Rice University in the United States discovered the synthesis process of bitumen into graphene

Rahman, assistant research professor of materials science and nanoengineering at Rice University, and his collaborators converted carbon-rich bitumen waste into useful and high-value graphene
using a unique flash joule heating (FJH) process.

The paper on the Flash Joule transformation method, published Nov.
18 in the journal Science, received funding from the U.
S.
Air Force Office of Scientific Research, the U.
S.
Army Corps of Engineers, and the
U.
S.
National Laboratory.

The paper mentions that petroleum crude oil produces a large amount of asphaltene during the refining process, which is currently estimated to be about 1 to 2 trillion barrels
worldwide.
However, bitumen poses complex problems in the treatment and production process, and is generally reused as fuel, or discarded into tailings ponds (slag piles), landfills and asphalt roads, but improper disposal and combustion can easily cause environmental damage
.

The researchers used flash joule heating (FJH) to convert low-value bitumen into a high-value derivative, flash graphene (AFG).

This method is able to produce flash graphene (several layers of graphene superimposed) in about 1 second, reducing the consumption
of a lot of energy and carbon dioxide.

Flash Joule heating (FJH) is a quartz tube between two copper electrodes, using variable pulses with voltages of 185V, 250V, 250V and 370V and a frequency of 1000Hz to shock the asphaltene, producing an extremely high temperature of nearly 3000 degrees, allowing the asphaltene to be converted into AFG
.

To test its mechanical properties, the researchers mixed epoxy resin with 1 wt% (percent by weight), 3 wt%, 5 wt% AFG, and compared
it with pure AFG for tensile strength, Young's modulus, and toughness.
The results showed that epoxy resin and 1% AFG blended the most mechanically as tensile strength increased by 37%, Young's modulus increased by 12%, and toughness increased by 75%.

In addition, in order to observe the thermal properties of epoxy-AFG nanocomposites, they injected white light into pure epoxy resin and epoxy-AFG nanocomposites, and observed the temperature rise of the materials with a thermal infrared (IR) camera
.

The results show that the induction heat of pure epoxy resin is concentrated in a small area and the temperature rise is more, but the thermal induction of epoxy resin-AFG nanocomposites is relatively dispersed, and the temperature rise is relatively small
.
They also found that the higher the AFG content, the less temperature rises, which also proves that epoxy-AFG nanocomposites conduct heat better
than pure epoxy resins.

The researchers also tested epoxy-AFG for corrosion resistance, wrapped it on mild steel (MS) as a corrosion protection layer, and found that the AFG content of 10 wt% in epoxy-AFG is better than pure epoxy and other wt% nanocomposites
.

Finally, they used epoxy resin-AFG nanocomposites to do 3D printing, and the printed product was placed at room temperature for 48 hours, and the object was continuously heated for 1 hour to 130 °C without deformation, and the test results were quite successful
.

Tests have proved that compared with general pure epoxy resin polymers, epoxy-AFG nanocomposites have excellent mechanical, thermal conduction and corrosion resistance, and can be used as 3D printing materials
.

Sadie, who works with Rahman, mixes graphene into composites and then into polymer inks used in 3D printers
.
He told Rice University Newsroom, "We have optimized its 3D printing ink to prove that it is printable
.
”

In addition, in the process of producing AFG using the FJH process in asphaltene, less pollution is produced, and the high-value allotrope graphene produced can be applied to industry
.

Rahman told Rice University Newsroom, "Asphaltenes are currently a big problem for the oil industry, and I think the oil industry will be interested in this because it is a sustainable way to reduce the carbon emissions
from burning asphaltenes.
" ”

In addition, the experiment reports chemist James Smith? Tour's team believes that flash joule heating is as effective for asphaltenes as it is for other raw materials, including plastics, e-waste, tires, fly ash, and car parts, and the researchers will next make more things out of these
graphenes.