Effective removal of PFAS by a novel multifunctional microbubble-mediated cathodic adsorption process

Area of Science:

• Environmental Chemistry
• Water Treatment Technologies
• Materials Science

Background:

• Per- and polyfluoroalkyl substances (PFAS) pose significant environmental and health risks.
• Conventional electro-sorption for PFAS removal is limited by cathodic capacity due to electrostatic repulsion.
• Developing efficient and robust methods for PFAS remediation is crucial.

Purpose of the Study:

• To develop a microbubble-mediated cathodic adsorption strategy to overcome limitations in electro-sorption for PFAS removal.
• To enhance the transport and adsorption of PFAS onto a novel cathode material.
• To investigate the efficiency and robustness of the proposed method for diverse PFAS and complex water matrices.

Main Methods:

• Utilized anodically generated oxygen microbubbles to transport PFAS to a superaerophilic carbon black-polytetrafluoroethylene modified carbon paper (CB-PTFE/CP) cathode.
• Employed the oxygen reduction reaction (ORR) to drive PFAS into cathode pores, overcoming electrostatic repulsion.
• Assessed removal efficiency for various PFAS (long-chain and short-chain) and evaluated performance in the presence of interfering substances.

Main Results:

• >90% removal of long-chain PFAS (PFOA, PFOS, PFNA, OBS) and ~40% removal of short-chain PFAS (GenX) within 1 hour.
• Robust performance maintained despite high concentrations of inorganic ions and dissolved organic matter.
• Removal kinetics for diverse PFAS were accelerated by 1.6-60 times compared to conventional electro-sorption.

Conclusions:

• The microbubble-mediated cathodic adsorption strategy effectively overcomes electrostatic repulsion, significantly enhancing PFAS removal.
• The CB-PTFE/CP cathode transforms electro-sorption into a dual-electrode system with accelerated kinetics.
• The method offers a multifunctional solution for concurrent removal of PFAS and other pollutants via in situ H2O2 generation and UV irradiation.