Photocatalysis is based on the activation of a semiconductor
surface (most often TiO2), by UV radiation below 380 nm,
which releases electrons from the semiconductor’s valence
band. Photogenerated electrons and holes react then with water,
dissolved oxygen and organic compounds to form radicals,
making a strongly oxidant environment [19]. Photocatalysis
presents critical advantages over other techniques. It is faster
than bioreactors and cheaper than ozonolysis and radiolysis.
Furthermore it can be achieved under direct sunlight, making
it cheaper to operate and independent from any power
source.