Photosensitization of a colloidal TiO2 semiconductor system with hypocrellin B

Determination of main species involved in the first steps of TiO2 photocatalytic degradation of organics with the use of scavengers: The case of ofloxacin

“…shown in Figure 8.a phosphate exerts no effect on OFX degradation nor on HCHO 14 formation rates (the latter during the first 30 min; for longer treatment times the 15 concentration of HCHO in solution was lower in absence of phosphate), but its presence 16 drastically reduces the formation of H 2 O 2 as shown in Figure 8.b. On the other hand, the 17 evolution of A 260nm when PO 4 3-was added differed from that of the control run, 18 similarly to what was observed in absence of O 2 (see Figure S7). 30 min when phosphate was used could indicate that the adsorption of formaldehyde 13 and its interaction with the catalyst surface is also avoided.…”

“…Possible mechanism of OFX photocatalysis 18 From the results presented and discussed in the above sections the mechanism showed 19 in Figure 9, similar to that of Cuquerella et al [17] (see Fig 2), is proposed for the 20 photocatalytic elimination of OFX in perchloric/perchlorate aerated medium at pH 7.…”

“…A c c e p t e d M a n u s c r i p t The evolution of H 2 O 2 and HCHO formed versus OFX eliminated showed in Figure S2 17 clearly supports the mechanism described in Figure 2 OFX acting as photosensitizing 18 agent. In fact, the phototoxicity of this fluoroquinolone antibiotic has been reported to 19 be related to the generation of different ROS [18,19].…”

“…This aspect was confirmed with experiments done using 16 natural sunlight instead of black light. The results, available in the supporting 17 information (see Figure S2), indicate that the photolysis of OFX, faster under solar light 18 due to a higher photon flux as well as the contribution of more energetic radiations, 19 clearly leads to the formation of H 2 O 2 and HCHO. From Figure S2 the ratio between 20 moles of HCHO formed per mole of OFX seems to be lower than one, which could be 21 attributed to the photolysis of HCHO.…”

“…In fact, the phototoxicity of this fluoroquinolone antibiotic has been reported to 19 be related to the generation of different ROS [18,19]. …”