Light and X-ray scattering from the early growth stages of zeolite A. Part I

Abstract

In situ dynamic light scattering and small angle X-ray scattering from clear homogenous solutions which synthesise zeolite A, is reported for the particle size range from nano- to micrometres. Clearly defined 'particle scattering' was only observed at sizes 80 nm radius of gyration. Between this and 2 μm the growth kinetics showed an activation energy of 75 kJ mol-1 from a fresh preparation and 71 kJ mol-1 from an aged preparation. Scattering signatures from the processes in the size range below 80 nm have been recorded and observation of the phenomena as a function of temperature has been used to distinguish some salient features. The early growth processes are consistent with rather close scattering contrast between the mother liquor and aluminosilicate zeolite embryos, their subsequent transformation to ca. 8 nm precursor particles and their growth after reaching a size from about 80 nm to micrometer size zeolite A crystals.