title: Sorption of perfluorooctanoic acid, perfluorooctane sulfonate and perfluoroheptanoic acid on granular activated carbon.
abstract: The sorption of perfluorooctane sulfonate (PFOS), perfluorooctanoic acid (PFOA), and perfluoroheptanoic acid (PFHpA) on granular activated carbon (GAC) was characterized and compared to explore the underlying mechanisms. Sorption of the three perfluoroalkyl acids (PFAAs) on GAC appeared to be a rapid intra-particle diffusion process, which were well represented by the pseudo-second-order rate model with the sorption rate following the order PFOS > PFOA > PFHpA. Sorption isotherm data were well fitted by the Freundlich model with the sorption capacity (Kf) of PFOS, PFOA and PFHpA being 4.45, 2.42 and 1.66 respectively. This suggests that the hydrophilic head group on PFAAs, i.e. sulfonate vs carboxylic, has a strong influence on their sorption. Comparison between PFOA and PFHpA revealed that hydrophobicity could also play a role in the sorption of PFAAs on GAC when the fluorocarbon chain length is different. Analyses using Attenuated Total Reflection (ATR)-Fourier Transform Infrared (FTIR) spectroscopy suggested possible formation of a negative charge-assisted H-bond between PFAAs and the functionalities on GAC surfaces, including non-aromatic ketones, sulfides, and halogenated hydrocarbons.
authors.affiliation: Department of Resources and Environmental Science, Northeast Agricultural University, Harbin, Heilongjiang 150030, China; Department of Crop and Soil Sciences, University of Georgia, Griffin, GA 30223, USA.
authors.forename: Di
authors.initials: D
authors.lastname: Zhang
authors.affiliation: Department of Crop and Soil Sciences, University of Georgia, Griffin, GA 30223, USA.
authors.forename: Qi
authors.initials: Q
authors.lastname: Luo
authors.affiliation: Department of Agricultural and Biological Engineering, University of Florida, Gainesville, FL 32611, USA.
authors.forename: Bin
authors.initials: B
authors.lastname: Gao
authors.affiliation: AECOM Inc., Environment, Atlanta, GA 30309, USA.
authors.forename: Sheau-Yun Dora
authors.initials: SY
authors.lastname: Chiang
authors.affiliation: AECOM Inc., Environment, Mechanicsburg, PA 17055, USA.
authors.forename: David
authors.initials: D
authors.lastname: Woodward
authors.affiliation: Department of Crop and Soil Sciences, University of Georgia, Griffin, GA 30223, USA. Electronic address: qhuang@uga.edu.
authors.forename: Qingguo
authors.initials: Q
authors.lastname: Huang
mesh_terms: D000327:Adsorption; D017738:Alkanesulfonic Acids / Q000737:chemistry*; D002210:Caprylates / Q000737:chemistry*; D002606:Charcoal / Q000737:chemistry*; D005466:Fluorocarbons / Q000737:chemistry*; D014874:Water Pollutants, Chemical / Q000737:chemistry
chemical_list: D017738:Alkanesulfonic Acids; D002210:Caprylates; D005466:Fluorocarbons; D014874:Water Pollutants, Chemical; D002606:Charcoal; C023036:perfluorooctanoic acid; C076994:perfluorooctane sulfonic acid
keywords: Attenuated Total Reflection -Fourier Transform Infrared (ATR-FTIR); Granular activated carbon (GAC); Perfluorinated alkyl substances (PFAAs); Sorption isotherm; Sorption kinetics