Evolution of the chemical composition, functional group, pore structure and crystallographic structure of bio-char from palm kernel shell pyrolysis under different temperatures

- Effect of pyrolysis temperature on the properties of PKSC was systematicly investigated.
- Higher temperature promoted content of C, the value of HHV and pH.
- Higher temperature led to the reduction of the content of the surface functional group but increase of the graphitization degree.
- SBET reached the maximum value of 403.99 m2/g at 650 °C.

Biochar, produced from the biomass slow pyrolysis technology, has been widely applied to the industry and agriculture. This paper investigated the effect of the pyrolysis temperature (250, 350, 450, 550, 650, and 750 °C) on the chemical composition, functional group, pore structure and crystallographic structure of biochar from palm kernel shell (PKS). The basic properties of biochar was mainly tested by a serial instruments including thermogravimetric analyzer (TGA), fourier transform infrared spectrometry (FTIR), automatic adsorption analyzer, X-ray diffractometer (XRD), Raman spectra, and solid-state 13C nuclear magnetic resonance spectra (13C NMR). The results showed that as the pyrolysis temperature increased: (1) the carbon content, HHV and pH value reached their maximum values of 78.95%, 31.55 MJ kg−1 and 10.03 at 750 °C, respectively, (2) the content of the surface functional group decreased, (3) the oxygen-contained carbon structure including O-alkyl-C and carboxylic-C decreased from 11.71% and 3.72% to 1.12% and 1.11%, respectively, while the aryl-C structure increased from 65.98% to 93.18%, (4) the specific surface area (SBET) reached the maximum value of 403.99 m2 g−1 at 650 °C. This systematic study on the evolution of the basic physicochemical characteristics will provide a good reference for the high value-added application of PKSC.

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