ITERFERENCE OF Mn~(2+), Co~(2+), Ni~(2+) AND Cu~(2+) IONS IN THE HETEROGENEOUS UV-CATALYSIS USING A TiO_2 SUSPENSION SYSTEM

摘要

The influence of transition metal ions, Mn~(2+), Co~(2+) , Ni~(2+) and Cu~(2+) , on the rate of pho-tocatalytic oxidation of 2-chlorophenol was studied at pH 3. The results shown that the photo-catalytic oxidation of 2-chlorophenol presenting in metal ions follows the Langmuir-Hinshelwood type behavior and the reaction byproducts display an inhibiting effect on degradation rate. Results of the theoretical analysis can be used to explain the inverse initial concentration effect of 2-chlorophenol in the apparent degradation rate constant. The surface oxidation rate of 2-chlorophenol was related with the oxidation and reduction potential of metal's standard potential. The higher electron voltage of metal ion the higher reaction rate of the surface oxida-tive was observed. From the analysis of mineralization of 2-chlorophenol, the transition metals ions generate a complex with the 2-chlorophenol oxidizing intermediate was proposed. The surface property was related with complex formation of metal ions and organic. The selectivity formation was relate with the organic-metal-complex competitive with 2-chlorophenol induces the reaction rate when increases the initial 2-chlorophenol concentration.