Adsorption of Textile Dyes on Crosslinked Chitosan Particles:Kinetics, Equilibrium and Thermodynamics

Abstract

yıneric adsorbent by crosslinking ınethod characterized by ıneans of Fourier transforın inf ared (FTIR) spectra, scanning electron ıııicroscopy (SEM) and Brunauer, Eınınett and Teller (BET) surface area analysis. The crosslinked clıitosan particles were investigated for the reınoval availability of texti!e dyes f oın aqueous solution. For tlıis purpose, the adsorption of Diınozol Red (OR) and Dinıozol Yellow (OY) was studied in batch ınode under various paraıneters suclı as adsorbent dosage, pH, contact time, teınperature and initial dye conceııtration. The experiınental results show that the adsorption was pH dependent with a high adsorption capacity of DR and DY in acidic range. Adsorption of textile dye ions reached equilibrium concentration in 72 hours. The adsorption capacities of the synthesized chitosan was 26.6 mg/g for dye OR and 28.2 mg/g for dye OY. The pseudo-second­order kinetic nıodel provided the best fit to tlıe experinıental data for the adsorption of OR and OY textile dyes by the chitosan particles. The equilibriuın adsorption data were analyzed by Langınuir, Freundlich and Oubinin-Radushkevich isotherın models. Thermodynamic parameters such as enthalpy change (6H0 ), free energy change (6G0) and entropy change (6S0) were estimated. The adsorption process was found to be spoııtaııeous and exothermic in nature. Results indicated that the synthesized chitosan was slıowıı to be a proın ising adsorbent for the reınoval of dyes froııı aqueous solutions.