Estudio del comportamiento electroquímico del Telurio en medio alcalino.
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Date
2024
Journal Title
Journal ISSN
Volume Title
Publisher
Universidad de Concepción
Abstract
Esta memoria de título se centró en el estudio del comportamiento electroquímico del ion telurito en medio alcalino, con el objetivo de evaluar preliminarmente la electrodepositación de telurio (Te) a partir de los parámetros cinéticos obtenidos. Para ello se utilizó una solución sintética de telurito a distintas concentraciones y pH, y además se evaluó el efecto de la presencia de selenio (Se). El estudio se llevó a cabo utilizando voltametría lineal sobre electrodo fijo y rotatorio, así como cronopotenciometrías para la obtención de depósitos masivos de Te.
En las pruebas de voltametria lineal sobre electrodo fijo, se identificaron los potenciales de reducción del ion telurito a telurio metálico y de este último a ditelururo bajo las diversas condiciones experimentales evaluadas. Además, se comprobó que la presencia de Se no tendría un efecto significativo sobre el comportamiento electroquímico del Te, dado que la cinética de reducción del Se es más lenta en comparación con la del Te. En las pruebas de voltametría lineal sobre electrodo de disco rotatorio de platino (EDR), se verificó la relación de Levich entre la corriente límite y la velocidad de rotación, obteniéndose un coeficiente de difusión para el ion telurito de 1.69×10-7 cm2/s a 25 °C, a un valor de pH de 14.4 y una concentración de 0.5 g/L de Te.
Finalmente, las pruebas de cronopotenciometría permitieron obtener depósitos masivos de Te a densidades de corriente de 2.22 mA/cm2 y 3.33 mA/cm2, con eficiencias de corriente del 87% y 82%, respectivamente.
Los resultados obtenidos, tanto en las pruebas de voltametría lineal como en las de cronopotenciometrías, contribuyen a la definición de las condiciones experimentales para el diseño de un proceso de electroobtención de Te metálico en medio alcalino.
This study focused on the study of the electrochemical behavior of the tellurite ion in an alkaline medium, with the objective of preliminarily evaluating the electrodepositing of tellurium (Te) based on the kinetic parameters obtained. For this purpose, a synthetic tellurite solution at different concentrations and pH levels was used, and the effect of the presence of selenium (Se) was also evaluated. The study utilized linear voltammetry on both stationary and rotating electrodes, as well as chronopotentiometry to obtain bulk tellurium deposits. In the linear voltammetry tests on the stationary electrode, the reduction potentials of the tellurite ion to metallic tellurium and from tellurium to ditelluride were identified for the different experimental conditions evaluated. Additionally, results indicated that the presence of Se did not have a significant effect on the electrochemical behavior of Te, given that the reduction kinetics of Se are slower compared to those of Te. In the linear voltammetry tests on the platinum rotating disk electrode (RDE), the Levich relationship between the limiting current and the rotation speed was verified, yielding a diffusion coefficient for the tellurite ion of 1.69×10-7 cm2/s at 25 °C, at a pH value of 14.4 and a concentration of 0.5 g/L of Te. Finally, in the chronopotentiometry tests, bulk Te deposits were obtained at current densities of 2.22 mA/cm2 and 3.33 mA/cm2, with current efficiencies of 87% and 82%, respectively. The results obtained, both from the linear voltammetry tests and the chronopotentiometry tests, contribute to defining the experimental conditions for designing a process for the electrowinning of metallic Te in an alkaline medium. e apparent RV variations mimicking planetary signals. This work demonstrates the effectiveness of simultaneous RV and activity tracer modeling in distinguishing planetary signals from stellar noise. Future observations with more precise spectrographs, such as ESPRESSO, may provide further clarity, but currently, our models favor the presence of three planets in the GJ581 system.
This study focused on the study of the electrochemical behavior of the tellurite ion in an alkaline medium, with the objective of preliminarily evaluating the electrodepositing of tellurium (Te) based on the kinetic parameters obtained. For this purpose, a synthetic tellurite solution at different concentrations and pH levels was used, and the effect of the presence of selenium (Se) was also evaluated. The study utilized linear voltammetry on both stationary and rotating electrodes, as well as chronopotentiometry to obtain bulk tellurium deposits. In the linear voltammetry tests on the stationary electrode, the reduction potentials of the tellurite ion to metallic tellurium and from tellurium to ditelluride were identified for the different experimental conditions evaluated. Additionally, results indicated that the presence of Se did not have a significant effect on the electrochemical behavior of Te, given that the reduction kinetics of Se are slower compared to those of Te. In the linear voltammetry tests on the platinum rotating disk electrode (RDE), the Levich relationship between the limiting current and the rotation speed was verified, yielding a diffusion coefficient for the tellurite ion of 1.69×10-7 cm2/s at 25 °C, at a pH value of 14.4 and a concentration of 0.5 g/L of Te. Finally, in the chronopotentiometry tests, bulk Te deposits were obtained at current densities of 2.22 mA/cm2 and 3.33 mA/cm2, with current efficiencies of 87% and 82%, respectively. The results obtained, both from the linear voltammetry tests and the chronopotentiometry tests, contribute to defining the experimental conditions for designing a process for the electrowinning of metallic Te in an alkaline medium. e apparent RV variations mimicking planetary signals. This work demonstrates the effectiveness of simultaneous RV and activity tracer modeling in distinguishing planetary signals from stellar noise. Future observations with more precise spectrographs, such as ESPRESSO, may provide further clarity, but currently, our models favor the presence of three planets in the GJ581 system.
Description
Tesis presentada para optar al Título profesional de Ingeniero Civil Metalúrgico
Keywords
Telurio, Electroquímica, Análisis electroquímico