Impregnation of trihexyl (tetradecyl) phosphonium bis (2, 4, 4-trimethylpentyl)
phosphinate, as an ionic liquid, into silica was carried out for removal of neodymium and
gadolinium ions from aqueous solution. Silica and the impregnated silica (Cyphos@ silica)
were characterized using FT-IR, SEM, XRD and TGA. Comparative sorption behavior of
silica and Cyphos@ silica for sorption of neodymium and gadolinium ions was investigated.
The experimental outcome revealed that the impregnation process enhanced the sorption
behavior of silica, from 18 to 67% for neodymium ion and from 20 to 89.45% for gadolinium
ion. From the kinetic studies, the sorption could be described well by pseudo-second-order
model. Langmuir and Freundlich isotherms were performed to determine the best fit
equation for the sorption process.