Impregnação dos óxidos MoO3/NiO por dispersão física e via úmida sobre Al-MCM-41 e SBA-15.

Abstract

The oil industry increasingly seeks materials that convert heavy hydrocarbons to light which have a higher added value. The strict environmental laws, the social pressure for fuel with better performance and the need for use of crude oil more and more heavy and with high nitrogen content, have generated a great demand for the development of hydrorefining catalysts. An example of promising catalysts is acidic mesoporous material because of its wide application as support for solid catalysts in industrial chemical process, raising a greater interest in many researchers driving research in this area. The mesoporous molecular sieve, AI-MCM-41 is an interesting catalyst support due to high thermal and hydrothermal stability, high surface area, high pore diameters which provide possibilities for the preparation of catalysts that have high dispersion metal NiMo on AI-MCM-41. Another interesting mesoporous support in catalysis is the mesoporous silica SBA-15, it has been widely studied, mainly due to its characteristics: thermal, chemical and mechanics stable, in addition to its ability to adsorb metal cations, allowing its use as support for metal catalysts. Thus, the aim of this work was to synthesize and characterize the support MCM-41 with the addition of aluminum (AI-MCM-41) and NiMo catalysts supported. The support AI-MCM-41 was synthesized with ratio Si/AI= 31,9 through the hydrothermal method at 150°C for 12 hours and characterized by XRD, EDX, FTIR, MEV and TG. In this work was used a sample of SBA-15 as support for NiMo catalysts previously synthesized and ceded to LabCAB by researchers from PUC-RJ. The catalysts were synthesized by the wet impregnation method and physical dispersion at concentrations of 4 and 8 wt% Mo03 and 2 wt% NiO and were characterized by XRD, EDX, FTIR and MEV. The results obtained from the characterization indicated that the hexagonal phase of the AI-MCM-41 were obtained, after calcination of the material there as an increase in the characteristic hexagonal ordering of the material. There was a reduction in the hexagonal phase ordering after impregnation of the oxides NiO and Mo03, still remain its hexagonal phase of mesoporous molecular sieve. The wet dispersion on AI-MCM-41 was more efficient when dispersed a lower Mo03 content and the physical dispersion when the content of Mo03 was increased. From the thermal analysis it was possible verify good thermal stability for both of supports, AI-MCM-41 and SBA-15. With the XRD for SBA-15 support, it was found good organization hexagonal mesoporous followed by hexagonal reduction after impregnation of the oxides NiO and Mo03. For both types of impregnation of the oxides on SBA-15 was found the presence of crystalline phases of molybdenum and niquel.