title: Batch and column study: sorption of perfluorinated surfactants from water and cosolvent systems by Amberlite XAD resins.
abstract: Amberlite XAD resins have been employed to a great extent as the sorbent for removing or concentrating organic compounds from different matrices. We present for the first time a systematic study on the sorption of perfluorochemical (PFC) surfactants, an emerging class of environmental contaminants, by XAD-7HP (moderately polar) and XAD-2 (nonpolar). The results show that XAD-7HP can strongly sorb PFCs at circumneutral pH; the isotherm-determined linear sorption coefficient can reach 10(6)L/kg. On the other hand, the sorption coefficient for XAD-2 was two orders of magnitude lower than that for XAD-7HP. PFC sorption on XAD-7HP increased with an increase of the perfluorocarbon chain length of PFC and a decrease of the solution pH, indicating the importance of hydrophobic and electrostatic effects. The sorption coefficient for XAD-7HP reduced markedly with increasing fraction of the organic cosolvent (methanol) in the water-cosolvent mixture; however, the trend could not be predicted by a log-linear cosolvency model. Furthermore, the statistical analysis of column test results showed that after regeneration XAD-7HP can be used at least eight times without significant loss of performance. Finally, the experimental results imply that XAD-7HP sorption of shorter-chained PFCs (≤5 perfluorinated carbons) from water can be thermodynamically favorable.
authors.affiliation: Department of Civil Engineering, University of Minnesota, Minneapolis, MN 55414, USA. xiaox095@umn.edu
authors.forename: Feng
authors.initials: F
authors.lastname: Xiao
authors.forename: Kerry Jade
authors.initials: KJ
authors.lastname: Davidsavor
authors.forename: Sangyoo
authors.initials: S
authors.lastname: Park
authors.forename: Michio
authors.initials: M
authors.lastname: Nakayama
authors.forename: Brian Ray
authors.initials: BR
authors.lastname: Phillips
mesh_terms: D000327:Adsorption; D005466:Fluorocarbons / Q000737:chemistry*; D011137:Polystyrenes / Q000737:chemistry*; D012117:Resins, Synthetic / Q000737:chemistry*; D012997:Solvents / Q000737:chemistry*; D013501:Surface-Active Agents / Q000737:chemistry*; D013816:Thermodynamics; D014867:Water / Q000737:chemistry*
chemical_list: D005466:Fluorocarbons; D011137:Polystyrenes; D012117:Resins, Synthetic; D012997:Solvents; D013501:Surface-Active Agents; D014867:Water; C003771:Amberlite XAD-2 resin