title: Phosphine functionalised multiwalled carbon nanotubes: a new adsorbent for the removal of nickel from aqueous solution.
abstract: Synthesised triphenylphosphine-linked multiwalled carbon nanotubes (Tpp-MWCNTs) were used to study the adsorption of nickel in aqueous solutions and their adsorption capabilities were compared with purified MWCNTs. The adsorption capacity increased with an increase in pH for all adsorbents. The adsorption equilibrium was reached in 40 and 30 min for purified MWCNTs and Tpp-MWCNTs, respectively. Both Freundlich and Langmuir isotherms used to investigate the adsorption process fitted the experimental data well with the correlation coefficient R2 close to 1 for all adsorbents. On the other hand, the experimental data fitted well with a pseudo second-order model. The speciation of nickel also influenced the adsorption on the purified and Tpp-MWCNTs. The adsorbents used in this study showed superior adsorption capacity when compared to other adsorbents reported in the literature.
authors.affiliation: Department of Chemical Technology, University of Johannesburg, Doornfontein Campus P.O Box 17011, Johannesburg, South Africa.
authors.forename: Muleja Anga
authors.initials: MA
authors.lastname: Adolph
authors.forename: Yangkou Mbianda
authors.initials: YM
authors.lastname: Xavier
authors.forename: Pillay
authors.initials: P
authors.lastname: Kriveshini
authors.forename: Krause
authors.initials: K
authors.lastname: Rui
mesh_terms: D000327:Adsorption; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D046529:Microscopy, Electron, Transmission; D037742:Nanotubes, Carbon / Q000737:chemistry* / Q000648:ultrastructure; D009532:Nickel / Q000737:chemistry*; D010720:Phosphines / Q000737:chemistry*; D016062:Porosity; D013499:Surface Properties; D013997:Time Factors; D014874:Water Pollutants, Chemical / Q000737:chemistry*; D018508:Water Purification / Q000379:methods
chemical_list: D037742:Nanotubes, Carbon; D010720:Phosphines; D014874:Water Pollutants, Chemical; D009532:Nickel; C044646:phosphine