Sorption of iodine-containing vapor onto chitosan

The kinetics of sorption of vapor over aqueous and aqueous-alcoholic solutions of potassium iodide and potassium iodine-iodide and over crystalline iodine onto chitosan powder or film was studied. The vapor diffusion coefficients in the initial and final sorption steps were calculated from the data obtained. For all the chitosan-sorbate vapor systems studied, the mass transfer relationships are not described by Fick's law and are characterized by anomalous sorption kinetics. The properties of chitosan powder after the uptake of the sorbate vapor were evaluated by electronic and IR spectroscopy, X-ray diffraction, and differential thermal and thermal gravimetric analysis. Sorption of iodine-containing vapor onto the polymer is accompanied by complexation of the components. The iodine-chitosan complexes are stable in storage and resistant to heat treatment. The results obtained served as a basis for developing a procedure for preparing kinetically and thermally stable powdered iodinated chitosan derivatives.