Effects of Pore Structure on <i>n</i>-Butane Adsorption Characteristics of Polymer-Based Activated Carbon

Abstract

In this study, the correlation between n-butane adsorption characteristics and pore characteristics of activated carbons (ACs) was investigated by activated polymer-based hard carbons (APHCs) using a carbon dioxide activation method. The structural characteristics of the ACs were observed by X-ray diffraction and Raman spectroscopy. The N2 adsorption isotherm characteristics at 77 K were confirmed by Brunauer–Emmett–Teller, Barrett–Joyner–Halenda, and nonlocal density functional theory equations. From the results, specific surface areas and total pore volume of the ACs were determined to be 1020–2440 m2/g and 0.42–1.30 cm3/g, respectively. As the activation time increased, the fraction of micropores decreased from 85% to about 40%. On the other hand, the porosity of the mesopores increased to about 60% from a ratio of about 10%. The specific power adsorption has been increased with the development of the mesopores and exhibited 20 960 sK/g at APHC-10–5 (540% higher compared to that of APHC-10–2). It was confirmed that the correlation between the adsorption capacity of n-butane and the pore characteristics of the ACs was determined by pore diameter of 1.5–4.5 nm.