Activation of Persulfate by Iron Filings and Oxidation of 1,4-Dioxane

Friday, 19 December 2014
Yake Wang1, Hua Zhong1, Ni Yan2 and Mark L Brusseau1,2, (1)University of Arizona, Department of Soil, Water and Environmental Science, Tucson, AZ, United States, (2)University of Arizona, Department of Hydrology and Water Resources, Tucson, AZ, United States
The use of iron filings to promote in-situ activation of persulfate for permeable reactive barrier systems is investigated with batch and column experiments. The application of the approach was illustrated for oxidation of 1,4-dioxane. The results of the batch experiments showed that in the absence of the iron filings both persulfate decomposition and dioxane degradation were slow, with pseudo first-order half-lives of 160 d-1 and 6.3 d-1, respectively. In the presence of the iron filings, persulfate decomposition and dioxane degradation was much faster, with reductions in concentrations of 86% and 34% in the first 30 minutes, respectively. Approximately 10% of the dioxane injected into a column packed with iron filings was degraded. Analysis of persulfate and sulfate concentrations in the column effluent produced balanced total sulfur. The rate coefficient obtained from the column experiments was similar to the value obtained from the batch experiments.