Determining the Mechanism of Gold Concentration from Solution on BAU-A Charcoal under Ultraviolet Irradiation
T. V. SMOLKINA1, A. S. BUYNOVSKIY1, P. B. MOLOKOV1, L. M. LEVCHENKO2, and N. A. KOLPAKOVA3
1 Seversk Technological Institute, Branch State Budget Educational Institution of Higher Professional Education “National Research Nuclear University MEPhl”
2 Nikolaev Institute of Inorganic Chemistry, Siberian Branch of the Russian Academy of Sciences
3 National Research Tomsk Polytechnical University
t-smolkina@mail.ru
Keywords: activated carbon BAU-A, oxygenated surface functional groups, ultraviolet irradiation, adsorption, tetrachloroaurate ion, Fourier transform infrared spectroscopy
Pages: 187-194
Abstract
Using the method of Fourier transform infrared spectroscopy, a study was performed concerning the composition of surface functional groups inherent in birch activated carbon BAU-A as well as changing their qualitative and quantitative composition in the course of gold sorption from chloride solutions with different composition under the action of ultraviolet irradiation and without it. It has been demonstrated that under the action of UV irradiation the amount of hydroxyl groups on the surface of birch activated carbon exhibits an increase, which results in an increase in its sorption capacity for [AuCl4]– anions. The method of EXAFS spectroscopy revealed that after the sorption from hydrochloric acid solutions, gold on the surface of birch activated carbon is in the form of dimers Au2Cl6 both after ultraviolet irradiation and without it. The sorption mechanism is suggested to involve the following stages: ion exchange of surface hydroxyl groups for the complex ions [AuCl4]– as well as the formation of dimers Au2Cl6 on the surface of carbon.
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