Synthesis of ZnO Nanoparticles by the Sol-Gel Protein Route: A Viable and Efficient Method for Photocatalytic Degradation of Methylene Blue and Ibuprofen

Abstract

The photocatalytic degradation of methylene blue dye and ibuprofen drug was studied in the presence of zinc oxide, synthetized by the protein sol-gel route. The catalyst, calcined at 1000 °C, presented a tendentious morphology to filaments characteristic of ZnO crystalline, characterized by X-ray diffraction (XRD) and confirmed by the presence of Zn energy band in X-ray photoelectron spectrometer (XPS). The result of ultraviolet (UV) light photodegradation of this work is comparable to others that made use of more complex routes, considering the degradation of 97% of methylene blue dye solution and the solution of the ibuprofen drug reached 60% of degradation after 1 h of light incidence. In this research, it is possible to report good degradation results, and the research differential is a material made with a simple and less aggressive route, capable of generating a stable and efficient material.

Photocatalytic degradation of ibuprofen using titanium oxide: insights into the mechanism and preferential attack of radicals

“…Reaction (8) refers to the beginning of the reaction process, which the formation of electronhole pair occurs caused by the action of irradiation, light. Subsequently, reactions ( 9)- (12) show the interaction of the contaminant with the catalyst surface forming three possible radicals due to the breakdown of the initial molecule (IBU*, IBU**, IBU***). As previously reported, 56,57 a band with a maximum value around 255 nm increases the intensity during the degradation of ibuprofen with UV irradiation according to the ultraviolet (UV)-visible spectroscopy results, which has been related to the generation of by-products such as decarboxylated, hydroxylated, dihydroxylated and demethylated species 68 and justies the formation of radicals.…”

“…Reaction (12) shows the capture of electrons by the oxygen present in the medium, forming superoxide radicals. The superoxide radicals formed react with the acid medium to form another radical species (HO 2 c), reaction (13).…”

“…S5. † The oxygen molecules react with the photogenerated electron to form the peroxyl radical (O 2 À c), reaction (12), which can react with H + forming the hydroperoxide radical (HO 2 c), reaction (13), or it can directly attack byproducts from the ibuprofen degradation. On the photocatalyst surface, water molecules react with positive vacancies to generate OHc radicals.…”

“…The presence of the OHc radical was confirmed through a model reaction using salicylic acid as a probe molecule.À c) and hydroperoxide (HO 2 c) radicals to degrade the organic materials and mineralize the contaminant to carbon dioxide and water. [11][12][13][14] Heterogeneous photocatalysis…”

“…À c) and hydroperoxide (HO 2 c) radicals to degrade the organic materials and mineralize the contaminant to carbon dioxide and water. [11][12][13][14] Heterogeneous photocatalysis…”