Oxalic acid was degraded by Mn(Ⅱ) catalytic ozonation

and its mechanism was discussed by a quantitative analysis.The experimental results demonstrated that the ozonation efficiency increased with adding Mn(Ⅱ)catalyst to oxalic acid solution

and that Rctof the ozonation system also increased.The degradation of oxalic acid by Mn(Ⅱ) catalytic ozonation included three parts : direct ozonation

oxidation reaction of hydroxyl radical produced from the decomposition of the dissolved ozone

oxidation reaction of Mn(Ⅳ)and Mn(Ⅶ).The pH of solution not only influenced the degradation efficiency of Mn(Ⅱ)/O3

but also determined the contributing proportions of three different oxidation reactions.When the pH was 2.9

the apparent rate constant of degradation of oxalic acid by Mn(Ⅱ)/O3 was 28.280×10-4 s-1

and the contributing proportion of three-oxidation reactions was fO3∶fOH∶frest=2.1∶19.0∶78.9However

when the pH values were 5.3

8.0 and 10.0

the apparent rate constants were 〖WTBZ〗1.597×10-4s-1

1.535×10-4s-1 and 1.545×10-4s-1

respectively

and the contributing proportion of the three-oxidation reactions were fO3∶fOH∶frest=24.9∶28.4∶46.7

fO3∶fOH∶frest=23.6∶54.5∶21.9 and fO3∶f OH∶frest=19.6∶74.4∶6.0respectively.