Adsorption and pre-concentration of Gd(III) and U(VI) from aqueous solution using artificial adsorbents

Adsorption of Gd(III) and U(VI) from aqueous solutions using artificial adsorbents based on magnesia was studied. The effect of different parameters affecting the adsorption of these metal ions separately was investigated. Comparison between the loading capacity of the prepared adsorbents (MF-1, MF-2) for Gd(III) and U(VI) was investigated. It was found that the loading capacity for Gd(III) is 66 and 450 mg/g which were reached after 4 and 16 adsorption stages for MF-1 and MF-2 adsorbents, respectively. For U(VI) the loading capacity of MF-1 was 26 mg/g after four adsorption stages and the capacity of MF-2 was 171.6 mg/g after only one adsorption stage. The possibility of reuse of the adsorbents after stripping the metal ions was studied. The studies showed that the capacity of MF-2 adsorbent for removal of Gd(III) and U(VI) higher than MF-1. Therefore, the feasibility for pre-concentration of these metals for MF-2 is also reported. It was found that after adsorption of the two metal ions on MF-2, the metals ions concentration in the stripping solutions recovered was concentrated 400 times for Gd(III) and 366 times for U(VI) than in the initial concentration. Also the separation of the two metal ions was found feasible. The results indicated that synthetic adsorbent MF-2 could be used as efficient adsorbents for removal of Gd(III) and U(VI) ions from radioactive wastewater.