Page 54 - חוברת תזות הנדסה ירוקה 2023

ability to release the adsorbed Eu3+ ions from the polysaccharides I and A, and to recycle them, was tested, using different salts and acids: HNO3, HCl, KNO3, NaNO3, NaHPO4, EDTA, KH2O4P and NaHCO3, at concentrations of 0.25M and 0.5M. It was found that all of them were ineffective in the case of I. However, in the case of A, HCl and HNO3 were found to be effective for releasing the metal ions from the polysaccharide. Yet, the second adsorption cycle resulted in low sorption yields of about 7%, while washing the A with distilled water before the recycling increased the sorption yield to 40%. The adsorption of Eu3+ ions with two types of polysaccharide films, cross-linked with glutaraldehyde )GA(, was also tested. It was found that films of I with GA produced lower yields than those produced by the hydrogels of I. In the case of K, one of the films yielded lower percentages than those of the hydrogels, and the other type yielded similar percentages. Nonetheless, the resulting films were very stable in the solution, and could be easily separated without the use of ethanol. Finally, to study the interactions between the Eu3+ ions and the polysaccharides, and the structural changes that occurred in the polysaccharides resulting from the adsorption of the Eu3+ ions, several analyses were performed: ATR-FTIR, TGA, SEM-EDS, SEM and XPS. The findings indicated that the Eu3+ ions were, indeed, attached to the polysaccharides by means of their functional groups and caused changes in the material’s structures and properties.
Keywords: Carrageenan, Eu3+, Polysaccharides, Adsorption.
This paper was published, based on the research results attained by:
O. Levy-Ontman, C. Yanay, O. Paz-Tal, & A. Wolfson, ”Iota-carrageenan as sustainable bio-adsorbent for the removal of europium ions from aqueous solutions,“ Materials Today Communications, 32, 2022.
Book Of Abstracts | Class 2022
54