Adsorption of some lanthanides on glassy tin arsenate

Glassy tin arsenate, Sn(HAsO4)2·2.7H2O (SnAs) was prepared and characterized. The uptake of lanthanide ions La3+, Sm3+, Eu3+, and Yb3+ was followed on the glassy tin arsenate in HNO3 solution at pH 1,2 and 4. The radiotracers are140La,153Sm,152mEu, and175Yb. 500 μl (4.0·10−5 mmole) of each solution of the tracer as a mixture plus 7.5 ml HNO3 solution at the desired pH were equilibrated with 0.1g of SnAs. The selectivity order (K d values) was found to be dependent on the pH. At pH 2 theK d values were high for all the studied metal ions [Yb (2065.4)>La (1976.1)>Sm (1826.4)>Eu (1754.4)]. TheK d values at pH 1 and 4 are quite low for all the metal ions studied. At pH 1 they range from ≈144 to 156 and at pH 4 they range from ≈70 to 79.