Effective 137Cs+ and 90Sr2+ immobilisation from groundwater by inorganic polymer resin Clevasol® embedded within a macroporous cryogel host matrix

The conservative fission products Cs-137 and Sr-90 are of concern when present in groundwater, as they present a radiological hazard to organisms and can be transported long distances from their source. To provide an interceptive permeable reactive barrier (PRB) solution which accommodates the throughflow of groundwater whilst removing Cs-137(+) and Sr-90(2+), we report the synthesis of a novel composite cryogel which performs as a permeable hierarchical sorbent. This material incorporates the ion-exchanger Clevasol (R) into a PVA-based cryogel host matrix with interconnected macropores, producing a composite cryogel (Clevasol (R)-PVACC). Clevasol (R)-PVACC enables the in-situ deployment of an ion-exchanger with rapid uptake kinetics for Cs-137(+) and Sr-90(2+), inside of a robust and permeable scaffold with green chemistry. Clevasol (R)-PVACC has a facile, one-pot and scalable synthesis, and can possibly also be used at other stages of the nuclear fuel cycle, such as radioactive liquor treatment. Critically, the incorporated Clevasol (R) resin is vitrifiable, which is optimal for long-term storage and geological disposal if high activities are adhered onto the resin. The effective partition coefficients (k(d)) and effective Langmuir uptake capacities (q(max)) of the Clevasol (R) resin in Sellafield groundwater simulant are respectively 10(5) mL/g and 298 mg/g for Cs+, and > 10(4) mL/g and 128 mg/g for Sr2+. (C) 2022 The Author(s). Published by Elsevier Ltd.