Phthalates Adsorption on Nanostructures for Environmental Remediation: an ab initio Study

Abstract

Phthalates are organic molecules found in various everyday materials, such as plastics, but they do not bond chemically to the product. Consequently, they are released and contaminate the environment. In humans, ingesting phthalates can stimulate a functionality similar to estrogen hormones, acting as endocrine disruptors, thus requiring selective adsorption. This paper demonstrates the use of cyclodextrins (CDs), which are useful due to their capacity for selective adsorption by the inclusion of organic molecules in their internal cavities to remove pollutants from water. Graphene (Gr) is also evaluated due to its interesting electronic properties and a large surface, making this nanomaterial ideal for molecule adsorption. Through ab initio simulations, three phthalate molecules, benzyl butyl phthalate (BBP), dicyclohexyl-phthalate (DCHP), and dipropyl phthalate (DPP) interacting with β-CD and Gr, were evaluated. The results indicate that a weak interaction occurs, through physical adsorption. β-CD interacting with phthalates tends to form a host-guest complex. In the case of Gr, weak adsorption is favored by π-π interactions and H-bonds. Therefore, this study shows that these nanosystems are promising for removing phthalate molecules from wastewater.