Biodiesel production by sulfated mesoporous titania–silica catalysts synthesized by the sol–gel process from less expensive precursors

Research Article published by ElsevierA sulfated titania–silica composite (S-TSC) was obtained through surface modification of mesoporous titania–silica composite synthesized using less expensive precursors; titanium oxychloride and sodium silicate as titania and silica sources respectively. A pre-formed titania sol facilitated the synthesis of a mesoporous composite with a high BET surface area (520 m2/g), suitable for surface modification using sulfuric acid to improve its catalytic performance. The materials synthesized via this process were examined by XRD, XRF, FTIR, SEM, TEM, TGA, and N2 physisorption studies. FTIR analysis showed the vibration band of the TiAOASi bond at 943 cm 1, suggesting the incorporation of titania into silica to form a composite. This vibration band was substantially shifted to 952 cm 1 after the attachment of the sulfate group. The catalytic activity of a series of as-prepared TSC, S-TSC calcined samples and pure H2SO4 were evaluated for esterification of oleic acid and transesterification of waste oil with methanol to yield methyl esters. It was observed that at these reaction conditions, S-TSC-450 and S-TSC-550 possessed high catalytic activity comparable to that of pure H2SO4 implying that surface modification of the titania–silica composite improves its acidic properties

Synthesis of mesoporous silica with superior properties suitable for green tire

Research Article published by Elsevier Volume 18, Issue 5, 25 September 2012In this article we report synthesis of mesoporous silica with superior properties for application in green tire (environmentally friendly tire) as filler. The synthesis was done using a newly innovated apparatus which produce mesoporous silica with superior properties. The desired superior properties are big pore size, optimum BET, large pore volume, uniform properties, and improved performance in real application as tire filler. Mesoporous silica was characterized by BET method and final product with a pore diameter of up to 37 nm was obtained without using surfactants. This is unprecedented step toward synthesis of silica that is suitable for tire industry

Enhancement of porosity of sodium silicate and titanium oxychloride based TiO2–SiO2 systems synthesized by sol–gel process and their photocatalytic activity

Research Article published by Elsevier Volume 179, 15 September 2013The textural properties of TiO2–SiO2 composites (TSCs) were successively enhanced using three approaches; (1) washing the hydrogels with different solvents, (2) using surfactant and (3) forming the TiO2 sol in ethanol medium. The sol–gel process was exquisitely used to form the composites using cost effective precursors. Initially, the precipitated hydrogels were washed with water or alcohol to evaluate the influence of washing on the dried hydrogels. Consequently, two composites were formed differently in the presence of stearic acid (SA) as a surfactant and the other by forming TiO2 sol in ethanol medium prior to reaction with silica source. The TSC powders were examined by XRD, N2 physisorption studies, FTIR, TGA, SEM, XRF and HRTEM. The BET surface area of the sample obtained after washing the hydrogels with ethanol (TSCE) was the largest (594 m2/g) while porosities of the composites obtained using stearic acid as a surfactant (TSCSA, 0.96 cm3/g) and ethanol as a medium to form the TiO2 sol (TSCES, 1.85 cm3/g) were relatively superior to those obtained under influence of changing washing solvent. Photocatalytic decolorization of methylene blue by the composites calcined at 800 °C revealed that the TSCES-800 possessed the highest activity of all the composites due to its superior properties