Zeolitic Imidazole Framework (ZIF)-Sponge Composite for Highly Efficient U(VI) Elimination

Area of Science:

• Materials Science
• Environmental Chemistry
• Nanotechnology

Background:

• Developing efficient adsorbents for heavy metal removal is crucial for environmental protection.
• Zeolitic imidazole frameworks (ZIFs) show potential in adsorption applications.
• Polyurethane sponge (PU) offers a versatile and scalable support material.

Purpose of the Study:

• To develop a simple and cost-effective method for preparing a ZIF-67/PU composite for uranium removal.
• To investigate the U(VI) adsorption performance of the ZIF-67/PU composite.
• To elucidate the adsorption mechanism of U(VI) onto the composite.

Main Methods:

• In situ hybridization technique to synthesize ZIF-67 nanoparticles on a PU sponge support, modified with PAM.
• Adsorption experiments to evaluate U(VI) elimination capacity using the Langmuir isotherm model.
• X-ray photoelectron spectroscopy (XPS) to investigate the adsorption mechanism.

Main Results:

• The ZIF-67/PU composite exhibited a high U(VI) adsorption capacity of 150.86 mg∙g⁻¹.
• Adsorption was primarily driven by electrostatic attraction and π-π stacking interactions.
• The mechanism involves complexation between ZIF-67's functional groups (C-N(H)/-OH) and U(VI).

Conclusions:

• The ZIF-67/PU composite is a highly effective and low-cost adsorbent for U(VI) removal.
• The in situ hybridization technique is a feasible approach for creating MOF-sponge composites.
• This method provides a promising solution for wastewater treatment and heavy metal remediation.