Adsorption of Anionic Metallophthalocyanines on Submicron Chitosan-Sulfate Particles in Aqueous Dispersions

The kinetic and capacity of the anionic metallophthalocyanines adsorption on the submicron chitosan-sulfate particles in aqueous dispersions were examined. Phthalocyanine dyes differing in the molecular size, as well as in the number and nature of the anionic groups, were used as model adsorbates. The suitability of well-known mathematical models for describing the adsorption kinetics was analyzed. Using the graphical testing method it was shown that the adsorption kinetics data are best fitted by the Ho-McKay pseudo-second-order model. The maximum adsorption is independent of the molecular size and tends to increase with decreasing solubility of the dye under the experimental conditions. It was proved that sulfonated metallophthalocyanines in the adsorption process partially replace the sulfate ions, thereby acting as polyanionic cross-linkers in the chitosan particle structure. Comparative evaluation of the dye desorption rates in the phosphate buffer was carried out.