Raw corn stalk (RCS) and raw corn cob (RCC) were obtained
from a farm near Shiraz, Iran. After removing the grains from the
cob and removing the leaves from the stalk, the biomasses were cut
into small slices. The samples were then ground through a 70-
mesh sieve to achieve a uniform particle size. Then the powder was
washed three times with distilled water and was dried in an oven
at 50 8C until constant weight. Leyva-Ramos [7] method was used
for oxidation of the corn stalk. The corn stalk was oxidized with
nitric acid solutions by adding 40 g corn stalk to 200 ml of the acid
solution in a flask. The concentration of the acid solutions was 1 M.
The solution containing the corn stalk was heated for 2 h keeping
the temperature at 50 8C. Afterward, the solution containing the
corn stalk was allowed to cool and drained to separate the solution.
The corn stalk was oxidized with nitric acid and was washed
several times with distilled water until the pH of the distilled water
ceased to change while washing. It was finally dried in an oven at
50 8C for 24 h