Non-ionic-microemulsion mediated growth of zeolite A

This report describes the synthesis of zeolite A (LTA) in non-ionic microemulsions. Parameters such as microemulsion composition, surfactant identity, and reaction conditions were investigated. Powder X-ray diffraction and field emission scanning electron microscopy were used to confirm zeolite crystallinity, phase purity, and morphology. The microemulsion induces rapid growth, as LTA formation begins within 2 h for some syntheses, compared to 12 h for the samples that did not contain the microemulsion components. Clear trends are also observed relating particle size and morphology to synthesis duration and microemulsion composition. Control experiments demonstrate that all components of the microemulsion are needed to form the target materials. Syntheses performed over longer time periods show that the zeolite particles aggregate and convert to denser phases such as socialite, indicating that the sub-micron sized particles initially formed cannot be stabilized for prolonged periods with the microemulsions employed. This work demonstrates that zeolite growth and morphology can be tuned based on various microernulsion conditions, opening the door for future applications. (c) 2005 Elsevier Inc. All rights reserved.