was evaluated. In order to validate the efficiency of the photo-Fenton process at
near-neutral pH on virus inactivation, the photocatalytic treatment was carried out in
natural water (Lake Geneva, Switzerland) and with a human virus (echovirus).
Finally, a conceptual mechanism interpretation was proposed regarding how solar
photo-Fenton acts on viruses in water, involving the key species Fe
2+ , Fe
3+ , and
H 2 O 2 , solar irradiance, organic matter, and their possible reactions and interactions,
where the probable virus adsorption onto iron particles has a significant effect on the
inactivation efficiency of MS2 coliphage by photo-Fenton treatment at near-neutral
pH [7].
11.2 Heterogeneous Photo-Fenton Reaction
Many homogeneous catalysts have been reported as efficient toward the Fenton
reaction. However, the main drawbacks of homogeneously catalyzed Fenton reactions include the need for large amounts of transition metal salts, the demand for
strong acidic system (pH ¼ 3–4), the subsequent management of massive sludge, as
well as the acidification of the effluents before the reaction, and the neutralization of
treated solutions before disposal. Heterogeneous catalysts offer the advantage of
allowing easier recycling from the effluent.
11.2.1 Membrane and Fabrics
Nafion film contains –SO 3 Na group with Na ions replaceable by Fe
3+ through a
simple ion exchange reaction. For example, Fe
3+ /Nafion catalyst was used for the
photo-Fenton degradation of Orange II in the presence of H 2 O 2 /visible light
[8]. However, it should be stressed that the Nafion film-based catalyst is too
expensive to be used for a practical application even though the catalyst can be
separated easily from solution. Yuranova et al. immobilized Fe
3+ ions on carbon
fabric for the discoloration of Orange II under visible light irradiation [9]. It was
observed that surface iron oxide and iron hydroxide are the catalytically active sites
on carbon fabric during the reaction. Bozzi et al. reported the immobilization of Fe
3+
on silica fabrics to degrade oxalates under visible light irradiation [10]. They
observed the existence of Fe
3+ /Fe
2+ mixed complex with oxalic acid on the surface
of the catalyst with time and reported the formation and disappearance of Fe–
carboxylates by infrared attenuated total reflection (IRATR) Fourier transform
spectroscopy and concomitant recycling of the resulting Fe
3+ back to the catalyst
surface.
11.2 Heterogeneous Photo-Fenton Reaction
261
near-neutral pH on virus inactivation, the photocatalytic treatment was carried out in
natural water (Lake Geneva, Switzerland) and with a human virus (echovirus).
Finally, a conceptual mechanism interpretation was proposed regarding how solar
photo-Fenton acts on viruses in water, involving the key species Fe
2+ , Fe
3+ , and
H 2 O 2 , solar irradiance, organic matter, and their possible reactions and interactions,
where the probable virus adsorption onto iron particles has a significant effect on the
inactivation efficiency of MS2 coliphage by photo-Fenton treatment at near-neutral
pH [7].
11.2 Heterogeneous Photo-Fenton Reaction
Many homogeneous catalysts have been reported as efficient toward the Fenton
reaction. However, the main drawbacks of homogeneously catalyzed Fenton reactions include the need for large amounts of transition metal salts, the demand for
strong acidic system (pH ¼ 3–4), the subsequent management of massive sludge, as
well as the acidification of the effluents before the reaction, and the neutralization of
treated solutions before disposal. Heterogeneous catalysts offer the advantage of
allowing easier recycling from the effluent.
11.2.1 Membrane and Fabrics
Nafion film contains –SO 3 Na group with Na ions replaceable by Fe
3+ through a
simple ion exchange reaction. For example, Fe
3+ /Nafion catalyst was used for the
photo-Fenton degradation of Orange II in the presence of H 2 O 2 /visible light
[8]. However, it should be stressed that the Nafion film-based catalyst is too
expensive to be used for a practical application even though the catalyst can be
separated easily from solution. Yuranova et al. immobilized Fe
3+ ions on carbon
fabric for the discoloration of Orange II under visible light irradiation [9]. It was
observed that surface iron oxide and iron hydroxide are the catalytically active sites
on carbon fabric during the reaction. Bozzi et al. reported the immobilization of Fe
3+
on silica fabrics to degrade oxalates under visible light irradiation [10]. They
observed the existence of Fe
3+ /Fe
2+ mixed complex with oxalic acid on the surface
of the catalyst with time and reported the formation and disappearance of Fe–
carboxylates by infrared attenuated total reflection (IRATR) Fourier transform
spectroscopy and concomitant recycling of the resulting Fe
3+ back to the catalyst
surface.
11.2 Heterogeneous Photo-Fenton Reaction
261