**María Luisa Rojas-Cervantes \* and Eva Castillejos**

Departamento de Química Inorgánica y Química Técnica, Facultad de Ciencias, UNED. Paseo Senda del Rey nº 9, Madrid 28040, Spain; castillejoseva@ccia.uned.es

**\*** Correspondence: mrojas@ccia.uned.es

Received: 1 February 2019; Accepted: 13 February 2019; Published: 2 March 2019

**Abstract:** Advanced oxidation processes (AOPs), based on the formation of highly reactive radicals are able to degrade many organic contaminants present in effluent water. In the heterogeneous AOPS the presence of a solid which acts as catalyst in combination with other systems (O3, H2O2, light) is required. Among the different materials that can catalyse these processes, perovskites are found to be very promising, because they are highly stable and exhibit a high mobility of network oxygen with the possibility of forming vacancies and to stabilize unusual oxidation states of metals. In this review, we show the fundaments of different kinds of AOPs and the application of perovskite type oxides in them, classified attending to the oxidant used, ozone, H2O2 or peroxymonosulfate, alone or in combination with other systems. The photocatalytic oxidation, consisting in the activation of the perovskite by irradiation with ultraviolet or visible light is also revised.

**Keywords:** perovskites; advanced oxidation processes (AOPs); Fenton-like; peroxymonosulfate; heterogeneous photocatalysis
