Separation and recovery of Rh, Ru and Pd from nitrate solution with a silica-based IsoBu-BTP/SiO2-P adsorbent

The separation of fission products Ru, Rh, and Pd will benefit both the nuclear fuel cycle and enlarge the platinum group metals source. A silica-based iso Bu-BTP/SiO 2 -P adsorbent was used to separate Ru, Rh, and Pd from nitrate solution. It exhibited good adsorption towards Ru, Rh, and Pd with the uptake rates over 95% at 55 °C in 0.1 M HNO 3 –3 M NaNO 3 solution and no adsorption towards 238 U(VI). The adsorption towards Ru, Rh, and Pd matched well with pseudo-second-order model with the equilibrium obtained within 24 h, 24 h and 0.5 h and Langmuir adsorption isotherm model with the saturation adsorption amounts as high as 0.37 mmol/g, 0.34 mmol/g and 0.71 mmol/g respectively. The adsorbed Pd, Rh, and Ru can be desorbed by 0.1 M HNO 3 –0.1 M thiourea , 2 M HCl and NaClO solution (CP) which is expected to realize their mutual separation in desorption stage using the above-mentioned eluents successively. Both FT-IR and XPS revealed that C N C played key role during adsorption and the adsorption needed the participation of NO 3 − to keep charge balance. In a word, iso Bu-BTP/SiO 2 -P is a promising adsorbent for separation and recovery Ru, Rh, and Pd, especially in the case of separating them from other fission products and actinides from high level liquid waste .