Nanosized Titania for Removing Cr(VI) and As(III) from Aqueous Solutions
Д. П. Ординарцев, Н. В. Печищева, А. А. Валеева, P. V. Zaitseva, A. D. Korobitsyna, А. А. Белозерова, A. A. Sushnikova, С. А. Петрова, K. Yu. Shunyaev, А. А. Rempel
Abstract
Results are described from studying the physicochemical properties of nanosized sorbents with a crystal structure of anatase and rutile, which are prepared by the high-energy milling of titania powders of respective modifications. Morphology, phase composition, and surface properties are studied by SEM, XRD, and XPS. The ξ-potential of sorbent suspensions as a function of pH is measured, and the point of zero charge is measured according to the shift in pH. It is found that milling for 8 h in an isopropyl alcohol medium results in a substantial increase in the number of crystallites with sizes of less than 10 nm; i.e., it greatly improves the sorption properties of titania with respect to ecotoxicants hexavalent chromium and trivalent arsenic ions, compared to the properties of the original material. The maximum amount of Cr(VI) is removed from aqueous solutions in acetate buffer medium at pH 5 and As(III) in hydrochloric acid medium at pH 2–3. A mechanism of adsorption is proposed.