Combining Soft-Templating and Post-Synthetic Methods for the Rational Design of an Amidoximated Metal-Organic...

Area of Science:

• Materials Science
• Environmental Chemistry
• Nanotechnology

Background:

• Metal-organic frameworks (MOFs) are explored for uranium extraction due to global resource shortages.
• Traditional microporous MOFs exhibit limitations in mass transfer and functionalization for efficient adsorption.
• Developing advanced adsorbents is crucial for sustainable uranium recovery from seawater.

Purpose of the Study:

• To design and synthesize novel mesoporous MOFs for enhanced uranium extraction from seawater.
• To investigate the impact of structural modifications on adsorption capacity, selectivity, and kinetics.
• To provide a theoretical framework for designing hierarchically porous materials for resource recovery.

Main Methods:

• Synthesis of a novel mesoporous MOF (meso-UiO-66-NH-CN) using perchlorate and Pluronic F127.
• Post-synthetic amidoximation to create mesoporous amidoximated MOFs (meso-UiO-66-NH-AO).
• Investigation of acetic acid's effect on material characteristics and uranium adsorption performance.

Main Results:

• The mesoporous structure facilitated high mass transfer rates and accessible active sites.
• Mesoporous amidoximated MOFs (meso-UiO-66-NH-AO) demonstrated a high adsorption capacity (312.5 mg g⁻¹).
• Excellent uranium selectivity (Kd = 213 × 10⁵ mL g⁻¹) and rapid adsorption kinetics were achieved in natural seawater.

Conclusions:

• Hierarchically porous MOFs, like meso-UiO-66-NH-AO, are effective for uranium extraction from seawater.
• The mesoporous architecture and amidoxime functionalization significantly enhance adsorption performance.
• This study offers valuable insights for designing advanced MOFs for sustainable resource recovery.