Synthesis of nanoporous carbon from mangosteen peel lignin extracted by using organosolv and soda processes

Abstract

Porous carbon has been widely utilized as adsorbent, catalysts, and electrode of electronic devices. One of raw materials that could be potentially for production porous carbon is lignin stemmed from biomass. The objective of this research is to study the characteristics of porous carbon produced by pyrolysis of lignin. The lignin was prepared by extraction of mangosteen peels in a batch three-neck vessel using organosolv (60% ethanol, 70°C, 4 hours) and soda processes (10% sodium hydroxide, 90°C, 3 hours). The black liquor was then precipitated with sulfuric acid and the solid produced was separated by filtration. Lignin was then pyrolyzed in a furnace under flowing N2 at 600 and 850°C temperature. Characterization methods (N2-pore analysis, Fourier transform infrared spectroscopy (FTIR) and thermal gravimetric analysis and scanning electron microscopy) were employed to investigate the properties of the raw material of lignin and porous carbon produced. From the extraction process of lignin, it was shown that extraction yield of the soda process (90%) was higher than the organosolv process (35%). FTIR spectra of organosolv and soda lignins displayed that both have functional groups of syringyl and guaiacyl units as typical features for standard lignin. When carrying pyrolysis to produce porous carbon, the organosolv-extracted lignin was more thermally stable. The pore analysis showed that the highest specific surface area of nanoporous carbon up to 595 m2/g was obtained.