PHOTOCATALYTIC REACTIONS INVOLVING HYDROXYL RADICAL ATTACK - II - KINETICS OF THE DECOMPOSITION OF TRICHLOROETHYLENE USING TITANIUM-DIOXIDE

The intrinsic reaction kinetics of the decomposition of trichloroethyl ene in water employing suspended titanium dioxide catalytic particles have been studied using near ultraviolet polychromatic radiation. Expe riments 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. C hem. Res. 34, 488 (1995)). Initial concentration of trichloroethylene was in the range of 0.15 x 10(-6) to 0.75 x 10(-6) mol cm(-3) while ca talyst concentration was varied from 0.1 x 10(-3) to 1.0 x 10(-3) g 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)). Ac cording to the resulting kinetic expression therein, the values of the kinetic constant are: alpha(1) = 2.46 x 10(-8) mol cm(-2) s(-1); alph a(2) = 1.57 x 10(11) g s einstein(-1); alpha(3,i) = 6.42 x 10(6) cm(3) mol(-1). (C) 1997 Academic Press.