Abstract
Monodisperse prolate spheroidal particles of barium sulfate were produced by the decomposition of the complex of barium and ethylenediaminetetraacetic acid with hydrogen peroxide in the presence of sulfate ions. The size and size distributions of the particles were measured by electron microscopy, and relations between particle size and various operational parameters, such as concentration of reagents, reaction time, reaction temperature and pH, were determined. The mean length of long axis of the particles could be varied in the range from 0.7 to 2.5 μm and the geometric standard deviation was below 1.2. The ratio of the long to short axis of particles was nearly constant under various experimental conditions. Monodisperse spherical BaSO4 particles could be produced by direct mixing of reagents at room temperature. Monodisperse prolate spheroidal and spherical aerosol particles were easily generated by nebulizing the BaSO4 colloidal solutions. Aerosol particles produced by the present method are useful for calibra tion of some aerosol measurement instruments as standard particles.
