Development of N,N,N',N'-tetra-2-ethylhexyl-thiodiglycolamide silica-based adsorbent to separate useful metals from simulated high-level liquid waste

Abstract

A novel silica-based adsorbent was synthesized by impregnating macroporous silica polymer composite (SiO₂-P) particles with a mixture of N,N,N',N'-tetra-2-ethylhexyl-thiodiglycolamide (TEHTDGA) and tri-n-octylamine (TOA). Then, the possibility of separating Pd(II) and other metal ions from simulated high-level liquid waste (HLLW) using the newly synthesized adsorbent (TEHTDGA + TOA)/SiO₂-P was evaluated based on various adsorption characteristics obtained via batch-adsorption experiments, such as the HNO₃ concentration, contact time, reaction temperature, adsorption isotherm, and chemical stability of the adsorbent. Furthermore, column separation experiments were performed based on the characteristics obtained from the batch-adsorption experiment, and the possibility of simultaneous separation of multiple metal ions was examined. The experimental results revealed that (TEHTDGA + TOA)/SiO₂-P performs well in the separation of multiple metal ions from simulated HLLW.

Keywords: Batch-adsorption experiment; Column separation experiment; Platinum-group metal; Silica-based adsorbent; Simulated high-level liquid waste.