Abstract: Research on controlling and removing perfluorinated compounds (PFCs) in water has become a prominent topic in environmental protection science. Forward osmosis (FO) membrane separation technology demonstrates significant potential in removing PFCs from water due to its unique advantages. This study focuses on the removal performance of two typical PFCs, namely PFOA and PFOS, in water using a self-developed composite thin layer membrane called silver chloride surface mineralized polyamide (TFC) FO membrane. The relationship between membrane surface performance and PFCs removal efficiency is analyzed. The influence of coexisting substances in water on the removal performance is also examined. Results reveal that the modified membrane exhibits enhanced surface hydrophilicity and increased negative charge. Both hydrophilicity and negative charge on the membrane surface increase with a higher degree of mineralization. The modified membrane also demonstrates improved forward osmosis performance, characterized by higher water flux and greater PFCs rejection. These improvements are observed as the mineralization degree increases within a certain range. However, excessive deposition of silver chloride may decrease the membrane’s rejection of PFCs. The TFC FO membrane, prepared by alternately soaking for four times during mineralization modification, demonstrates the most effective removal of PFCs, with removal rates of 96.2% for PFOA and 95.7% for PFOS. Furthermore, it exhibits the highest water flux at 22.5 L/m²·h. The interaction between the FO membrane and PFCs is primarily governed by hydrophobic and electrostatic forces. The modified FO membrane effectively rejects PFCs by reducing the hydrophobic effect and enhancing the electrostatic repulsion between the membrane and PFCs. Yet, the presence of different substances in water can influence the hydrophobic and electrostatic interaction between the FO membrane and PFCs, ultimately affecting the rejection performance of PFCs.

Key words: perfluorinated compounds, water environment, forward osmosis membrane, modification, removal mechanism