Desalination characteristics of TFN-RO membrane incorporated with ZIF-8 nanoparticles

•ZIF-8 incorporated nanocomposite membrane was successfully prepared for RO desalination.•The hydrophilicity of the prepared membranes increased with loading and then decreased.•Remarkable reduction in the fouling tendency was achieved.

Nanoparticle addition to membranes is advancing the performance of separation processes and improving the flux without jeopardizing the selectivity. However, fouling-resistance improvement of RO membranes is still needed in the desalination industry. The objective of this paper is to investigate the addition of ZIF-8 to the membrane selective-layer and its effect on the improvement of membrane fouling-resistance. SEM images of ZIF-8 nanoparticle showed a rhombic dodecahedral shape with an apparent uniform size of around 80 nm and BET surface area of 735 m2/g while membrane images showed a typical ridge and valley structure of aromatic polyamide (PA). The contact angle of the best performing membrane PZ4 (33.2°) was much lower than that of the control membrane (62.8°) suggesting higher surface-hydrophilicity. The permeate flux of PZ4 increased 53% compared to the control PA membrane under brackish water conditions while maintaining high salt rejection of 99.4%. Under fouling conditions with BSA, the control PA membrane lost more than 50% of its initial flux while PZ4 lost only 13% after 4 h of continuous operation. This study showed that ZIF-8 nanoparticles can significantly enhance the polyamide fouling-resistance and in the case of PZ4 membrane, the fouling was remarkably reduced by more than 75%.

Graphical abstractDownload high-res image (96KB)Download full-size image