Capture of Carbon Dioxide in Lamellar Phase Liquid Crystals
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One of the most important environmental concerns the earth faces today is the release of greenhouse gases and other gases that accumulate in the atmosphere. Among these gases, carbon dioxide is one of the most abundant ones responsible for the greenhouse effect. When looking at large scale fossil fuel emissions, the only technology capable of reducing the CO2 emissions today is capture and storage of CO2 (CCS). The main issue with this technology is the high energy consumption in the regeneration of the solvent applied. Extensive work and resources are put into research and development of this technology. In this study, a nonionic triblock copolymer commercially available as a Pluronic called L92 was modified through a two-step reaction synthesis to achieve terminal amine groups. The amine end groups are able to chemically react with CO2, and the reacted end groups are also able to physically absorb CO2 in a subsequent absorption step. The quality of the modified Pluronic was tested through analyses such as Thermogravimetric analysis and a fluorescamine assay. The thermogravimetric analysis showed that the modified Pluronic had a high purity for all produced batches, between 95-99wt% pure polymer. The fluorescamine assay was conducted to quantify the terminal amine groups. The yields of amine groups were variable, between 10-47% for the batches produced. Due to this, a batch-to-batch reproducibility could not be calculated. The main purpose of the study was to see if a Pluronic-amine system in 70wt% double distilled water was able to absorb more CO2 than the Pluronic systems investigated earlier by Sandra Rodríguez Fabià and Petr Patzelt. An 80.9 g sample of 70wt% Pluronic-amine was injected CO2 through a multistage program in a CPA202 calorimeter. For some reason, the stirrer could not be used during the program for this sample. The total amine loading of this sample was 4.2 g CO2/kg solvent, which is worse than the reference sample of 70wt% unmodified L92. This sample had a total CO2 loading of 12.5 g CO2/kg solvent. The Pluronic-amine sample did also have a lower loading of CO2 when compared to the systems investigated by Sandra Rodríguez Fabià and Petr Patzelt. This was probably due to unreacted terminal amine groups since the injected CO2 could not be evenly spread throughout the sample. In addition to the CO2 capture experiment, experiments such as pulse field gradient diffusion experiments in a low field-NMR and rheological experiments have been conducted on L92-amine 70wt%. The rheological properties of the modified Pluronic were investigated before and after the injection of CO2 and did not seem to change notably due to the poor loading. The PFG diffusion experiment was only performed on L92-amine 70wt% before CO2 injection. Compared to the reference sample of L92 70wt%, the L92-amine sample seemed to have a more gradual phase transition happening already at 35°C. The reference sample seemed to have a phase transition happening at 45°C.