The influence of the preparation factors such as casting solution composition, different methods of coal modification, evaporation time of solvent and their optimization on performance of cellulose acetate heterogeneous reverse osmosis membranes have been studied. Three types of membranes were made from a blend of cellulose acetate (CA) and coal by weight ratios 1:1.5, 1:1.75 and 1:2. The powdered coal was modified with nitric acid and aryl diazonium salts in acetonitrile medium at constant modification time. The membranes were prepared by phase inversion process from a casting solution of cellulose acetate-coal and magnesium perchlorate in acetone water mixture at varying evaporation time of solvent at constant temperature using the same gelation medium. The composition of raw and modified coals was examined by IR spectroscopy. Membranes obtained with a casting solution composition of cellulose acetate-coal in weight ratios of 1:1.5 and 1:1.75, modified coals and longer evaporation time of solvent showed the best performance.
Keywords: heterogeneous membranes, modified coals, optimization factors, reverse osmosis