The Functionalized N-Rich Covalent Organic Framework for Palladium Removal from Nuclear Wastewater

Area of Science:

• Materials Science
• Environmental Chemistry
• Nuclear Engineering

Background:

• Efficient palladium (Pd(II)) adsorption from acidic radioactive waste is vital for vitrification safety and precious metal recovery.
• Existing adsorbents often lack stability and selectivity under harsh acidic conditions, limiting practical application.
• Developing robust materials for selective metal ion capture in challenging environments remains a significant challenge.

Purpose of the Study:

• To synthesize and characterize a novel covalent organic framework (DHTP-TPB COF) for selective Pd(II) adsorption.
• To evaluate the adsorption capacity, kinetics, selectivity, and reusability of DHTP-TPB COF in acidic media.
• To elucidate the adsorption mechanism of Pd(II) onto the DHTP-TPB COF using spectroscopic and theoretical methods.

Main Methods:

• Synthesis of DHTP-TPB COF, a nitrogen-rich covalent organic framework.
• Adsorption experiments to determine Pd(II) uptake capacity, kinetics, and selectivity in simulated acidic radioactive waste.
• Characterization using FT-IR, XPS spectroscopy, and Density Functional Theory (DFT) calculations to understand the adsorption mechanism.

Main Results:

• DHTP-TPB COF demonstrated rapid Pd(II) adsorption kinetics, reaching equilibrium within 10 minutes.
• Achieved a high adsorption capacity of 142.8 mg/g and excellent reusability in 1.0 M nitric acid.
• Showcased remarkable selectivity for Pd(II) even in the presence of 13 interfering ions, attributed to strong N-Pd affinity.

Conclusions:

• DHTP-TPB COF exhibits superior performance for selective Pd(II) capture from acidic radioactive waste.
• The material's stability, high capacity, and selectivity make it a promising candidate for practical applications.
• This study highlights the potential of tailored covalent organic frameworks for effective remediation and resource recovery in challenging environments.