Figure 9
The possible way of phenoxyl radicals and reactive oxygen species production. The yellow field indicate the Fenton reaction. Ph-OH means phenolic compound. The phenolic compound may undergo autoxidation to produce phenoxyl radical, superoxide radical anion (O2·−) and hydrogen cation (H+). O2·− and H+ react to form hydrogen peroxide and oxygen. In the presence of same transition metals (e.g. Fe(III)) the phenoxyl radicals and reduced metal cations (Fe(II)) are produced. Finally, H2O2 is reduced to ·OH and Fe(II) is oxidised to Fe(III) in the Fenton reaction.
