Recovery of nitrate and fluoride salts from stainless steel pickling wastewater with flow-electrode capacitive deionization

Flow-electrode Capacitive Deionization (FCDI) is an innovative method for practical salt removal and recycling applications. Here, we report that FCDI facilitates the recovery of nitrate and fluoride salts from brines produced during the wastewater treatment process in a stainless steel pickling lin...

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Main Authors: Niklas Köller, Dustin Roedder, Christian J. Linnartz, Mark Enders, Florian Morell, Patrick Altmeier, Matthias Wessling
Format: Article
Language:English
Published: Elsevier 2025-11-01
Series:Journal of Hazardous Materials Letters
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Online Access:http://www.sciencedirect.com/science/article/pii/S2666911025000085
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author Niklas Köller
Dustin Roedder
Christian J. Linnartz
Mark Enders
Florian Morell
Patrick Altmeier
Matthias Wessling
author_facet Niklas Köller
Dustin Roedder
Christian J. Linnartz
Mark Enders
Florian Morell
Patrick Altmeier
Matthias Wessling
author_sort Niklas Köller
collection DOAJ
description Flow-electrode Capacitive Deionization (FCDI) is an innovative method for practical salt removal and recycling applications. Here, we report that FCDI facilitates the recovery of nitrate and fluoride salts from brines produced during the wastewater treatment process in a stainless steel pickling line. Laboratory-scale experiments with synthetic wastewaters were used to evaluate the influence of (a) the membrane thickness, (b) feed flow rates, and (c) applied voltage on the outlet concentrations and the average salt transfer rate. In continuous single-pass experiments, the flow rates of diluate and concentrate have the greatest influence on the resulting outlet concentrations in the FCDI process as they directly influence the residence time. The operating voltage of the FCDI process can be varied to increase the ratio of fluoride over nitrate for recycling.
format Article
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institution OA Journals
issn 2666-9110
language English
publishDate 2025-11-01
publisher Elsevier
record_format Article
series Journal of Hazardous Materials Letters
spelling doaj-art-c25ab4e9683342b19b68073e76c79a372025-08-20T02:02:07ZengElsevierJournal of Hazardous Materials Letters2666-91102025-11-01610014810.1016/j.hazl.2025.100148Recovery of nitrate and fluoride salts from stainless steel pickling wastewater with flow-electrode capacitive deionizationNiklas Köller0Dustin Roedder1Christian J. Linnartz2Mark Enders3Florian Morell4Patrick Altmeier5Matthias Wessling6RWTH Aachen University, Aachener Verfahrenstechnik-Chemical Process Engineering, Forckenbeckstraße 51, Aachen 52074, GermanyRWTH Aachen University, Aachener Verfahrenstechnik-Chemical Process Engineering, Forckenbeckstraße 51, Aachen 52074, GermanyRWTH Aachen University, Aachener Verfahrenstechnik-Chemical Process Engineering, Forckenbeckstraße 51, Aachen 52074, Germany; DWI - Leibniz Institute for Interactive Materials e.V., Forckenbeckstraße 50, Aachen 52074, GermanySIMA-tec GmbH, Schier 12c, Schwalmtal 41366, GermanyOutokumpu Nirosta GmbH, Oberschlesienstraße 16, Krefeld 47807, GermanyPCCell GmbH, Lebacher Straße 60, Heusweiler 66265, GermanyRWTH Aachen University, Aachener Verfahrenstechnik-Chemical Process Engineering, Forckenbeckstraße 51, Aachen 52074, Germany; DWI - Leibniz Institute for Interactive Materials e.V., Forckenbeckstraße 50, Aachen 52074, Germany; Corresponding author at: RWTH Aachen University, Aachener Verfahrenstechnik-Chemical Process Engineering, Forckenbeckstraße 51, Aachen 52074, Germany.Flow-electrode Capacitive Deionization (FCDI) is an innovative method for practical salt removal and recycling applications. Here, we report that FCDI facilitates the recovery of nitrate and fluoride salts from brines produced during the wastewater treatment process in a stainless steel pickling line. Laboratory-scale experiments with synthetic wastewaters were used to evaluate the influence of (a) the membrane thickness, (b) feed flow rates, and (c) applied voltage on the outlet concentrations and the average salt transfer rate. In continuous single-pass experiments, the flow rates of diluate and concentrate have the greatest influence on the resulting outlet concentrations in the FCDI process as they directly influence the residence time. The operating voltage of the FCDI process can be varied to increase the ratio of fluoride over nitrate for recycling.http://www.sciencedirect.com/science/article/pii/S2666911025000085Flow-electrode capacitive deionizationStainless steel picklingSalt brinesNitrateFluoride
spellingShingle Niklas Köller
Dustin Roedder
Christian J. Linnartz
Mark Enders
Florian Morell
Patrick Altmeier
Matthias Wessling
Recovery of nitrate and fluoride salts from stainless steel pickling wastewater with flow-electrode capacitive deionization
Journal of Hazardous Materials Letters
Flow-electrode capacitive deionization
Stainless steel pickling
Salt brines
Nitrate
Fluoride
title Recovery of nitrate and fluoride salts from stainless steel pickling wastewater with flow-electrode capacitive deionization
title_full Recovery of nitrate and fluoride salts from stainless steel pickling wastewater with flow-electrode capacitive deionization
title_fullStr Recovery of nitrate and fluoride salts from stainless steel pickling wastewater with flow-electrode capacitive deionization
title_full_unstemmed Recovery of nitrate and fluoride salts from stainless steel pickling wastewater with flow-electrode capacitive deionization
title_short Recovery of nitrate and fluoride salts from stainless steel pickling wastewater with flow-electrode capacitive deionization
title_sort recovery of nitrate and fluoride salts from stainless steel pickling wastewater with flow electrode capacitive deionization
topic Flow-electrode capacitive deionization
Stainless steel pickling
Salt brines
Nitrate
Fluoride
url http://www.sciencedirect.com/science/article/pii/S2666911025000085
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