Mass transport in thin supported silica membranes

In this thesis multi-component mass transport in thin supported amorphous silica membranes is discussed. These membranes are micro-porous, with pore diameters smaller than 4Å and show high fluxes for small molecules (such as hydrogen) combined with high selectivities for these molecules with respect to larger ones. The chemical and thermal stability of silica membranes are favourable compared to those of organic membranes. These properties make silica membranes interesting candidates for separation of permanent gases in chemically and thermally aggressive environments. The field of membrane science is briefly introduced, with emphasis on the relevance of inorganic membranes for the chemical process industry. Several aspects of supported amorphous micro-porous silica layers are discussed, followed by the project objectives and thesis outline

The effect of hydrocarbon pollution on polysulfone-based membranes in aqueous separations

This work investigates the influence of hydrocarbon pollution on the performance of desalination membranes with a polysulfone support. Toluene was chosen as the model hydrocarbon compound and permeation measurements were performed on two commercial membranes with a polysulfone support in water saturated with toluene. Over time, the TriSep TS80 membrane under analysis broke down and the delamination of the separation layer was observed. The influence of the polysulfone layer on the membrane deterioration was studied in detail by the use of a model system of a thin polysulfone film on top of a silicon wafer. In situ spectroscopic ellipsometry, and in situ optical microscopy revealed that the non-ideality of the hydrocarbon in water system initiates a dewetting of the polysulfone layer which is the root cause of the membrane failure

Developing teamwork skills beyond cross-cultural barriers: a case study for engineering students in higher education

In 2013, our university has implemented a new educational model that puts team projects at the core of all BSc programmes, requiring that students develop teamwork skills. On top of this, in 2018, our Chemical Science & Engineering BSc has become an English-taught, international programme. In consideration of this challenging transition, we have developed additional training to facilitate students' acquisition of knowledge, skills, tools, and attitudes to aid conscientious intercultural teamwork. For this, it is paramount that students become aware of, and learn to appreciate, differences in the educational and cultural backgrounds of themselves and their peers. Concurrently, students should practice what they have learned and adjust their behaviour when appropriate. In this paper, we share our experiences, best practices, and lessons learned. More specifically, our study: i) explores which factors are key to a successful intercultural team, ii) investigates how diversity in teams can be cherished and used for the benefit of the team, its members, and its goals, and iii) how these teamwork skills can effectively be taught in engineering programmes. Building on this, the paper describes how the new curricular education has been designed, what is taught, and how an inclusive, regardful, and pleasant atmosphere has been created for the intercultural project teams

Synthesis and characterization of polyimide-based mixed matrix membranes for CO2/CH4 separation

El contenido de componentes ácidos en el gas natural crudo es cada vez mayor, lo que hace crucial una necesidad el uso de tecnologías de separación con mayor eficiencia. Se requieren avances significativos en las tecnologías existentes de separación de gases por membrana para producir un sistema de membrana con mayor estabilidad térmica, resistencia a los contaminantes y a la plastificación inducida por el CO2 y así competir con otras tecnologías. Uno de los enfoques más factibles es hacer una membrana de matriz mixta (MMM), que combina materials orgánicos (polímero) con partículas inorgánicas con el objetivo de explotar las ventajas sinérgicas de cada material: alta permeabilidad de los rellenos dispersos, alta selectividad y fácil procesabilidad de los polímeros. El estudio se enfoca en el desarrollo de MMMs para aplicaciones enfocadas a separación de gas natural. En la investigación se usaron polímeros con fracciones constituidas por aromáticos y copolímeros de estructura altamente rígida como el 6FDA (nuevo 6FDA-bisP, 6FDA-ODA y 6FDA-DAM) con nanopartículas que poseen estructuras organometálicas a base de zeolita y zirconio (ZIF-8 CO2-philic UiO-66, Zr-BDC). En este trabajo proporciona una síntesis detallada de MOFs nanométricos, así como un procedimiento de modificación posterior a la síntesis, métodos de fabricación de MMMs, y finalmente estrategias para tener una interacción optimizada de la interfaz. Se presenta una caracterización exhaustiva y sistemática para comprender las morfologías e interacciones de la membrana que incluyen un modelo molecular para entendr su efecto en la separación de gases. Además, se evaluaron los rendimientos de separación de gases utilizando mezclas de gases constituidas principalmente por CO2 y CH4 en varias concentraciones molares, a diferentes presiones de alimentación y temperatura. También se investigó la estabilidad de las MMMs en separacines a alta presión con variantes en parámetros incluyendo la presencia de impurezas de gas natural (por ejemplo, H2S) con el objetivo de imitar un proceso real de separación de membrana. En general, el estudio confirma que con un método apropiado de fabricación de MMMs, así como la selección apropiada del relleno inorgánico para las mejoras deseadas en la membrana, las copolímidas investigadas tienen un enorme potencial para aplicaciones de separación de gases CO2/CH4.<br /

Temperature calibration procedure for thin film substrates for thermo-ellipsometric analysis using melting point standards

Precise and accurate temperature control is pertinent to studying thermally activated processes in thin films. Here, we present a calibration method for the substrate–film interface temperature using spectroscopic ellipsometry. The method is adapted from temperature calibration methods that are well developed for thermogravimetric analysis and differential scanning calorimetry instruments, and is based on probing a transition temperature. Indium, lead, and zinc could be spread on a substrate, and the phase transition of these metals could be detected by a change in the C signal of the ellipsometer. For water, the phase transition could be detected by a loss of signal intensity as a result of light scattering by the ice crystals. The combined approach allowed for construction of a linear calibration curve with an accuracy of 1.3 C or lower over the full temperature range