Self-catalytic degradation of ortho-chlorophenol with Fenton's reagent studied by chemiluminescence.
The degradation of ortho-chlorophenol using Fenton's reagent was studied by chemiluminescence (CL). Without a special CL reagent, a weak CL emission from the mixture of ferrous ion and hydrogen peroxide was observed at room temperature. The CL intensity was increased by the addition of ortho-chlorophenol into the mixed solution. When the temperature was raised to 65 degrees C, the CL intensity was enhanced strongly. The CL mechanisms for the system H2O2-Fe2+ with and without ortho-chlorophenol were studied by examining the CL spectrum, gas chromatography-mass spectrometry and electron spin resonance spectrum. The effects of various free radical scavengers, surfactants and fluorescence compounds on the CL intensity were also investigated. A self-catalytic oxidation mechanism was proposed. The results showed that singlet oxygen was the main emitter for the system H2O2-Fe2+. The strong CL from the system H2O2-Fe(2+)-ortho-chlorophenol was due to singlet oxygen and electronically excited quinone. The benzenediol-like intermediate product formed during the phenol oxidation process greatly promoted the Fenton's reaction and led to higher CL intensity. Chemiluninescence is a novel approach for the investigation of the oxidation of some organic pollutants by Fenton's reagent.
Beijing Key Laboratory of Microanalytical Methods and Instrumentation, Department of Chemistry, Tsinghua University, Beijing 100084, China. Linz08@mail.tsinghua.edu.cn
SourceJournal of environmental sciences (China) 24:3 2012 pg 550-7
Electron Spin Resonance Spectroscopy
Pub Type(s)Journal Article
Research Support, Non-U.S. Gov't