a process for preparing a reverse osmosis membrane that includes : providing a polyamine , a polyfunctional acid halide , and a flux increasing additive having the formula z + b − where z + is an easily dissociable cation and b − is a beta - diketonate ; combining the polyamine , polyfunctional acid halide , and flux increasing additive on the surface of a porous support membrane ; and interfacially polymerizing the polyamine and the polyfunctional acid halide , and flux increasing additive on the surface of the porous support membrane to form a reverse osmosis membrane comprising the porous support membrane and a discrimination layer comprising a polyamide . the reverse osmosis membrane is characterized by a flux that is greater than the flux of the same membrane prepared in the absence of the flux increasing additive .