Nitrate Removal from Drinking Water by Using Commercial Nanofiltration

Abstract

The aim of the present work was to investigate the efficiency of commercial nanofiltration: NF90 (Dow-Film Tec) in reducing nitrate concentration from water. Salt rejection was studied using KNO₃, NaNO₃ and K₂SO₄. The influence of the operating pressure, feed concentration and temperature were studied. The influence of sulfate on the retention of KNO₃ salt was also examined. To examine the influence of the nature of associated cation on nitrate retention, the retentions of two nitrate salts, KNO₃ and NaNO₃ were compared. The experiment results show that nitrate retention increases sharply by increasing the pressure from 4 to 8 bars and becomes stable at higher pressures but decreases by increasing temperature and also by increase in sulfate ion and nitrate salts concentrations. The retention of KNO₃ was always lower than that of NaNO₃.