Adsorption and desorption behavior of water and organic vapor of allophanic soil–templated porous carbon materials

Abstract

We have synthesized several kinds of porous carbon material by template method using 2 kinds of natural allophanic soil purchased in Japan as template materials. To determine the hydroscopic properties of the templated porous carbon specimens, we measured their water adsorption and desorption isotherms around room temperature (283, 293 and 298 K). We also measured porous and chemical properties of the templated porous carbon specimens, and investigated the relationships between pore development and their water isotherms. The features of the isotherm curves of the templated porous carbon specimens were different from those of common activated carbon used as a reference, and the features in this study were dependent on template materials rather than carbon ingredients. Some of the templated porous carbon specimens had water adsorption isotherms that rose sharply at approximately 80% relative humidity (RH), and the desorption isotherms dropped off at 60% RH. The results indicate the possibility of application of these specimens as effective adsorbents that are not susceptible to moisture as compared with common activated carbon. The specimens are also assumed to be useful as humidity control materials.