title: Dechlorination Mechanism of 2,4-Dichlorophenol by Magnetic MWCNTs Supported Pd/Fe Nanohybrids: Rapid Adsorption, Gradual Dechlorination, and Desorption of Phenol.
abstract: 2,4-dichlorophenol was effectively removed from water using magnetic Pd/Fe nanoparticles supported on multiwalled carbon nanotubes (MWCNTs). The adsorption kinetics, isotherms, and energy for 2,4-dichlorophenol and its partially (4-chlorophenol, 2-chlorophenol) and completely (phenol) dechlorinated products are presented and discussed. The adsorption capacity was 2,4-dichlorophenol > 4-chlorophenol > 2-chlorophenol > phenol for MWCNTs. MWCNTs-Fe3O4-Pd/Fe nanohybrids provided rapid adsorption, gradual dechlorination, and final desorption of phenol, which is attractive as a remediation technology. Over 82.7% of the phenol was desorbed and released to the aqueous phase after 72 h due to its low adsorption capacity, leaving the majority of active sites available on the surface of MWCNTs-Fe3O4-Pd/Fe. The nanohybrids maintained high activity in five consecutive in situ experiments, and they were retrievable using magnetic separation. MWCNTs-Fe3O4-Pd/Fe nanohybrids outperform unsupported Pd/Fe nanoparticles, which were difficult to retrieve, and were easily passivated and aggregated.
authors.affiliation: State Key Laboratory of Estuarine and Coastal Research, East China Normal University , Shanghai 200062, China.
authors.forename: Jiang
authors.initials: J
authors.lastname: Xu
authors.affiliation: State Key Laboratory of Estuarine and Coastal Research, East China Normal University , Shanghai 200062, China.
authors.forename: Xue
authors.initials: X
authors.lastname: Liu
authors.affiliation: Department of Civil and Environmental Engineering, Carnegie Mellon University , Pittsburgh, Pennsylvania 15213, United States.|Center for Environmental Implications of Nanotechnology, Carnegie Mellon University , Pittsburgh, Pennsylvania 15213, United States.
authors.forename: Gregory Victor
authors.initials: GV
authors.lastname: Lowry
authors.affiliation: State Key Laboratory of Estuarine and Coastal Research, East China Normal University , Shanghai 200062, China.
authors.forename: Zhen
authors.initials: Z
authors.lastname: Cao
authors.affiliation: State Key Laboratory of Estuarine and Coastal Research, East China Normal University , Shanghai 200062, China.
authors.forename: Heng
authors.initials: H
authors.lastname: Zhao
authors.affiliation: School of Civil and Environmental Engineering, University of Technology Sydney , Ultimo, NSW 2007, Australia.
authors.forename: John L
authors.initials: JL
authors.lastname: Zhou
authors.affiliation: Department of Environmental Engineering, Zhejiang University , Hangzhou 310058, China.
authors.forename: Xinhua
authors.initials: X
authors.lastname: Xu
keywords: 2,4-dichlorophenol; MWCNTs-Fe3O4−Pd/Fe nanohybrids; adsorption; catalytic dechlorination; desorption