Preparation of Activated Carbons with Large Specific Surface Areas from Biomass Corncob and Their Adsorption Equilibrium for Methane, Carbon Dioxide, Nitrogen, and Hydrogen

Abstract

Activated carbons were produced from agricultural waste corncob using K2CO3 and H3PO4 as activators. The optimal activation temperature for producing the largest BET specific surface area and pore volume of the carbon was 800 °C for K2CO3 activation (sample CK-800) and 500 °C for H3PO4 activation (sample CP-500). The maximum BET specific surface area and pore volume of the resultant carbons were 1450 m2/g and 1.1 cm3/g for K2CO3 activation and 1069 m2/g and 1.0 cm3/g for H3PO4 activation, respectively. The two produced carbons for high pressure carbon dioxide, methane, and nitrogen separation and hydrogen storage were closely investigated. The adsorption isotherm model based on the Toth equation together with the Benedict–Webb–Rubin (BWR) equation of state for determination of the gas phase fugacity provides a satisfactory representation of the high pressure carbon dioxide, methane, and nitrogen equilibrium adsorption. The adsorption isotherm model based on the Langmuir–Freundlich equation together with t...