The catalytic purification of CO-rich air

Stable heterogeneous catalysts for the oxidative removal of CO from air at ambient temperatures have been developed. An alumina support impregnated wi th PdCl2, CuCl2, and CuSO4 is described. Optimal activity was obtained with Pd 0.020 mol/kg, Cu 0.50 mol/kg, CuCl2 20-30% of total Cu, a 2- to 24-hr s oak, filtration of surplus raffinate, and a 2- to 4-hr firing in air at 200 -350 degrees C. The catalysts are effective at 20-26 degrees C and relative humidities in the 15-90% range. They are reversibly deactivated by complet ely dry or water-saturated air streams. These catalysts have been tested at space velocities up to 30,000 hr(-1). I n contact with <100 ppm CO, they are highly efficient, removing similar to 99% of the CO with contact times of similar to 120 msec (pseudo-first order k' > 25 sec(-1)). At much higher CO concentrations, the maximum CO loading rate-limited by the Cu(I) reoxidation rate-is approximately 17 mu mol CO p er mu mol Pd per hour.