Advanced Catalytic Membrane Characterisation and Gas Permeation Properties for Enhanced Ethyl Lactate Conversion
- 1 Center for Process Integration and Membrane Technology, School of Engineering, the Robert Gordon University, Aberdeen, UK
- 2 Center for Process Integration and Membrane Technology, School of Engineering, the Robert Gordon University, Aberdeen, UK
- 3 Center for Process Integration and Membrane Technology, School of Engineering, the Robert Gordon University, Aberdeen, UK
- 4 Center for Process Integration and Membrane Technology, School of Engineering, the Robert Gordon University, Aberdeen, UK
Abstract
In this work, membrane evaluation, gas permeation properties and characterisation have been presented. A silica composite membrane was prepared, characterized and used for the permeation tests with four carrier gases to determine the most suitable carrier gas for enhancing the analysis of esterification product with gas chromatograph. The carrier gases used for the permeation tests were carbon dioxide (CO 2 ), argon (Ar), helium (He) and nitrogen (N 2 ). The permeation analysis was carried out between the gauge pressure range of 0.10 - 1.00 bar and temperature of 60 ℃ . The gas flow rate was found to increase with respect to gauge pressure. The order of the gas flow rate with respect to the gauge pressure was Ar > CO 2 > He > N 2 . The surface morphology and elemental composition of the membrane were analysed using scanning electron microscopy coupled with energy dispersive analysis of x-ray (the Zeiss EVO LS10). The SEM results exhibited a defect-free surface while the EDAX results identified different elements on the spectra including titanium (Ti), silicon (Si) and oxygen (O). Liquid nitrogen adsorption method (Quantachrome 2013 model) was used for the surface area and pore size distribution analysis. The Brunauer-Emmette-Teller (BET) surface area results of the 5 th and 6 th dip-coated membranes were 1.497 and 0.253 m 2 /g respectively, while the Barrette-Joyner-Halender (BJH) curves gave a pore size of 4.184 and 4.180 nm respectively for the 5 th and 6 th dip-coated membranes indicating a mesoporous structure. The BET curve exhibited a type IV isotherm. The BJH curve of the 6 th dip-coated membrane showed a significant reduction in flow rate after the modification process. The membrane recorded a permeance in the range of to . The permeance relationship with the inverse square root of the gas molecular weight showed a linear proportionality with the flow of carrier gases confirming Knudsen flow mechanism of gas transport.
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