The novel composite mechanism of ammonium molybdophosphate loaded on silica matrix and its ion exchange breakthrough curves for cesium

Abstract

Long-lived 137Cs (over 30 years), a byproduct of the spent fuel fission processes, comprises the majority of high-level and prolific heat-generating waste in downstream processing. This study reports a novel sequential annealing mechanism with cross-linked network of polyvinyl alcohol, fabricating the composite of ammonium molybdophosphate loaded on silica matrix (SM-AMP20, 20wt% AMP) as an excellent granular ion exchanger for removal Cs+. When the matrix is remarkably sequential annealed, well-dispersed SM-AMP20 particles are formed by firmly anchoring themselves on controlling the porous characteristics and stable structure. The material crystallizes in the complex cubic space group Pn-3m with cell parameters of crystalline AMP formation. The breakthrough curve of Cs+ by SM-AMP20 follows the Thomas model with a high removal rate of 88.23% (∼10mg/L of Cs+) and breakthrough time as high as 26h (flow rate Q≈2.5mL/min and bed height Z≈11cm) at neutral pH. We also report on sorbents that could efficiently remove Cs+ ions from complex solutions containing different competitive cations (Na+, Al3+, Fe3+, and Ni2+, respectively) in large excess. Furthermore, this study shows that there is a probability for SM-AMP20 to recycle cesium using an eluent of 2–3mol/L NH4NO3 solution.