Oxidation of chlorophenols in soil at natural pH by catalyzed hydrogen peroxide: the effect of soil organic matter

• Published in: Chemosphere (Oxford) 2002, Vol.46 (1), p.67-73
• Main Authors: Kuei-Jyum Yeh, Carol, Kao, Yu-Ann, Cheng, Chung-Pin
• Format: Article
• Language: English
• Subjects: Adsorption; Algorithms; Applied sciences; Catalysis; Chlorophenol; chlorophenols; Chlorophenols - chemistry; Chlorophenols - isolation & purification; Decontamination. Miscellaneous; Earth sciences; Earth, ocean, space; Engineering and environment geology. Geothermics; Exact sciences and technology; Fenton oxidation; Humic Substances - chemistry; Humic Substances - isolation & purification; hydrogen peroxide; Hydrogen Peroxide - administration & dosage; Hydrogen-Ion Concentration; Iron - administration & dosage; Natural soil pH; Oxidation-Reduction - drug effects; Pollution; Pollution, environment geology; Soil - analysis; Soil and sediments pollution; Soil organic matter; Soil Pollutants - isolation & purification
• ISSN: 0045-6535; 1879-1298
• DOI: 10.1016/S0045-6535(01)00110-2

This investigation reports on the effects of soil organic matter (SOM) during the oxidation of chlorophenols with Fe 2+-catalyzed H 2O 2 (Fenton oxidation) system. The soil pH was 7.1 and was not altered. Sorption experiments of soil pre-treated under various oxidation conditions were performed. Concentrations of organic matter in the liquid phase and soil before and after oxidation were analyzed. The results were correlated to the observation in batch Fenton oxidation tests. They showed that the oxidation of chlorophenols at natural soil pH depended on the dose of H 2O 2 and Fe 2+. The soil organic content did not vary significantly after various Fenton treatments, while the sorption of chlorophenols was 10–25% less by the oxidation. The concentration of chlorophenols in the liquid phase exhibited a “decrease and rebound” phenomenon in the batch Fenton oxidation tests. It appeared that the oxidation of SOM resulted in the release of sorbed chlorophenols which were then oxidized by the excess H 2O 2. An “oxidation–desorption–oxidation” scheme was proposed to describe one of the interaction mechanisms among the oxidant, SOM, and chlorophenols during oxidation.