Melamine does not react with hydroxyl radicals (Fenton process, H2O2 photolysis).
Melamine is degraded by TiO2 photocatalysis and homogeneous SO4−.
The rate dependence on concentration, pH and surface fluorination indicates an outer sphere mechanism.
Hole-mediated oxidation transforms −NH2 into −NO2.
The TiO2 shallow hole has a E° ≥ 2.4 V vs NHE.