Degradation Of Azo Dyes（Acid Orange 7 And Congo Red）by O₃ Activated With Micro Zero-valent Zinc

Azo dyes have been widely used in textiles and leather products.They are typical organic wastewater with teratogenic,carcinogenic and mutagenic effects in the environment,which have a serious threat to the security of our water environment.Owing to its complex structure,high chromaticity and poor biodegradability,traditional treatments for azo dyes are not efficient.Therefore,the degradation of azo dyes is receiving increasing attention for environmental protection.Catalytic ozonation technology is considered to be an easy operated,favored,greener,and cleaner technology for the removal of toxic organic pollutants from wastewater.In this paper,Acid orange 7 and Congo red were degraded by a combination of Zn（0）and O₃,and their impact factors and reaction mechanism were investigated.The thesis includes two parts.In Part Ⅰ:In Zn（0）/O₃ system,the influence of the factors including zinc dosage,A07 initial concentration,initial pH and temperature on the degradation of A07 was studied.And the possible reaction mechanism and pathway according to measure the exchange of zinc ions concentration,pH and intermediate products were discussed.The results showed that the Zn（0）and O₃ had a significant synergistic effect on degradation of A07,and the degradation rate of A07 in Zn（0）/O₃ system was much higher than in the system of O₃ or Zn（0）alone.What’ s more,the zinc dosage,A07 initial concentration and initial pH played an important role in this process.94%of the initial AO7（50 mg/L）was removed after 30 min when the initial pH was 5.86 at 25 ℃ and the reaction exhibited a characteristics of pseudo-first-order kinetics.In Part Ⅱ:In Zn（0）/O₃ system,the influence of the factors including zinc dosage,CR initial concentration,initial pH and temperature on the degradation of CR was investigated.And the possible reaction mechanism and pathway according to measure the exchange of zinc ions concentration,pH and intermediate products were discussed.The results showed that the Zn（0）and O₃ had a significant synergistic effect on degradation of CR,and the degradation rate of CR in the system of Zn（0）/O₃ was much higher than in the system of O₃ or Zn（0）alone.What’s more,the zinc dosage,CR initial concentration and initial pH played an important role in this process.92%of the initial CR（50 mg/L）was removed after 30 min when the initial pH=5.91 at 25 ℃ and the reaction exhibited a characteristics of pseudo-first-order reaction kinetics.