Abstract: An interfacial polymerization process (IFP) for preparing a highly permeable TFC RO membrane by contacting on a porous support membrane for IFP, a polyfunctional acyl halide monomer and a polyamine monomer and recovering a highly permeable thin film (TFC) reverse osmosis (RO) membrane. At least one of solutions may contain nanoparticle additives which may release ions into solution and at least one of the solutions may contain additional ions from a second additive. The presence of the nanoparticle additives during IFP may increase the hydrophilicity and/or permeability of the recovered membrane compared to a control membrane. The presence of the additional ions from the second additive may also increase the permeability of the recovered membrane.