Offgas analysis and pyrolysis mechanism of activated carbon from bamboo sawdust by chemical activation with KOH

Abstract

Bamboo sawdust was used as the precursor for the multipurpose use of waste. Offgases released during the activation process of bamboo by KOH were investigated quantitatively and qualitatively by a gas analyzer. TG/DTG curves during the pyrolysis process with different impregnation weight ratios (KOH to bamboo) were obtained by a thermogravimetric analyzer. Pyrolysis mechanism of bamboo was proposed. The results showed that the offgases were composed of CO, NO, SO₂ and hydrocarbon with the concentration of 1 372, 37, 86, 215 mg/L, respectively. Thermogravimetric analysis indicated that the pyrolytic process mainly experienced two steps. The first was the low temperature activation step (lower than 300°C), which was the pre-activation and induction period. The second was the high temperature activation step(higher than 550°C), which was a radial activation followed by pore production. The second process was the key to control the pore distribution of the final product.

Keywords

offgas / pyrolysis mechanism / activated carbon / bamboo

References

[1] Wang X. F., tian Y., Zhang H. P. Preparation and Activation Mechanism of high Specific Surface Area Coal-based Activated Carbon[J]. CIESC J., 2009, 60(3): 733-737.

[2] Mitani S., Lee S. I., Saito K., . Activation of Coal Tar Derived Needle Coke with K₂CO₃ into an Active Carbon of Low Surface Area and Its Performance as Unique Electrode of Electric Double-layer Capacitor[J]. Carbon, 2005, 43(14): 2 960-2 967.

[3] Xing W., Qiao S. Z., Ding R. G., . Superior Electric Double Layer Capacitors Using Ordered Mesoporous Carbons[J]. Carbon, 2006, 44(2): 216-224.

[4] Aravindhan R., Rao J. R., Nair B. U. Preparation and Characterization of Activated Carbon from Marine Macro-algal Biomass[J]. J. Hazard. Mater., 2009, 162(2–3): 688-694.

[5] Cotoruelo L. M., Marques M. D., Rodriguez-Mirasol J., . Lignin-based Activated Carbons for Adsorption of Sodium Dodecylbenzene Sulfonate: Equilibrium and Kinetic Studies[J]. J. Colloid Interf. Sci., 2009, 332(1): 39-45.

[6] Do D. D., Junpirom S., Do H. D. A new Adsorption-desorption Model for Water Adsorption in Activated Carbon[J]. Carbon, 2009, 47(6): 1 466-1 473.

[7] Lua A. C., Yang T., Guo J. Effects of Pyrolysis Conditions on the Properties of Activated Carbon Prepared from Pistachio-nut Shells[J]. J. Anal. Appl. Pyrol., 2004, 72: 279-287.

[8] Linares-Solano A., Salinas-Martınez de Lecea C., Cazorla-Amoros D., . Porosity Development and Steam Activation in a Fluidzed Bed Reactor[J]. Energy Fuels, 2000, 14(1): 142-149.

[9] Carrott P. J. M., Carrott M. M. L. R., Mourao P. A. M. Pore Size Control in Activated Carbons Obtained by Pyrolysis Under Different Conditions of Chemically Impregnated Cork[J]. J. Anal. Appl. Pyrol., 2006, 75(2): 120-127.

[10] Wang X. F., Zhang H. P., Chen H. Q. Preparation and Characterization of High Specific Surface Area Activated Carbon from Bamboo by KOH Activation[J]. J. Functional Mater., 2006, 37(4): 675-679.

[11] Choy K. K. H., Barford J. P., McKay G. Production of Activated Carbon from Bamboo Scaffolding Waste-process Design, Evaluation and Sensitivity Analysis[J]. Chem. Eng. J., 2005, 109(1/3): 147-165.

[12] Gregg S. J., Sing K. S. W. Adsorption, Surface Area and Porosimetry[M], 1982 New York Academic Press 42

[13] Barrett E. P., Joyner L. C., Halenda P. H. The Determination of Pore Volume and Area Distributions in Porous Substances[J]. J.Am. Chem. Soc., 1951, 73: 373-380.

[14] Dubinin M. M., Herry D. A. Progress in Surface and Membrane Science[M], 1975 London Academic Press 102