Rui Li and Abolghasem Shahbazi of the North Carolina A&T State University have suggested Hydrothermal Carbonization (HTC) as an efficient and scalable route to synthesize carbon particles at low temperature. Carbon spheres can be prepared with controlled size and with oxygenated functional groups on the surface, and have attracted considerable attention due to their applications as super capacitors, catalyst supports, and adsorbents. (Trends in Renewable Energy, vol. 1, 43-56. doi:10.17737/tre.2015.1.1.009)
“Over a long period of time, the hydrothermal process was mainly focused on producing aqueous products such as phenol, furan derivatives, and organic acids or its fuel potential application. Because of multiple applications of carbon spherical particles, a renaissance of HTC to synthesize carbon spheres gradually came back to our sight since 2001,” said Li.
Simple sugars have been effectively employed as HTC starting materials. Spherical carbon particles were prepared through either a direct hydrothermal process, or a hydrothermal process followed by a carbonization process. The size and the size distribution of colloidal carbon spheres were influenced by processing temperature, reaction time, and the concentration of starting material.
Applications of HTC carbons include absorbents for removal of ions in water and lithium-ion batteries. Due to the good dispersion and functional groups prepared by the HTC method, carbon spheres can be ideal catalyst supports with a core-shell or hollow structure.
“The mechanism of glucose HTC is confirmed, however, the mechanism for real biomass conversion is still under investigation, because of unknown contributions from lignin, protein, and lipid. The model is needed to predict the particle size and the size distribution from process parameters. The new applications of carbon spheres are also being investigated,” said Li.
Contact: http://futureenergysp.com/index.php/tre/article/view/9 .