Research Information System
Thesis Type: Postgraduate
Institution Of The Thesis: Gazi University, Fen Bilimleri Enstitüsü, Turkey
Approval Date: 2010
Thesis Language: Turkish
Student: Başak IŞIKSOY
Supervisor: Fatma Suna Balcı
Abstract:Pillared intercalated clays (PILCs) are one of the example of porous materials be used as attractive adsorbent and catalyst support due to being stable as thermally, high surface area, regular sized orosities. Iron and chromium are preferred metals at catalytic applications due to their diverse oxidation states. While pillaring by iron gives the thermal stability to the structure, the presence of chromium increases the number of catalytic active sites. In this study, Base(OH)/Metal(M) (Fe and/or Cr) ratio keeping as 2,0 Fe-, Cr- and Fe/Crmixed PILCs were synthesized by using calcium saturated bentonite clay mineral calcined at 300 and 5000C then the product properties were investigated by use of variety of characterization techniques. 77 K nitrogen adsorption/desorption isotherms of samples resembled the type IV isotherm according to IUPAC (International Union of Pure and Applied Chemistry) classification with type B hysteresis. While surface area and adsorbed total gas volume values increased to 97 m2/g and 118 cm3/g values respectively for iron-pillared clay calcined at 3000C, these values showed little decreases related to original clay mineral for chromium-pillared clay samples. At the result of the XRD (X-ray difraction patterns) analyses results showed that the basal spacing values of pillared clays increased. For the iron containing pillared clays due to delamination generally two peaks were observed at small angle region (reflection angles 2θ :1-10o). The XRD, EDS (Energy-dispersive Xray spectroscopy) and XPS (X-ray photoelectron spectroscopy) results showed the incorporation of the metals to the structure. By the iron-chromium mixed pillaring, with the increasing of the chromium incorporation success the metal content increased to 13,45 mass % for iron/chromium pillared clay from 4,48 mass % value of chromium-pillared clay. With XPS analysis iron element was observed at 785 eV binding energy as Auger and chromium was observed at average 577 eV binding energy Cr 2p3/2 orbital. Main FTIR bands of clays were retained in the pillared structure and PILCs showed bands assigned to Lewis (L), Bronsted (B) acid sites.