Trichloroethylene Degradation by Various Forms of Iron Activated Persulfate Oxidation with or without the Assistance of Ascorbic Acid

The oxidation of trichloroethylene (TCE), by Fe²⁺ activated persulfate (PS) to generate the sulfate radical (SO₄^–•) is limited due to the scavenging of SO₄^–• by excess Fe²⁺. This study focused on evaluating the potential for TCE oxidative degradation by iron activated persulfate (IAP) (including soluble iron and solid iron minerals), with the assistance of ascorbic acid (AsA). AsA, a water-soluble two-proton donor, may act as a reductant and a chelator, which may reduce iron oxides or complex soluble iron for PS activation. The results indicated that PS oxidation and various types of iron (Fe²⁺, Fe³⁺, FeOOH, Fe₂O₃) activated PS are able to degrade TCE in the presence or absence of AsA and are dependent upon the PS concentrations applied. Furthermore, the TCE degradation could be accelerated in the iron minerals activated PS system with the assistance of AsA. In addition, synthesized iron minerals with higher specific surface area resulted in a higher PS activation efficiency (i.e., lower PS consumption) and exhibited a higher degree of TCE degradation than that observed in commercial iron minerals activated PS systems.