Fenton reaction acceleration using maltose and ascorbic acid

Abstract

The degradation of various organic dyes such as methyl red (METR), indigo carmine (INDC) and methylene blue (MEBL)
was studied in the presence of the hydrogen peroxide and metal ion (Cu²⁺, Fe²⁺). Ascorbic acid increased degradation
activity of the reaction, which was promoted by sugar (maltose) addition. High oxygen consumption was also observed in
the course of the Fenton reaction in the presence of maltose. Some dyes (INDC) needed the presence of oxygen for their
degradation while oxygen inhibited the degradation of others (METR). Presence of the maltose in the Fenton reaction
increased oxygen consumption. Electron donor (e.g. ascorbic acid) together with the suitable electron acceptor (e.g. oxygen)
and an activation mechanism is needed for the additional natural substances degradation. The activation mechanism can be
based on various compounds such as transient metals, hydrogen peroxide, nitrite, natural organic compounds degradation
products and other. The dye bleaching in the presence of the reducing agent is probably the result of the reversible/irreversible
dye reduction and irreversible dye oxidation, which can be realised in the presence or absence of oxygen.