Adsorption of eosin Y on polyelectrolyte complexes based on chitosan and arabinogalactan sulfate

Positively charged polyelectrolyte complexes (PECs) were synthesized from two polysaccharides chitosan and arabinogalactan sulfate by self-assembly method as potentially efficient adsorbents for medical and environmental purposes. The obtained PEC particles of submicron size were comprehensively characterized by dynamic and electrophoretic light scattering, FTIR spectroscopy and scanning electron microscopy. The adsorption properties of the synthesized PECs were determined by optical methods using eosin Y as a model anionic dye. A temporal evolution of dye absorption spectra was revealed during the equilibration process in the eosin Y-PEC system; the decay can be described by three characteristic times with maximal value of 35 min. The adsorption within the pH range of 3.0-5.6 can be appropriately described by Langmuir-Freundlich model with the maximal adsorption capacity of 500 mg g(-1). The increase of ionic strength has no significant effect on adsorption capacity of PECs, however it results in the increase of the heterogeneity factor from 0.82 up to 2.35. The revealed relationships were discussed in terms of predominantly electrostatic adsorbate-adsorbent interactions. The synthesized PECs demonstrated high colloidal stability along with a high removal efficiency of dye at low pH values that makes them very attractive eco-friendly dye adsorbent with improved biocompatibility.