Fast carbon nanofiber growth on the surface of activated carbon by microwave irradiation: A modified nano-adsorbent for deep desulfurization of liquid fuels

• Fast growth of carbon nanofibers on the surface of activated carbon was performed.
• Microwave assisted chemical vapor deposition was successfully implemented.
• Methane and ethane were studied as carbon sources, comparatively.
• Efficient performance of the material was observed in desulfurization liquid fuel.
• Modified AC showed 87% higher efficiency in sulfur removal rather than regular AC.

Carbon nanofibers were fabricated on the surface of regular activated carbon (AC) by microwave-assisted chemical vapor deposition (CVD) method. Methane and ethane were comparatively used as the source gases to figure out the textural and particulate properties and efficiency of the produced nano-adsorbents in sulfur adsorption from a fuel model. AC granules were firstly impregnated with nickel and exposed to a flow of hydrocarbon–nitrogen mixture through a stationary bed. A 900 W household microwave apparatus was used as the energy source to decompose the hydrocarbon and grow up nanofibers on the surface. Effect of catalyst fraction, radiation time and inlet gas flow rate were studied as the influential synthesis parameters. The 0.5 wt% Ni-impregnated AC was exposed to equal mole fraction of N2–hydrocarbon mixture with WHSV of 6.7 ml/g min and the result revealed the highest yield of nanofibers growth on the surface. The diameter of nanofibers made from ethane was almost twofold over the diameter of nanofibers made from methane. Thiophene and dibenzothiophene removal were comparatively investigated by a series of batch adsorption experiments with a model fuel comprising n-octane. The sulfur removal efficiency was improved up to 87% compared with the original AC. During two hours contact time, the sulfur content of solution was decreased from 290 to 45 ppm by the modified AC surface.

Synthesis of carbon fibers was carried out by chemical vapor deposition of methane and ethane on the surface of activated carbon. Methane/ethane decomposed by microwave radiation and the carbon fibers were grown faster in presence of Ni catalyst. Those fibers made from ethane were thicker than the others made by methane.Figure optionsDownload as PowerPoint slide