title: Enhanced sorption of perfluorooctane sulfonate (PFOS) on carbon nanotube-filled electrospun nanofibrous membranes.
abstract: Multi-walled carbon nanotube-filled electrospun nanofibrous membranes (MWCNT-ENFMs) were prepared by electrospinning. The addition of MWCNTs (0.5 wt.% vs. ENFMs) doubled the specific surface area and tensile strength of the ENFMs. The MWCNT-ENFMs were used to adsorb perfluorooctane sulfonate (PFOS) in aqueous solutions. The sorption kinetics results showed that the sorption rate of PFOS onto the MWCNT-ENFMs was much higher than the sorption rate of PFOS onto the pure ENFMs control, and the pseudo-second-order model (PSOM) described the sorption kinetics well. The sorption isotherms indicated that the sorption capacity of the MWCNT-ENFMs for PFOS (16.29±0.26 μmol g(-1)) increased approximately 18 times, compared with the pure ENFMs (0.92±0.06 μmol g(-1)). Moreover, the solution pH significantly affected the sorption efficiency and sorption mechanism. The MWCNT-ENFMs were negatively charged from pH 2.0-10.0, but the electrostatic repulsion between the MWCNT-ENFMs and PFOS was overcome by the hydrophobic interactions between PFOS and the MWCNTs or nanofibers. The strong hydrophobic interactions between PFOS and the MWCNTs played a dominant role in the sorption process. For the pure ENFMs, the electrostatic repulsion was conquered by the hydrophobic interactions between PFOS and the nanofibers at pH>3.1. In addition to the hydrophobic interactions, an electrostatic attraction between PFOS and the pure ENFMs was involved in the sorption process at pH<3.1.
authors.affiliation: State Key Laboratory of Water Environment Simulation, School of Environment, Beijing Normal University, Beijing 100875, PR China.
authors.forename: Yunrong
authors.initials: Y
authors.lastname: Dai
authors.forename: Junfeng
authors.initials: J
authors.lastname: Niu
authors.forename: Lifeng
authors.initials: L
authors.lastname: Yin
authors.forename: Jiangjie
authors.initials: J
authors.lastname: Xu
authors.forename: Kang
authors.initials: K
authors.lastname: Sun
mesh_terms: D000327:Adsorption; D017738:Alkanesulfonic Acids / Q000032:analysis / Q000737:chemistry*; D005466:Fluorocarbons / Q000032:analysis / Q000737:chemistry*; D057927:Hydrophobic and Hydrophilic Interactions; D007700:Kinetics; D037742:Nanotubes, Carbon / Q000737:chemistry*; D014865:Waste Disposal, Fluid / Q000379:methods; D014874:Water Pollutants, Chemical / Q000032:analysis / Q000737:chemistry*; D018508:Water Purification / Q000379:methods
chemical_list: D017738:Alkanesulfonic Acids; D005466:Fluorocarbons; D037742:Nanotubes, Carbon; D014874:Water Pollutants, Chemical; C076994:perfluorooctane sulfonic acid
keywords: Carbon nanotubes; Electrospun nanofibrous membranes; PFOS; Sorption; Water purification