High-efficiency separation of palladium from nitric acid solution using a silica-polymer-based adsorbent isoPentyl-BTBP/SiO2-P

Abstract

A silica-polymer-based adsorbent (isoPentyl-BTBP/SiO2-P) was prepared via a vacuum impregnation method for efficient and continuous separation of palladium from complex systems. The results revealed that the distribution coefficient (Kd) value of isoPentyl-BTBP/SiO2-P toward Pd in 3 M HNO3 solution was 5226 mL/g, with a maximum adsorption capacity of 31.7 mg/g. Besides, isoPentyl-BTBP/SiO2-P exhibited a superior adsorption selectivity toward Pd to the other 14 coexisting interfering fission product ions, with the separation factor SFPd/M value over 433 in 0.1–6 M HNO3 solution. Moreover, column experiments results demonstrated that isoPentyl-BTBP/SiO2-P can efficiently separate Pd with approximately 100% recovery, from simulated high level liquid waste (HLLW) solutions with multiple competing ions. Finally, X-ray photoelectron spectroscopy and Fourier transform infrared spectroscopy analysis results revealed strong interactions between nitrogen-containing functional groups (C-NC) and Pd throughout the adsorption process, wherein the NO3− acting as the counterions to balance the charge. In conclusion, isoPentyl-BTBP/SiO2-P has shown promising applications for effectively separating Pd from multi-component and highly acidic environments.