Abstract

The removal of trace caesium (¹³⁷Cs), trace strontium (⁸⁹Sr, ⁹⁰Sr/⁹⁰Y) and trace cobalt (⁵⁷Co) from aqueous solution by synthetic sodium and potassium birnessites has been studied by a batch technique. Distribution coefficients were determined as a function of pH in four solutions: water, 0.005 M sodium tetraborate, 0.005 M sodium citrate and 0.0001 M EDTA. Other effects studied were increasing sodium ion, potassium ion and complexing agent concentration. Key synthesis parameters (ageing time, MnO₄⁻/Mn²⁺ ratio) were tuned in order to maximise trace cobalt sorption efficiencies. The optimised material was tested for the removal of caesium, strontium and cobalt from a nuclear power plant floor drain simulant. A sodium birnessite sample was also screened for the removal of ⁶³Ni, ⁵⁴Mn, ⁵⁹Fe, ⁶⁵Zn and ²³⁶Pu radionuclides.