title: As-synthesized multi-walled carbon nanotubes for the removal of ionic and non-ionic surfactants.
abstract: This research deals with the application of untreated multi-walled carbon nanotubes (MWCNT) in their agglomerates form for the removal of non-ionic (TX-100), cationic (CTAB) and anionic (SDBS) surfactants from aqueous media. In order to optimize the removal process, the influence of several key parameters was investigated including contact time under different solid/liquid ratios, initial solution pH, temperature, along with ultrasonication assistance and desorption assays. Experimentations revealed that pH variation enhanced the removal capacities at optimum values of 6, 2 and 8 for TX-100, SDBS and CTAB, respectively, and that hydrophobic interaction is a major adsorption factor, especially for non-ionic surfactant with possible electrostatic interactions occurring for the ionic ones. As well, removal efficiencies peaked for an optimum temperature range between 35 and 45 °C. As for the ultrasonication assistance, it enhanced the overall removal capacities, especially that of the ionic surfactant, with an enhancement of 52% for the case of SDBS after 1h of treatment. The modeling results revealed that the pseudo-second order model provided the best correlation of the dynamic data and that the process was controlled by intraparticle diffusion phenomena. At equilibrium, and under optimized experimental conditions, untreated MWCNTs showed promising removal capacities with 359, 312 and 156 mg/g for TX-100, SDBS and CTAB, respectively.
authors.affiliation: Laboratory of Green Chemistry, Faculty of Technology, Lappeenranta University of Technology, Sammonkatu 12, 50130 Mikkeli, Finland. Electronic address: chaker.necibi@lut.fi.
authors.forename: Mohamed Chaker
authors.initials: MC
authors.lastname: Ncibi
authors.affiliation: Laboratoire COVACHIM-M2E, Université des Antilles et de la Guyane, BP 250, 97157 Pointe à Pitre Cedex, Guadeloupe, France.
authors.forename: Sarra
authors.initials: S
authors.lastname: Gaspard
authors.affiliation: Laboratory of Green Chemistry, Faculty of Technology, Lappeenranta University of Technology, Sammonkatu 12, 50130 Mikkeli, Finland.
authors.forename: Mika
authors.initials: M
authors.lastname: Sillanpää
mesh_terms: D000327:Adsorption; D001557:Benzenesulfonates / Q000032:analysis / Q000737:chemistry; D000077286:Cetrimonium; D002593:Cetrimonium Compounds / Q000032:analysis / Q000737:chemistry; D008855:Microscopy, Electron, Scanning; D037742:Nanotubes, Carbon / Q000737:chemistry*; D011092:Polyethylene Glycols / Q000032:analysis / Q000737:chemistry; D016062:Porosity; D013499:Surface Properties; D013501:Surface-Active Agents / Q000032:analysis* / Q000737:chemistry; D000069453:Ultrasonic Waves; D014874:Water Pollutants, Chemical / Q000032:analysis* / Q000737:chemistry; D018508:Water Purification / Q000379:methods*
chemical_list: D001557:Benzenesulfonates; D002593:Cetrimonium Compounds; D037742:Nanotubes, Carbon; D013501:Surface-Active Agents; D014874:Water Pollutants, Chemical; C551282:polyethylene glycol monooctylphenyl ether; D011092:Polyethylene Glycols; C001114:dodecylbenzenesulfonic acid; D000077286:Cetrimonium
keywords: Carbon nanotubes; Characterization; Optimization; Removal; Surfactants