Foundation of kinetics model for TiO2-photocatalyzed degradation of organic compounds in suspending system

With O, S-dimethyl acetyl phosphoramidothioate(DMAPT) as objective compound , the kinetics model for TiO2-photocatalyzed degradation in suspending syst em was studied in DGF-1 model photochemistry reaction instrument. The main parameters involved in the model are TIO dosage, effective light intensity, geometrical radius and empirical parameter of the reactor, initial concent ration of the reactant, rate constants of the second-order reaction of OH. radical, and physical properties of the reactant(such as molar volume and a queous solubility). The different DMAPT concentrations were used to validat e the funtion. The model preferably predicted the photocatalytic degradatio n of other compounds, such as trichloroethylene (TCE), tetrachloroethylene( PCE), p-dichlorobeneze(DCB) and carbon tetrachloride (CTC). For the system with C-0(TCE) = 22. 1 mg/L, C-0(PCE) = 20 mg/L, C-0(DCB) = 40 mg/L, the tim e needed for complete degradation is 3, 4 and 5 min respectively. The react ion rate is proportional to the half-order of incident light intensity with in the range of 1. 38 similar to 6. 05 W/cm(2). The optimum catalyst dosage increases with increasing the incident light intensity.