Investigations on Some Titania Supported Catalysts

Titania is a versatile metal oxide with multiple applications. Titania supported catalysts are reported to be much more active compared to conventional silica or alumina supported ones in some reactions. TiO2 (anatase) having high surface area, with better crystallinity and high onset temperature of rutilation can be prepared by thermal hydrolysis of titanyl sulfate solution under controlled conditions. Calcinations at 350oC for 6 hrs were necessary to crystallize anatase. Method of preparation and percentage of the loaded metal oxides have greater influence on surface area. Drastic decrease in surface area was observed upon rutilation. Rutilation started at different temperatures depending on the metal oxide and the method of preparation. TiO2 should be characterized with high surface area, phase purity and high onset temperature of rutilation.Which should be well above the optimum temperature of a designated reaction in which it is employed as a catalyst. Variation in physical properties, depending upon the method of preparation is greater in TiO2 supported catalysts. Methanation activity was found to be highly dependent on nickel concentration present on the surface of the pellets. The methanation activity is strongly influenced by support material. The rate and turn over frequency of methanation and toluene oxidation activity of these catalysts are also equally important from an industrial point of view.

Studies on immobilization of Bacteria

Cell immnhilizatinn technology in a rapidly expanding arna in the endeavour of microbial fnrmentatiwn.During the lnmt 15 years anveral prnceafinn have been developed and more are in developmental atage of approaching commercial utilizatinn.In the present programme it was planned to develop an optimized process for the innobilization of alpha amylase producing Bacillus polymyxa (CBTB 25) an isolate obtained from Cochin University campus primarily for the production of alpha-amylase.Optimal concentration of support material that attributaa stability and maximal activity to the immobilized cell beads was determined using different concentrations of sodium aliginate as support and estimation of amylase production.An overeall assessment of the data obtained for the various studies conducted denotes that immobilized cells synthesize alpha-amylase at comparable rates with free cells and produce reducing sugara at a higher level than free cells.Results indicated that both phosphate and citrate buffers could be used for disrupting the immobilized beads since they enforced maximal release of cells through leaching from the beads within one hour.On comparative analysis it was observed that immobilized cells could synthesize alpha amylase at similar levels with free cells of B.polymyxa.On Co-immobilization of B.Polymyxa with S.cerevisiae,the co-immobilizate beads could effeciently convert starch directly to ethanol with a yield of 14.8% at 1 : 2 ratio.