Navegando por Autor "Gurgel, G. H. M."
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Artigo Effects of MnO2/In2O3 thin films on photocatalytic degradation 17 alpha-ethynylestradiol and methylene blue in water(Springer, 2018-05-23) Ferreira, T. L. B.; Garcia, Laurênia Martins Pereira; Gurgel, G. H. M.; Nascimento, Rubens Maribondo do; Godinho Junior, Mario; Rodrigues, Murillo Henrique de Matos; Delmonte, Maurício Roberto Bomio; Motta, Fabiana Villela daIn recent years, there has been a growing concern about some substances in the aquatic environment such as methylene blue dye (MB) and 17α-ethynylestradiol (EE2) hormone, mainly from waste textile and pharmaceutical industries, respectively. This waste, which is not effectively treated, generates large amounts of contaminated effluents. Textile industries, which use dyes mainly in their dyeing and finishing processes, generate a lot of effluent contamination by dyes. The 17α-ethynylestradiol hormone which is used in different contraceptive pills and in hormone replacement therapy, is the main substance found in the aquatic environment because of its high resistance to biodegradation. It is known that conventional water treatment processes, which involve the steps of coagulation, flocculation and sedimentation among others, have been reported to be ineffective in the removal of dyes and hormones. The heterogeneous photocatalysis has attracted great interest from many research groups around the world due to its potential application as a pollutant degradation method. For this purpose, the present work evaluated the performance of MnO2/In2O3 thin films in the degradation process of the blue methylene and 17α-ethynylestradiol in aqueous solutions. The degradation processes were monitored by UV–Vis spectroscopy and HPLC chromatography. From these analyzes, the concentration of the solutions was evaluated and it was possible to infer that the MnO2/ In2O3 thin films significantly promoted a degradation of 89% of 17α-ethynylestradiol, however, the degradation of the methylene blue was not efficientArtigo Influence of the number of layers and crystallization temperature on the photocatalytic activity of Tio2 / In2 o3 thin films(MedCrave Group, 2017-07-20) Paskocimas, Carlos Alberto; Garcia, Laurênia Martins Pereira; Gurgel, G. H. M.; Lovisa, Laura Ximena; Nascimento, Rubens Maribondo do; Delmonte, Maurício Roberto Bomio; Motta, Fabiana Villela daThe TiO2/In2 O3 thin films were prepared by the spin coating method, varying their number of layers (4, 8 and 16 layers). The Method of polymerization of complex (CPM) was used to synthesize the precursor resins in order to produce thin films. The TiO2/In2 O3 films were heat–treated at 300°C, 500°C and 700°C and characterized by X–ray diffraction, scanning electron microscopy (FEG–SEM), atomic force microscopy (AFM), UV–vis spectrophotometer and photoluminescence (PL). It was found that the band gap energy of the as–prepared TiO2/In2 O3 composite thin films decrease as temperature increases. According to the UV–vis diffuse reflectance spectra, the TiO2/In2 O3 composite shows good visible–light absorption ability. The photoluminescent properties of the films were studied at room temperature using a wavelength of 350nm excitation. High photoluminescent intensity was observed for the films treated at 300°C heat, studied in different films. The photocatalytic activity of the composite TiO2/In2 O3 was evaluated by the hotodecomposition of methylene blue dye in aqueous solution and showed that all the composite samples presented excellent photocatalytic performance even when recycled. This study shows that the coupling of TiO2 with In2O3 is an effective way to increase the TiO2 absorption in the visible region for catalytic applications and that the temperature has a greater influence on the results than the number of layers