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Synthesis And Characterization Of Amorphous Silica Nanoparitcles From Aqueous Silicates Uisng Cationic Surfactants, M Abou Rida, F Harb
Synthesis And Characterization Of Amorphous Silica Nanoparitcles From Aqueous Silicates Uisng Cationic Surfactants, M Abou Rida, F Harb
Journal of Metals, Materials and Minerals
In this work amorphous silica was synthesized using sodium silicate and hydrochloric acid by precipitation according to St?ber method. A system of chemical reactions has been developed which permits the controlled growth of silica particles using two different cationic surfactants as the dispersing agents. These surfactants were cetyltrimethylammonium bromide [CTAB] and dodecyltrimethylammonium bromide [DTAB]. The synthesized silicas were characterized by using X-ray diffraction (XRD), Infrared Spectroscopy (IR), Scanning Electron Microscopy (SEM), Energy Dispersive Spectroscopy (EDX) and Dynamic light scattering (DLS). Addition of a dispersing agent in the reaction reduced the particle size of the silica produced. The average size of …
Sio2-Included Cesium Polyoxotungstate Catalysts For Oxidation, W Trakarnpruk, W Kanjina
Sio2-Included Cesium Polyoxotungstate Catalysts For Oxidation, W Trakarnpruk, W Kanjina
Journal of Metals, Materials and Minerals
SiO2-included cesium polyoxotungstate catalysts were synthesized by a sol-gel method and characterizied by FTIR, XRD and N2 adsorption isotherms. XRD patterns prove that the cesium polyoxotungstate is uniformly dispersed in the silica network. The catalysts were used in oxidation of cyclohexane with H2O2. The products are cyclohexanol and cyclohexanone. The catalysts prepared by using a copolymer surfactant show higher surface area and exhibit higher activity. These catalysts are truly heterogeneous and can be reused at least 3 times.
A Simple Method For Production Of Humidity Indicating Silica Gel From Rice Husk Ash, J Nayak, J Bera
A Simple Method For Production Of Humidity Indicating Silica Gel From Rice Husk Ash, J Nayak, J Bera
Journal of Metals, Materials and Minerals
The objective of the present work is to develop a procedure for obtaining and characterizing active blue silica from rice husk ash. About 25 wt.% silica powder (from total mass of rice husk) of 95% pure silica could be produced after heat-treating at 700°C for 6 hours. A simple method based on alkaline extraction followed by acid precipitation was developed to produce pure silica hydrogel from RHA. A well-defined very minimum amount CoCl2-containing blue silica gel was prepared by impregnation of the aqueous solution of the salt to silica hydrogel, ageing and drying method. The sharp colour changing from blue …