“Doughnut”-like Clay Microparticles Fabricated Using a Hybrid Method of Spray Drying and Centrifugal Disc Atomization

Change in the shape of clay microparticles is essential for applications such as adsorption of toxic elements, microencapsulation, and liquid chromatography. To increase the surface area of the hectorite microparticles, doughnut-like morphology with uniform particle size was realized using a hybrid method of spray drying and centrifugal disc atomization. Addition of tetrasodium pyrophosphate to the aqueous hectorite dispersion was critical for the change in shape; this can be explained with reference to changes in the repulsive interparticle interactions.