Membranes Based on PTMSP and Hypercrosslinked Polystyrene for Gas Separation and Thermopervaporative Removal of Volatile Organic Compounds from Aqueous Media

Abstract

In order to increase the efficiency of membranes in the processes of gas separation and thermopervaporative isolation of volatile organic compounds from aqueous media, mixed-matrix membranes based on polytrimethylsilylpropine (PTMSP) with an amount of hypercrosslinked polystyrene (HCPS) particles up to 50 wt % have been obtained and experimentally studied for the first time. The industrial sorbent Purolite Macronet™ MN200 was chosen as HCPS due to its high sorption capacity for volatile organic compounds. It has been found that HCPS particles are nonuniformly distributed over the membrane volume and the membranes show a distinct asymmetry when the HCPS content in PTMSP is more than 30 wt %. In the cross section, the membranes represent composite membranes with a thin selective layer (PTMSP) and a porous support (HCPS). It has been established that the permeability coefficients for light gases increase with an increase in the MN200 concentration in the membrane material from 0 to 20 wt %. The introduction of HCPS in an amount of more than 20 wt % in PTMSP leads to an increase in permeability coefficients by 4–7 times, with the selectivity decreasing. The properties of PTMSP membranes with different HCPS fillings were studied during the thermopervaporative separation of benzene–water, toluene–water, and o-xylene–water binary solutions and a multicomponent BTX–water mixture. It has been found that the permeate flux and the separation factor increase with an increase in the HCPS content in PTMSP for all the studied solutions. The maximum values of the separation factor (>900) for all processed solutions were obtained for PTMSP membranes with a HCPS content of 30 wt %.