Removal of trichloroethylene in groundwater with two oxidants: siderite catalyzed hydrogen peroxide and sodium persulfate

Trichloroethylene (TCE), a widely used solvent, is often determined in groundwater and is one of biologically refractory organic contaminants. The aim of the study is to use a new chemical oxidation method to degrade TCE source pollution in groundwater. Fenton-like reactions (hydrogen peroxide catalyzed by iron minerals generates hydroxyl radicals) and sodium persulfate activation (sodium persulfate activated by heat/iron minerals to produce sulfate radicals) have strong oxidative capacity to degrade a wide range of organic contaminants. In this work, hydrogen peroxide and/or sodium persulfate catalyzed by siderite (designated as STO, SO, PO systems, respectively) degrading TCE in groundwater were investigated. Removal rates of TCE in STO, SO, and PO systems were 100%, 57%, 20%, respectively. The order of TCE removal rates is in agreement with that of hydroxyl radicals generated in the systems, indicating that hydroxyl radicals play a critical role in removing TCE. No by-product except CO₂, Cl⁻ and H₂O generated as final products in the STO system suggests that TCE was near completely mineralized. The results show that the STO is an effective method to treat TCE contaminated source in groundwater.