Preparation and characterization of novel composites based on chitosan and clinoptilolite with enhanced adsorption properties for Cu2+.
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.
Dragan
Ecaterina Stela
ES
Department of Functional Polymers, Petru Poni Institute of Macromolecular Chemistry, Aleea Grigore Ghica Voda 41A, 700487 Iasi, Romania. sdragan@icmpp.ro
Dinu
Maria Valentina
MV
Timpu
Daniel
D
D000327:Adsorption; D048271:Chitosan / Q000737:chemistry*; D003300:Copper / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D008855:Microscopy, Electron, Scanning; D017641:Zeolites / Q000737:chemistry*
C083175:clinoptilolite; D017641:Zeolites; D003300:Copper; D048271:Chitosan