Fluorenone-Based COFs with Electron-Relay Function for Highly Efficient Photocatalytic Uranium Extraction from...

Area of Science:

• Environmental Science
• Materials Science
• Chemistry

Background:

• Uranium contamination poses significant environmental and health risks due to its toxicity and radioactivity.
• Photocatalytic reduction of U(VI) to U(IV) is a key remediation strategy, but hindered by slow electron transfer.
• Covalent organic frameworks (COFs) show potential as photocatalysts, but require improved charge separation and interfacial electron transfer.

Purpose of the Study:

• To design and synthesize a novel COF incorporating fluorenone units to act as electron relay stations.
• To enhance intramolecular charge separation and interfacial electron injection for efficient uranium remediation.
• To evaluate the performance of the optimized COF in removing uranium from wastewater.

Main Methods:

• Synthesis of a conjugated COF (Py-FO-COF) featuring incorporated fluorenone units.
• Investigation of intramolecular charge dissociation and donor-acceptor interactions.
• Assessment of photocatalytic uranium reduction efficiency and adsorption capacity under visible light.
• Testing in real uranium-containing tailings wastewater.

Main Results:

• The optimized Py-FO-COF achieved 99.6% uranium removal and an adsorption capacity of 1057.1 mg g⁻¹ under visible light.
• The fluorenone units enhanced charge dissociation and provided binding sites for UO₂²⁺, improving electron transfer.
• The material demonstrated high efficiency (>98%) in treating real tailings wastewater, with excellent selectivity and recyclability.

Conclusions:

• Integrative molecular design of COFs with electron relay stations is crucial for high-performance photocatalysts.
• The developed Py-FO-COF offers an effective and robust solution for radioactive wastewater remediation.
• This approach holds promise for addressing environmental challenges posed by uranium contamination.