Preparation of Composite of ZnS Nanoparticles and Montmorillonite by Cavitation Deposition

P. Praus, R. Dvorský, L. Svoboda, B. Kostura
VŠB-Technical University of Ostrava, CZ

Keywords: composite, ZnS nanoparticles, montmorillonite, cavitation deposition

Summary:

The ZnS-montmorillonite (MMT) nanocomposite was formed by cavitation implosion of ZnS nanoparticles into MMT pores. As a result of very high impact velocities at collisions of ZnS nanoparticles and MMT particles increase of a number of ZnS nanoparticles in ZnS-MMT can be expected. The method of cavitation deposition utilizes implosion of cavitation bubbles, which were formed by nucleation on external surface of dispersed particles. Density of nanoparticles in the aqueous dispersion is very high and cavitation bubbles nucleated on walls of the caring MMT particles catch photoactive ZnS nanoparticles on expanding surface with high probability. Performed analyses showed that the method of cavitation deposition lead to increase of specific surface area at cca 214 % of that originated by standard mechanical shaking. The total content of ZnS in the ZnS-MMT composite increased from 7 wt. % (shaking) to 10.5 wt. %. If ZnS nanoparticles are bound to surface of a caring material in a monolayer arrangement then nanocomposite photocatalytic efficiency should be proportional to product of specific surface area and a total content of deposited ZnS. Hence, the photocatalytic efficiency of ZnS-MMT nanocomposite prepared by the cavitaion method was about 300 % in comparison with the composite prepared by shaking.