Location: Commodity Utilization ResearchTitle: Structural transformation of biochar black carbon by C60 superstructure: Environmental implications
|PIGNATELLO, JOSEPH - Connecticut Agricultural Experiment Station|
|WHITE, JASON - Connecticut Agricultural Experiment Station|
|HU, SZU-TUNG - University Of Texas At Austin|
|FERREIRA, PAULO - University Of Texas At Austin|
Submitted to: Scientific Reports
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/4/2016
Publication Date: 9/18/2017
Citation: Uchimiya, M., Pignatello, J.J., White, J.C., Hu, S.-T., Ferreira, P.J. 2017. Structural transformation of biochar black carbon by C60 superstructure: Environmental implications. Scientific Reports. (7):11787 (11 pages).
Interpretive Summary: This work presents a novel production pathways of natural nanoparticles in the presence of man-made nanomaterials. Proposed green method can be used to extract carbon quantum dots from natural materials that are present in soils. This will provide an avenue to replace costly industrial processes currently used to produce commercial-grade nanomaterials.
Technical Abstract: Aqueous fullerene C60 nanoparticles (nC60) are frequently considered within the environmental engineering community as the aggregate of 60-carbon molecules. This study employed transmission electron microscopy (TEM) and x-ray diffraction (XRD) to demonstrate that nC60 formed via prolonged stirring (nC60-stir) is in fact a supercrystal, i.e., a nanocrystalline superlattice composed of face-centered cubic (fcc) close-packing of near-spherical C60 superatoms. The nC60-stir supercrystals (˜100 nm) completely disintegrated the pecan shell biochar pellets (2 mm) produced at high temperature (700 °C) into powder in the aqueous phase to form a stable, gel-like colloidal (<100 nm) suspension. The amorphous carbon structure of biochar was preserved after the disintegration that only occurred above the weight ratio of 30,000 biochar to nC60-stir. We hypothesize that nC60-stir supercrystals are retained on the amorphous carbon (graphene-like sheets linked by aliphatic carbon chains) of biochar by van der Waals of similar strength to that holding C60 molecules together within the supercrystal. The physically retained C60 supercrystals could subsequently undergo a phase transformation within the nanopores of biochar to destabilize and physically disintegrate the biochar pellets into nanoparticles.