Sonochemical Reduction of Silver Ions in Nano-Porous Y-Zeolite

Silver ions are reduced by 24 kHz ultrasonic waves in ion-exchanged Ag+-Y zeolite. Zeolite is both a good selective catalyst and an excellent support with high surface area that is well known in petrochemical industry. Silver ions are introduced into the nano-porous (1.2nm) zeolite lattice by ionexchange. After the reduction process, silver particles are placed both in the cavities, in nanometric sizes and on the external surfaces of the zeolite. Fast and simple reduction of silver ions in the zeolite, in the lab-scale is important for researchers who work on catalytic uses of metallic silver-zeolite. Several reduction methods have been reported but reduction by ultrasonic waves is a new, simple and sizecontrollable method with a high practical value which doesn't need any complicated facility. In sonochemical process, the collapse of bubbles formed by ultrasonic waves, cause the formation of reducing radicals that consequently reduce the silver ions. It is concluded that the higher the silvercontent, the larger the silver crystals formed on the external surface of zeolite. Also, the addition of 1- propanol to the aqueous reaction solution doesn't cause better reduction. All samples are irradiated under the same ultrasonic conditions. The samples are analyzed by XRD, SEM and EDS.

Keywords:

silver-zeolite composite , silver , nano-porous zeolites , sonochemical reduction