Особливості комплексоутворення на поверхні кремнезему, що містить тіосечовинну групу

• Date: 2013
• Main Authors: Nazarchuk, G. I., Stolyarchuk, N. V., Melnyk, I. V., Goncharyk, V. P., Zub, Yu. I.
• Format: Article
• Language: Russian
• Published: Chuiko Institute of Surface Chemistry National Academy of Sciences of Ukraine 2013
• Online Access: https://surfacezbir.com.ua/index.php/surface/article/view/509
• Journal Title: Surface

The features of the complexes formation of the thiourea ligand groups with Hg2+ in the surface layers of sorbents is discussed in the work. It was shown that the sorbents obtained by templating method have high kinetic characteristics. In the case of xerogel, the sorption equilibrium was established only on day 4. It was determined that only 1:1 complexes are formed for the samples with low surface concentration of thiourea groups (1,6 µmol/m2). The highest SSC value (~ 355-370 mg/g) was also observed for the same samples. At concentrations of thiourea groups above 10 µmol/m2, initially formed complexes of 1:2, which, after increasing equilibrium concentration of the mercury (II) ions in the solution, were transformed into 1:1 complexes. Finally, when the surface layer has a polymeric structure, even the formation of 1:2 complexes does not ensure the participation of all thiourea groups in the complex formation, thereby substantially decreasing the SSC value. For all the sorbents, the absorption of Hg2+ ions is accompanied with a decrease in the pH value, indicating the transition of the portion of thiourea ligand groups to thiol form. This is consistent with IR spectroscopy data. There was demonstrated the possibility desorption of mercury (ІІ) from the surface of the used sorbents by triple treatment with 1M hydrochloric acid.