Amberlite XAD-7 resin was impregnated with p-tert-butylsulfinylcalix arene. Niobium(V) was collected on the impregnated resin in yields of more than 90% around pH 5.4, whereas tantalum(V) was negligibly collected. The collected niobium(V) was desorbed with 9 M sulfuric acid nearly quantitatively, hence the separation of niobium(V) from tantalum(V) was successfully achieved.
- Amberlite XAD resin
- Chelating reagent-impregnated sorbent