摘要：The existence of excessive inorganic salts is a great threat to water security for the surrounding residents in the northwest of China where the groundwater is widely used as the main source of drinking water. Aiming at the target water quality, in order to achieve the economic and efficient desalination and provide guidance for choosing membrane components in the practical membrane process, the performance of water production and ion separation characteristics of the two kinds of nanofiltration (NF) membranes (NF270 and NF90) were studied. The influence of operating pressure and inlet flow on water purifying efficiency by the two commercial NF membranes were also evaluated.The results revealed that under the optimized conditions (0.5 MPa, 350 L·h-1), the ion rejection rates by NF270 reached 99.42%, 81.69%, 34.65% for SO4 2-, F-, Cl-, respectively, whereas the rejection rates by NF90 for SO4 2-, F-, Cl-, NO3- were up to 99.76%, 98.16%, 96.31%, 84.66%, respectively. Consequently, NF270 possesses a stronger ion selective separation property which is more suitable for the removal of bivalent ion with a high permeate flux. While the NF90 can remove nitrate effectively in particular.
