Coexisting ions and long-chain per- and polyfluoroalkyl substances (PFAS) inhibit the adsorption of short-chain PFAS by granular activated carbon

Yi Zhang, Amanda Thomas, Onur Apul, Arjun K. Venkatesan

Research output: Contribution to journalArticlepeer-review

17 Scopus citations

Abstract

We assessed the competitive adsorption between long-chain and short-chain PFAS and the impact of coexisting ions to understand the mechanisms leading to the early breakthrough of short-chain PFAS from granular activated carbon (GAC) filters. Three pairs of short-chain and long-chain PFAS representing different functional groups were studied using GAC (Filtrasorb 400) in batch systems. In bisolute systems, the presence of long-chain PFAS decreased the adsorption of short-chain PFAS by 30–50% compared to their single solute adsorption capacity (0.22–0.31 mmol/g). In contrast to the partial decrease observed in bisolute systems, the addition of long-chain PFAS to GAC pre-equilibrated with short-chain PFAS completely desorbed all short-chain PFAS from GAC. This suggested that the outermost adsorption sites on GAC were preferentially occupied by short-chain PFAS in the absence of competition but were prone to displacement by long-chain PFAS. The presence of inorganic/organic ions inhibited the adsorption of short-chain PFAS (up to 60%) but had little to no impact on long-chain PFAS, with the inhibitory trend inversely correlated with Kow values. Study results indicated that the displacement of short-chain PFAS by long-chain PFAS and charge neutralization are important mechanisms contributing to the early breakthrough of short-chain PFAS from GAC systems.

Original languageEnglish (US)
Article number132378
JournalJournal of Hazardous Materials
Volume460
DOIs
StatePublished - Oct 15 2023

All Science Journal Classification (ASJC) codes

  • Environmental Engineering
  • Environmental Chemistry
  • Waste Management and Disposal
  • Pollution
  • Health, Toxicology and Mutagenesis

Keywords

  • Breakthrough
  • Competitive sorption
  • Electrostatic interaction
  • GAC
  • Short-chain PFAS

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