No abstract

Adsorption of Mo(VI) and W(VI) ions from water with nanosized anatase has been studied. This process depends on sorption conditions (temperature, contact duration, etc.) and sample characteristics (composition, specific surface area, coherent scattering regions, etc.). Maximal recovery efficiency for Mo(VI) and W(VI) was achieved with the use of the samples of commercial Hombifine N (R Mo = 99.90 %) and Degussa P25 (R Mo = 99.99 %, R W = 99.75 %) and nanosized anatase modified with H 2 O 2 (R Mo,W = 99.75 %) under optimal conditions of sorption.

Nanocomposites TiO 2 /SiO 2 with photocatalytic and adsorptive properties were prepared by codispersing of η-modification and anatase (commercial Hombifine N) and SiO 2 (opal, granules, ultrafine) in ethanol (or ethanol-water mixture in the presence of chlorophylls or porphyrins) with ultrasonic treatments of the mixture (method 1) and an aqueous solution of KOH with a microwave treatment (method 2), as well as the introduction of SiO 2 in the reaction mixture during the synthesis of TiO 2 by brief hydrolysis of sulfate titanyl (method 3). It was found that the state of titania in the sample (X-ray amorphous or nanocrystalline) and its deposition on SiO 2 nanocomposites depend on the method and the conditions of obtaining. It was established that the photocatalytic activity of nanocomposite TiO 2 /SiO 2 (granules) (method 1) photosensitized by coproporphyrin I in the visible range and the photocatalytic activity of nanocomposite TiO 2 /SiO 2 (opal) (method 3) in the near UV range exceed activity of the commercial sample of TiSiO 4 by more than 20-fold and ~7-fold, respectively. It was shown that the nanocomposite TiO 2 /SiO 2 (opal) significantly reduces the concentration of cations (in particular, Be, Ni, Bi) in the model water systems.