Covalent-crosslinking IRMOF-3-NH2/PVC ultrafiltration membrane for simultaneous removal of bisphenol A and Cd2+ ions in water

Interface design is critical for preparing high-performance adsorption-based ultrafiltration membranes, especially for separating small organic molecules or heavy metal ions from water. A new covalently cross-linked IRMOF-3-NH2/PVC membrane with dual functions of ultrafiltration and adsorption was fabricated by the phase inversion method. The performance of the prepared membranes was evaluated for the removal of complex contaminants from water. The results showed that with the addition of IRMOF-3-NH2, the anti-fouling, mechanical and adsorption properties of the IRMOF-3-NH2/PVC membranes were significantly improved simultaneously. When 8 wt% IRMOF-3-NH2 was added to PVC, the contact angle of the filter membrane decreased from 95.8° to 68.2°, the pure water flux increased from 158.2 L/(m2·h·bar) to 326.7 L/(m2·h·bar), and the tensile strength increased from 3.24 MPa to 3.83 MPa. More importantly, the membranes could achieve retention rates of 96%, 92% and 79% for BSA, BPA and Cd2+ ions, respectively. By regenerating the membrane with a mixture of ethanol and acetic acid, the membrane could maintain a high retention capacity after five cycles. This study might provide some new insights into the fabrication of adsorptive ultrafiltration membrane for preventing the production of waste while increasing efficiencies in the uses of water.