Efficient and Selective Removal of Palladium from Simulated High-Level Liquid Waste Using a Silica-Based Adsorbent NTAamide(C8)/SiO2-P

Jiaxuan Shi; Junli Wang; Wentao Wang; Xuan Wu; Hui Wang; Jianwei Li

doi:10.3390/nano14060544

Efficient and Selective Removal of Palladium from Simulated High-Level Liquid Waste Using a Silica-Based Adsorbent NTAamide(C8)/SiO₂-P

Nanomaterials (Basel). 2024 Mar 20;14(6):544. doi: 10.3390/nano14060544.

Authors

Jiaxuan Shi¹, Junli Wang^{1

2}, Wentao Wang², Xuan Wu², Hui Wang², Jianwei Li¹

Affiliations

¹ State Key Laboratory of Chemical Resource Engineering, College of Chemical Engineering, Beijing University of Chemical Technology, Beijing 100029, China.
² Department of Radiochemistry, China Institute of Atomic Energy, Beijing 102413, China.

Abstract

In order to realize the effective separation of palladium from high-level liquid waste (HLLW), a ligand-supported adsorbent (NTAamide(C8)/SiO₂-P) was prepared by the impregnation method in a vacuum. The SiO₂-P carrier was synthesized by in situ polymerization of divinylbenzene and styrene monomers on a macroporous silica skeleton. The NTAamide(C8)/SiO₂-P adsorbent was fabricated by impregnating an NTAamide(C8) ligand into the pore of a SiO₂-P carrier under a vacuum condition. The adsorption performance of NTAamide(C8)/SiO₂-P in nitric acid medium has been systematically studied. In a solution of 0.2 M HNO₃, the distribution coefficient of Pd on NTAamide(C8)/SiO₂-P was 1848 mL/g with an adsorption percentage of 90.24%. With the concentration of nitric acid increasing, the adsorption capacity of NTAamide(C8)/SiO₂-P decreases. Compared to the other 10 potential interfering ions in fission products, NTAamide(C8)/SiO₂-P exhibited excellent adsorption selectivity for Pd(II). The separation factor (SF_{Pd/other metals} > 77.8) is significantly higher than that of similar materials. The interference of NaNO₃ had a negligible effect on the adsorption performance of NTAamide(C8)/SiO₂-P, which maintained above 90%. The adsorption kinetics of Pd(II) adsorption on NTAamide(C8)/SiO₂-P fits well with the pseudo-second order model. The Sips model is more suitable than the Langmuir and Freundlich model for describing the adsorption behavior. Thermodynamic analysis showed that the adsorption of Pd(II) on NTAamide(C8)/SiO₂-P was a spontaneous, endothermic, and rapid process. NTAamide(C8)/SiO₂-P also demonstrated good reusability and economic feasibility.

Keywords: NTAamide(C8)/SiO2-P adsorbent; adsorption; high-level liquid waste; palladium(II).

Grants and funding

This research received no external funding.