Kinetic Study and Modeling of the Degradation of Aqueous Ammonium/Ammonia Solutions by Heterogeneous Photocatalysis with TiO2 in a UV-C Pilot Photoreactor

The degradation mechanism of NH4+/NH3 in aqueous solutions by heterogeneous photocatalysis (TiO2/SiO2) and photolysis UV-C pilot photoreactor has been studied. Under the conditions used, can be decomposed both photolytically photocatalytically, without disregarding stripping processes. greatest is achieved at highest pH studied (pH 11.0) higher lamp irradiation power used (25 W) with performances 44.1% (photolysis) 59.7% (photocatalysis). experimental kinetic data fit well a two parallel reactions mechanism. A low affinity ammonia for adsorption surface reaction on photocatalytic fiber was observed (coverage not than 10%), indicating influence phenomena rate, homogeneous phase being predominant over phase. proposed validated, confirming that it consistent photolytic formation nitrogen gas, one hand, nitrate, other hand. At optimal conditions, rate constants were k3 = 0.154 h−1 disappearance k1 3.3 ± 0.2 10−5 k2 1.54 0.07 10−1 appearance nitrate respectively.