In this project we aim to develop new materials for the selective removal and long-term sequestration of radioactive Sr-90. This is of importance in Japan to help in the clean-up activities around the Fukushima Daiichi Nuclear Power Plant and in the UK to help in the clean-up of legacy waste at the Sellafield site and elsewhere. Although materials exist for removing Sr-90 from contaminated water, all have some limitations and/or high cost and therefore basic research aimed towards making new and improved materials is justified. The ideal adsorbent would be highly selective for Sr-90 in the presence of larger amounts of competitive cations (e.g. Ca, Mg, Na or K), be stable and effective over a large pH range, have a good capacity for Sr-90, be reusable, be easily made in bulk at low cost and have a simple and proven route to a safe and stable wasteform after its end of use. We target materials that have the potential to fulfil all of these criteria based on preliminary synthesis work already done in Japan (Shinshu and Tohuku Universities) with essential research in the UK supporting the characterisation and understanding of how the materials work (Diamond Light Source) and the production of wasteforms after use (University of Sheffield).