[Catalyzed oxidation of catechol by the heterogeneous Fenton-like reaction of nano-Fe3O4-H2O2 system].

A Fenton-like system, consisting of magnetite (Fe3O4) and hydrogen peroxide (H2O2), was utilized to remove refractory organic pollutants using the hydroxyl radicals generated from the decomposition of H2O2. The characteristic of the catalyzed oxidation of catechol in a nano-Fe3O4-H2O2 Fenton-like system was studied. The catalytic activity of the synthesized nano-Fe3O4 was compared to that of the purchased micro-Fe3O4. The effect of initial H2O2 concentration on the oxidation of catechol was also studied. Results showed that the removal of catechol and total organic carbon and the decomposition of H2O2 were faster in the nano-Fe3O4-H2O2 system than in the purchased-Fe3O4-H2O2 system. The removal of catechol achieved nearly 100% in the former system. The catalyzed oxidation of catechol in nano-Fe3O4-H2O2 system followed pseudo-first-order kinetics. The decomposition of H2O2 could be fitted by third-order kinetics. The release of total iron was below 0.3 mg x L(-1), implying that the homogeneous Fenton reaction was not dominant. Therefore, surface reaction controlled heterogeneous Fenton-like reaction mechanism was deduced.