# Surface Modification of Graphene Oxide for Fast Removal of Per- and Polyfluoroalkyl Substances (PFAS) Mixtures from River Water

## TL;DR

A new graphene oxide material effectively removes harmful PFAS chemicals from river water.

## Contribution

A novel cationic surfactant-modified graphene oxide adsorbent for efficient PFAS removal is introduced.

## Key findings

- GO modified with CTAC achieved nearly 100% PFAS removal in river water.
- Adsorption mechanisms include electrostatic and hydrophobic interactions.
- Performance was stable across varying pH, ionic strength, and organic matter.

## Abstract

Per- and polyfluoroalkyl
substances (PFAS) make up a diverse group
of industrially derived organic chemicals that are of significant
concern due to their detrimental effects on human health and ecosystems.
Although other technologies are available for removing PFAS, adsorption
remains a viable and effective method. Accordingly, the current study
reported a novel type of graphene oxide (GO)-based adsorbent and tested
their removal performance toward removing PFAS from water. Among the
eight adsorbents tested, GO modified by a cationic surfactant, cetyltrimethylammonium
chloride (CTAC), GO-CTAC was found to be the best, showing an almost
100% removal for all 11 PFAS tested. The adsorption kinetics were
best described by the pseudo-second-order model, indicating rapid
adsorption. The isotherm data were well supported by the Toth model,
suggesting that PFAS adsorption onto GO-CTAC involved complex interactions.
Detailed characterization using scanning electron microscopy-energy
dispersive X-ray spectroscopy, Fourier transform infrared, thermogravimetric
analysis, X-ray diffraction, and X-ray photoelectron spectroscopy
confirmed the proposed adsorption mechanisms, including electrostatic
and hydrophobic interactions. Interestingly, the performance of GO-CTAC
was not influenced by the solution pH, ionic strength, or natural
organic matter. Furthermore, the removal efficiency of PFAS at almost
100% in river water demonstrated that GO-CTAC could be a suitable
adsorbent for capturing PFAS in real surface water.

Graphene oxide coated with cetyltrimethylammonium chloride
rapidly removed a mixture of short- and long-chain PFAS in river water.