Photocatalytic Reduction of Nitrates and Combined Photodegradation with Ammonium

Bare titania and metal-promoted TiO2 catalysts were employed in the treatment of nitrates, which are ubiquitous pollutants wastewater. The results show that process can be carried out under visible light (from a white LED lamp) and, best case, 23.5% conversion nitrate was obtained over 4 h with full selectivity towards N2 by employing 0.1 mol% Ag/TiO2 prepared flame spray pyrolysis. Moreover, performance worse when testing same tap water (11.3% conversion), due to more complex composition matrix. Finally, it found photoreduction effectively performed combination photo-oxidation ammonium without loss activity, opening up possibility treating highly polluted wastewater single process. latter employs two contaminants simultaneously as electron holes scavengers, very good selectivity, completely new we may call Photo-Selective Catalytic Reduction (Photo-SCR).