Adsorption behaviour of copper onto a novel modified chitosan material: thermodynamic study

摘要

The adsorption behaviour of Cu(II) was investigated in the presence of a new material. This material was obtained from chitosan (Ch) and polyvinyl alcohol (PVA) at different weight percentages (35/65, 50/50 and 65/35), dripping this mixture in a NaOH solution, and then subjecting to crosslinking reaction under nitrogen atmosphere at 353K with ethylene glycol diglycidyl ether to improve its resistance to acids and alkalis. Adsorption test were conducted to evaluate the optimal Ch/PVA ratio, 35/65 ratio presented the best adsorption capacity. The interaction between Cu(II) and functional groups of Ch/PVA was determined by Fourier transformed infrared spectroscopy. Kinetics and isotherm experiments were performed to evaluate the adsorption behaviour of Cu(II). The kinetic experimental data were best fitted to pseudo-second-order model and equilibrium data to the Langmuir model. Thermodynamics parameters such as free Gibbs energy (G degrees), enthalpy (H degrees) and entropy (S degrees) were calculated. These parameters indicated spontaneous and endothermic adsorption process.