Optimization of kinetic pore size for methane storage behavior of pitch-based activated carbon fibers

Pitch-based activated carbon fibers were prepared for application to methane storage. Chemical activation was accomplished by treatment with potassium hydroxide and heat, leading to increased specific surface area and micropore volume. Structural properties and morphology were evaluated by X-ray diffraction and scanning electron microscopy, respectively. Textural properties and microporosity were determined from N₂/77 K adsorption-desorption isotherms using the Brunauer-Emmett-Teller equation and the Horvath-Kawazoe method. The methane storage capacity is influenced by activation time. This is attributed to the creation of a narrow distribution of micropores, which is a factor closely related to the methane storage capacity. This indicates that the methane storage behavior depends on the pore volume. Although a large pore volume is desirable for methane storage, the size of the pores in the activated carbon fibers that facilitate the activation process is also a significant factor.