Pervaporation of Aqueous Ethanol Mixtures through Poly(Dimethyl Siloxane) Membranes

Abstract

The separation of ethanollwater mixtures by pervaporation with a poly(dimethy1 siloxane) membrane has been studied. The membrane exhibited ethanol selectivity during all process runs. Investigations focused on the effects of temperature and permeate-side pressure on membrane transport with dilute ethanol feed solutions. An increase in temperature increased the flux exponentially but had little effect on selectivity. As the permeate-side pressure was increased, the flux decreased. Selectivity did not change appreciably over the pressure range evaluated. Studies also analyzed the effect of feed concentration on flux and selectivity. Flux increased and selectivity decreased as the ethanol feed concentration increased. The permeate concentration profile is superior to a standard vapor-liquid equilibrium curve at low ethanol feed concentrations.

Platform Molecule Removal from Aqueous Mixture with Organophilic Pervaporation: Experiments and Modelling

“…It can be stated at higher ethanol concentration the separation effectiveness of the organophilic pervaporation membranes are decreased, similar tendency have been already published by Slater et al [25], Lazarova et al [27], Vane [34], Chai et al [35] and Fu et al [36]. Table 2, Table 3 and Table 4 summarize the estimated values of transport coefficients, activation energies, exponential parameters and minimized objective functions of the two models.…”

Enhanced Pervaporation Performance of Multi-layer PDMS/PVDF Composite Membrane for Ethanol Recovery from Aqueous Solution

“…As the feed concentration increased from 5 to 30 wt%, the separation factor decreased from 15.0 to 4.1, and the total flux increased from 452.2 to 818.6 g/m 2 h with the operation temperature of 60°C. The effect of ethanol feed concentration on pervaporation performance of multilayer PDMS/PVDF composite membrane was similar to that of PDMS composite membrane reported in literatures [16][17][18]. As the feed concentration increased, the free volume in PDMS membrane also increased due to the increase of swelling degree of PDMS membranes.…”

Polysiloxaneimide membranes for removal of VOCs from water by pervaporation

“…However, they usually have poor mechanical strength, and the studies to improve their mechanical properties have been carried out by introducing a siloxane-imide block or graft copolymer structure. [12][13][14][15][16] These studies showed that pervaporation selectivity and permeation flux towards organic compounds decreased with decreasing the fraction of the siloxane group. The observation indicates that polysiloxaneimide homopolymer membranes are expected to show good pervaporation performances, but the pervaporation studies with polysiloxaneimides have not been reported yet.…”