In this paper, the Fe3+ doped rutile phase TiO2 nanotubes arrays (NTAs) were prepared in a low temperature water-assistant crystallization method. It is noteworthy that the Fe3+ doping hardly hinders either the crystallization of rutile TiO2 NTAs or the highly-ordered nanotubular morphologies. Moreover, Fe3+ did not form other compound impurities, which indicated that Fe3+ substitute Ti4+ into the lattice of TiO2. With the introduction of Fe3+, the light absorption range of TiO2 NTAs extends from the ultraviolet band to the visible light range. Photocatalytic testing results indicate that Fe3+ doped TiO2 NTAs can effectively improve the degradation rate of methyl orange aqueous solution in visible light, and the TiO2 NTAs with 0.2 mol/L Fe3+ doping exhibits the highest photocatalytic degradation efficiency.
5 February 2025 in Journal of Radioanalytical and Nuclear Chemistry
Lead free piezoelectric crystals of (KxNa1−x)NbO3 (x = 0.11 and 0.17) have been grown by the modified Bridgman method. The structure and chemical composition of the obtained crystals were determined by X-ray diffraction (XRD) and electron probe microanalysis (EPMA). The domain structure evolution with increasing temperature for (KxNa1−x)NbO3 (x = 0.11 and 0.17) crystals was observed using polarized light microscopy (PLM), where distinguished changes of the domain structures were found to occur at 400 °C and 412 °C respectively, corresponding to the tetragonal to tetragonal phase transition temperatures. Dielectric measurements performed on (K0.11Na0.89)NbO3 crystals exhibited tetragonal to tetragonal and tetragonal to cubic phase transitions temperatures at 405 °C and 496 °C, respectively.
The activity concentrations of TENORM including 226Ra, 232Th and 40K of the ten main brands of glazed tiles produced in China and their radiological hazard parameters such radium equivalent radioactivity, alpha index, external exposure index, absorbed dose rate in air indoors, indoors annual effective dose, and activity concentration index are measured and estimated. The activity concentrations of 226Ra, 232Th, 40K in glazed tile samples are within the international tile reference values for 226Ra (30–200 Bq·kg−1), 232Th (20–200 Bq·kg−1) and 40K (160–1410 Bq·kg−1). The estimated mean values of radiological hazard parameters such as radium equivalent radioactivity, alpha index, external exposure index, indoors annual effective dose, and activity concentration index are also found to be below the international recommended limits or referenced values. The mean value of the absorbed dose rate in air indoors is within the country average range of 20–190 nGy·h−1. Moreover, combined with statistical analysis, it is concluded that the activity concentrations of 226Ra and 232Th in glazed tile samples have a strong correlation with the calculated radiological parameters, which has a significant impact on radioactivity in glazed tiles. Finally, it can be concluded that the ten brands of glazed tiles used in decoration of building materials are identified as grade A, which are unlikely to have a significant radiological hazard to the public. Therefore, the production, marketing and use scope of glazed tiles should be not restricted, but the early monitoring and classification should be done.