Amino acid-based nanoparticles-incorporated thin-film nanocomposite forward osmosis membranes for efficient desalination and heavy metal ions rejection

The current study explores potential applications of state-of-the-art thin-film nanocomposite forward osmosis (TFN-FO) membranes, modified with histidine-functionalized graphene quantum dots (His-GQDs) and MIP-202(Zr) nanoparticles (NPs), for sustainable desalination and heavy metal ions rejection. The porous and layered structure of the applied NPs, along with various hydrophilic functional groups on their surface, contribute to improving the fabricated membranes' ion/water separation performance. The successful preparation and incorporation of desired NPs into the polyamide layer was investigated using typical analytical methods. Under the common FO test conditions, the best-performing TFN-MQ₂ membrane displayed a water flux of 21.8 LMH, which was over 1.5 times greater than the water flux of blank TFC. Simultaneously, the selectivity was found to be approximately 1.7 times greater than that of the unmodified TFC membrane. Moreover, the optimal TFN-MQ₂ membrane exhibited superior rejection rates for Cu²⁺ ions (98.5 %) and Pb²⁺ ions (98.1 %), surpassing all other samples in heavy metal ion rejection. The findings of this study suggest that carefully choosing cost-efficient and eco-friendly nanofillers (such as amino acid-based NPs) can enhance the desalination performance of TFN-FO membranes and bolster their resistance to fouling and rejection of heavy metal ions. Not to mention, the overall costs of membrane production will be reduced.