Ash content of the activated carbon was determined according to
ASTM D3174-73 standard. The specific surface area and pore structure
parameters of the activated carbons are determined by using a surface
area analyzer (Micromeritics ASAP 2020). Iodine number of the activated
carbon was determined using the sodium thiosulfate volumetric
method [25]. In order to determine quantitatively and qualitatively surface
functional groups of the activated carbon, Boehm's titration method
[24] and FT-IR analysis were applied, respectively. pzc value of the
carbon was measured by using Malvern Nanosizer ZS-3600 zetasizer. A
scanning electron microscope was used to examine the surface morphology
of the grape stalk and activated carbons obtained. The samples
for SEM analysis were prepared by sputter-coating the surface with Au.
The elemental composition was analyzed by EDX. Particle size distribution
and elemental analysis of the samples were performed using
Malvern Master Sizer 3000 and LECO CHNS 932 Elemental Analyzer,
respectively.