3.5. UV-vis Spectroscopy Analysis

Measurements of the UV–vis spectra at room temperature for CS, ZnAl, and ZnAl/CS solids were recorded on a SHIMADZU UV-2550 spectrophotometer (Kyoto, Japan). In order to record the measurements, a solution of chitosan (10⁻² g/L) was prepared by adding a stoichiometric amount of 10⁻¹ M perchloric acid to the chitosan solution. Given the water content and the degree of deacetylation of the chitosan, the chitosan–perchloric acid solution was then stirred at an appropriate speed to complete the dissolution before recording the measurements. Samples of ZnAl and ZnAl/CS were prepared by depositing the aqueous dispersions onto quartz glass slides and drying them in air. The concentration of ZnAl and the ratio of ZnAl to ZnAl/CS were the same for both the UV-Vis spectra.