2.2.2. Surface modification
A known amount of AC1 was oxidized at 25 C using H2O2 (30%)
at a ratio of 1:2 and 2:5 (m:v). The reaction mixture was treated in
two steps. In the first step, the mixture was heated at 70 C for 4 h,
and in the second step, the mixture was subjected to ultrasound in
an ultrasonic oscillator for 4 h. The reaction solution was removed,
and the oxidized sample was washed until it was stable at a pH of
approximately 7. The washed samples were then dried for 4 h at a
temperature of 110 C and marked as AC1-1 and AC1-2.