Abstract:

The effects of metaphenylene diamine (MPD）and trimesoyl chloride (TMC）concentration on the performance of reverse osmosis (RO）composite membranes were investigated.Different alcohols were added to the aqueous solution of MPD in order to improve the performance of as-prepared membranes.The maximal flux was found to be twice of the original flux.FTIR results suggest that the hydroxyl groups of alcohols reacted with TMC to form ester bonds and thus terminated the extension of polyamide molecular chains, and reduced the cross-linked degree of network structure, so that solute molecules are easy to penetrate through the membranes.The connection between membrane separation performance and solubility parameters of alcohols was investigated.When the solubility of alcohol is close to that of polyamide, the alcohol is easy to dissolve and penetrate in the nascent polyamide membrane, and therefore increases the reaction between the alcohol and TMC.The experiments exhibit that the addition of alcohols is an effective method for preparation of composite membrane with high flux. Under the optimum experimental conditions, the best mass fraction of additional alcohols in water phase is between 5% and 10% and as-prepared composite membranes exhibit high flux with a little sacrifice on rejection.