Preparation,Characterization and Luminescence Study of Chitosan Membrane and Powder Forms with Eu3 + and Tb3 +

Chitosan membranes with trivalent lanthanide ion Eu^{3 +} were prepared at a ratio of 3:1 w/w (chitosan:lanthanide). There was no membrane formation at a ratio of 1:1 w/w (chitosan: Eu^{3 +} or Tb^{3 +}); in this case a white solid powder was obtained. Both chitosan compounds were characterized by elemental analysis (CHN), thermal analysis (TG/DTG), scanning electron microscopy (SEM) and luminescence spectroscopy. CHN analysis was performed only for chitosan compounds in powder form, suggesting that these compounds have the general formula QUILn.6H₂O, where QUI = Chitosan and Ln = Eu^{3 +} or Tb^{3 +}. The results of TG/DTG curves for chitosan membranes with Eu^{3 +} ion indicate that the introduction of this metal into the chitosan structure causes gradual degradation in residual carbons, showing lower weight loss in the Eu^{3 +} membranes compared to pure chitosan membrane. Analysis of luminescence demonstrated that chitosan membranes with Eu^{3 +} ion exhibit emission in the visible region, showing emission bands from chitosan and Eu^{3 +} moieties. For chitosan with Eu^{3 +} and Tb^{3 +} ions compounds, in powder form, the analysis of luminescence suggested that chitosan is not transferring energy to the lanthanide ion; however, the chemical region where the lanthanide ion is found breaks the selection rules and favors the emission of these ions.