The characteristics of crosslinked PAA composite membrane for separation of aqueous organic solutions by reverse osmosis

Crosslinked polyacrylic acid (PAA) composite membranes have been prepared. The reverse osmosis (RO) separation properties of crosslinked PAA composite membrane for aqueous solutions of organics, such as alcohols, amines, aldehydes, acids, ketones, esters, etc., have been studied. It was found that the solute rejection ( Ra) and the volume fluxes of solutions ( Jv) for 1000 ppm ethanol, ethylamine and ethyl aldehyde reached 66.2%, 51.0%, 84.0% and 0.90×10 −6, 0.40×10 −6, 0.40×10 −6 m 3/m 2 s, respectively, in the conditions of 5.0 MPa and 30°C. The solute rejections increased with the increase of the molecular weights of alcohols, amines and aldehydes. The order of solute rejections for alcohols and amines with different structures was tert->sec->iso-> n-. The separation results ( Ra>70%) for ketones, esters, phenols and polyols have been obtained by the crosslinked PAA composite membrane. The morphology of the membrane has also been observed by SEM technique.