Polyoxometalate/Cellulose Nanofibrils Aerogels for Highly Efficient Oxidative Desulfurization

Area of Science:

• Materials Science
• Catalysis
• Environmental Chemistry

Background:

• Polyoxometalates (POMs) show promise for oxidative desulfurization (ODS) but suffer from poor recyclability due to high solubility.
• Limited surface area of POMs restricts substrate interaction, hindering catalytic efficiency.
• Immobilizing POMs on 3D structured materials offers a strategy to overcome these limitations.

Purpose of the Study:

• To develop a recyclable and efficient catalyst for oxidative desulfurization (ODS) by immobilizing phosphotungstic acid (PTA) onto cellulose nanofibril (CNF) aerogels.
• To investigate the structural, thermal, and catalytic properties of the prepared A-CNF/PTA aerogel.
• To demonstrate the stability and reusability of the novel aerogel catalyst for sulfur removal.

Main Methods:

• Cellulose nanofibrils (CNFs) were modified with (3-Aminopropyl) trimethoxysilane (APTS) to create positively charged surfaces.
• Phosphotungstic acid (PTA) was loaded onto the modified CNFs, followed by gelation to form the A-CNF/PTA aerogel.
• Fourier-transform infrared spectroscopy (FT-IR), UV-Visible spectroscopy (UV-VIS), Brunauer-Emmett-Teller (BET) analysis, scanning electron microscopy (SEM), and thermogravimetric analysis (TGA) were used for characterization.

Main Results:

• Successful deposition of PTA onto aminosilane-modified CNF surfaces was confirmed by FT-IR.
• BET and SEM analyses revealed an increased specific surface area and a uniform 3D network structure for the aerogels.
• The A-CNF/PTA aerogel exhibited excellent catalytic performance, achieving 100% substrate conversion within 120 minutes at room temperature.
• The catalyst maintained high efficiency (91.2% conversion) even after five cycles, demonstrating good stability and recyclability.

Conclusions:

• The developed A-CNF/PTA aerogel provides a stable and recyclable platform for POM-based oxidative desulfurization.
• This method offers a scalable and facile approach for immobilizing POMs onto 3D structured materials for catalytic applications.
• The enhanced surface area and structural integrity of the aerogel contribute to its superior catalytic activity and reusability.