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Breakthrough and desorption of PFAS in aged GAC filters during drinking water treatment – a question of DOM composition

McEvoy, Aina ; Szopińska, Małgorzata ; Kozłowska-Tylingo, Katarzyna ; Murphy, Kathleen ; Cimbritz, Michael LU orcid ; Davidsson, Åsa LU orcid and Falås, Per LU (2026) In Water Research 304.
Abstract

Shifts in dissolved organic matter (DOM) composition, caused by seasonal or episodic events, can significantly alter the removal of per- and polyfluoroalkyl substances (PFAS) by granular activated carbon (GAC). To investigate how changes in feedwater composition impact PFAS removal in aged GAC, a 20-day experiment was conducted in eight parallel small-scale columns. Columns were filled with aged GAC from a full-scale drinking water treatment plant that still retained >80% efficiency for removing the sum of PFAS21 from groundwater. The GAC was exposed to feedwaters with varying DOM composition and aromaticity. The removal performance was evaluated using fluorescence spectroscopy combined with measurements of 14C-labelled... (More)

Shifts in dissolved organic matter (DOM) composition, caused by seasonal or episodic events, can significantly alter the removal of per- and polyfluoroalkyl substances (PFAS) by granular activated carbon (GAC). To investigate how changes in feedwater composition impact PFAS removal in aged GAC, a 20-day experiment was conducted in eight parallel small-scale columns. Columns were filled with aged GAC from a full-scale drinking water treatment plant that still retained >80% efficiency for removing the sum of PFAS21 from groundwater. The GAC was exposed to feedwaters with varying DOM composition and aromaticity. The removal performance was evaluated using fluorescence spectroscopy combined with measurements of 14C-labelled PFOA and unlabelled PFAS. This combination facilitated an assessment of changes in both DOM composition and PFAS removals. The results showed that a change in DOM composition of the feedwater resulted in the desorption of shorter-chained PFAS from the GAC and a simultaneous increase in the adsorption of lower molecular weight DOM, resulting in higher aromaticity in the outgoing water. These findings suggest a dynamic sorption process in which newly introduced DOM in the GAC feedwater competes for adsorption sites, potentially displacing previously adsorbed PFAS. Experiments with carbon–14 labelled perfluorooctanoic acid (14C-labelled PFOA) indicated that an increase in feedwater DOM aromaticity, while maintaining a constant dissolved organic carbon (DOC) concentration, resulted in earlier breakthrough. This highlights the need to monitor and evaluate not only the quantity of DOM in feedwater, but also its composition.

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author
; ; ; ; ; and
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
Aromaticity, Column test, Drinking water, Micropollutants, Water quality
in
Water Research
volume
304
article number
126326
publisher
Elsevier
external identifiers
  • scopus:105042640032
  • pmid:42335540
ISSN
0043-1354
DOI
10.1016/j.watres.2026.126326
language
English
LU publication?
yes
id
58cfa91d-cf4f-47d2-af8d-9e1017eb11f9
date added to LUP
2026-09-29 09:34:31
date last changed
2026-09-30 02:52:27
@article{58cfa91d-cf4f-47d2-af8d-9e1017eb11f9,
  abstract     = {{<p>Shifts in dissolved organic matter (DOM) composition, caused by seasonal or episodic events, can significantly alter the removal of per- and polyfluoroalkyl substances (PFAS) by granular activated carbon (GAC). To investigate how changes in feedwater composition impact PFAS removal in aged GAC, a 20-day experiment was conducted in eight parallel small-scale columns. Columns were filled with aged GAC from a full-scale drinking water treatment plant that still retained &gt;80% efficiency for removing the sum of PFAS21 from groundwater. The GAC was exposed to feedwaters with varying DOM composition and aromaticity. The removal performance was evaluated using fluorescence spectroscopy combined with measurements of <sup>14</sup>C-labelled PFOA and unlabelled PFAS. This combination facilitated an assessment of changes in both DOM composition and PFAS removals. The results showed that a change in DOM composition of the feedwater resulted in the desorption of shorter-chained PFAS from the GAC and a simultaneous increase in the adsorption of lower molecular weight DOM, resulting in higher aromaticity in the outgoing water. These findings suggest a dynamic sorption process in which newly introduced DOM in the GAC feedwater competes for adsorption sites, potentially displacing previously adsorbed PFAS. Experiments with carbon–14 labelled perfluorooctanoic acid (<sup>14</sup>C-labelled PFOA) indicated that an increase in feedwater DOM aromaticity, while maintaining a constant dissolved organic carbon (DOC) concentration, resulted in earlier breakthrough. This highlights the need to monitor and evaluate not only the quantity of DOM in feedwater, but also its composition.</p>}},
  author       = {{McEvoy, Aina and Szopińska, Małgorzata and Kozłowska-Tylingo, Katarzyna and Murphy, Kathleen and Cimbritz, Michael and Davidsson, Åsa and Falås, Per}},
  issn         = {{0043-1354}},
  keywords     = {{Aromaticity; Column test; Drinking water; Micropollutants; Water quality}},
  language     = {{eng}},
  month        = {{10}},
  publisher    = {{Elsevier}},
  series       = {{Water Research}},
  title        = {{Breakthrough and desorption of PFAS in aged GAC filters during drinking water treatment – a question of DOM composition}},
  url          = {{http://dx.doi.org/10.1016/j.watres.2026.126326}},
  doi          = {{10.1016/j.watres.2026.126326}},
  volume       = {{304}},
  year         = {{2026}},
}