Natural and engineered clays and clay minerals for the removal of poly- and perfluoroalkyl substances from water: State-of-the-art and future perspectives

Raj Mukhopadhyay, Binoy Sarkar, Kumuduni Niroshika Palansooriya, Jaffer Yousuf Dar, Nanthi S. Bolan, Sanjai J. Parikh, Christian Sonne, Yong Sik Ok

Research output: Contribution to journalReview articlepeer-review

10 Citations (Scopus)

Abstract

Poly- and perfluoroalkyl substances (PFAS) present globally in drinking-, waste-, and groundwater sources are contaminants of emerging concern due to their long-term environmental persistence and toxicity to organisms, including humans. Here we review PFAS occurrence, behavior, and toxicity in various water sources, and critically discuss their removal via mineral adsorbents, including natural aluminosilicate clay minerals, oxidic clays (Al, Fe, and Si oxides), organoclay minerals, and clay-polymer and clay‑carbon (biochar and graphene oxide) composite materials. Among the many remediation technologies, such as reverse osmosis, adsorption, advanced oxidation and biologically active processes, adsorption is the most suitable for PFAS removal in aquatic systems. Treatment strategies using clay minerals and oxidic clays are inexpensive, eco-friendly, and efficient for bulk PFAS removal due to their high surface areas, porosity, and high loading capacity. A comparison of partition coefficient values calculated from extracted data in published literature indicate that organically-modified clay minerals are the best-performing adsorbent for PFAS removal. In this review, we scrutinize the corresponding plausible mechanisms, factors, and challenges affecting the PFAS removal processes, demonstrating that modified clay minerals (e.g., surfactant, amine), including some commercially available products (e.g., FLUORO-SORB®, RemBind®, matCARE™), show good efficacy in PFAS remediation in contaminated media under field conditions. Finally, we propose future research to focus on the challenges of using clay-based adsorbents for PFAS removal from contaminated water due to the regeneration and safe-disposal of spent clay adsorbents is still a major issue, whilst enhancing the PFAS removal efficiency should be an ongoing scientific effort.

Original languageEnglish
Article number102537
JournalAdvances in Colloid and Interface Science
Volume297
DOIs
Publication statusPublished - 2021 Nov

Keywords

  • Clay-biochar composites
  • Clays and clay minerals
  • Clean water and sanitation
  • Green and sustainable remediation
  • Poly- and perfluoroalkyl substances

ASJC Scopus subject areas

  • Surfaces and Interfaces
  • Physical and Theoretical Chemistry
  • Colloid and Surface Chemistry

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