Fabrication of epoxy/SiO2/ZnO superhydrophobic nanocomposite mesh membranes for oil-water separation: Correlating oil flux to fabrication parameters via Box-Behnken design

Abstract

Superhydrophobic nanocomposite mesh membranes were constructed by facile scalable spray deposition method without using low surface energy modifiers for oil-water separation. The Box-Behnken design was applied to study the influence of the main fabrication parameters consisting of spray solution concentration (g.L−1), the mass ratio of SiO2:ZnO (wt%), and the mass ratio of epoxy resin to the total nanoparticles (wt%) on the permeation flux of mesh membranes. The results indicated that increasing the concentration of spray solution led to a decrease in the oil flux due to increasing the coating thickness. The permeation flux first decreased with an increase in the weight percentage of epoxy resin in the spray solution because of the formation of the high density of SiO2/ ZnO coating and then slowly increased due to decreasing coating thickness. The best performance of chloroform flux of 18.3E+03 L/m2.h and separation efficiency of >97% corresponded to the fabricated mesh membrane with 80 wt% of SiO2 to ZnO, 33.33 wt% of epoxy resin to total nanoparticles, and 30 g.L−1 of spray solution concentration. This mesh membrane exhibited superior superhydrophobic properties, outstanding chemical resistance, and excellent mechanical durability. The coated mesh displayed good icephobic characteristics with low ice adhesion.