An X-ray photoelectron spectroscopy study of uranyl-chitosan interaction

An X-ray photoelectron spectroscopy study of uranium sorption by spherically-granulated chitosan in sulphate solutions, as well as the study of the nature of the U(VI) - chitosan interaction was carried out in this work. The X-ray photoelectron spectroscopy analysis showed that the uranyl - chitosan interaction results in the formation of complexes with aminogroup nitrogen, and possibly chitin ring oxygens and free hydroxyl groups in the equatorial plane. Under the UHV in the spectrometer chamber, the uranyl-amin and uranyl-hyroxide bonds were shown to break and tetravalent uranium compounds were shown to form on the sample surface. Hydroxyl groups were shown to evaporate. The calculated DG0 = -1,3 kJ/mol can be an evidence of several concurrent processes, some of which require energy, as well as of the formation of a surface chemical compound. U ovom radu prikazano je proucavanje sorpcije uranijuma sferno granuliranim hitosanom u sulfatnom rastvoru i prirode U(VI) - hitosan interakcije posredstvom rendgen-indukovane fotoelektronske spektroskopije. Fotoelektronskom spektroskopskom analizom potvrdjeno je da interakcija uranil - hitosan dobija oblik kompleksa sa azotnom aminogrupom, sa mogucim kiseonicima hitinskog ringa i slobodnim hidroksilnim grupama u ekvatorijalnoj ravni. U spektrometarskoj komori u ultravisokom vakuumu, pokazalo se da se veze uranil-amina i uranil-hidroksida kidaju, a da se legura tetravalentnog uranijuma obrazuje na povrsini uzorka dok hidroksilne grupe isparavaju. Izracunati DG0 = -1,3 kJ/mol moze se smatrati pokazateljem vise konkurentnih procesa od kojih neki zahtevaju energiju, kao i naznakom formiranja povrsinskih legura.