Comparison of Manganese Dioxide and Permanganate as Amendments with Persulfate for Aqueous 1,4-Dioxane Oxidation

Abstract

Persulfate (PS) is widely used to degrade emerging organic contaminants in groundwater and soil systems, and various PS activation methods (e.g., energy or chemical inputs) have been considered to increase oxidation strength. This study investigates PS activation through manganese amendment in the form of potassium permanganate (KMnO4) and manganese dioxide (MnO2) to subsequently degrade the emerging and recalcitrant groundwater contaminant 1,4-dioxane (1,4-D). The activation of PS by MnO2 was confirmed by radical trap and by product formation. The degradation kinetics of 1,4-D by PS was also compared with varying amendments of KMnO4 and MnO2. The results showed that MnO2 activated PS, which increased the degradation rate constant of 1,4-D. KMnO4 activation of PS was not observed even though the binary oxidant mixture did enhance the degradation of 1,4-D. These results have implications for applying in situ chemical oxidation in subsurface systems, especially for conditions wherein manganese exists naturally in groundwater or aquifer minerals to support possible PS activation.

Insights into the potential applications of permanganate/peroxymonosulfate systems: enhancement via amorphous MnO2, effects of water matrices, and optimization using response surface methodology

“…Injecting aqueous KMnO 4 can increase the manganese content of groundwater or aquifers, potentially supporting in situ activation of PMS to enhance the ISCO effect on hard-to-degrade organic contaminants. 30 However, the mechanism of the KMnO 4 /PMS system in micropollutant control in groundwater has not been systematically investigated, and there is a need to extend its effectiveness and applicability to the removal of a wide range of organic pollutants, which is essential for solving diverse environmental pollution problems.…”

Contaminant Transport and Fate

“…Besides drawing attention to the type and volume of contaminants being introduced into the environment, their analysis highlights the influence of major storms on propagating those solutes into aquifers. The activation of persulfate (PS) oxidant through manganese amendment to subsequently degrade a recalcitrant groundwater contaminant, 1,4-dioxane was examined by Bridges et al (2021) [2]. Their results showed that MnO 2 activated PS and increased contaminant degradation rate constants.…”