| In the present work, we have explored numerous ways to reduce the mean particle size of zeolite A, keeping the economic imperatives in mind. In addition to this, efforts were directed towards reducing the crystallization time and having a more narrow particle size distribution. Besides the study of more conventional parameters such as temperature, alkalinity, water content etc., the effect of using microwaves, centrifuge and ultrasonication was also explored. It was expected that the highly localized temperatures of thousands of degree Kelvin and pressures of hundreds of atmospheres produced by ultrasonication might disrupt the nucleation process in a manner so as to lead to smaller crystals. Surprisingly, it was found that the application of ultrasonication does not lead to any decrease in the particle size. Both ultrasonication and stirring being different forms of agitation, one expected to find crystals with similar morphology in the aforementioned two cases. However, the crystal morphologies obtained in the two cases are completely different which was rather unexpected.; Another method to get small zeolite crystals has been the addition of nano-particles of various materials to act as substrates for zeolite A nucleation and growth. Synthesis using Titania Hombikat and Titania Hombifine has given promising results in this regard and zeolite A crystals nucleated on the surface on these substrates in the size range of about 0.3 mum were obtained. (Abstract shortened by UMI.)... |
