The specific surface areas, average pore sizes, and pore volumes
of the sorbents were determined by nitrogen adsorption/desorption
isotherm method at liquid nitrogen temperature using the
Accelerated Surface Area and Porosimetry (ASAP 2000, Micromeritics
Co., USA). Prior to the analysis, the samples were degassed
overnight at 105 _C. The Brunauere Emmette Teller (BET) model
was applied to calculate the apparent surface area