The development of next-generation zeolite materials for the remediation of aqueous nuclear decommissioning waste

Reed, James (2025). The development of next-generation zeolite materials for the remediation of aqueous nuclear decommissioning waste. University of Birmingham. Ph.D.

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Abstract

In the nuclear industry, materials capable of selective adsorption of caesium-137 and strontium-90 are paramount in the processing of nuclear effluent. This work pioneers the partial interzeolite transformations of natural zeolites to enhance the ion-exchange properties, thus producing industrially viable materials from a cost effective, single-step process.
Firstly, a methodology has been developed enabling a controlled partial transformation from natural zeolites (mordenite and clinoptilolite) to zeolite P. This process has been applied to produce powdered and granular composite materials, suitable for a variety of applications. A high level of control is demonstrated, facilitating the production of composite materials with a desired blend of parent phase and zeolite P.
A series of batch ion-exchange experiments suggest partially transformed natural zeolites are promising materials for the abatement of caesium and strontium from nuclear waste streams: drastic improvements to the strontium capacity and rate of uptake are observed whilst the high caesium selectivity of the parent material is maintained. These findings are validated in flow experiments using active liquor, where granular composite materials outperformed both their respective parents and Mud Hills clinoptilolite in the removal of Cs-137 and Sr-90.
Furthermore, the combination of SEM, XCT and local, image-guided micro-diffraction experiments provide comprehensive characterisation of the granular composite materials. This allows for bulk macroscale mechanisms of transformations from a mordenite and a clinoptilolite to be postulated.
Finally, the superior ion-exchange properties of Mud Hills clinoptilolite, in comparison to other isostructural natural materials, is explored. A suite of characterisation techniques and adsorption studies allows for several theories to be presented, potentially streamlining the selection process for future ion-exchange materials, which is an integral part of the UK’s decommissioning efforts.

Type of Work:

Thesis (Doctorates > Ph.D.)

Award Type:

Doctorates > Ph.D.

Supervisor(s):