t-Butanol is another well-known radical scavenger and its
presence in water or wastewater can negatively influence photocatalytic ozonation [83]. However, Beltran et al. [9] reported an
increase in the photocatalytic ozonation rate of sulfamethoxazole
and diclofenac by the addition of t-butanol to the oxidation medium. These effects were attributed to t-butanol reducing the surface tension and viscosity of the aqueous solution, increasing the
ozone concentration in the film layer closest to the gas–water
interface which increased the efficiency of the oxidation process.
These results, and similar results reported by Villasenor et al. [48]
on the degradation of phenol, indicated the oxidation of these
pollutants occurred by direct ozonation rather than by interaction
with free radicals. However, Villasenor et al. [48] also reported
the presence of t-butanol increased the concentration of degrada-