Photoadsorption of Cr(VI) on titanium dioxide modified by high-energy milling

• Published in: Inorganic chemistry communications Vol. 154; p. 110968
• Main Authors: Pechishcheva, N.V., Ordinartsev, D.P., Valeeva, A.A., Zaitceva, P.V., Korobitsyna, A.D., Sushnikova, A.A., Petrova, S.A., Shunyaev, K.Yu, Rempel, A.A.
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01-08-2023
• Subjects: Adsorption; chromium(VI); High energy milling; Photoadsorption; Photocatalysis; Titanium dioxide; chromium(VI); High energy milling; Adsorption; Photoadsorption; Titanium dioxide; Photocatalysis
• ISSN: 1387-7003; 1879-0259
• DOI: 10.1016/j.inoche.2023.110968

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•Nanosized rutile and anatase were obtained by high-energy milling.•Milling improve the ability to adsorb Crtot and remove Cr(VI) under UV-irradiation.•Acetic buffer presence in solution improve chromium photoadsorption by TiO2.•Milled anatase samplewassuccessfully used to removeCr(VI)from a real wastewater.
Microcrystalline powders of rutile and anatase were milled in a high-energy planetary mill down to obtain nanosized TiO2 powders (the size of coherent scattering region (CSR) about 30 nm and 60 nm, respectively). The resulting powders were characterized by HRTEM, Brunauer-Emmett-Teller (BET), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and the ξ-potential of the aqueous suspensions was determined. High-energy milling made it possible to significantly increase the ability of TiO2 to remove chromium from aqueous solutions. The effectiveness of the powders for not only Cr(VI) removing but also total chromium adsorption under UV-irradiation and short wavelength visible light has been shown. This is important, since Cr(III) does not remain in the aqueous medium and cannot be oxidized back to Cr(VI) under the influence of some environmental factors. It is possible to remove more than 99.9 % of total chromium and 100 % of chromium hexavalent from a 50 mg·L-1 solution of Cr(VI) using milled anatase. XPS showed that, upon the photoadsorption, Cr(VI) is reduced to Cr(III). The presence of an acetate buffer in the solution promotes the most efficient removal of chromium. This work shows a simple way to obtain a highly effective material with potential applications for the removal of high toxic hexavalent chromium from industrial wastewater. The milled anatase sample was successfully tested to remove Cr (VI) from a real wastewater sample.