The effects of copper ions on the catalytic degradation of azo dye acid chrome dark blue

The effect of Cu²⁺ on the catalytic degradation of Acid chrome dark blue (ACDB) in UV-TiO₂ process and Fenton process was studied. In these two processes, Cu²⁺ markedly inhibited the degradation of ACDB. These inhibition effects had an obvious relationship with the concentration of Cu²⁺. The experimental results indicated that in pH 5.0 buffer solution, ACDB reacted with Cu²⁺ with the formation of new complex Cu(ACDB)₂. This interaction was favorable to protect some groups in ACDB from the oxidation of reactive oxygen species generated in UV-TiO₂ process and Fenton process, and consequently had suppressing effects on degradation of ACDB.