Regeneration experiments
The regeneration was carried out in a cylindrical Pyrex vessel
(500 mL) placed in a water bath with a magnetic stirrer. The pent
adsorbent was dried at 100 C and then introduced into 200 mL
H2O2 solution 8.3 102 M with magnetic stirring to maintain a
uniform suspension. The solution pH was adjusted to 3 (±0.1)
throughout the reaction. The reaction was run for 8 h. (these conditions
were selected based on our previous research on the catalytic
performance of magnetic Fe3O4 activated carbon in the
heterogeneous Fenton reaction (Nguyen et al., 2011)). When the
regeneration reaction was stopped, the regenerated carbon was
dried in a vacuum oven at 100 C and separated: 0.1 g was used
for extraction to ensure that complete regeneration had occurred
and the remainder was weighed for another cycle of operation.
The adsorption regeneration cycle was repeated five times. The
MO adsorption capacity of each cycle was determined.