7.1 Water desalination with chemically modified carbon nanotube electrodes

Capacitive deionization (CDI) is a novel water desalination technology that makes use of porous electrodes to remove ions from water under the action of an electrical voltage difference(1). CDI has the potential to specifically remove certain ions from water, either valuable ions, such as lithium, or unwanted ions, such as arsenic.

To selectively remove ions, we will use electrodes made of carbon nanotubes that are chemically treated to selectively remove ions from water (2). We will develop small-scale desalination units that treat water samples containing mixtures of salt, and study the effectiveness of separation. We will develop and use theoretical models to understand the process better.

Research challenge
The challenge is to develop functional CDI units that selectively remove ions using redox-molecules attached to electrodes made of carbon nanotubes, and investigate performance (capacity to remove ions, and rate) and to improve the process by novel cell designs and chemistries. Carbon nanotube material is provided in various formats by a Dutch start-up company and in the project we collaborate with international partners. The aim is to develop scientific knowledge of the CDI process using redox functionalized electrodes, both by experiment and theory. Theory will make use of porous electrode theory, which is an extension of mass transfer theory to include effects of charge and electrical potentials.

We are looking for a candidate with an MSc degree in the field of physics, chemical or mechanical engineering, or an equivalent degree. A background in environmental science or electrochemistry is not required.

We are looking for a candidate, who

· is interested in doing scientific research, with a strong wish to figure out in detail how things work;
· can communicate their results in writing, presentations and discussions;
· has an interest in theoretical modelling of the process at hand;
· is precise and dedicated to make sure experiments and calculations are as good as needed;
· is inventive in figuring out new ways to study a system by theory or experiments;
· likes to write.

The research project is part of the Wetsus research theme Concentrates.
The following companies are part of the theme: Shell (, Dow (, Aquacare (, PWN ( and Evides (

Promotor: Prof.dr. Bert van der Wal (Wageningen University, Dept. Environmental Technology)
Wetsus supervisors: Dr. Maarten Biesheuvel

For more information contact

Please do NOT send your CV directly to this email address. Only complete applications sent via the website will be evaluated (How to Apply).

Wetsus, Leeuwarden, The Netherlands

(1) Suss et al. (
(2) Su and Hatton ( (

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