THURSDAY, JANUARY 5, 2023
Researchers from Rice University and the University of Calgary, Canada, recently transformed a crude oil byproduct, asphaltene, into graphene for thermal, anti-corrosion and 3D printing applications.
Muhammad Rahman, an assistant research professor of materials science and nanoengineering, is a lead corresponding author of the paper in the journal Science Advances, alongside Rice chemist James Tour, materials scientist Pulickel Ajayan and Md Golam Kibria, an assistant professor of chemical and petroleum engineering at the University of Calgary, Canada.
About the Process
Using the university's flash Joule heating process, Rahman is converting asphaltenes into turbostratic, or loosely aligned, graphene to mix with composites. Rice reports that this process uses up material otherwise burned for reuse as fuel or discarded into tailing ponds and landfills.
Additionally, the world has a reserve of more than 1 trillion barrels of asphaltene. Using some of this reserve, Rice says, as a feedstock for graphene would be beneficial for the environment.
“Asphaltene is a big headache for the oil industry, and I think there will be a lot of interest in this,” said Rahman, who characterized the process as both a scalable and sustainable way to reduce carbon emissions from burning asphaltene.
“The government has been putting pressure on the petroleum industries to take care of this,” said Rice graduate student and co-lead author M.A.S.R. Saadi.
“There are billions of barrels of asphaltene available, so we began working on this project primarily to see if we could make carbon fiber. That led us to think maybe we should try making graphene with flash Joule heating.”
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Researchers from Rice University and the University of Calgary, Canada, recently transformed a crude oil byproduct, asphaltene, into graphene for thermal, anti-corrosion and 3D printing applications. |
According to the release, since asphaltenes are already 70% to 80% carbon, researchers combined it with about 20% of carbon black to add conductivity. They then flashed it with a jolt of electricity, reportedly turning it into graphene in less than a second.
Any other elements in the feedstock, such as hydrogen, nitrogen, oxygen and sulfur, are vented away as gases.
“We try to keep the carbon black content as low as possible because we want to maximize the utilization of asphaltene,” Rahman said.
Afterwards, Saadi mixed the graphene into composites and polymer inks for 3D printers. He said that they “optimized the ink rheology” to show that it is printable, with inks having no more than 10% of graphene mixed in.
Saadi also noted that mechanical testing of printed objects is upcoming.
Rice graduate student Paul Advincula, a member of the Tour lab, is co-lead author of the paper. Co-authors are Rice graduate students Md Shajedul Hoque Thakur, Ali Khater, Jacob Beckham and Minghe Lou, undergraduate Aasha Zinke and postdoctoral researcher Soumyabrata Roy; research fellow Shabab Saad, alumnus Ali Shayesteh Zeraati, graduate student Shariful Kibria Nabil and postdoctoral associate Md Abdullah Al Bari of the University of Calgary; graduate student Sravani Bheemasetti and Venkataramana Gadhamshetty, an associate professor, at the South Dakota School of Mines and Technology and its 2D Materials of Biofilm Engineering Science and Technology Center; and research assistant Yiwen Zheng and Aniruddh Vashisth, an assistant professor of mechanical engineering, of the University of Washington.
The research was funded by the Alberta Innovates for Carbon Fiber Grand Challenge programs, the Air Force Office of Scientific Research, the U.S. Army Corps of Engineers and the National Science Foundation.
Other Rice Graphene Research
Prior to its work with asphaltene, Tour’s flash Joule heating process has been used with other materials such as plastic, electronic waste, tires, coal fly ash and car parts, to produce graphene.
Back in 2020, researchers at Rice used the process to make flash graphene out of recycled plastic, using the ACDC process that mixed post-consumer plastic with carbon black, and then processed into turbostratic graphene via times pulses of AC and DC electricity.
This DC jolt process differs from the norm, which entails raising the temperature of the carbon source with direct current, and the result is a “high-quality turbostratic graphene.”
Tour estimated that at an industrial scale, the ACDC process could produce graphene for about $125 in electricity costs per ton of plastic waste. And he further poses that this could be a possible way to deal with the Pacific Garbage Patch, an island of plastic waste roughly the size of Texas that has formed in the Pacific Ocean.
In April 2021, researchers at Rice said that they'd optimized a process to convert waste from rubber tires into graphene that could then be used to strengthen concrete. While it was acknowledged that recycled tire waste is already used in Portland cement, the researchers noted that graphene itself had been proven to strengthen cementitious materials at the molecular level.
To recover the graphene from the tires, the researchers used a “flash” process that they introduced in 2020. The process exposes material to a jolt of electricity that removes everything but the carbon atoms. Those atoms then reassemble into turbostratic graphene, which is more soluble that graphene produced from graphite and therefore easier to use in composite materials.
According to Rice, the lab flashed tire-derived carbon black and found about 70% of the material converted to graphene. When flashing shredded rubber tires mixed with plain carbon black to add conductivity, about 47% converted to graphene. (Elements besides carbon were vented out for other uses.)
For the actual process, the electrical pulses lasted between 300 milliseconds and one second. The lab calculated that the electricity used in the conversion process costs about $100 per ton of starting carbon.
The researchers then blended minute amounts of tire-derived graphene—0.1 weight/percent (wt%) for tire carbon black and 0.05 wt% for carbon black and shredded tires—with Portland cement and used it to produce concrete cylinders.
After curing for seven days, the cylinders showed gains of 30% or more in compressive strength. After 28 days, 0.1 wt% of graphene sufficed to give both products a strength gain of at least 30%.
Tagged categories: 3D Printing; Coating chemistry; Coating Materials; Colleges and Universities; Corrosion protection; Environmental Controls; Graphene; Green coatings; Oil and Gas; Program/Project Management; Recycled building materials; Research and development; Sustainability
