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Impact of swelling characteristics on the permselective properties of multi-layer composite membranes for water removal from alcohols.
Citation:
Vane, L., V. Namboodiri, M. Abar, AND F. Alvarez. Impact of swelling characteristics on the permselective properties of multi-layer composite membranes for water removal from alcohols. International Congress on Membranes and Membrane Processes, San Francisco, CA, July 31 - August 04, 2017.
Impact/Purpose:
The poster describes the modeling of robust, high-performance membranes to remove water from solvents to enable the reuse of the solvent. This work is part of solvent reclamation research being done under SHC 3.63.2.
Description:
The removal of water from organic solvents and biofuels, including lower alcohols (i.e., methanol, ethanol, propanol, and butanol), is necessary for the production, blending, and reuse of those organic compounds. Water forms an azeotrope with many hydrophilic solvents, complicating the separation of water/solvent mixtures. The use of water-selective membranes in a pervaporation or vapor permeation process enables the removal of water from the solvents, even when an azeotrope is present. Common hydrophilic polymer membranes often swell in water, resulting in permeabilities and selectivities that are dependent on the water content of the feed mixture. Recent work has shown the benefit of overcoating a hydrophilic water-permselective membrane with a non-swelling perfluoropolymer fil. The perfluoropolymer layer reduces the activity of water the hydrophilic polymer layer experiences, thereby reducing swelling in that layer and increasing the water selectivity of the multi-layer membrane relative to the selectivity of the base hydrophilic polymer, usually at the expense of permeability. In this work, the effect of overcoating the hydrophilic layer with polymer films of various swelling characteristics was modelled. Top layers that swell in the solvent offer some advantages, particularly with regard to the water permeance of the multi-layer composite.