Studies on reverse osmosis separation of aqueous organic solutions by PAA/PSF composite membrane

The reverse osmosis (RO) separation of aqueous organic solutions, such as a lcohols, amines, aldehydes, acids, ketones, and esters etc., by PAA (polyac rylic acid)/PSF (polysulfone) composite membrane has been studied. It was f ound that the separation results for aliphatic alcohols, amines and aldehyd es are satisfactory, the solute rejection (R-a) and the volume fluxes of so lutions (J(V)) for 1000 ppm ethanol, ethylamine and ethyl aldehyde are 66.2 %, 61.0%, 84.0% and 0.90 x 10(-6), 0.35 x 10(-6), 0.40 X 10(-6) m(3)/m(2) . s, respectively, at 5.0 MPa and 30 degrees C. R-a increased with increasin g molecular weights of alcohols, amines and aldehydes, and the R-a for n-am yl alcohol, n-butylamine and n-butyl aldehyde reached 94.3%, 88.6% and 96.0 %, respectively. Satisfactory separation results (R-a > 70%) for ketones, e sters, phenols and polyols have been obtained with the PAA/PSF composite me mbrane. The effect of operating pressure on the properties of reverse osmos is has also been investigated. Analysis of experimental data with Spiegler- Kedem's transport model has been carried out and the membrane constants suc h as reflection coefficient sigma, solute and hydraulic permeabilities omeg a and L-p for several organic solutes have been obtained.