The effect of composition on the growth and morphology of zeolite A in solution

The zeolite LTA (Linde type A) framework is composed of an equal amount of silica and alumina arranged in a three-dimension tetrahedral structure. This high alumina content zeolite possesses a strong negative surface charge in a basic solution due to the substitution of aluminum atoms into a SiO4 tetrahedral structure making it difficult to form a continuous layer in solution. Synthesis parameters such as synthesis duration, chemical composition, and synthesis temperature were varied. The crystallization kinetics was carried out using the particle size measurement, percent crystallinity from x-ray diffraction analysis, infrared absorption of tetrahedra using attenuated total reflectance Fourier transform infrared spectroscopy, and the exponential growth model. The results showed that the zeolite A crystallization in a solution depends on the chemical kinetics of the zeolite formation, surface charge of the substrate, and the mass transfer in the solution. © 2004 Materials Research Society