Sorption of 60Co from aqueous solutions on layered double hydroxides of Mg, Al, and Nd

Sorption of ⁶⁰Co from aqueous solutions of various compositions on layered double hydroxides (LDHs) of Mg, Al, and Nd in carbonate and hydroxide forms and on layered double oxides (LDOs) of Mg and Al was studied. ⁶⁰Co is poorly sorbed from aqueous nitrate solutions onto LDH-Mg-Al-OH. The ⁶⁰Co distribution coefficient K _d does not exceed 50 ml g^?1 at a phase contact time of 15 min and V/m = 50 ml g^?1. At the same time, ⁶⁰Co is efficiently sorbed from 10^?3?C10^?5 M aqueous Co(NO₃)₂ solutions onto LDH-Mg-Al and LDH-Mg-Nd with CO ₃ ^2? in the interlayer space. At a phase contact time of 15 min and V/m = 50 ml g^?1, K _d exceeds 2 × 10⁴ ml g^?1 for LDH-Mg-Nd and does not exceed 5 × 10³ ml g^?1 for LDH-Mg-Al. The ⁶⁰Co desorption from LDH-Mg-Nd-CO₃ into 0.05?C0.2 M solutions of Na₂CO₃, NaNO₃, (NH₄)₂C₂O₄, and Na₂H₂EDTA and into distilled water was studied. Na₂H₂EDTA is the most efficient desorbing agent. After 15-min contact of LDHMg(⁶⁰Co)-Nd-CO₃ with 0.1 and 0.05 M Na₂H₂EDTA solutions, the degree of desorption of ⁶⁰Co is ??100 and ??99%, respectively.