I am degrading PAH dissociated in toluene using TiO2, however I do not find mechanisms in the literature that explain how this degradation is occurring, since the literature only demonstrates the degradation and generation of OH radicals in the presence of water.
Dear Luana Andrade
1. Positive holes (h+) of excited TiO2 also can oxidize organic pollutants (Direct oxidation).
2. O2 from air can react with the conduction band of TiO2 to produce -•O2 radicals which can oxidize PAH.
To confirm this, I suggest you to carry out quenching tests or ESR analysis to check the formation of oxidizing species (positive holes and -•O2)
- p-benzoquinone and sodium oxalate can be used to quench -•O2 and h+, respectively. With the addition of p-benzoquinone as a scavenger for -•O2, the oxidaton may decrease since the activity of -•O2 is blocked.
- You may also check/avoid the formation of -•O2 if you carry out your photocatalytic experiments in closed N2 medium.
Regards
RD
Luana
1. There is no dissociation of PAHs - it is simple solubility in organic solvent.
2. Did you checked the concentration changes of PAHs caused by adsorption on TiO2 - experimenta without light or external oxidants?
Regards
G
Dear Ridha Djellabi
Thank you so much for your answer, it will help me a lot.
Best Regards.
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