Catalyzed Hydrogen Peroxide Treatment of Polychlorinated Biphenyl Contaminated Sandy Soils

Abstract

This paper reports the results of the treatment of polychlorinatedbiphenyl (PCB) contaminated sandy soils (100 mg kg-1 Aroclor 1242) with the Fenton advanced oxidation process (AOP). The results obtained in the various assays permitted the optimization of conditions as follows: 5% H2O2; 100 ppm of Fe3+; and a ratio of sandy soil mass/volume of oxidizing solution (m/V) of 1/3 g mL-1. In addition, these tests established the need for agitation and dispensed with the need for heat. The results obtained confirm that the oxidation process occurs in solid phase (on the PCBs adsorbed to soil particles), producing 98% elimination of the original PCB structure and 82% dechlorination, all within a reaction time of 72 hr. The degree of elimination was found to be dependent on the level of congener chlorination and the process displays a pseudo first order kinetics. In addition, the Fenton chemical oxidation process may be complemented by subsequent aerobic biological degradation which, after 15 days, produces 72% mineralization of the products generated during the chemical oxidation process.