Chromatographic separation of platinum group metals from simulated high level liquid waste using macroporous silica-based adsorbents

•Three novel macroporous silica-based adsorbents are used in this study.•Chromatographic separation behavior of Ru, Rh and Pd were studied by column method.•Separation effects of every column experiment for aim elements were compared.•A relatively excellent chromatographic separation operating for PGMs was obtained.

To separate platinum group metals (PGMs) from high level liquid waste, three novel macroporous silica-based adsorbents, namely, (Crea + Dodec)/SiO2-P, (Crea + TOA)/SiO2-P and (MOTDGA + TOA)/SiO2-P, were synthesized by introducing extractants Crea (N′,N′-di-n-hexyl-thiodiglycolamide), TOA (Tri-n-octylamine), MOTDGA (N,N′-dimethyl-N,N′-di-n-octyl-thiodiglycolamide) along with theirs modifier, Dodec (n-dodecyl alcohol), into 50 μm diameter SiO2-P particles by impregnation. Chromatographic separation of PGMs from simulated high level liquid waste was investigated by column method. It was found that 100% of Pd(II) and Re(VII) could be eluted out from simulate HLLW in 3.0 M HNO3 solution using three adsorbents. For Ru(III) and Rh(III), high temperature has distinct effect on the adsorption rate and a further study for Ru(III) and Rh(III) is necessary to separate them from HLLW completely. In all six column experiments, a relatively satisfactory chromatographic separation operating for PGMs from simulated HLLW was obtained using (Crea + TOA)/SiO2-P adsorbent packed column at 323 K.