An Innovative Advanced Oxidation Technology for Effective Decomposition of Formaldehyde by Combining Iron Modified Nano-TiO2 (Fe/TiO2) Photocatalytic Degradation with Ozone Oxidation

Combined AOPs for Formaldehyde Degradation Using Heterogeneous Nanostructured Catalysts

“…Moreover, this synergy can be related to the roles of iron as an electron acceptor, to facilitate charge separation in TiO2 photocatalyst, thereby reducing the non-desired electron/hole recombination and thus increasing the rate of OH• formation through the first and second reaction in Scheme 1. Similar results have been reported for homogeneous TiO2-Fe system in phenol degradation [19], for Azo dye [25] and for bisphenol A [15] and for Fe doped TiO2 [20,21,23].…”

“…The heterogeneous PAN-Fe catalyst comprised 0.12 mg/cm 2 of FeSO4 (i.e., similar content to the TiO2 content of the previous experiment, i.e., optimal composition defined elsewhere [32]), which corresponded to a total of 6 mg of ferrous sulfate in the system. All the trials have been carried out under UV irradiation; it shall be kept in mind that in presence of iron sulfate the UV absorbance of the system around 290 nm was quite high, owing to the absorption properties of this compound [23]. The newly generated ferrous ions react again with H 2 O 2 generating hydroxyl radical and ferric ion and, in this way, the cycle continues.…”

“…It can be noted that the combination of TiO2 and Fe 2+ showed the best result, i.e., there was a synergy deriving from the combination of photocatalysis and photo-Fenton since the combined process gave better results than the simple sum of the two distinct processes. This synergy can be due to the fact that in presence of iron sulfate the UV absorbance of the system around 290 nm increased, owing to the absorption properties of this compound, therefore favoring UV activation [23]. Moreover, this synergy can be related to the roles of iron as an electron acceptor, to facilitate charge separation in TiO2 photocatalyst, thereby reducing the non-desired electron/hole recombination and thus increasing the rate of OH• formation through the first and second reaction in Scheme 1.…”

“…Li et al [22] studied the effect of the content of Fe on the photocatalytic performance of doped TiO 2 on the degradation of gaseous formaldehyde and found that doped TiO 2 exhibited higher photocatalytic activity under visible light irradiation. Cheng et al [23] mixed TiO 2 with iron oxide to produce modified photocatalysts (Fe/TiO 2 ) and then coated them on a supporting medium of fiberglass and studied the degradation of gaseous formaldehyde using these supported catalysts. They concluded that the enhancement of formaldehyde decomposition by iron-doped TiO 2 may be attributed to the facts that the doped iron ions could effectively enhance the absorption of UV-visible wavelength, increase the photocatalytic reactivity and retard the recombination of electron and electron-hole pairs, which thus contributed to the increase of formaldehyde decomposition efficiency.…”

“…However, authors using Fe-doped titania [20][21][22][23][24] did not mention the photo-Fenton reaction and did not adjust pH accordingly.…”