Upgrading of zirconia membrane performance in removal of hazardous VOCs from water by surface functionalization

To upgrade the membrane separation process, there is a tremendous need to understand the process from the point of view of the membrane materials, e.g., their chemistry and material features. Functionalized by various alkyl- and fluoroalkylsilanes, zirconia membranes (pore size 3 and 200 nm)were systematically investigated from the material, physiochemical, and tribological points of view. The work shows the successful utilization of the modified ceramic membranes to niche application of water purification. Stable organic-inorganic membranes were applied in vacuum membrane distillation (VMD)for removal of hazardous volatile organic compounds (VOCs)butanol, methyl-tert-butyl ether, and ethyl acetate. Wettability, surface roughness, and adhesion were investigated, taking into account the type of modifiers (fluorine-free)and molecules with a different degree of fluorination. The impact of the type of reactive group in non-fluorinated modifiers on the material features and the separation effectiveness were discussed. Furthermore, mechanical and chemical stabilities were studied. The most significant was that utilization of non-fluorinated modifier makes it possible to generate stable hydrophobic membranes, with high reactivity during grafting, suitable for VMD. These membranes possess better transport properties and high mechanical stability in comparison with fluorinated ones.