title: Adsorption of a cationic surfactant by a magsorbent based on magnetic alginate beads.
abstract: Adsorption of cetylpyridinium chloride (CPC), a cationic surfactant, by magnetic alginate beads (MagAlgbeads) was investigated. The magnetic adsorbent (called magsorbent) was prepared by encapsulation of magnetic functionalized nanoparticles in an alginate gel. The influence on CPC adsorption of several parameters such as contact time, pH and initial surfactant concentration was studied. The equilibrium isotherm shows that adsorption occurs through both electrostatic interactions with charge neutralization of the carboxylate groups of the beads and hydrophobic interactions inducing the formation of surfactant aggregates in the beads. The dosage of calcium ions released in the solution turns out to be a useful tool for understanding the adsorption mechanisms. Adsorption is accompanied by a shrinking of the beads that corresponds to a 45% reduction of the volume. Adsorption kinetic experiments show that equilibrium time is strongly dependent on the surfactant concentration, which monitors the nature of the interactions. On the other hand, since the pH affects the ionization state of adsorption sites, adsorption depends on the pH solution, maximum adsorption being obtained in a large pH range (3.2-12) in agreement with the pKa value of alginate (pKa=3.4-4.2). Finally, due to the formation of micelle-like surfactants aggregates in the magnetic alginate beads, they could be used as a new efficient magsorbent for hydrophobic pollutants.
authors.affiliation: Sorbonne Universités, UPMC Univ Paris 06, UMR 8234, PHENIX, F-75005 Paris, France; CNRS, UMR 8234, PHENIX, F-75005 Paris, France; Utilities Performance - Eau et Industrie 14, Rue des Écoles Saint-Nicolas-des-Eaux, 56930 Pluméliau, France. Electronic address: layaly.obeid@upmc.fr.
authors.forename: Layaly
authors.initials: L
authors.lastname: Obeid
authors.affiliation: Sorbonne Universités, UPMC Univ Paris 06, UMR 8234, PHENIX, F-75005 Paris, France; CNRS, UMR 8234, PHENIX, F-75005 Paris, France. Electronic address: nelkolli@yahoo.fr.
authors.forename: Nadia
authors.initials: N
authors.lastname: El Kolli
authors.affiliation: Sorbonne Universités, UPMC Univ Paris 06, UMR 8234, PHENIX, F-75005 Paris, France; CNRS, UMR 8234, PHENIX, F-75005 Paris, France. Electronic address: noelle.dali@gmail.com.
authors.forename: Noëlle
authors.initials: N
authors.lastname: Dali
authors.affiliation: Sorbonne Universités, UPMC Univ Paris 06, UMR 8234, PHENIX, F-75005 Paris, France; CNRS, UMR 8234, PHENIX, F-75005 Paris, France. Electronic address: delphine.talbot@upmc.fr.
authors.forename: Delphine
authors.initials: D
authors.lastname: Talbot
authors.affiliation: Sorbonne Universités, UPMC Univ Paris 06, UMR 8234, PHENIX, F-75005 Paris, France; CNRS, UMR 8234, PHENIX, F-75005 Paris, France. Electronic address: sebastien.abramson@upmc.fr.
authors.forename: Sébastien
authors.initials: S
authors.lastname: Abramson
authors.affiliation: Utilities Performance - Eau et Industrie 14, Rue des Écoles Saint-Nicolas-des-Eaux, 56930 Pluméliau, France. Electronic address: m.welschbillig@utilities-performance.com.
authors.forename: Mathias
authors.initials: M
authors.lastname: Welschbillig
authors.affiliation: Sorbonne Universités, UPMC Univ Paris 06, UMR 8234, PHENIX, F-75005 Paris, France; CNRS, UMR 8234, PHENIX, F-75005 Paris, France. Electronic address: valerie.cabuil@upmc.fr.
authors.forename: Valérie
authors.initials: V
authors.lastname: Cabuil
authors.affiliation: Sorbonne Universités, UPMC Univ Paris 06, UMR 8234, PHENIX, F-75005 Paris, France; CNRS, UMR 8234, PHENIX, F-75005 Paris, France. Electronic address: agnes.bee@upmc.fr.
authors.forename: Agnès
authors.initials: A
authors.lastname: Bée
keywords: Adsorption; Alginate; Alginate bead; Beads; Cetylpyridinium chloride; Ferrofluid; Magnetic; Magsorbent; Surfactant; Water remediation