Synthesis and topology of the reaction of mercury jarosite in NaOH medium
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In this work, we propose the slow addition of reagents to a Fe2(SO4)3·nH2O solution contained in a one-liter glass reactor, which in turn was immersed in oil in order to improve heat transfer. Hg(NO3)2·H2O was slowly added using different temperature, pH and stirring conditions. The obtained precipitates were vacuum filtered and rinsed with hot distilled water to remove the iron, sulfate and nitrate excess. A total of 11 syntheses were performed, and the obtained products were characterized by dichromatometry, gravimetry, Atomic Absorption Spectroscopy (AAS), X-ray diffraction (XRD) and Scanning Electron Microscopy-Energy Dispersive X-ray Spectroscopy (SEM-EDS), as well as Inductively Coupled Plasma Spectrometry (ICP). Of the syntheses we performed, synthesis number four is the one that presents optimal experimental conditions in order to obtain mercury jarosite: 0.27 mol L–1 Fe2(SO4)3·nH2O, 0.58 mol L–1 Hg(NO3)2·H2O, 93 °C (366 K) and 400 rpm mechanical stirring for 24 h. The synthesized sample has the approximate formula Hg0.4(H3O)0.2Fe2.71(SO4)2.17(OH)4.79(H2O)2.12; 9.59 grams of this compound were obtained. The study on the topology of the reaction of mercury jarosite in alkaline medium (NaOH) was conducted under the following conditions: 0.05 mol L–1 NaOH, pH 12.70, T 30 °C (303 K), d0 38 µm and 500 rpm magnetic stirring. SEM-EDS results indicate that the OH– ions diffuse from the bulk of the solution, through the ash layer, and towards the particle, while the (SO4)2– and Hg2 ions diffuse from an unreacted core towards the solution, which suggests that the kinetic model that best describes the dissolution is that of constant size spherical particles and unreacted core. © GDMB. All rights reserved.
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In this work, we propose the slow addition of reagents to a Fe2(SO4)3·nH2O solution contained in a one-liter glass reactor, which in turn was immersed in oil in order to improve heat transfer. Hg(NO3)2·H2O was slowly added using different temperature, pH and stirring conditions. The obtained precipitates were vacuum filtered and rinsed with hot distilled water to remove the iron, sulfate and nitrate excess. A total of 11 syntheses were performed, and the obtained products were characterized by dichromatometry, gravimetry, Atomic Absorption Spectroscopy (AAS), X-ray diffraction (XRD) and Scanning Electron Microscopy-Energy Dispersive X-ray Spectroscopy (SEM-EDS), as well as Inductively Coupled Plasma Spectrometry (ICP). Of the syntheses we performed, synthesis number four is the one that presents optimal experimental conditions in order to obtain mercury jarosite: 0.27 mol L–1 Fe2(SO4)3·nH2O, 0.58 mol L–1 Hg(NO3)2·H2O, 93 °C (366 K) and 400 rpm mechanical stirring for 24 h. The synthesized sample has the approximate formula Hg0.4(H3O)0.2Fe2.71(SO4)2.17(OH)4.79(H2O)2.12; 9.59 grams of this compound were obtained. The study on the topology of the reaction of mercury jarosite in alkaline medium (NaOH) was conducted under the following conditions: 0.05 mol L–1 NaOH, pH 12.70, T 30 °C (303 K), d0 38 µm and 500 rpm magnetic stirring. SEM-EDS results indicate that the OH– ions diffuse from the bulk of the solution, through the ash layer, and towards the particle, while the (SO4)2– and Hg2%2b ions diffuse from an unreacted core towards the solution, which suggests that the kinetic model that best describes the dissolution is that of constant size spherical particles and unreacted core. © GDMB. All rights reserved.
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Alkaline decomposition; Characterization; Mercury jarosite; Synthesis Alkalinity; Approximation algorithms; Atomic absorption spectrometry; Chemicals removal (water treatment); Energy dispersive spectroscopy; Heat transfer; Inductively coupled plasma; Iron compounds; Mercury (metal); Metallurgy; Scanning electron microscopy; Sodium hydroxide; Sulfur compounds; Synthesis (chemical); Topology; Approximate formulas; Atomic absorption spectroscopy; Energy dispersive X ray spectroscopy; Inductively coupled plasma spectrometry; Jarosites; Mechanical stirring; Optimal experimental conditions; Stirring conditions; Absorption spectroscopy
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