Abstract
The author clarified the characteristic of activated carbon prepared from biomass (rind of sugar cane bagasse (rind), pith of sugar cane bagasse (pith), rice straw (rice), bamboo (barn)) with different ratios of NaOH. In addition, the characteristic of electric double-layer capacitance of each activated carbon was clarified.
Raw materials carbonized for 1 h at 973 K were used as a sample, and the sample was activated for 1 h at 1073 K with the different ratios of NaOH. High BET specific surface area (SBET) of our activated carbon was obtained (more than 2400 m2/g). The N2 absorption isotherm at 77 K indicated type I of IUPAC. As analysis of αs-plot, activated carbon prepared from rind, pith and rice (AC-rind, AC-pith, AC-rice) were microporous with average pore diameter (Wave) in the range of 0.7-1.4 nm. On the other hand, activated carbon prepared from bam (AC-barn) was microporous with Wave below 0.7 nm.
Comparison of SEM images between raw carbonized materials and the activated carbon indicated that AC-rind, AC-rice and AC-barn remained proper biomass structure as capillaries after activation.
The electric double-layer capacitance (Cdl) of each raw material increased with an increase of Stotal. When the Wave was focused, Cdl of AC-barn was nearly constant above 0.8 nm and Cdl of AC-rice was nearly constant above 1.1 nm. On the other hand, Cdl of AC-rind and AC-pith increased with an increase of Wave. From the above results, the high Cdl of AC-pith and AC-rind was considered to be due to wide Wave.
