Leakage of octyl(phenyl)-N,N-di-isobutylcarbamoylmethylphosphine oxide from a macroporous silica-based chelating polymeric adsorption material and its recovery by some selected porous adsorbents

The leakage behaviour of a neutral chelating agent, i.e. octyl(phenyl)-N,N-di-isobutylcarbamoylmethylphosphine oxide (CMPO), from its macroporous silica-based (CMPO/SiO2-P) extraction resin (a novel polymeric adsorption material developed in the MAREC process) and the recovery of CMPO by some selected polymer- and silica-based porous adsorbents were investigated by column operation in 0.01 M HNO3 at 25 degrees C or 50 degrees C. The concentration of CMPO in the effluent leaking from CMPO/SiO2-P was determined as ca. 48 ppm at 25 degrees C and ca. 37 ppm at 50 degrees C. The corresponding elution volumes and the amounts of CMPO leaking were 8700.9 BV/g and 239.3 mg/g at 25 degrees C and 11842.9 BV/g and 359.4 mg/g at 50 degrees C, respectively. The adsorption experiment showed that a polymer-based porous material, SEPABEADS(R) SP-825, was capable of recovering CMPO effectively from 0.01 M HNO3. Its adsorption ability towards CMPO was considerably greater than those of macroporous silica-based SiO2-P particles, polymer-based Amberlite(TM) XAD-7 and activated carbon. The bed volume and the amount of CMPO adsorbed by SEPABEADS(R) SP-825 at the breakthrough point at 25 degrees C were 13549.2 BV/g and 498.7 mg/g, respectively, thereby demonstrating that SEPABEADS(R) SP-825 was promising for the recovery of CMPO from Am(Ill)- and Cm(III)-containing solutions in the MAREC process.