Dynamics of adsorption and oxidation of organic molecules on illuminated titanium dioxide particles immersed in water

M.A. BLESA; R. J. CANDAL; S. A. BILMES

Colloids and Surface Science

Plenum Pub Corp

Año: 2004; p. 1 - 38

Heterogeneous photo-oxidation of organic molecules on the surface of titanium dioxide particles or films is mediated by the adsorption of the substrate and by the homogeneous oxidation by free OH· radicals released from surface ºOH groups upon hole capture. Multi-electron oxidations, or the oxidation of mixtures of organic substrates leads to a complex manifold of reactions. Simple modeling demonstrates that simple langmuirian expressions suffice to describe a variety of reported experimental findings, without need to all for more elaborate adsorption isotherms. The decrease in the surface apparent affinity for the substrate, zero-order dependencies on substrate concentration, surface poisoning by reaction products, various values for the oxidation of lengths of different substrates, and maxima in the plots of rate vs. substrate concentration, can all be modeled by langmuirian kinetics