Surface-Mediated Extraction and Photoresponse Modulation of Bisphenol A Derivatives: A Computational Study

Abstract

2,2'-bis(4-hydroxyphenyl) propane (BPA) and its metabolites 4-methyl-2,4-bis(p-hydroxyphenyl)pent-2-ene (M-1) and 4-methyl-2,4-bis(4-hydroxyphenyl)pent-1-ene (M-2) are common in drinking water and hard plastics and thus pose serious health hazards. These are also known as endocrine disrupting chemicals (EDCs). In this paper, we discuss the surface-mediated adsorption mechanism and subsequent changes in the electronic structure of EDCs. This is in view of their separation from environment and possible photodecomposition. Computational investigation based on density functional theory and ab initio molecular dynamics was performed on bisphenol compounds (BPA, M-1, and M-2) as guest and affinity-based separation media as substrate. Static properties (at 0 K) and conformational dynamics upon physisorption (at T = 300 K) depict the potential of 2H-MoS2 surface for reversible adsorption/desorption and selective isolation of these EDCs. In contrast, layered graphene supports very strong surface adsorption and assures complete removal of EDCs. In particular, optical response of the EDCs gets tuned upon surface adsorption. Hence, understanding the surface adsorption and modulation of the electronic structure would reveal possible means for extraction and photodegradation of a major class of environmental pollutants by specific choice of surface.