Development of Self-Cleaning g-C3N4/Zn(OH)2 Nanocomposite-Coated Mesh for Oil-Water Emulsion Separation

Abstract

It has been widely recognized that efficient approachesto water-oilseparation need to be developed and designed. It is the objectiveof this study to improve and optimize the performance of g-C3N4 for oil-water separation by anchoring Zn(OH)(2). Additionally, the as-prepared g-C3N4/Zn(OH)(2) nanocomposites containing different amounts ofZn(OH)(2) were investigated to determine the effect of twofactors of porosity and surface defects in the water-removing of oil-watermixtures. The results show that oxygen-containing groups in this specificg-C3N4/Zn(OH)(2) nanocomposite havea greater impact on wettability behavior and water-removing separationperformance than porosity. Density functional theory (DFT) calculationsdemonstrated that the adsorption energy of water is larger than thatof oil molecules on the g-C3N4/Zn(OH)(2), confirming that the prepared coated mesh can be used as a potentialmaterial for water-oil separation. Moreover, the self-cleaningproperty of the nanocomposite-coated mesh was demonstrated by theremoval of adsorbed oil in contact with the surface. In this study,it was also attempted to perform water and oil separation with goodperformance. Therefore, the perfluorooctanoic acid (PFOA) was alsoused to reduce energy in g-C3N4@Zn(OH)(2)@PFOA mesh, leading to super-hydrophilic/super-oleophobic wettability.Ultimately, a new mesh coated with g-C3N4@Zn(OH)(2)@PFOA nanocomposite was successfully separated oil-in-wateremulsion with a high efficiency of 99.99%.