Recovery of esters from dilute aqueous solutions by vapor permeation

초록

The vapor permeation characteristics of ester compounds (ethyl acetate, EA; ethyl propionate, EP; and ethyl butyrate, EB) through a tube-type surface-modified alumina-silane hydrophobic membrane were investigated. Experiments were performed to evaluate the effects of the feed concentration (0.15-0.60 wt%) and temperature (30-50degreesC) on the separation of EA, EP, and EB from aqueous solutions. It was found that the permeation flux increased with increasing feed ester concentration and operating temperature. The fluxes of EA, EP, and EB at 0.60 wt% feed concentration and 40degreesC were 282, 506, 742 g/m(2.)h, which were much higher than those of PDMS polymer membrane. The separation factors for the 0.15-0.60 wt% feed solutions of EA, EP, and EB at 40 degreesC were in the range of 28.1-93.9, 145.3-162.6, and 260.4-268.8, respectively. Phase separation occurred in the permeate when collected in a cold trap, because the concentration of the ester in the permeate was much higher than its solubility.

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