Construction of MXene-MOF membranes with photocatalytic self-cleaning for enhanced oil-water emulsion separation

The worldwide shortage of clean water is a well-recognized challenge, moreover, the water system is undergoing serious oil pollution. Due to the superior separation efficiency and cost-effectiveness, membrane separation technology has gained prominence for treating oily wastewater. Nevertheless, its wider adoption is largely hindered by the persistent issue of membrane fouling. Recently, hydrophilic modification offers a promising solution to mitigate this issue, and proven to be both simple and effective. In this study, MXene-MOF composite membranes with photocatalytic self-cleaning properties were constructed by using self-assembly techniques. The membrane flux is 2534.89 +/- 13.63 L m-2 h-1 bar-1, with separation efficiency exceeding 99.7 %. Notably, the water contact angle drops below 5 degrees within 5 s, attributed to the hydroquinone-functionalized coating on the BIC@MIL-101(Fe) surface, effectively preventing oil adhesion onto the membrane surface. The incorporation of functionalized BIC@MIL-101(Fe) nanoparticles further improves the membrane's photocatalytic self-cleaning performance, furtherly enhancing its anti-fouling capabilities. Following 10 cycles of water cleaning and photocatalytic self-cleaning experiments, high water flux and separation efficiency are maintained, with a flux recovery rate >= 90 %. The anti-fouling mechanism of the membrane is further elucidated using the extended Derjaguin-Landau-Verwey-Overbeek (XDLVO) theory. The current findings highlight the considerable potential of MXene-MOF composite membranes for effectively treating oily wastewater.