Studies on reverse osmosis for water pollution control

Abstract

Reverse osmosis separations of sodium ortho- and polyphosphates, lecithin, ethyl phosphate, sodium nitrite, nitrate, chloride, fluoride and sulfate, ammonium chloride, glutamic acid, and phenyl mercuric acetate and benzoate in aqueous solutions at solute concentrations less than 2000 ppm were studied using improved porous cellulose acetate membranes at 250 psig. Solute separations were essentially independent of feed concentration under the test conditions used. With a film preshrunk at 82°C, the solute separations for sodium phosphates, NaNO3, NaNO2, NH4Cl, glutamic acid, NaCl, NaF, and Na2SO4 were 99.6, 91.2, 91.6, 95.3, 99.1, 96.2, 96.6 and 99.2 percent respectively, and the average membrane flux was 14.4gpd ft−2; with a film shrunk at 75°C, the separations for the above solutes were 99.4, 81.5, 83.0, 87.3, 98.6, 89.7, 94.4, and 98.9 per cent respectively, and the average membrane flux was 30.6 gpd ft−2. The separations obtained for lecithin were > 99 per cent, and those for the others were lower.