Facile preparation of ordered mesoporous Nb,Ta-MCM-41 by hydrothermal direct synthesis using columbite ore as metal source

Abstract – The current study aims to prepare an Nb,Ta-containing ordered mesoporous catalyst MCM-41, using hydrated mixed oxide of niobium and tantalum, extracted from the columbite ore processing, as an alternative source of these metals. Direct hydrothermal synthesis was employed to incorporate the metals into the molecular sieve structure using the TEOS + sodium silicate mixture as silica source and varying Nb and Ta content in terms of Si/Me (Me = Nb and Ta) molar ratios of 60, 30 and 15 to evaluate the influence of the charge of these metals on both structural formation and properties of the material. The material was characterized by XRD, SEM, TEM, N2 adsorption, UV–Vis-DRS, and FTIR investigations to the incorporation of the metal into the MCM-41 framework. The techniques employed proved the successful replacement of Si atoms by metallic cations of Nb and Ta. The catalyst showed good structural order preservation and surface area (>600 m2 g-1) with mesoporous behavior with capillary condensation even at a higher metal load. This research signifies a successful procedure of a novel bimetallic mesoporous material with promising properties for several applications using an abundant ore as a metal source.