Efficient and Selective Removal of Palladium from Simulated High-Level Liquid Waste Using a Silica-Based Adsorbent...

Area of Science:

• Materials Science
• Radiochemistry
• Environmental Engineering

Background:

• Effective separation of palladium from high-level liquid waste (HLLW) is crucial for nuclear waste management and resource recovery.
• Existing methods often face challenges with selectivity, efficiency, and economic feasibility.
• Development of advanced adsorbents is necessary to address these challenges.

Purpose of the Study:

• To synthesize and characterize a novel ligand-supported adsorbent, NTAamide(C8)/SiO2-P, for palladium separation.
• To evaluate the adsorption performance, selectivity, and kinetics of the adsorbent in nitric acid medium.
• To assess the reusability and economic feasibility of the developed adsorbent for practical applications.

Main Methods:

• Synthesis of SiO2-P carrier via in situ polymerization of divinylbenzene and styrene on a silica skeleton.
• Fabrication of NTAamide(C8)/SiO2-P adsorbent by vacuum impregnation of NTAamide(C8) ligand into the SiO2-P carrier.
• Systematic study of adsorption performance, selectivity, kinetics, and thermodynamics in nitric acid solutions.

Main Results:

• NTAamide(C8)/SiO2-P exhibited a high distribution coefficient (1848 mL/g) and adsorption percentage (90.24%) for Pd(II) in 0.2 M HNO3.
• The adsorbent demonstrated excellent selectivity for Pd(II) over other fission products, with a separation factor > 77.8.
• Adsorption kinetics followed a pseudo-second order model, and thermodynamic analysis indicated a spontaneous, endothermic, and rapid process.

Conclusions:

• NTAamide(C8)/SiO2-P is a highly effective and selective adsorbent for palladium separation from HLLW.
• The adsorbent shows good reusability and economic feasibility, making it a promising candidate for industrial applications.
• The study provides a viable solution for palladium recovery and management in nuclear waste processing.