Layer-by-layer assembly of nanozeolite based on polymeric microsphere: Zeolite coated sphere and hollow zeolite sphere

Zeolite beta, silicalite-1, ZSM-5, and TS-1 coated spheres have been prepared successfully through layer-by-layer assembly of nanozeolite/ polymer multilayers on polystyrene (PS) microspheres, and hollow zeolite spheres have been obtained by removal of the core by calcination. In the adsorption process of nanozeolites onto the polvelectrolyte-modified template spheres, it has been found that zeta potential of the zeolite colloidal solution that determines the electrostatic interaction has important effects on the zeolite adsorption procedure. The charge on the original sphere template is not necessary. because proper polyelectrolyte modification could change the surface property of the template and make it suitable for layer-by-layer adsorption. The influences of zeolite type and/or size (40-120 nm), the number of zeolite/poly(diallyl-dimethlammonium) layer pairs, and the template sphere size (0.53-10.3 mum) on the preparation of the hollow zeolite spheres were also discussed.