Nanofiltration (NF) and Reverse-Osmosis (RO) Membranes for Aqueous Ammonium Nitrate Salt Rejection: Experimental Studies

Herein, two commercially available spiral-wound nanofiltration (NF) and reverse-osmosis (RO) membrane elements were tested for aqueous ammonium nitrate salt separation. The effect of feed concentration and salt rejection as a function of transmembrane pressure were evaluated. NF and RO membranes exhibited 60% and 92% ammonium nitrate salt rejection, respectively, upon the initial feed concentration of 0.1 wt% at a seven-bar operating pressure. High ammonium nitrate salt rejection by the RO membrane was owing to its relatively small pore size compared to the NF membrane. It was found experimentally that the commercially available RO and NF membrane elements can be used for ammonium nitrate salt rejections from industrial effluents at ambient conditions.