Host: The Society of Chemical Engineers, Japan
Activated carbons were prepared from various food wastes, such as kitchen garbage, lactic acid fermentation residuals and saccharification residuals, by steam-activation of carbonized samples. The food wastes were carbonized at 773 K in inert atmosphere and the carbonized samples were activated by steam. Activated carbons, with enough BET surface areas compared with a commercial activated carbon, were successfully prepared. The effect of the heating rates at the carbonization stage on the porous properties of the resultant activated carbons was investigated by using nitrogen adsorption-desorption method. Activated carbons prepared at a slow heating rate showed high mesoporosity compared with the carbons prepared at a fast heating rate. Moreover, the carbonized wastes were also treated by HCl prior to the steam activation in order to improve the mesoporosity of activated carbons. It was found that the pores of the carbons developed by using the pre-treatment method in the region of the pore radii around 2 nm. The surface hydrophobicity of the activated carbons was also investigated by water vapor adsorption. The liquid-phase adsorption properties of phenol, bisphenol-A, and dye (Black-5) on the obtained activated carbons were examined through the long-period adsorption tests. Some of the activated carbons prepared from saccharification residuals showed higher adsorption capacities for phenol and Black-5 than the commercial carbon.
