活性艳红X-3B的Fenton氧化降解机理研究

Degradation Mechanism of Reactive Brilliant Red X-3B by Fenton Process

采用UV-Vis、IR和GC-MS研究了X-3B的Fenton降解机理,结合X-3B的结构和亲电理论,提出了其Fenton氧化降解路径。染料分子首先在-N=N-C靠近萘环的C-N和C-NH两处断裂,产生三种中间产物:邻羟基重氮苯内盐、萘醌和4,6-二氯-1,3,5-三嗪-2-氨。邻羟基重氮苯内盐释放出N2,即偶氮基团的氮原子转化为N2,而其他氮原子被氧化为NO3-。染料中的C、H、S和Cl原子分别矿化为CO2、H2O、SO42-和Cl-,但部分有机碳仍存在于难以被.OH氧化降解的草酸-Fe3+络合物中。

Degradation mechanism of X-3B by Fenton process was investigated through UV-Vis, IR and GC-MS. The probable degradation pathway of X-3B was concluded according to the experiment results as well as the structure of dye and electrophilic theory. Dye molecule was attacked by hydroxyl radicals and broken at the C-N bond close to the naphthalene ring of -N =N-C and C-NH bond. Three primary intermediates were generated, including 2-hydroxy- benzenediazonium hydroxide inner salt, naphthalene quinones and 4, 6-dichloro-1, 3, 5-triazin-2-amine. The inner salt released nitrogen gas and the other nitrogen atoms of X-3B molecule were mineralized to nitrate ions. The C, H, S and Cl elements in X-3B were transformed to CO2, H2O, SO4^2- and Cl^- respectively. However, some C element existed in the Fe^2＋-oxalato complexes which were hardly oxidized by hydroxyl radicals.