Advanced electrochemical oxidation for the simultaneous removal of manganese and generation of permanganate oxidant

Emerging electrochemical systems, such as advanced electro-oxidation, provide a potentially powerful alternative to conventional oxidation processes which can often be unsuitable for small, remote and decentralised system applications. The one electro-oxidation process, which may be well suited for...

Full description

Saved in:
Bibliographic Details
Published in:Environmental science water research & technology 2020-09, Vol.6 (9), p.245-2415
Main Authors: McBeath, Sean T, Wilkinson, David P, Graham, Nigel J. D
Format: Article
Language:English
Subjects:
Boron
Constants
Contaminants
Current density
Diamonds
Drinking water
Electrochemical oxidation
Electrochemistry
Free radicals
Hydroxyl radicals
Manganese
Mass transport
Mathematical models
Oxidants
Oxidation
Oxidation process
Oxidizing agents
Pollutant removal
Rate constants
Raw water
Removal
Scale (corrosion)
Water pollution
Water supply
Water treatment
Citations: Items that this one cites
Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:Emerging electrochemical systems, such as advanced electro-oxidation, provide a potentially powerful alternative to conventional oxidation processes which can often be unsuitable for small, remote and decentralised system applications. The one electro-oxidation process, which may be well suited for these applications, is the use of high oxygen overpotential boron-doped diamond (BDD) electrodes, as a pre-oxidation step for the removal of various raw water contaminants. While BDD electro-oxidation has been studied extensively for the abatement of organic micropollutants, its application as a pre-oxidation technology for the removal of soluble manganese (Mn 2+ ) in source waters for drinking water supply, has not been reported to-date. In this study, we summarise the results of tests using a bench-scale electro-oxidation system and synthetic Mn 2+ solutions in order to consider the simultaneous removal of manganese and the generation of permanganate. The results showed that total manganese was reduced by 9.1, 38.7 and 57.4% at current densities of 10, 40 and 80 mA cm −2 , respectively, with an initial Mn 2+ concentration of 39 μM. Increased Mn removal at higher current density was attributed to increased generation of, and reaction with, hydroxyl radicals, indicated by a direct proportional relationship between pseudo-first order reaction rate constants for methanol (&z.rad;OH radical scavenger) and current density. A mathematical model was developed to describe Mn removal under mass transport limitations, and was found to correlate well with experimental data. Finally, a completely novel synthesis pathway for the generation of permanganate species (Mn 7+ ) is presented, whereby concentrations up to 0.9 μM were synthesised from Mn 2+ in circumneutral conditions. Emerging electrochemical systems, such as advanced electro-oxidation, provide a potentially powerful alternative to conventional oxidation processes which can often be unsuitable for small, remote and decentralised system applications.
ISSN:2053-1400
2053-1419
DOI:10.1039/d0ew00261e