title: Sorption of Cu(II) Ions on Chitosan-Zeolite X Composites: Impact of Gelling and Drying Conditions.
abstract: Chitosan-zeolite Na-X composite beads with open porosity and different zeolite contents were prepared by an encapsulation method. Preparation conditions had to be optimised in order to stabilize the zeolite network during the polysaccharide gelling process. Composites and pure reference components were characterized using X-ray diffraction (XRD); scanning electron microscopy (SEM); N₂ adsorption-desorption; and thermogravimetric analysis (TG). Cu(II) sorption was investigated at pH 6. The choice of drying method used for the storage of the adsorbent severely affects the textural properties of the composite and the copper sorption effectiveness. The copper sorption capacity of chitosan hydrogel is about 190 mg·g(-1). More than 70% of this capacity is retained when the polysaccharide is stored as an aerogel after supercrititcal CO₂ drying, but nearly 90% of the capacity is lost after evaporative drying to a xerogel. Textural data and Cu(II) sorption data indicate that the properties of the zeolite-polysaccharide composites are not just the sum of the properties of the individual components. Whereas a chitosan coating impairs the accessibility of the microporosity of the zeolite; the presence of the zeolite improves the stability of the dispersion of chitosan upon supercritical drying and increases the affinity of the composites for Cu(II) cations. Chitosan-zeolite aerogels present Cu(II) sorption properties.
authors.affiliation: Institut Charles Gerhardt, UMR 5253 CNRS/UM2/ENSCM/UM1, Matériaux Avancés pour la Catalyse et la Santé, ENSCM, 8 rue Ecole Normale, 34296 Montpellier Cedex 5, France. djelad_am@yahoo.fr.|Laboratoire de Chimie Des Matériaux, Département de Chimie, Faculté des Sciences Exactes et Appliquées, Université Oran 1-Ahmed Benbella, B.P. 1524 Elmenaouar, Oran 31000, Algeria. djelad_am@yahoo.fr.
authors.forename: Amal
authors.initials: A
authors.lastname: Djelad
authors.affiliation: Faculté de Chimie, Université des Sciences et de la Technologie d'Oran-Mohamed Boudiaf, USTO, B.P. 1505 Elmenaouar, Oran 31000, Algeria. amine_morsli@yahoo.fr.
authors.forename: Amine
authors.initials: A
authors.lastname: Morsli
authors.affiliation: Institut Charles Gerhardt, UMR 5253 CNRS/UM2/ENSCM/UM1, Matériaux Avancés pour la Catalyse et la Santé, ENSCM, 8 rue Ecole Normale, 34296 Montpellier Cedex 5, France. mike.robitzer@enscm.fr.
authors.forename: Mike
authors.initials: M
authors.lastname: Robitzer
authors.affiliation: Laboratoire de Chimie Des Matériaux, Département de Chimie, Faculté des Sciences Exactes et Appliquées, Université Oran 1-Ahmed Benbella, B.P. 1524 Elmenaouar, Oran 31000, Algeria. abengueddach@gmail.com.
authors.forename: Abdelkader
authors.initials: A
authors.lastname: Bengueddach
authors.affiliation: Institut Charles Gerhardt, UMR 5253 CNRS/UM2/ENSCM/UM1, Matériaux Avancés pour la Catalyse et la Santé, ENSCM, 8 rue Ecole Normale, 34296 Montpellier Cedex 5, France. direnzo@enscm.fr.
authors.forename: Francesco
authors.initials: F
authors.lastname: di Renzo
authors.affiliation: Institut Charles Gerhardt, UMR 5253 CNRS/UM2/ENSCM/UM1, Matériaux Avancés pour la Catalyse et la Santé, ENSCM, 8 rue Ecole Normale, 34296 Montpellier Cedex 5, France. quignard@enscm.fr.
authors.forename: Françoise
authors.initials: F
authors.lastname: Quignard
mesh_terms: D000327:Adsorption; D002413:Cations, Divalent / Q000737:chemistry*; D048271:Chitosan / Q000737:chemistry*; D003300:Copper / Q000737:chemistry*; D005782:Gels; D053761:Nanocomposites / Q000737:chemistry* / Q000648:ultrastructure; D014961:X-Ray Diffraction; D017641:Zeolites / Q000737:chemistry*
chemical_list: D002413:Cations, Divalent; D005782:Gels; D017641:Zeolites; D003300:Copper; D048271:Chitosan
keywords: aerogel; biomass; chitosan; composites; metal sorption; zeolite X