Hydrophilic Selective Nanochannels Created by Metal Organic Frameworks in Nanofiltration Membranes Enhance Rejection of Hydrophobic Endocrine Disrupting Compounds.

Abstract

Rejection of endocrine-disrupting compounds (EDCs) by thin film composite (TFC) polyamide membranes remains to be a challenging issue in wastewater reclamation applications due to the unfavourable hydrophobic interaction between EDCs and membrane. Herein, we investigated the incorporation of hydrophilic metal organic frameworks (MOFs) into polyamide layer to create water/EDCs selective nanochannels for enhancing EDCs rejection. Using MIL-101(Cr) MOF as a nanofiller, the water flux of MOF0.20 TFC membrane (0.20 wt/v % MOF in n-hexane) was 2.3 times of that of the control. The rejection rates against EDCs involving methylparaben, propylparaben, benzylparaben and bisphenol A (BPA) by MOF0.20 were also significantly higher than the respective values of the control membrane, with the water/EDC selectivity (e.g., A/BBPA) of MOF0.20 approximately doubled compared to that of the control. Further single salt rejection and gold nanoparticle filtration tests confirmed that the hydrophilic nanochannels created by MOFs played a critical role in membrane transport, accounting for the significant enhancement of EDCs rejection of the modified TFC membrane. This study demonstrates a promising membrane modification protocol using hydrophilic MOFs for achieving selective removal of EDCs and high-efficient wastewater reclamation using TFC membranes.