In silico approach to investigating the adsorption mechanisms of short chain perfluorinated sulfonic acids and perfluorooctane sulfonic acid on hydrated hematite surface. (1st May 2017)

• Record Type: Journal Article
• Authors: Feng, Hongru; Lin, Yuan; Sun, Yuzhen; Cao, Huiming; Fu, Jianjie; Gao, Ke; Zhang, Aiqian
• Is Part Of: Water research. Volume 114(2017)
• Page Start: 144
• Page End: 150
• Publication Date: 2017-05-01
• Subjects: Perfluorinated sulfonic acids -- Forcite -- CASTEP -- Adsorption; PFSA perfluorinated sulfonic acids -- PFBS perfluorobutane sulfonic acid -- PFPS perfluoropentane sulfonic acid -- PFHxS perfluorohexane sulfonic acid -- PFHpS perfluoroheptane sulfonic acid -- PFOS perfluorooctane sulfonic acid -- DFT density functional theory -- MD molecular dynamics -- COMPASS condensed-phase optimized molecular potentials for atomistic simulation studies -- RDF radial distribution function; Water -- Pollution -- Research -- Periodicals; 363.7394
• DOI: 10.1016/j.watres.2017.02.024
• Languages: English
• ISSNs: 0043-1354

Abstract

Abstract: Short chain perfluorinated sulfonic acids (PFSAs) that were introduced as alternatives for perfluorooctane sulfonic acid (PFOS) have been widely produced and used. However, few studies have investigated the environmental process of short chain PFSAs, and the related adsorption mechanisms still need to be uncovered. The water-oxide interface is one of the major environmental interfaces that plays an important role in affecting the adsorption behaviour and transport potential of the environmental pollutant. In this study, we performed molecular dynamics simulations and quantum chemistry calculations to investigate the adsorption mechanisms of five PFSAs and their adsorption on hydrated hematite surface as well. Different to the vertical configuration reported for PFOS on titanium oxide, all PFSAs share the same adsorption configuration as the long carbon chains parallel to the surface. The formation of hydrogen bonds between F and inter-surface H helps to stabilize the unique configuration. As a result, the sorption capacity increases with increasing C-F chain length. Moreover, both calculated adsorption energy and partial density of states (PDOS) analysis demonstrate a PFSAs adsorption mechanism in between physical and chemical adsorption because the hydrogen bonds formed by the overlap of F ( p ) orbital and H ( s ) orbital are weak intermolecular interactions while the physical adsorption are mainly ascribed to the electrostatic interactions. This massive calculation provides a new insight into the pollutant adsorption behaviour, and in particular, may help to evaluate the environmental influence of pollutants. Graphical abstract: Highlights: Models of PFSAs adsorption on hydrated hematite (0 0 0 1) surface are presented. PFOS have higher adsorption intensity than other short chain PFSAs on hematite/water interface. The mechanism relies on the fluorine-hydrogen interaction is presented. An appeal to the public to be vigilant of the potential problems may be caused by the short chain PFSAs in environment.