Modular intensified ion exchange utilising agitated tubular reactors

The aim of the proposal is to understand the extent to which an agitated tubular reactor can increase the efficiency of ion exchange using monolith pellets, and the mechanisms by which it intensifies the ion exchange process.

While commonly used static ion exchange columns are simple in design, they are not operationally efficient. This is because of the slow adsorption kinetics. The innate kinetic restrictions means that relative achievable flowrates are low, and a number of columns are normally used in in parallel, or the ion exchange has to be replaced over relatively fast timeframes.

As an example, this has led to 1000s of m3 of exhausted ion exchange media building-up at Sellafield, as part of the Site Ion Exchange Effluent Plant (SIXEP). Previous work has indicated that introducing agitation to tubular ion exchange column significantly increased both the available flowrates and number of column volumes that can be processed until material exchange capacity.

The working assumption is that the agitation leads to enhanced mixing and solute-ion exchange reactions. The work proposed in this project will expand significantly on these prior preliminary investigations to fully elucidate the mechanisms of process intensification in ion exchange columns, to enable full optimisation of these systems for future modular effluent treatment units.