High capacity oil adsorption by graphene capsules

Area of Science:

• Materials Science
• Nanotechnology
• Environmental Science

Background:

• Graphene capsules (GCs) are emerging materials with potential applications in adsorption.
• Controlling the size and properties of GCs is crucial for optimizing their performance.

Purpose of the Study:

• To synthesize graphene capsules (GCs) of varying sizes using chemical vapor deposition.
• To evaluate the oil adsorption performance of these GCs.

Main Methods:

• Chemical vapor deposition (CVD) synthesis of GCs using MgO particles of different sizes as templates.
• Characterization of GC size and pore volume.
• Measurement of oil adsorption capacity using diesel fuel.

Main Results:

• GCs were synthesized in sizes ranging from tens to thousands of nanometers.
• A direct correlation was observed between GC size, pore volume, and oil adsorption capacity.
• The highest achieved oil adsorption capacity was 156 g diesel per gram of GC, significantly exceeding that of expanded graphite.
• Adsorption capacity increased proportionally with fluid viscosity.
• Capillary adsorption within the limited entrance of the GCs likely contributed to the high adsorption capacity.

Conclusions:

• GCs synthesized via CVD offer high oil adsorption capabilities.
• GC size and pore volume are key parameters for optimizing oil adsorption.
• The unique structure of GCs, potentially involving capillary effects, enhances their performance in adsorbing viscous fluids like diesel.