The mechanism of
photodegradation of organic pollutants in seawater
by TiO2-based catalysts irradiated by visible light was
first explored by adding holes and free radical traps. The results
showed that the photogenerated holes formed by the catalyst played
a key role in the degradation of organic pollutants, regardless of
whether the photodegradation occurred in seawater or pure water. Considering
that the Yb-TiO2-rGO catalyst has a strong adsorption for
organics, the salt ion almost did not interfere with the adsorption
of pollutants by Yb-TiO2-rGO. Therefore, the degradation
performance of Yb-TiO2-rGO did not remarkably change in
the two water systems. For P25-ZN with a weak adsorption capacity
for organics, several salt ions in the seawater hindered the contact
of pollutants with the catalyst surface. Thus, the degradation rate
of P25-ZN for phenol was significantly reduced. After the solvothermal
reduction treatment for catalysts using ethylene glycol (EG) as the
solvent, the increase in the Ti3+ content in the catalyst
improved the visible-light response and activity of the catalyst.
In addition, a small amount of EG grafted on the catalyst surface
promoted the photocatalytic reaction process on the catalyst surface,
thereby effectively resisting the interference of salt ions.