ABSTRACT
Single Zinc, Nickel and cadmium adsorption from aqueous solution onto silica extracted from agro-residue is reported. and is consider a low cost method for recovery of Zn and Cd in the production of Ga-67 and In-111 isotopes in Egypt's Cyclotron and also solve environmental problem from burning of rice husks. The dependence adsorption on contact time, adsorbent type and adsorption medium and also pH was investigated showing that there is a difference in minimum contact time for different metal ions and the mechanism of adsorption of metal ions on silica extracted from rice husks were also studied. Therefore, silica extracted from rice husk is considered as a better replacement technology for recovery of enriched zinc and cadmium were used in preparation of targets for 67Ga and 111In production due to low cost and good efficiency in this application.