Fe3+/tannic acid assisted preparation of dynamic assembled hollow fiber nanofiltration membrane with salt tolerance

In this study, a hollow fiber nanofiltration membrane with excellent salt tolerance and anti-fouling properties was successfully prepared by Fe 3+ /tannic acid (TA) assisted dynamic assembly technology. The results showed that when the concentration of Fe 3+ and TA was 0.1   g·L -1 , the rejection rate of Na 2 SO 4 was 91.34%, and the permeability was 12.44   L·m -2 ·h -1 ·bar -1 . The salt tolerance test showed that the rejection rate did not change significantly in the range of 1-5   g·L -1 Na 2 SO 4 concentration. The rejection rate of the membrane to 5   g·L -1 Na 2 SO 4 solution was 85.22%, thanking to the strong binding force between the Fe 3+ -TA coordination bonds. The high hydrophilicity of the coating layer and the dense structure of the Fe 3+ -TA coordination network significantly reduced the irreversible adsorption of pollutants, which provided the membrane with stable permeability after three times of fouling-cleaning cycles with bovine serum albumin (BSA) and humic acid (HA) as model pollutants. The dense network structure formed by dynamic assembly assisted with Fe 3+ -TA coordination was the key to the high rejection and salt tolerance of the membrane, which provided a new strategy for the development of high-performance nanofiltration membranes for high-salt wastewater treatment in practical applications.