The removal of ionic contaminants from aqueous streams represents a significant energetic cost in many industrial processes. In particular, deionization devices find extensive use in the food industry, the production of chemicals, and the treatment of waste streams. In contrast to the complete removal of all dissolved species by membrane-based methods, such as reverse osmosis, efficient deionization technologies for the selective removal of ionic contaminants remains a fundamental challenge. The currently available technologies for the selective removal of ions from water are very energy-intensive and fundamentally unsustainable. The established process for the selective capturing of ionic species is heavily reliant on ion-exchange resins with an affinity for binding specific ionic species (e.g. heavy metals, nitrates, etc.). Besides the environmental impact related to the production of these resins, this method is energetically intensive due to the heavy use of strong acids and bases that are frequently needed to remove the absorbed ions from the resins in order to regenerate their absorption capacity. Moreover, the complex factory operation dictated by the frequent regeneration of the resins limits the applicability of the process and thus provides a barrier to the innovation of sustainable process chains. Electrodialysis is another method for ion removal that uses ion-exchange membranes in combination with electric currents. However, this technique involves redox reactions at the electrode to sustain currents, leading to the unwanted production of gasses such as hydrogen, chlorine, and oxygen. Electrodialysis also needs extensive pre-treatment of the water. There is a clear need for continuously-operating and selective deionization methods that can operate uninterruptedly at limited energy usage while incorporating sustainable material sources. The development of an all-electric and selective ion transport mechanism is an important challenge that is tackled in the proposed SpeciDI project. The SpeciDI project provides a framework for the cooperation of the TU Delft and Avsalt aimed at the development of ion-specific electrosorption technology for the removal of ionic contaminants from industrial and agricultural aqueous streams. Specifically, to enable such a technology TU Delft together with Avsalt will carry out a detailed study of the electrokinetic transport of ionic species in multi-channel capacitive deionization (mc-CDI) devices. The main focus will be on devices that are based on commercially available electrode materials, such as activated carbon, graphene-oxide based materials, and carbon nanofoam derivatives. These carbon-based materials combine key characteristics such as good electrical conductivity, chemical stability and high specific surface area. However, the microscopic characteristics of the transport of various ion species through the microporous medium has not been investigated yet, which precludes the selective removal of ionic species through this route. The mc-CDI method can therefore not yet be applied in the removal of specific ion contaminants from a mixture. In this project, we will combine the development of a quantitative computational framework of the underlying transport mechanism with in-depth measurements of the electrokinetics to investigate the mechanisms of absorption and transport of various ions in mc-CDI devices. The resulting insights will be used to optimize the electrodes to the level of being commercially applicable for selective ion removal, by tailoring the pore structure and chemical surface modifications.
<script type="text/javascript">
<!--
document.write('<div id="oa_widget"></div>');
document.write('<script type="text/javascript" src="https://www.openaire.eu/index.php?option=com_openaire&view=widget&format=raw&projectId=nwo_________::bf83d7bfaa698af25467efd8e19b3de3&type=result"></script>');
-->
</script>
<script type="text/javascript">
<!--
document.write('<div id="oa_widget"></div>');
document.write('<script type="text/javascript" src="https://www.openaire.eu/index.php?option=com_openaire&view=widget&format=raw&projectId=nwo_________::bf83d7bfaa698af25467efd8e19b3de3&type=result"></script>');
-->
</script>