Analysis of the effect of saturation gas, solution temperature and concentration on OH radical formation by ultrasonic irradiation for hydrogen production optimization

Abstract

[ES] En el siguiente Trabajo de Fin de Máster se estudian los métodos dosimétricos de Weissler y Fricke para caracterizar la formación de radicales hidroxilo por radiación ultrasónica. Se emplea un transductor de frecuencia simple de 24 kHz con una amplitud al 100% . Se analizan los efectos de diferentes gases disueltos ( argón, nitrógeno y aire), así como el efecto de la temperatura inicial de la solución para analizar su impacto en la formación de radicales OH. También se analiza el efecto de la concentración de la solución. La importancia de una mayor cantidad de radicales OH radica en su impacto para la producción de hidrógeno, ya que dichas partículas pueden interactuar con otras para formar este elemento. La aplicación de ultrasonido a una solución acuosa ciertamente puede conllevar la obtención de hidrógeno, así como mejorar la transferencia de masa en un proceso electroquímico como la electrolisis.

[EN] There is an increasing need to improve the way we obtain and use energy, as with traditional methods planet Earth is becoming less and less habitable. In this regard, the use of hydrogen as a clean energy vector has acquired special relevance nowadays. The production of hydrogen is still expensive and mostly not environmentally friendly; however, it is expected to change in the coming years. One of the areas being investigated for a better and cleaner production of hydrogen is the use of power ultrasound. Although this technology still needs further research, it has already shown promising results. The application of ultrasound to an aqueous solution can certainly lead to synthesize hydrogen, as well as improving mass transfer in an electrochemical process such as electrolysis. In this master’s thesis, Weissler and Fricke dosimetry methods are used in order to characterize the formation of hydroxyl radicals by ultrasonic radiation using a simple 24 kHz frequency ultrasound generator. The importance of a greater quantity of OH radicals lies in their impact in hydrogen production, since these particles can interact with others to form this element. The effects of different dissolved gases (argon, nitrogen and air) are analyzed, as well as the effect of the initial temperature of the solution with the purpose to analyze its impact on the formation of OH radicals. The effect of the concentration of KI with the Weissler dosimetry is also analyzed. It is discussed the most suitable combination of these parameters that enhance OH radical obtention and potentially, hydrogen production. An overview is also provided about the main mechanisms of power ultrasound and its relation to sonochemical production of hydrogen, including an outline of the main dosimetry methods.