UNS: The Oxidative Potential of Manganese Oxides in Passive Water Treatment Systems

University Of Wisconsin-Madison, Madison WI

Investigators

Abstract

1509879 Ginder-Vogel Naturally occurring and synthetic manganese oxides are among the strongest, naturally occurring oxidants and can destroy hazardous organic compounds. Organic compounds are widespread among aqueous pollutants and include many endocrine disrupting compounds, biologically active hormones, and antibiotics. These chemicals are generally not removed nor significantly degraded by traditional primary and secondary wastewater treatment technologies, resulting in their discharge to and presence in drinking water sources, including surface and groundwater. Thus the focus of this project is to explore the use of manganese oxides as inexpensive passive oxidants to remove a variety of organic contaminants from water. The objectives of the proposed research are to: (1) assess the reactivity of target organic compounds with manganese oxides, and, (2) investigate the impact of environmental conditions on manganese oxide reactivity. The PIs will (1) assess the reactivity and transformation mechanisms of target organic compounds (e.g., model phenols and phenolic contaminants) with delta-MnO2 (a pure Mn(IV) oxide) and previously uncharacterized manganese solids collected from a drinking water treatment system, while quantifying changes in solid-phase manganese oxide chemistry, (2) quantify the role of dissolved O2 in limiting manganese oxide surface passivation during contaminant oxidation, and, (3) quantify the impact of competing reactions on target contaminant transformation. The proposed work will yield important insights into the fundamental and practical considerations that govern the ability of manganese oxides to degrade organic contaminants in environmental settings. Due to their high reactivity, manganese oxides could be applied to remove recalcitrant organic contaminants in a variety of water treatment applications. For example, manganese oxide-based filter media could be used in green infrastructure, such as bioretention ponds, permeable pavements, green roofs and vegetated swales, to oxidize a wide range of contaminants in urban stormwater. Similarly, a layer of manganese oxides could be installed below the geosynthetic or clay-based liners typically used to contain landfill or manure lagoon leachate. This project will provide research, teaching and mentoring opportunities for a graduate student and a research opportunity for an undergraduate summer intern each summer.