The effect of surfactants on the interfacial rates of reaction of CO2 and CO with liquid iron oxide

Abstract

The 14CO2-CO isotope exchange technique has been used to measure the rates of dissociation of CO2 on liquid iron oxide containing the surface active components P2O5 or Na2O, principally at 1673 K. The apparent first-order rate constant is found to decrease monotonically with small additions of P2O5 up to a factor of about 4 at 3.5 mol pct. Vaporization losses prevented detailed studies of the effect of Na2O, but it is shown that there is probably a twofold increase in the rate constant at a concentration of about 0.2 wt pct and a fivefold increase at a concentration between 0.5 and 1.6 wt pct. A smoothed surface potential model, based upon the Vol’kenshtein model for catalysis by semiconductors, is developed, and it is shown that the required surface potential changes due to the segregation of P2O5 and Na2O are physically reasonable.