Abstract:

In ordrt to explore the degradation possibility of monoazo dye acid red(AR37) and its transformation mechanism under attack of reactive oxygen species, a semi-empirical experssion was obtained by means of photocatalytic technology and central composite design based on the responsesurface method. The influences of different factors on the photocatalysis efficiency of acid red (AR37) were investigated. The optimal conditions are：substrate concentration of 90 μmol/L, TiO2 amount of  2.3 g/L, reaction temperature of 12.5 ℃ and initial solution pH value of 8.7. The influences of selected anions and cations on the degradation of AR37 were also studied. It was observed that Na+, Fe2+, Fe3+ and Zn2+ have significant inhibitory effect on the degradation of AR37 while Cu2+ accelerate the degradation of AR37. On the other hand, anions such as CrO42-, SO42-, ClO3-, MnO4- and Cl- has certain inhibitory effect on the degradation of AR37. Finally, the degradation intermediates of AR37 were identified by gas chromatography-mass spectrometer. The results show that in the photocatalytic process, after N= N and C-N bonds in AR37 molecules are broken, the further hydroxylation reaction is the main degradation path.

Key words: acid red 37, photocatalytic, titanium dioxide, degradation kinetics