Recovery of Palladium (II) by biodeposition using a pure culture and a mixed culture

Abstract

Despite limited availability of platinum group metals such as palladium (Pd), there is an increasing demand to use them especially as catalysts. However, conventional recovery of these metals has proven detrimental to the environment, therefore, sustainable recycling and production is required. Biological synthesis of Pd (0) has proven to be an innovative method for recovery of palladium. This study aims to investigate the deposition of Pd at different concentrations by a pure isolate of Desulfovibrio desulfuricans and a consortium of Sulphatereducing bacteria. The reduction was accelerated at the expanse of formate as an electron donor at a pH of 4. The results showed that after 12 hours of incubation a black precipitate of reduced Pd formed, the consortium produced a higher percentage reduction of 90% at a concentration of 2mM while the pure isolate had a percentage reduction of 77%. SEM showed electron oblique deposits on the surface of the bacteria, the deposits were between 40nm and 50nm in size. The use of the consortium proved to be highly efficient for the potential bioremediation of palladium contaminated environments.