Modification of pillared layered clays for scavenging radiostrontium from acidic aqueous environments

Abstract

A Pillared Layered Clay (PILC), code-named FREZEN, has been developed as a potential antidote for trapping radiostrontium in the gastrointestinal tract of ruminants. The ion exchange behaviour of FREZEN has been studied, with particular emphasis on Sr+2 exchange in acidic solutions. As for most sorbents and ion ex­ changers, strontium uptake by FREZEN remains sufficiently good over a pH range of 5-11, but a sharp diminution is observed at pH values below 4. Furthermore, at lower pH values, hydronium ions (H3O+) successfully compete with strontium cations already uptaken by FREZEN. An extended "back-exchange" effect, charac­terized by fast kinetics, is thus observed.

In order to impede the diffusion and prevalence of Η3Ο+, a modification of the microporous space in FREZEN has been carried out via intercalation of suitable organic molecules. Work currently underway reveals that this approach is capable of improving the performance properties of the PILC. Experimental results with glycerol as the intercalated organic agen will be presented and discussed.