English
• Subjects: Alcohol recovery; artificial membranes; butanol; Chemistry; Colloidal state and disperse state; ethanol; Exact sciences and technology; General and physical chemistry; Hydrophobic silica; hydrophobicity; Membranes; Pervaporation; Poly[1-(trimethylsilyl)-1-propyne]; silica; Thin film composite membrane
• ISSN: 0376-7388; 1873-3123
• DOI: 10.1016/j.memsci.2011.10.035

► Successful preparation of highly permeable thin film silica filled PTMSP membranes. ► Favoured membrane comprises a 2.4 μm thick top layer and 25 wt.% silica. ► Superior performance of prepared membranes in benchmark study. Supported silica filled poly[1-(trimethylsilyl)-1-propyne] (PTMSP) membranes were optimised in terms of silica filler loading and top layer thickness, and applied in the pervaporative separation of dilute aqueous ethanol and butanol mixtures (5 wt.%). Addition of hydrophobic silica clearly increased the permeate flux at the expense of the alcohol/water selectivity. Based on its maximal pervaporation separation index (PSI) an optimum was found for a 25 wt.% silica filled membrane with a PTMSP separating layer of 2.4 μm thickness. This membrane exhibited a flux of 9.5 kg m −2 h −1 in combination with an ethanol/water separation factor of 18.3. In the pervaporation of a butanol/water mixture, a flux of 9.5 kg m −2 h −1 and accompanying separation factor of 104 was obtained. A benchmark of this optimised supported PTMSP-silica nanohybrid membrane against two commercially available PDMS-based membranes clearly demonstrated the superior flux/selectivity combination of the prepared thin film silica filled PTMSP membranes in the removal of alcohols from dilute aqueous mixtures. Compared to the commercial membranes, a 4- and 3-fold increase in flux and a 2- and 3-fold increase in alcohol/water separation factor was observed for the optimised supported PTMSP-silica membrane in the separation of a 5 wt.% ethanol/water and butanol/water mixture, respectively.