Article
Reversible adsorption and desorption of PFAS on inexpensive graphite adsorbents via alternating electric field
RSC Advances
(2021)
Abstract
Per- and polyfluoroalkyl substances (PFAS) have been extensively utilized in practical applications that
include surfactants, lubricants, and firefighting foams due to their thermal stability and chemical
inertness. Recent studies have revealed that PFAS were detected in groundwater and even drinking water
systems which can cause severe environmental and health issues. While adsorbents with a large specific
surface area have demonstrated effective removal of PFAS from water, their capability in desorbing the
retained PFAS has been often neglected despite its critical role in regeneration for reuse. Further, they
have demonstrated a relatively lower adsorption capacity for PFAS with a short fluoroalkyl chain length.
To overcome these limitations, electric field-aided adsorption has been explored. In this work, reversible
adsorption and desorption of PFAS dissolved in water upon alternating voltage is reported. An
inexpensive graphite adsorbent is fabricated by using a simple press resulting in a mesoporous structure
with a BET surface area of 132.9 10.0 m2 g1. Electric field-aided adsorption and desorption
experiments are conducted by using a custom-made cell consisting of two graphite electrodes placed in
parallel in a polydimethylsiloxane container. Unlike the conventional sorption process, a graphite
electrode exhibits a higher adsorption capacity for PFAS with a short fluoroalkyl chain
(perfluoropentanoic acid, PFPA) in comparison to that with a long fluoroalkyl chain (perfluorooctanoic
acid, PFOA). Upon alternating the voltage to a negative value, the retained PFPA or PFOA is released into
the surrounding water. Finally, we engineered a device module mounted on a gravity-assisted apparatus
to demonstrate electrosorption of PFAS and collection of high purity water.
Disciplines
Publication Date
October 26, 2021
DOI
10.1039/D1RA04821J
Publisher Statement
This article is Open Access
Citation Information
Bishwash Shrestha, M. Amin Ezazi, Sanjay Ajayan and Gibum Kwon. "Reversible adsorption and desorption of PFAS on inexpensive graphite adsorbents via alternating electric field" RSC Advances Vol. 11 Iss. 55 (2021) p. 34652 - 34659 ISSN: 2046-2069 Available at: http://works.bepress.com/mohammadamin-ezazi/3/