MICROBIAL PREPARATION AND CATALYTIC ACTIVITY OF PALLADIUM NANOPARTICLES ON THE METAL-REDUCING BACTERIUM Shewanella oneidensis

摘要

Microbial reduction and deposition of palladium nanoparticles was achieved at room temperature and pH 7, using resting cells of the metal ion-reducing bacterium Shewanella oneidensis, when either formate or lactate was provided as the electron donor. The bioreductive deposition of palladium was a fast process: 5 mM aqueous Pd(II) ions were completely reduced to crystalline solid Pd(0) within 60 min. Biogenic palladium nanoparticles 5-10 nm in size were located on the bacterial cells. The biomass-supported Pd(0) nanoparticles were tested for catalytic activity in the chemical reduction of 0.5 mM soluble Cr(VI), achieving 100% conversion to Cr(III) at room temperature and pH 4 within 30 min.