Effect of chelating agent on oxidation rate of aniline in ferrous ion activated persulfate system at neutral pH

ZHANG Yong-qing(张永清)^{1, 2}, XIE Xiao-fang(谢晓芳)¹, HUANG Shao-bin(黄少斌)^{1, 2, 3}, LIANG Hai-yun(梁海云)¹

(1. College of Environment and Energy, South China University of Technology, Guangzhou 510006, China;
2. Guangdong Provincial Key Laboratory of Atmospheric Environment and Pollution Control,
Guangzhou 510006, China;
3. State Key Laboratory of Pulp and Paper Engineering, South China University of Technology,
Guangzhou 510640, China)

Abstract:In the interest of accelerating aniline degradation, Fe²⁺ and chelated Fe²⁺ activated persulfate oxidations were investigated in neutral pH condition. Three kinds of chelating agents were selected including citric acid, oxalic acid and ethylenediamine tetraaceatate (EDTA) to maintain available Fe²⁺. The results indicate that the concentration of chelating agent and ferrous ion didn’t follow a linear relationship with the degradation rate of aniline. A 1/1 ratio of chelating agent/Fe²⁺ results in a higher degradation rate compared to the results by other ratios. The oxidation enhancement factor using oxalic acid was found to be relatively low. In contrast, citric acid is more suitable chelating agent in the ferrous iron activated persulfate system and aniline exhibits a highest degradation with a persulfate/Fe²⁺/citric acid/aniline molar ratio of 50/25/25/1 compared to other molar ratios.

Key words:chelating agent; persulfate; aniline; ferrous ion