SYNTHESIS AND CHARACTERIZATION OF VANADIUM ALUMINUM PILLARED CLAY

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Thesis Type: Postgraduate

Institution Of The Thesis: Gazi University, Fen Bilimleri Enstitüsü, Turkey

Approval Date: 2008

Thesis Language: Turkish

Student: Aylin TECİMER

Supervisor: Fatma Suna Balcı

Abstract:

Pillared clays have area of usage as catalyst support due to high surface area and controlled pore structure. Although pillared clays that pillared with aluminium (Al-pillared clay) have thermal stability, they aren't show enough activity in the cataliytic applications. Catalytic activity of the Al-pillared clays can be improved by the incorporation of appropriate metal compound to the structure. In this study, by using bentonite clay mineral and keeping the base(OH)/metal(Al) ratio as 2,0 aluminium pillared clay was produced as support. By use of vanadyl sulphate hydrate (VOSO4xH2O) or sodium metavanadate (NaVO3), and wet impregnation, washing after wet impregnation and impregnation methods, vanadium in two different amount of was loaded as active compound to the Al-pillared clay that calcined at 3000C. Loading of vanadium caused decreases in the XRD peak intensity and the basal spacing belonging Al-pillared clay. The nitrogen adsorption/desorption study showed that, the highest surface area after Al-pillared clay, was observed for NaVO3 loaded by impregnation and calcined at 3000C and the lowest surface area was observed for NaVO3 loaded by wet impregnation and calcined at 5000C. The EDS analysis showed the rise in, Al2O3/SiO2 ratio relative to raw clay. The NaVO3 loading resulted higher V2O5/SiO2 ratio than the other vanadium source did. The layered structure of Al-PILC and the placement of vanadium particles between these layers and onto the clay particles' surface were observed in the TEM analyses. Fast dehydration and mass loss within the room temperature and 3000C temperature range, then decreases in mass loss and solid-solid reaction with hydroxylation at 900º C was observed in TGA/DTA analyses of samples. With XPS that vanadium is binding with 2p3/2 orbital were observed. The consistence of V-O-Al and V-O-Si bonds and Bronsted and Lewis acid centers were observed in FTIR results.