Researchers at Oak Ridge National Laboratory in Tennessee have demonstrated that carbon from waste tires can be functionalized with sulfonic acid to catalyze esterification of oleic acid or a mixture of fatty acids into biodiesel.

“Waste tires were converted to hard carbon, then functionalized with catalytically active -SO3H groups on the surface through an environmentally benign process that involved the sequential treatment with L-cysteine, dithiothreitol and H2O2,” states the abstract of a publication, titled “Novel Acid Catalysts from Waste-Tire-Derived Carbon: Application in Waste-to-Biofuel Conversion,” published Aug. 1 in Chemistry Select. “When benchmarked against the same waste-tire-derived carbon material treated with concentrated sulfuric acid at 150 degrees Celsius, similar catalytic activity was observed. Both catalysts could also effectively convert oleic acid or a mixture of fatty acids and soybean oil to usable biofuels at 65 C and 1 atm without leaching of the catalytic sites.”

The study was conducted with collaborators Wake Forest University and Georgia Institute of Technology. ORNL co-author Parans Paranthaman said the patent-pending approach provides an environmentally benign pathway for inexpensive products from waste tires, and is a step toward large-scale biofuel production.

Previous ORNL studies have shown carbon powders can be used in developing lithium-ion, sodium-ion and potassium-ion batteries and supercapacitors.