Photocatalytic Reactions Involving Hydroxyl Radical Attack

Abstract

The intrinsic reaction kinetics of the decomposition of trichloroethylene in water employing suspended titanium dioxide catalytic particles have been studied using near ultraviolet polychromatic radiation. Experiments were carried out in a one-dimensional one-directional reactor placed inside the loop of a batch recycling system (1, Cabrera,et al.,Ind. Eng. Chem. Res.33, 3031 (1994); 2, Alfano,et al.,Ind. Eng. Chem. Res.34, 488 (1995)). Initial concentration of trichloroethylene was in the range of 0.15×10−6to 0.75×10−6mol cm−3while catalyst concentration was varied from 0.1×10−3to 1.0×10−3g cm−3. Oxygen concentration was always in excess of the stoichiometric demand. Results were analyzed in terms of a reaction model previously developed in Part I (3, Alfano,et al.,J. Catal.172, 370 (1997)). According to the resulting kinetic expression therein, the values of the kinetic constant are: α1=2.46×10−8mol cm−2s−1; α2=1.57×1011g s einstein−1; α3,i=6.42×106cm3mol−1.