Photocatalytic Degradation of Mixed Dyes in Aqueous Phase by MgAlTi and ZnAlTi Mixed Oxides
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ORIGINAL PAPER
Photocatalytic Degradation of Mixed Dyes in Aqueous Phase by MgAlTi and ZnAlTi Mixed Oxides Laura V. Castro1 · E. Ortíz‑Islas2 · Ma. E. Manríquez1 · E. Albiter1 · Román Cabrera‑Sierra1 · B. Alvarado‑Zavala1
© Springer Science+Business Media, LLC, part of Springer Nature 2020
Abstract This study reported the synthesis and evaluation of mixed metal oxides MgO/Al2O3–TiO2 and ZnO/Al2O3–TiO2 as heterogeneous photocatalysts for the potential degradation of a mixture of organic dyes such as methylene blue and methyl orange. First, hydrotalcites were synthesized by two different methods (conventional and microwave); then they were treated at 500 °C to obtain the corresponding Mg/Al–Ti and Zn/Al–Ti mixed metal oxides. The Layered Double Hydroxide (LDH) and the Mixed Metal Oxides were characterized by N2 adsorption–desorption, X-ray Diffraction, Fourier transform infrared, X-Ray photoelectron Spectrometry and Scanning Electron Microscopy. The degradation processes of the dyes were carried out under ultraviolet light irradiation and absorbance readings were compared using a UV–vis spectrometer. The ensuing degradation of products was corroborated through a mass spectrometry analysis. According to the photodegradation efficiency of dyes under UV irradiation, the activity of the samples showed the following order: ZnAlTiM > ZnAlTiC > MgAlTiC > MgAlTiM. The improvement in the activity of ZnAlTiM may be attributed to its lowest reflectance and highest degree of UV light absorbance, its smallest valence band and its ZnO-support interaction. Degradations of 25% and 68% were achieved for methyl orange and methylene blue, respectively, after 120 min of reaction. The degradation process conforms to the Langmuir–Hinshelwood type kinetic model. Graphic Abstract
Electronic supplementary material The online version of this article (https://doi.org/10.1007/s11244-020-01345-5) contains supplementary material, which is available to authorized users. Extended author information available on the last page of the article
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Vol.:(0123456789)
Topics in Catalysis
Keywords MgO–Al2O3–TiO2 · ZnO–Al2O3–TiO2 · Mixed metal oxides · Photodegradation · Hydrotalcites · Methylene blue · Methyl orange
1 Introduction Currently, pollution derived from the textile printing and dyeing industries has mainly had an impact on public health and ecosystems. These industries use large amounts of water as a solvent, for transport, and as reaction media. So, wastewater is frequently contaminated with several organic compounds such as dyes, which are the most common ones [1]. The presence of dyes in the environment, which results from their release along with industrial wastewater, increases the biotoxicity and carcinogenicity effects in humans. Furthermore, dyes are usually poorly biodegradable or recalcitrant under normal conditions due to their complex structure and physical properties (poor solubility). Specifically, methylene blue (MB) is used for direct staining and printing in the textile industry, so it is commonly found in thei
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