Comparison and Analysis of Determination Results of Nutrients in Seawater by Two Reverse Osmosis Membranes

The influence on the nutrients in seawater by two kinds of reverse osmosis membranes was explored.Comparison and analysis were investigated by cellulose acetate membrane and mixed cellulose ester membrane at the same aperture （0.45 μ m）. The results showed that no DSI was detected, but NH₄⁺-N、NO₃^--N、NO₂^--N and DIP could be detected when the samples were filtered with untreated mixed cellulose ester membrane.DSI and NO₂^--N were not detected, but NH₄⁺-N、NO₃^--N and DIP were detected when the sample was filtered with untreated cellulose acetate membrane. The various nutrients were not detected by the mixed cellulose ester membrane treated with ultrapure water or dilute acid, while NH₄⁺-N and NO₃^--N were still detected by the cellulose acetate membrane treated with ultrapure water or dilute acid, and the effect of cellulose acetate membrane treated with acid is greater than that of filter membrane treated with ultrapure water. Compared with the untreated and ultrapure water treated cellulose acetate membranes, ester membrane treated with acid has on effect on the determination of NO₂^--N.