title: Preparation and characterization of novel composites based on chitosan and clinoptilolite with enhanced adsorption properties for Cu2+.
abstract: Novel ionic composites based on chitosan (CS) and clinoptilolite (CPL), a widespread natural zeolite, were prepared in this work as microspheres by a "tandem" ionic/covalent cross-linking. The mass ratio between CPL and CS was varied in the range 1:10-1:2. The ionic gelation of CS was performed with sodium tripolyphosphate and epichlorohydrin was used as covalent cross-linker. An abrupt increase of the adsorption capacity for Cu(2+) with the increase of the CPL content loaded in the composite compared with cross-linked CS was observed, up to 20 wt.% of CPL. The external stimuli which control the adsorption of Cu(2+) were solution pH and temperature. The optimum adsorption pH was 5.0 and the adsorption process was well described by the pseudo-second-order kinetics. The maximum adsorption capacity of metal ions was observed after the 2nd cycle of adsorption, for all composites.
authors.affiliation: Department of Functional Polymers, Petru Poni Institute of Macromolecular Chemistry, Aleea Grigore Ghica Voda 41A, 700487 Iasi, Romania. sdragan@icmpp.ro
authors.forename: Ecaterina Stela
authors.initials: ES
authors.lastname: Dragan
authors.forename: Maria Valentina
authors.initials: MV
authors.lastname: Dinu
authors.forename: Daniel
authors.initials: D
authors.lastname: Timpu
mesh_terms: D000327:Adsorption; D048271:Chitosan / Q000737:chemistry*; D003300:Copper / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D008855:Microscopy, Electron, Scanning; D017641:Zeolites / Q000737:chemistry*
chemical_list: C083175:clinoptilolite; D017641:Zeolites; D003300:Copper; D048271:Chitosan