Overcoming configuration and fouling limitations in capacitive deionization for efficient multicomponent PFAS...

Area of Science:

• Environmental Science
• Materials Science
• Chemical Engineering

Background:

• Per- and polyfluoroalkyl substances (PFAS) are persistent environmental contaminants requiring effective removal technologies.
• Short- and ultrashort-chain PFAS pose treatment challenges due to their unique properties.
• Existing water treatment methods struggle with multicomponent and challenging water matrices.

Purpose of the Study:

• To develop an integrated membrane capacitive deionization (IMCDI) system for efficient PFAS removal.
• To enhance electrosorption and reduce fouling in challenging water conditions.
• To investigate the performance of mesoporous carbon hollow sphere (MCHS) electrodes with a novel hydrogel interface.

Main Methods:

• Fabrication of IMCDI system using MCHS electrodes coated with polyvinyl alcohol/polyethyleneimine (PVA/PEI) hydrogel.
• Electrosorption experiments with mixed perfluorocarboxylic acids (PFCAs) from C3 to C8.
• Benchmarking of MCHS-based capacitive deionization (CDI) and IMCDI configurations.
• Performance evaluation in synthetic multicomponent solutions and real industrial wastewater.

Main Results:

• The IMCDI system demonstrated consistent removal of various PFCAs, including short- and ultrashort-chain variants.
• Higher charge utilization and a charge efficiency (CE) of 66.1% were achieved with IMCDI for high PFAS levels.
• The integrated membrane electrode (IME) exhibited excellent operational stability and anti-fouling resilience (>80% performance retention).
• 68.66% PFAS removal was achieved in industrial wastewater with an energy intensity of 1.07 Wh/g PFOA removed.

Conclusions:

• Interfacial reconfiguration of CDI systems can significantly improve PFAS-targeted electrosorption.
• The developed IMCDI system effectively addresses fouling sensitivity in complex, high-loading water.
• This technology offers a promising solution for removing persistent PFAS from industrial wastewater.