Title: Removal of pesticides in water by CeO2-WO3 mixed-oxide catalysts

Abstract

The water pollution due to the emerging contaminants as pesticides, pharmaceutics and/or plasticizers, is an urgent environmental problem strictly connected to the safety of the human and ecosystem life. In the recent years, the combination of different Advanced Oxidation Processes (AOPs) can be a performing strategy to remove these recalcitrant contaminants in water. In this contest, we have examined the (photo) catalytic activity of CeO2-WO3 materials for the degradation of the orto-phenylphenol fungicide comparing the photocatalytic, the Fenton and the photo-Fenton-like processes. The samples were synthesized through deposition-precipitation mediated with the hexamethylenetetramine (HMTA) surfactant. The chemico-physical properties of the materials were examined by Raman, UV Vis Diffuse Reflectance (Uv-vis DRS) and X-Ray photoelectron (XPS) spectroscopies, N2 adsorption-desorption measurements and transmission electron microscopy (TEM). The (photo)catalytic measurements were made through a home-made photoreactor irradiated by a solar lamp. The degradation of the fungicide was measured by UV-vis spectroscopy. An efficient heterojunction was formed between the CeO2 and the WO3 oxides which allowed to obtain a good degradation percentage of the pesticide (65%) employing the solar photo Fenton-like reaction that among the three AOPs was the best performing process. The addition of WO3 on CeO2 facilitated the ionic exchange between the Ce and the W ions, boosting the redox properties of cerium oxide. The strong interaction between the CeO2 and WO3 and the peculiar properties of this unconventional composite pave the way to its use as promising material for water depollution.

Biography

Roberto Fiorenza is a PhD in chemical Science. The main scientific interests are focused on some environmental (VOCs oxidation, air and water purification) and industrial (H2 production and purification, CO2 valorization) applications of heterogeneous catalysis with particular concern on semiconductors -based materials for photocatalysis. He won the Young Scientist Award at E-MRS (European Materials Research Society) 2017 (“Photocatalytic material for energy and environment “), the best PhD thesis 2018 for the Catania Gioeni's Accademy, and the “Adolfo Parmaliana prize 2019” for the best PhD thesis in the field of catalysis for a sustainable development. Presently he is a researcher in industrial chemistry at University of Catania (Italy).