2024.03 Electro-regeneration of PFAS-laden activated carbon

Development of an on-site electrochemical regeneration method of activated carbon filters for PFAS removal

Perfluoroalkyl and polyfluoroalkyl substances (PFAS) are a class of halogenated hydrocarbons that are widely used because of their special properties. These highly Persitent, Mobile and Toxic (PMT) molecules pose significant challenges in water treatment,  as removal and degradation are both extremely challenging. Anticipated stringent guidelines for drinking water and waste water discharge necessitate the development of new treatment technologies.

Several water treatment technologies for the removal of PFAS are available, including granular activated carbon (GAC) filters. While effective for the removal of long-chain PFAS components, the removal of (ultra) short-chain PFAS, such as trifluoroacetic acid (TFA), is limited. Furthermore, the application of GAC filters requires frequent re-activation. This reactivation of GAC filters has a significant environmental impact: the activated carbon filters have to be transported to a reactivation facility where reactivation is performed at  high temperatures (>1000 °C). 

Research challenges
In this project, our aim is to explore an innovative concept for on-site regeneration of activated carbon filters, in which we electrically charge the activated carbon granules to desorb PFAS, which we refer to as electro-regeneration. After an adsorption step, we regenerate the PFAS granules by charging these electrically. The charging will result in the desorption of PFAS from the electrically negatively charged carbon granules. In this project, we will develop this technology and we will study the interactions between PFAS molecules and an electrically charged carbon surface. The interplay between hydrophobic and charged-based interactions is of particular importance. Based on our findings, we will study various electrode materials, water matrices, operational conditions, and reactor designs. Furthermore, we will study the possibilities for the removal of (ultra) short-chain PFAS in an electrochemical cell.

Your assignment
You will study the interactions between PFAS components and electrically charged activated carbon. To that end, you will conduct precise experiments, and you will rigorously analyze experimental data. You will compare the data with theory and you will refine the  understanding of the mechanisms involved. Based on your experimental and theoretical findings, you will propose strategies to enhance PFAS removal and to improve the regeneration performance of the adsorbents, for example by chemical modification of the activated carbon material, by adjusting the process conditions or by designing and testing innovative process schemes. Furthermore, you will explore the technological feasibility of adapting this electro-regeneration concept to effectively target (ultra) short chain PFAS, such as trifluoroacetic acid (TFA), from water.

Your Profile
We are looking for a student having an MSc degree in environmental engineering, water technology or chemical engineering, or a related education that combines aspects of chemistry and physics, someone who has a strong interest in electrochemical engineering and interfacial science. You have a talent to perform accurate experiments and you are able to critically analyze experimental data. You like to read scientific literature critically, and you like to think deeply about a technological process to find out what are the key mechanisms based on experimental data and theoretical understanding. Finally,  you can clearly communicate your research results in personal discussions, presentations and by writing reports and scientific papers.

Keywords: adsorption technology, interfacial science, electrochemistry, PFAS, process modelling

Supervisory Team: University promotor and co-promotor: Prof. Dr. Ir. Bert van der Wal (Wageningen University, Environmental Technology), Dr.Ir. Jouke Dykstra (Wageningen University, Environmental Technology)
Wetsus supervisor: Dr. ir. Sam Rutten

Project partners: Desalination & Concentrates

Only applications that are complete, in English, and submitted via the application webpage before the deadline will be considered eligible.

Guidelines for applicants:  https://phdpositionswetsus.eu/guide-for-applicants/