Enhanced removal of hydrophobic endocrine disrupting compounds from wastewater by nanofiltration membranes intercalated with hydrophilic MoS2 nanosheets: Role of surface properties and internal nanochannels

Abstract

The presence of endocrine disrupting compounds (EDCs) in water and wastewater poses potential risks on aquatic environment and human health. Conventional polyamide (PA) nanofiltration (NF) membrane showed poor rejection against EDCs due to unfavorable hydrophobic interaction. In this study, we introduced MoS2 nanosheets (NS) to PA NF membrane by pre-deposition before the interfacial polymerization process, creating hydrophilic surface and nanochannels in the PA rejection layer to enhance removal of hydrophobic EDCs from wastewater. Results showed that the MoS2 NS intercalated membrane simultaneously enhanced water permeance and EDCs rejection, with water/EDC selectivity nearly 6 times larger compared to the control. The enhanced EDC rejection was primarily attributed to the suppressed hydrophobic interaction between membrane surface and hydrophobic EDCs, as well as the selective effect by the MoS2 NS-induced nanochannels. Further calculation based on the solution-diffusion theory indicated that for MoS2 NS intercalated membranes the selective nanochannels played a more important role than the hydrophilic surface in impeding the transport of EDCs across the PA layer. The feasibility of the MoS2 NS intercalated PA membrane for EDC removal was also verified using EDC-contaminated real wastewater. The results of this work highlight the potential of using the designed NF membranes for efficient removal of targeted organic micropollutants from water and wastewater.