Preparation and characterization of new PA-MOF/PPSU-GO membrane for the separation of KHI from water

A hydrostable and hydrophilic porous metal-organic framework (MOF)-UiO-66-NH2 was successfully synthesized and characterized. The prepared UiO-66-NH2 nanoparticles were incorporated into the dense selective polyamide (PA) layer over the surface of the polyphenylsulfone (PPSU)-graphene oxide (GO) support layer to make a new thin film nanocomposite (TFN) membrane for the treatment of wastewater containing Kinetic hydrate inhibitor (KHI). Attenuated total reflection infrared (ATR-IR), X-ray diffraction (XRD), and transmission electron microscopy (TEM) analyses of UiO-66-NH2 all confirmed that it was synthesized favorably. The as-prepared membranes were evaluated by ATR-IR, field emission scanning electron microscopy (FESEM), atomic force microscope (AFM), thermal gravimetric analysis (TGA), tensile strength, and contact angle techniques. The results showed that embedment of UiO-66-NH2 nanoparticles notably changes the membrane chemistry and morphology, leading to an improvement of separation performance because of the porous structure and hydrophilic nature of UiO-66-NH2. The incorporation of UiO-66-NH2 enhanced the thermal stability and mechanical strength (26%) of the membrane compared to the unmodified membrane, confirming the formation of a strong nanofiller-polymer matrix interface. The result demonstrated that the leaching out of the incorporated nanoparticles from the membrane was so small that it can be ignored. The surface hydrophilicity of the PA-MOF layer was improved 38% due to the of UiO-66-NH2 nanoparticles loading. The best performing M-TFN2 membrane (incorporated with 0.05% UiO-66-NH2) exhibited an increased permeate flux from 38 L/m2·h to 59.9 L/m2·h compared to the unmodified membrane; while the KHI rejection remained higher than 96%. Besides, the newly developed membrane exhibited remarkable improvement in the antifouling property (FRR of 97.8%) and an excellent long-term stability.