Tailored alumina nanocomposite membranes featuring MIL-125-NH2 metal-organic frameworks for oily wastewater treatment

Abstract

Ceramic membranes offer significant potential for addressing challenging and harsh wastewater streams such as produced water (PW) and surfactant-stabilized oil/water (O/W) emulsions. This study focuses on developing a stable and a uniformly structured active layer solely composed of MIL-125-NH2 MOF on a ceramic Alumina support. A stable covalent bonding approach was employed using interfacial polymerization, with isophthaloyl chloride (IPC) acting as the organic crosslinker during interfacial polymerization reaction. Three distinct MIL-125-NH2 decorated membranes M50, M75, and M100 were prepared by using varying MOF concentrations. Surface wettability analysis of the membranes indicated that the MIL-125-NH2 MOF active layer displayed super-hydrophilic characteristics in the air (water contact angle = 0°) and super-oleophobic characteristics underwater (oil contact angle = 161.5°). In oil separation experiments, all the MIL-125-NH2 deposited membranes displayed >99% oil rejection. Among the fabricated membranes, M50 demonstrated the highest water flux of 2100 Lm−2 h−1 under a transmembrane pressure of 2 bar. The MIL-125-NH2 MOF deposited membranes also showed stable performance under longer-run filtration. This study would be a simple and effective method of decorating MOFs as an active layer on ceramic support for efficient O/W emulsion separation and desalination applications.