Two kinds of reverse osmosis (RO)membrane for brackish water (BW)and sea water (SW)were prepared with trimesoyl chloride (TMC)and m-phenylenediamine (MPD)on the polysulphone supporting film through interfacial polymerization technique.The membranes were compared using permeation experiments with salt water

scanning electronic microscopy (SEM)

X-ray photoelectronic spectroscopy (XPS)and atomic force microscopy (AFM）.The study shows that SWRO membrane has higher rejection for NaCl but low flux for water compared to the BWRO membrane

because the surface of SWRO membrane contains more hydrophilic group (—COOH)according to the XPS result

and presents lower roughness according to the result of SEM and AFM.