화학공학소재연구정보센터
Chemical Engineering Journal, Vol.217, 256-265, 2013
Graphite oxide/chitosan composite for reactive dye removal
In the current work a novel composite material consisted of cross-linked chitosan (Ch) and graphite oxide (GO) (and not graphene oxide, as numerous studies deal with) was prepared for the removal of Reactive Black 5 dye. After synthesis, the full characterization with various techniques (SEM/EDAX, FTIR, XRD, DTA, DTG, TGA) was achieved revealing many possible interactions/forces of dye-composite system. Through the latter interactions, the possible adsorption mechanism was elucidated and explained. Also, the adsorption evaluation of the composite material presented high adsorption capacity (277 mg/g at 25 degrees C). Equilibrium experiments are also performed studying the effect of pH on adsorption (optimum 2) and desorption (optimum 12), initial dye concentration, contact time (pseudo-first, -second order equations and a generalized fractal kinetic model), temperature (isotherms at 25, 45 and 65 degrees C fitted to Langmuir, Freundlich, Langmuir-Freundlich model) and ionic strength. A full thermodynamic evaluation was carried out, calculating the parameters of enthalpy, free energy and entropy (Delta H-0, Delta G(0), and Delta S-0). The adsorption behavior of the composite material was also compared with the respective of its components (GO and Ch). (C) 2012 Elsevier B.V. All rights reserved.