Extraction behaviors of uranyl peroxo cage clusters by mesoporous silica SBA-15.

Sorption of soluble uranyl peroxo cage clusters (U60 [UO(O)(OH)] and U24Pp [(UO)(O)(PO)]) by mesoporous sorbent SBA-15 has been studied. Sorption kinetics of U60 and U24Pp are both best described by a pseudo-second-order model. However, only in the U60 sorption, intraparticle diffusion is the rate-determining step, and both pore size and pore volume of SBA-15 positively influence the U sorption capacity. Sorption isotherms of U60 and U24Pp are better fitted by the Langmuir and Freundlich isotherm models, respectively. The differences of sorption behaviors between two clusters by SBA-15 may result from differences of the sizes and terminal ligands of the clusters. [ABSTRACT FROM AUTHOR]