title: Enhanced adsorption of PFOA and PFOS on multiwalled carbon nanotubes under electrochemical assistance.
abstract: Removal of perfluorooctanoic acid (PFOA) and perfluorooctane sulfonate (PFOS) from aqueous solution has attracted wide attention in light of their environmental persistence, bioaccumulation, and potential toxicity. Although various destructive technologies were developed, removal of PFOX (X = A and S) under mild conditions are still desirable. In this work, multiwalled carbon nanotubes (MWNTs) were applied to remove PFOX in electrochemically assistant adsorption. Electrosorption kinetics and isotherms were investigated relative to open circuit (OC) adsorption and adsorption on powder MWNTs. Compared with powder MWNTs adsorption, the initial adsorption rate (υ(0)) of 100 μg/L PFOX at 0.6 V increased 60-fold (PFOA) and 41-fold (PFOS) according to pseudosecond-order kinetics model and the maximum electrosorption capacity (q(m)) of PFOX (50 μg/L to 10 mg/L) increased 150-fold (PFOA) and 94-fold (PFOS) simulated with Langmuir model. These significant improvements were assumed to benefit from enhanced electrostatic attraction under electrochemical assistance. Furthermore, the used MWNTs were found to be regenerative and reusable. This work provides not only a new approach to effective removal of perfluorochemicals from aqueous solution but also a low energy-consumption and environmentally-friendly strategy for application of carbon nanotubes in water treatment.
authors.affiliation: Key Laboratory of Industrial Ecology and Environmental Engineering (Ministry of Education), School of Environmental Science and Technology, Dalian University of Technology , Linggong Road 2, Dalian 116024, People's Republic of China.
authors.forename: Xiaona
authors.initials: X
authors.lastname: Li
authors.forename: Shuo
authors.initials: S
authors.lastname: Chen
authors.forename: Xie
authors.initials: X
authors.lastname: Quan
authors.forename: Yaobin
authors.initials: Y
authors.lastname: Zhang
mesh_terms: D000327:Adsorption; D017738:Alkanesulfonic Acids / Q000737:chemistry*; D002210:Caprylates / Q000737:chemistry*; D055664:Electrochemical Techniques / Q000379:methods*; D004566:Electrodes; D004573:Electrolytes / Q000737:chemistry; D005466:Fluorocarbons / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D008956:Models, Chemical; D037742:Nanotubes, Carbon / Q000737:chemistry* / Q000648:ultrastructure; D059027:Recycling; D013696:Temperature
chemical_list: D017738:Alkanesulfonic Acids; D002210:Caprylates; D004573:Electrolytes; D005466:Fluorocarbons; D037742:Nanotubes, Carbon; C023036:perfluorooctanoic acid; C076994:perfluorooctane sulfonic acid