Application of ZnO nanostructures in ceramic and polymeric membranes for water and wastewater technologies: A review

Advances in nanotechnology and nanomaterials have led to the development of nanostructured membranes. Zinc oxide (ZnO), a multifunctional nanomaterial, has been postulated as a filler in polymeric and ceramic membranes to improve properties such as roughness, permeability, and fouling resistance. This review is a comprehensive overview of recent progress on the following: i) ZnO nanostructure preparation and characterization, ii) ZnO growth techniques, iii) fabrication of ZnO-based polymeric and ceramic membranes and iv) environmental application studies in water and wastewater technologies using ZnO-embedded polymeric and ceramic membranes. The review also covers approaches to control membrane properties to reduce fouling and biofouling, increase the solvent flux, increase pollutant rejection, and control swelling and deswelling membrane properties. Finally, the main expected applications on membrane-driven processes for environmental applications of water treatment are also analysed.