November 14th, 2021
A recent study found that biochar nanoparticles (BCN), or graphene oxide, derived from spruce wood and wheat straw, can improve corrosion resistance in zinc-rich epoxy coatings. The study, published in Progress in Organic Coatings, suggests a more sustainable option for the coatings industry.
Researchers included Yong Tian from the School of Science of Qingdao University of Technology and Zhenxiao Bi and Gan Cui from the College of Pipeline and Civil Engineering of China University of Petroleum.
Four kinds of coatings were prepared for analysis:
- Pure zinc-rich coating (0-ZRC);
- Graphene oxide-based zinc-rich coating (GO-ZRC);
- Sulfonated multiwall carbon nanotube-based zinc-rich coating (SM-ZRC); and
- SM-GO-based zinc-rich coating (SG-ZRC).
The coatings were then studied via open circuit potential (OCP), an electrochemical impedance spectroscopy (EIS), a salt spray test, a 3D confocal microscope and an electro scanning electron microscope (SEM). Researchers found that coatings with the presence of GO increased the shielding effect of zinc particles, improving corrosion resistance.
The study also found that biochar increases the interlayer spacing of coatings. GO's galvanic corrosion is relatively weak, and that carbon nanotube should not be used to modify GO in zinc-rich coatings.
Other Biochar Studies
In 2019, researchers at the University of Sheffield, in South Yorkshire, England, had found a use for pine needles beyond holiday decor.
Cynthia Kartey, a Ph.D. student in the university's Department of Chemical and Biological Engineering, argued that different products—including paint—could be made from chemicals extracted when pine needles are processed.
According to Kartey, about 85 percent of pine needles' makeup is a complex polymer known as lignocellulose. The structure is broken down into a solid by-product, biochar and a liquid product, bio-oil, which typically contains glucose, phenol and acetic acid, which can be used for making paint and adhesives.
Researchers said that the ultimate goal would be to use the chemicals to replace less sustainable substances used in the industry.
