Reversible adsorption and desorption of PFAS on inexpensive graphite adsorbents via alternating electric field
| Autor: | Mohammadamin Ezazi, Bishwash Shrestha, Gibum Kwon, Sanjay Ajayan |
|---|---|
| Rok vydání: | 2021 |
| Předmět: |
Materials science
Polydimethylsiloxane General Chemical Engineering Sorption 02 engineering and technology General Chemistry 010501 environmental sciences 021001 nanoscience & nanotechnology 01 natural sciences 6. Clean water chemistry.chemical_compound Adsorption chemistry Chemical engineering Specific surface area Desorption Thermal stability Graphite 0210 nano-technology 0105 earth and related environmental sciences BET theory |
| Zdroj: | RSC Advances. 11:34652-34659 |
| ISSN: | 2046-2069 |
| DOI: | 10.1039/d1ra04821j |
| Popis: | 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 g−1. 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. |
| Databáze: | OpenAIRE |
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