title: Electrochemically enhanced adsorption of nonylphenol on carbon nanotubes: Kinetics and isotherms study.
abstract: Removal of nonylphenol (NP) from aqueous solution has attracted widely attention due to its aquatic toxicity and potential to disrupt the endocrine system. In an effort to develop the effective and environment-friendly treatment method for NP, adsorption of 4-n-nonylphenol (4-NP) on multi-walled carbon nanotubes (MWCNTs) under electrochemical assistance was studied. The adsorption kinetics and isotherms were investigated at different polarization potentials and compared with those of open circuit (OC) and powder MWCNTs adsorption. The adsorption kinetics was simulated by the model including pseudo-first-order model, pseudo-second-order model and intraparticle diffusion model. The isotherm was simulated with Langmuir model and Freudlich model, respectively. Experimental results indicated that 4-NP is able to be efficiently removed at a potential of -0.6V. Comparing with that of powder MWCNTs adsorption, the initial adsorption rate υ0 at -0.6V increased 7.9-fold according to pseudo-second-order model and the maximum adsorption capacity qm improved 1.7-fold according to Langmuir model. The improved adsorption effect at negative potential was ascribed to enhanced π-π electron-donor-acceptor (EDA) interaction between 4-NP and MWCNTs under electrochemical assistance.
authors.affiliation: Key Laboratory of Industrial Ecology and Environmental Engineering (MOE), School of Environmental Science and Technology, Dalian University of Technology, Linggong Road 2, Dalian 116024, PR China.
authors.forename: Xiaona
authors.initials: X
authors.lastname: Li
authors.forename: Shuo
authors.initials: S
authors.lastname: Chen
authors.forename: Liying
authors.initials: L
authors.lastname: Li
authors.forename: Xie
authors.initials: X
authors.lastname: Quan
authors.forename: Huimin
authors.initials: H
authors.lastname: Zhao
mesh_terms: D000327:Adsorption; D055664:Electrochemical Techniques; D052244:Endocrine Disruptors / Q000302:isolation & purification*; D005618:Fresh Water / Q000737:chemistry*; D006860:Hydrogen Bonding; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D008855:Microscopy, Electron, Scanning; D015233:Models, Statistical; D037742:Nanotubes, Carbon / Q000737:chemistry* / Q000648:ultrastructure; D010636:Phenols / Q000302:isolation & purification*; D055672:Static Electricity; D013816:Thermodynamics; D014874:Water Pollutants, Chemical / Q000302:isolation & purification*
chemical_list: D052244:Endocrine Disruptors; D037742:Nanotubes, Carbon; D010636:Phenols; D014874:Water Pollutants, Chemical; C025256:nonylphenol
keywords: Electrosorption; Multi-walled carbon nanotubes; Nonylphenol