Indirect Electrochemical Regeneration of Manganese Oxide (MnOx) – Coated Media

Document Type

Article

Date of Original Version

9-1-2025

Abstract

Manganese (Mn) in drinking water poses aesthetic, health, and operational concerns. One common removal method involves adsorbing soluble Mn(II) onto manganese (III/IV) oxide (MnOx)-coated media, but this approach typically relies on chemical reagents for surface regeneration. In systems lacking chemical storage, dosing, and containment capacity, this may be impractical. This study demonstrated an alternative regeneration technique using an electrochemical reactor for in situ oxidant production at conditions relevant to drinking water treatment. The reactor generated oxidants, likely free chlorine, and increased the pH of the applied water. Across batch-scale recirculating, intermittent regeneration, and single-pass continuous regeneration experiments, electrochemically regenerated MnOx-coated media produced ~90% removal of Mn(II), achieving a common treatment goal of 0.02 mg/L. Regeneration was also confirmed by analyzing the average oxidation state of the MnOx surface. Performance depended on several factors, such as raw water Mn, applied voltage, and alkalinity. Although modeling and Mn fractionation suggested limited homogenous oxidation of Mn(II), the formation of some colloidal MnOx may have confounded results in some experimental situations. These findings highlight a promising, reagent-free strategy for regenerating oxide-coated media, expanding its applicability for water treatment, especially in isolated systems and point-of-use applications.

Publication Title, e.g., Journal

AWWA Water Science

Volume

7

Issue

5

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