Dihydrotetrazine-Functionalized Zirconium-Based Metal-Organic Frameworks for High-Capacity Oil Denitrogenation

Area of Science:

• Materials Science
• Environmental Chemistry
• Nanotechnology

Background:

• Zirconium-based metal-organic frameworks (Zr-MOFs) possess high stability and tunable functionality.
• Zr-MOFs are promising for pollutant removal applications.
• Nitrogen-containing compounds (NCCs) are common pollutants in oil.

Purpose of the Study:

• To synthesize dihydrotetrazine (DHTZ)-functionalized Zr-MOFs (UiO-66(Zr)-DHTZ and MIL-140(Zr)-DHTZ).
• To evaluate their efficiency in removing quinoline (Qui) and indole (Ind) from model oil.
• To investigate the adsorption mechanism and recyclability.

Main Methods:

• Post-synthesis linker exchange (PSLE) to introduce DHTZ groups.
• Adsorption experiments at room temperature.
• Characterization using X-ray photoelectron (XPS) and Fourier-transform infrared (FT-IR) spectroscopies.

Main Results:

• DHTZ-functionalized Zr-MOFs exhibited significantly improved removal capacities for Qui and Ind.
• UiO-66(Zr)-DHTZ showed higher adsorption (1426 mg/g Qui, 1176 mg/g Ind) than MIL-140(Zr)-DHTZ (619 mg/g Qui, 511 mg/g Ind).
• Adsorption capacities correlated with surface area; recyclability was maintained over five cycles.

Conclusions:

• Dihydrotetrazine functionalization enhances Zr-MOF performance for NCC removal.
• UiO-66(Zr)-DHTZ and MIL-140(Zr)-DHTZ are effective and stable adsorbents.
• Specific host-guest interactions facilitate adsorption of nitrogen-containing pollutants.