Studies on distribution and reverse osmosis properties of cellulose acetate derivatives for organic compounds

Abstract Particles of cyanoethyl cellulose acetate (CACN), hydroxypropyl cellulose acetate (CAHP) and cellulose acetate have been prepared from the same solutions as used for casting of reverse osmosis (RO) membranes. The distribution properties of these materials for alcohols have been studied by liquid chromatography. It was found that alcohols were attracted to the surfaces of these membrane materials. The Kd values increased with increasing carbon numbers of n-alkyl alcohols. The order for alcohols with different structures was n-> iso-> sec-> tert-. The separation properties of the RO membranes cast from these materials for alcohols have also been investigated. It was found that the solute rejections for n-alkyl alcohols reached a maximum for alcohol molecules containing three carbon atoms. The order of solute rejection for alcohols with different structures was tert-> sec-∼ iso-> n-. The results from liquid chromatography and reverse osmosis experiments are discussed with respect to the chemical nature of the organics in terms of polar, nonpolar and steric effects estimated using the Taft number (σu*), the Small number (s) and a steric parameter (Es), respectively. The differences in performance of the solute between the liquid chromatography and the reverse osmosis processes are also discussed.