Composite zeolite ion-exchangers for nuclear waste remediation.
Lead Research Organisation:
UNIVERSITY OF BIRMINGHAM
Abstract
The ability of zeolites - microporous materials comprised primarily of silicon, aluminium and oxygen - to exchange the cations with the surrounding media underpins multiple technologies which impact modern life, for example, water purification, water softening (including in detergents) and remediation of nuclear waste. Mined natural zeolite deposits have cost and formulation advantages over synthetic zeolites and, in some cases, offer a ready supply of zeolite frameworks which are difficult to obtain synthetically with high purity. However, use of natural zeolites is limited because of the restricted number of frameworks found naturally, and source variability in chemical properties they display. Developing methods to modify, control and tailor the chemistry of natural zeolites is an important scientific challenge.
Research from the PI's group has recently demonstrated that partial interzeolite transformation (PIZT) – where a parent zeolite structural is partially converted to a new zeolite using low-temperature chemical transformations – can be performed on natural zeolite granules to form core-shell composites of two zeolite structures with complementary ion-exchange chemistry whilst retaining the granule morphology (hemical Science, (2024), 10.1039/D4SC02664K). These have demonstrated exceptional promise as replacement strontium/caesium sorbents for remediation of aqueous waste in the nuclear industry - addressing an urgent industrial challenge. However, the mechanical properties of the granules are suboptimal for use in flow systems; this hampers translation to higher technology-readiness levels. To overcome this, links must be forged between the PIZT conditions, microstructure and mechanical properties.
The primary aim of the proposal is to develop the capability to simultaneously control the mechanical and chemical properties of granular composite zeolites (GCZs) formed by PIZT. Assembling a new team of collaborators from academia, industry, research centres and central facilities, the proposed research will link synthesis conditions, material structure - ranging from the atomic- to macro-scale - with the full range of relevant physical properties. This will deliver the fundamental understanding required to engineer optimised strontium/caesium sorbents for nuclear waste remediation.
This primary aim will be accomplished through addressing the following specific objectives:
O1 Elucidate how PIZT conditions determine the phase, morphology and ion-exchange properties of GCZ.
O2. Determine the mechanical properties and failure mechanisms of GCZs through new collaborations with the Henry Royce Institute and the National X-ray Computed Tomography Centre.
O3. Uncover the atomic- and micron-scale mechanisms of PIZT in forming GCZs.
O4. Explore structure-led synthesis of GCZs to generate new ion-exchange materials with targeted properties.
A further objective of the proposed programme, aligned with the funding call, is to transform the burgeoning nuclear research programme of the PI from being focused primarily on atomic-scale materials chemistry into a wider material engineering standpoint, taking into account microstructural and mechanical properties, ultimately accelerating these materials towards optimisation and deployment. This will be achieved by establishing two new partnerships with UKRI-funded centres with complementary expertise - the Henry Royce Institute and the National X-ray Computed Tomography Centre - whilst deepening established connections with Diamond Light Source, Sellafield Ltd and National Nuclear Laboratory.
In the short term, this project will provide a step-change in the number of natural zeolite sources available for development as ion-exchangers for the nuclear industry. In the longer term, far-reaching impact for these materials is envisaged in a diverse range of applications where multiple complementary chemical properties are required from single materials sources – from catalysis to carbon dioxide capture.
Research from the PI's group has recently demonstrated that partial interzeolite transformation (PIZT) – where a parent zeolite structural is partially converted to a new zeolite using low-temperature chemical transformations – can be performed on natural zeolite granules to form core-shell composites of two zeolite structures with complementary ion-exchange chemistry whilst retaining the granule morphology (hemical Science, (2024), 10.1039/D4SC02664K). These have demonstrated exceptional promise as replacement strontium/caesium sorbents for remediation of aqueous waste in the nuclear industry - addressing an urgent industrial challenge. However, the mechanical properties of the granules are suboptimal for use in flow systems; this hampers translation to higher technology-readiness levels. To overcome this, links must be forged between the PIZT conditions, microstructure and mechanical properties.
The primary aim of the proposal is to develop the capability to simultaneously control the mechanical and chemical properties of granular composite zeolites (GCZs) formed by PIZT. Assembling a new team of collaborators from academia, industry, research centres and central facilities, the proposed research will link synthesis conditions, material structure - ranging from the atomic- to macro-scale - with the full range of relevant physical properties. This will deliver the fundamental understanding required to engineer optimised strontium/caesium sorbents for nuclear waste remediation.
This primary aim will be accomplished through addressing the following specific objectives:
O1 Elucidate how PIZT conditions determine the phase, morphology and ion-exchange properties of GCZ.
O2. Determine the mechanical properties and failure mechanisms of GCZs through new collaborations with the Henry Royce Institute and the National X-ray Computed Tomography Centre.
O3. Uncover the atomic- and micron-scale mechanisms of PIZT in forming GCZs.
O4. Explore structure-led synthesis of GCZs to generate new ion-exchange materials with targeted properties.
A further objective of the proposed programme, aligned with the funding call, is to transform the burgeoning nuclear research programme of the PI from being focused primarily on atomic-scale materials chemistry into a wider material engineering standpoint, taking into account microstructural and mechanical properties, ultimately accelerating these materials towards optimisation and deployment. This will be achieved by establishing two new partnerships with UKRI-funded centres with complementary expertise - the Henry Royce Institute and the National X-ray Computed Tomography Centre - whilst deepening established connections with Diamond Light Source, Sellafield Ltd and National Nuclear Laboratory.
In the short term, this project will provide a step-change in the number of natural zeolite sources available for development as ion-exchangers for the nuclear industry. In the longer term, far-reaching impact for these materials is envisaged in a diverse range of applications where multiple complementary chemical properties are required from single materials sources – from catalysis to carbon dioxide capture.
People |
ORCID iD |
| Phoebe Allan (Principal Investigator) |