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In this contribution, a radiometric powder analysis of two samples of K-feldspar from the pegmatite from Kovářov was carried out. On its basis, lattice parameters were calculated and both samples were classified as microclines using the method described by Orville (1967). [ABSTRACT FROM AUTHOR]

The preparation of anodic TiO2 nanotube layers has been performed using electrochemical anodization of Ti foil for 4 h at different voltages (from 0 V to 80 V). In addition, a TiO2 thin layer has been also prepared using the sol–gel method. All the photocatalysts have been characterized by XRD, SEM, and DRS to investigate the crystalline phase composition, the surface morphology, and the optical properties, respectively. The performance of the photocatalyst has been assessed in versatile photocatalytic reactions including the reduction of N2O gas and the oxidation of aqueous sulfamethoxazole. Due to their high specific surface area and excellent charge carriers transport, anodic TiO2 nanotube layers have exhibited the highest N2O conversion rate (up to 10% after 22 h) and the highest degradation extent of sulfamethoxazole (about 65% after 4 h) under UVA light. The degradation mechanism of sulfamethoxazole has been investigated by analyzing its transformation products by LC-MS and the predominant role of hydroxyl radicals has been confirmed. Finally, the efficiency of the anodic TiO2 nanotube layer has been tested in real wastewater reaching up to 45% of sulfamethoxazole degradation after 4 h. [ABSTRACT FROM AUTHOR]

The composites of BiVO4 and g-C3N4 (BiVO4/g-C3N4) were synthesised by the calcination of a mixture of monoclinic BiVO4 and bulk g-C3N4 at 300 °C for 4 h. Both components were previously prepared by the precipitation of Bi(NO3)3 with NH4VO3 and annealing of melamine. X-ray photoelectron spectroscopy (XPS) identified the presence of C–O and C=O bonds as well as metal nitrides which confirmed the formation of a heterojunction between BiVO4 and g-C3N4. The heterojunction was also indicated by UV–Vis diffuse reflectance (DRS) and photoluminescence (PL) spectroscopy. The band gap energies were determined at 2.42–2.46 eV of BiVO4 and 2.75–2.82 eV of bulk g-C3N4. The specific surface area was 23–28 m2 g−1 of the composites and 6 m2 g−1 and 35 m2 g−1 of pure BiVO4 and g-C3N4, respectively. The photocatalytic activity of the composites was investigated by the decomposition of Acid Orange 7 (AO7) and nitrous oxide. In case of AO7, the BiVO4/g-C3N4 (1:3) composite was the most active one and the main role in the reaction was played by photoinduced holes forming hydroxyl radicals. At the decomposition of N2O, the most important species were the photoinduced electrons and the BiVO4/g-C3N4 (1:1) composite was the most active photocatalyst. [ABSTRACT FROM AUTHOR]

Zr/TiO2 anatase photocatalysts with 0.5, 1, 2, 5 and 7.5 mol.% Zr were prepared using pressurized hot water crystallization and their photocatalytic activity was explored in acid orange 7 photodegradation. Parent TiO2 was also prepared and tested. From all tested photocatalysts, 2 mol.% Zr/TiO2 showed the highest photoactivity, and 7.5 mol.% Zr/TiO2 showed the lowest photoactivity. The poor photoactivity of 7.5 mol.% Zr/TiO2 can be explained by the amorphous ZrO2 present in the surface layer (~1–3 μm depth) of TiO2 anatase nanocrystallite agregates which changed the aggregate morphology and shielded the anatase nanocrystallite surface. The type and amount of defects (e.g., oxygen vacancies, lattice defects) did not effect the photoactivity of Zr/TiO2 in AO7 photodegradation. The addition of Zr to TiO2 significantly affects the photocatalyst morphology and the location where amorphous ZrO2 forms. The optimal Zr loading in TiO2 was determined to be 2 mol.%. Highlights: The type and amount of defects do no effect the Zr/TiO2 photoactivity. Amorphous ZrO2 in surface layer of TiO2 agregates shields the anatase nanocrystallites surface. Amorphous ZrO2 in surface layer of TiO2 agregates decreases the Zr/TiO2 anatase photoactivity Zr4+ dopation in TiO2 affects crucially photocatalyst morphology. 2 mol.% Zr/TiO2 shows the highest photoactivity in acid orange 7 degradation. [ABSTRACT FROM AUTHOR]

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