Catalytic Hydrogenation of Nitrate in Water Using a Pd-Cu/Al2O3 Catalyst and Dilute H-2 Microbubbles

摘要

The catalytic hydrogenation of nitrate was performed in solutions containing 20 mg/dm(3) using a Pd-Cu/Al2O3 catalyst (synthesized with a Cu/Pd ratio of 0.25) together with microbubbles (radii < 50 mu m) of 9.4-43.7 % H-2 in N-2. Significant enhancement of the hydrogenation rate was observed due to the application of the microbubbles. The nitrate conversion factors for microbubble hydrogenation were approximately 1.7-3.8 times greater than those obtained using conventional macrobubbles (radii > 1500 mu m). The application of microbubbles was also effective during hydrogenation in a more concentrated nitrate solution containing 77 mg/dm(3) .