ZnO degrades ethyl paraben faster than P25 TiO2 under solar radiation.
Paraben and ZnO concentration, reaction time, humic acid in water affect kinetics.
Hydroxylated and dealkylated by-products are formed early during the reaction.
By-products are more stable but less estrogenic than ethyl paraben.
Dissolved zinc concentration in the liquid phase is minimal (<12 mg/L).