Interpretations about methylene blue adsorption by surface modified chitin using the statistical physics treatment

In this work, the adsorption of methylene blue (MB) on surface modified chitin (SMC) was studied at molecular level using the statistical physics theory. SMC adsorbent was prepared, characterized and applied for MB adsorption. Equilibrium curves were obtained at different temperatures (298, 308, 318 and 328 K) and interpreted by the statistical physics formulism. The parameters, such as, 'n' (number of adsorbed molecule(s) per site), 'N (m) ' (receptor site density) and 'c (1/2)' (concentration at half saturation) were estimated and interpreted in detail. At finally, an interaction mechanism was proposed. The results revealed that the MB adsorption on SMC can be successfully represented by the statistical physics theory. The statistical physics parameters showed that the physicochemical interactions between MB and SMC are dependent of the temperature. At 298 K, the MB molecules were anchored by one or two receptor sites, in parallel to the SMC surface (probably hydroxyl and N-acetyl groups on the SMC surface). Otherwise, at 308, 318 and 328 K, the 'n' values higher than 1, indicated a perpendicular anchorage.