RESUMEN
The decontamination of radioactive materials on the surfaces of nuclear facilities has generated large quantities of waste from the rapid development of the nuclear industry, posing a potential threat globally. Strippable coating has been employed for some time to remove radioactive contamination due to its high performance and removability, flexibility, and compatibility with various substrates. Herein, an aqueous strippable coating based on an adsorbent/polyvinyl alcohol (PVA) polymer was developed to remove radioactive uranium from stainless-steel surfaces that showed greater decontamination than that of DeconGel, with an efficiency of 87.2% for 5 g/L uranium and 95.5% for 22.5 g/L uranium, along with a high repeatability and better mechanical properties. Furthermore, the prepared coating was versatile and could be applied to a range of substrate surfaces (lacquered, aluminum, glass, plastic, and ceramic), with outstanding performance ranging from 79.2 to 95.4% for 1 g/L uranium. The prepared coating could also be applied through brushing or spraying to horizontal or vertical substrates. The exceptional performance could be due to the synergistic effect of the introduction of ethylene diamine tetra-acetic acid disodium salt (EDTA-2Na) as a chelating agent and the nano-adsorbent CaCO3/TiO2.
RESUMEN
CuO-CeO2 nanocatalysts with different amounts of Mn dopping (Mn/Cu molar ratios of 0.5 : 5, 1 : 5 and 1.5 : 5) were synthesized by flame spray pyrolysis (FSP) method and tested in the catalytic oxidation of CO. The physicochemical properties of the synthesised samples were characterized systematically, including using X-ray diffraction (XRD), Raman spectroscopy, field-emission scanning electron microscopy (FESEM), Brunauer-Emmett-Teller (BET), X-ray photoelectron spectroscopy (XPS), oxygen-temperature programmed desorption (O2-TPD), hydrogen-temperature programmed reduction (H2-TPR) and in situ diffuse reflectance infrared Fourier transform spectroscopy (in situ DRIFTS). The results showed that the 1Mn-Cu-Ce sample (Mn/Cu molar ratio of 1 : 5) exhibited superior catalytic activity for CO oxidation, with the temperature of 90% CO oxidation at 131 °C at a high space velocity (SV = 60 000 mL g-1 h-1), which was 56 °C lower than that of the Cu-Ce sample. In addition, the 1Mn-Cu-Ce sample displays excellent stability with prolonged time on CO stream and the resistance to water vapor. The significantly enhanced activity was correlated with strong synergetic effect, leading to fine textual properties, abundant chemically adsorbed oxygen and high lattice oxygen mobility, which further induced more Cu+ species and less formation of carbon intermediates during the CO oxidation process detected by in situ DRIFTS analysis. This work will provide in-depth understanding of the synergetic effect on CO oxidation performances over Mn doped CuO-CeO2 composite catalysts through FSP method.
RESUMEN
Photocatalytic reduction of aqueous Cr(VI) was successfully achieved on nanostructured SnIn(4)S(8). The SnIn(4)S(8) particles with flower-like nanostructure were synthesized via a facile solvothermal method. UV-vis diffuse reflectance spectra (DRS) indicated that the SnIn(4)S(8) particles had strong absorption in visible region and the band gap was estimated to be from 2.27 to 2.35 eV. The photocatalytic reduction of aqueous Cr(VI) by flower-like SnIn(4)S(8) was evaluated under visible light (λ>400 nm) irradiation. The polyvinyl pyrrolidone (PVP) assisted SnIn(4)S(8) sample exhibits excellent removal efficiency of Cr(VI) (~97%) and good photocatalytic stability. The predominant photocatalytic activity is due to its large surface area, strong absorption in visible-light region and excellent charge separation characteristics.