Abstract
The ability of glutaraldehyde cross-linked chitosan beads (GCC beads) as synthetic adsorbent for adsorptive removal of Pb(II) ions from aqueous solutions is investigated in the present study. The biosorbent has been characterised by Brunner, Emmett, and Teller (BET) analysis, Fourier transform infrared (FTIR) spectroscopy and scanning electron microscopy (SEM) techniques. Equilibrium and column flow adsorption characteristics of Pb(II) ions on the biosorbent were studied. The effects of experimental variable parameters such as pH, concentration of metal ion, amount of adsorbent, contact time, temperature and interfering ions on adsorption have been investigated. The equilibrium data are fitted to pseudo-first order, pseudosecond order, fractionary order, chemisorption, Weber-Morris and Boyd models. Based on R-2 and error function values, it is observed that the kinetic data are better fitted to pseudo-second-order kinetic model and chemisorption model. The experimental data are analysed using Langmuir, Freundlich, and Sips adsorption isotherm models. The monolayer adsorption capacity of GCC beads as obtained from Langmuir isotherm at 35 degrees C is found to be 204.0 mg/g. The thermodynamic constants of the adsorption process: Delta H-0, Delta S-0 and Delta G(0) are evaluated. The results show that biosorption of Pb(II) ions on GCC beads are endothermic and spontaneous.