The adsorption characteristics of organic contaminants on graphene oxide coated alumina substrate: Experiments and molecular dynamics simulations

Dibutyl phthalate (DBP) and n-dodecane are commonly found as organic contaminants in industrial production. In this study, the wetting behavior of the two contaminants on the surface of alumina before and after coating with graphene oxide is investigated using wetting experiments and molecular dynamics simulations. The experimental results show that graphene oxide increases the spreading area of the two contaminants on the substrate surface. After coating with graphene oxide, the contact angle of DBP decreased from 30.02 degrees +/- 0.24 degrees to 20.26 degrees +/- 0.36 degrees. The contact angle of n-dodecane decreased from 16.56 degrees +/- 0.57 degrees to 6.92 degrees +/- 0.11 degrees in the presence of graphene oxide. The results show the adsorption ability of the substrate for both polar and dispersive liquids is enhanced after coating with graphene oxide. Molecular dynamics simulations are performed to investigate the internal wetting mechanism. By altering the composition of functional groups on the surface of graphene oxide, we discovered that, under the same degree of oxidation, hydroxyl groups on the surface of graphene oxide reduce the contact angles of DBP and n-dodecane, weakening their adhesion energy with the substrate. This article reveals the influence of graphene oxide on the wetting mechanism of organic contaminants and explores the reasons that affect the wetting properties of organic contaminants.