Efficient removal of perfluorinated compounds with the polyamide nanofiltration membrane and membrane fouling resistance analysis

Perfluorinated compounds (PFCs) are significant pollutants known for their high toxicity and resistance to natural degradation, posing a severe threat to both the global environment and human health. In this study, a polyamide (PA) membrane with an intermediate layer structure of MXene-TiO2 (referred to as MXT-NFM) was utilized for the removal of PFCs. Experimental results confirm that MXT-NFM exhibited remarkable capacity in intercepting PFCs, accompanied by the high water flux. To gain insights into the mechanisms governing membrane fouling induced by PFCs, inorganic ions, and organics, a series of fouling tests were conducted using MXT-NFM under diverse conditions. Additionally, the XDLVO theory was employed to provide a theoretical perspective on the interactions occurring during the fouling process. The findings suggest that the MXene-TiO2 intermediate layer contributed to the exceptional hydrophilicity and rough surface properties, enabling multiple functionalities. These include alleviating membrane pore plugging, improving the physical configuration of the PA layer, and effectively mitigating fouling phenomena in coexisting systems during practical applications. Moreover, the particle size of pollutant colloids and the acid–base interaction were identified as decisive factors influencing the development of membrane fouling.