Recycling Of Spent Mosi₂ And Photocatalytic Performance Of MoO₃

Along with the development of MoSi2 in the industrial expansion of the application field and laboratory research is unceasingly thorough, factory and laboratory generated large amounts of spent molybdenum disilicide. In Mo Si2, molybdenum occupies a large proportion(63 wt%). Molybdenum is a kind of rare metal and recycling of spent molybdenum disilicide molybdenum is very important. So, we use Mo Si2 as secondary molybdenum-renewable resources, and the product is applied to solvent-containing wastewater treatment, not only can reasonably handle spent Mo Si2, realize effective recycling of precious resources, but also can bring very considerable economic and environmental benefits, turning waste into treasure and protect the environment.By using the method of evaporation and condensation, we get Mo O3 with different sizes and morphologies from the spent Mo Si2. XRD, SEM, UV-Vis and other detection methods are analyzed on the structure, morphology and properties of samples. With methylene blue as degradable material, we studied the photocatalytic activity and stability of Mo O3 in different catalytic conditions, discussed the growth mechanism and photocatalytic mechanism of Mo O3 crystals, obtained the following conclusions:(1) As the evaporation temperature increases, Mo O3 crystal whisker became smaller, more compact, the color gradually deepened. Due to the different conditions during the experiment, Mo O3 crystals with different sizes and morphologies was obtained. The sheet-like α-Mo O3 had a width of several to several tens of microns and a length of about 1 mm, relatively coarser grains. The strip α-Mo O3 had a width of 3-13 μm and a length of several tens to several hundreds of micrometers, we obtained a spherical Mo O3, diameter between tens of nanometers to tens of microns. Crystallinity of the sheet and strip Mo O3 was good, a single sheet was a nearly perfect single crystal. There was smooth connection, stacking and aggregation between the spherical Mo O3 atoms. Spectral analysis showed that the product was pure.(2) The bandgap of as-prepared Mo O3 was about 2.96 e V, it can strongly absorb the light whose wavelengths below 430 nm. As a photocatalyst under visible light, it exhibited significant photocatalytic activity.(3) In the low concentration range, the as-prepared Mo O3 material showed good photocatalytic activity, when the catalytic reaction time reaches 30 min, the degradation rate had reached 90%; for a given concentration of the solution, with the increasing amount of addition of the as-prepared Mo O3, the photocatalytic effect became more significant. The Photocatalytic degradation rate of the solution with the as-prepared Mo O3 can reach up to 96%, while the P25(Ti O2) and commercial Mo O3 can only reach about 43.17% and 55%, respectively. Compared with the P25 and commercial Mo O3, the as-prepared Mo O3 showed better photocatalytic activity.There are 43 figures, 7 tables and 76 references in the paper.