Mn(Ⅱ)/O3降解草酸作用机制的定量化解析

化工学报 ›› 2009, Vol. 60 ›› Issue (2): 428-434.

Mn(Ⅱ)/O3降解草酸作用机制的定量化解析

臧兴杰;张华;石锐;童少平;马淳安

浙江工业大学化学工程与材料学院;绿色化学合成技术国家重点实验室培育基地

出版日期:2009-02-05 发布日期:2009-02-05

Quantitative study on mechanism of Mn(Ⅱ) catalytic ozonation of oxalic acid

ZANG Xingjie; ZHANG Hua; SHI Rui;TONG Shaoping; MA Chun’an

Online:2009-02-05 Published:2009-02-05

摘要/Abstract

摘要：

利用Mn(Ⅱ)/O3氧化体系降解了草酸, 探讨并定量化解析了Mn(Ⅱ)催化臭氧化降解草酸的作用机制。结果表明,加入Mn(Ⅱ)能明显提高臭氧化降解草酸的效率, 体系R_ct值也有所增大。Mn(Ⅱ)/O3降解草酸的途径主要包括以下3种方式: 第一, 臭氧的直接氧化反应; 第二,羟基自由基(水中溶解臭氧分解产生)的氧化反应; 第三, Mn(Ⅳ)和Mn(Ⅶ)等高价锰对草酸的氧化反应。溶液pH值不但直接影响Mn(Ⅱ)/O3降解草酸的效率, 而且还决定了三者的贡献大小。在本实验条件下, 当pH值为2.9时, Mn(Ⅱ)/O3降解草酸的表观反应速率常数为28.280×10^-4 s^-1, 三者对草酸降解的百分比贡献为f_O3∶f_OH∶f_rest=2.1∶19.0∶78.9当pH值为5.3、8.0和10.0时, 草酸降解的表观反应速率常数分别为1.597×10^-4 s^-1、1.535×10^-4 s^-1和〖WTBZ〗1.545×10^-4 s^-1, 三者的百分比贡献分别为f_O3∶f_OH∶f _rest=24.9∶28.4∶46.7、f_O3∶f_OH∶f_rest=23.6∶54.5∶21.9和f_O3∶f_OH∶f_rest=19.6∶74.4∶6.0。

关键词:

草酸;臭氧;降解, Mn(Ⅱ)

Abstract:

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 R_ct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)/O₃was 28.280×10^-4 s^-1 ,and the contributing proportion of three-oxidation reactions was f_O3∶f_OH∶f_rest=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 f_O3∶f_OH∶f_rest=24.9∶28.4∶46.7,f_O3∶f_OH∶frest=23.6∶54.5∶21.9 and f_O3∶f _OH∶f_rest=19.6∶74.4∶6.0respectively.

Key words:

草酸;臭氧;降解, Mn(Ⅱ)

臧兴杰, 张华, 石锐, 童少平, 马淳安. Mn(Ⅱ)/O3降解草酸作用机制的定量化解析 [J]. 化工学报, 2009, 60(2): 428-434.

ZANG Xingjie, ZHANG Hua, SHI Rui, TONG Shaoping, MA Chun’an. Quantitative study on mechanism of Mn(Ⅱ) catalytic ozonation of oxalic acid[J]. CIESC Journal, 2009, 60(2): 428-434.