TFN nanofiltration membrane incorporating ZIF-8@MXene for efficient removal ReO4- from simulated nuclear-contaminated wastewater

In an effort to explore the potential application prospects of membrane separation technology in treating nuclear-contaminated wastewater, a TFN nanofiltration membrane incorporating the ZIF-8@Ti 3 C 2 T x nanocomposite was successfully synthesized using the interfacial polymerization method. This involved doping the microemulsion of ZIF-8@Ti 3 C 2 T x into the aqueous (organic) phase. The morphology and structure of ZIF-8@MXene nanocomposites and TFN nanofiltration membranes were characterized. The selective removal of ReO 4 - from simulated radioactive wastewater using the TFN nanofiltration membrane was evaluated. The results indicated that the ZIF-8@Ti 3 C 2 T x composite, uniformly dispersed in the polymer, effectively enhanced the pore structure and polarity of the nanofiltration membrane, thereby improving its permeability. The electronegativity of ZIF-8@Ti 3 C 2 T x also enhanced the negative charge on the surface of the polymer membrane, significantly improving the membrane’s performance in rejecting ReO 4 - while maintaining a low retention rate for Na + . This design facilitates the efficient selection of ReO 4 - from high-salinity wastewater. In addition, the layer spacing of Ti 3 C 2 T x further improved the screening of ReO 4 - and Na + . However, when 0.75 g·L −1 of microemulsion was added, it became challenging to disperse the microemulsion completely in the organic phase. This led to the agglomeration of composites in the nanofiltration membrane, weakening both flux and selectivity. Optimal performance was achieved with a microemulsion doping amount of 0.5 g·L −1 , resulting in the nanofiltration membrane M-O-1 exhibiting the best performance (Jp = 41.92 L·m 2 ·h −1 and R(ReO 4 - ) = 65.81%). Even at a high salt concentration (20 g·L −1 ), the M-O-1 membrane retained approximately 55% of pollutants after continuous operation for 5 h, indicating that the TFN nanofiltration membrane containing ZIF-8@Ti 3 C 2 T x holds significant promise for selectively extracting 99 Tc from wastewater with a high salt content.