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Fukuda, Hiroki

University of British Columbia

The increasing burden of organic wastes and the need for sustainable waste management have driven the exploration of technologies for converting waste into valuable biochemicals. Medium-chain fatty acids (MCFAs), derived from organic wastes, offer significant potential due to their wide range of industrial applications. This thesis investigates the development and optimization of supported liquid membranes (SLMs) for the selective recovery of MCFAs from organic waste streams. To tackle these challenges, the research focuses on the selective recovery of MCFAs using SLMs. Synthetic organic waste streams were utilized to study the impact of parameters such as partition coefficients and operating temperatures on MCFA recovery efficiency and selectivity. The findings show that SLMs can achieve high recovery rates and selectivity for MCFAs while minimizing the transfer of short-chain fatty acids (SCFAs) and other solvents, establishing a basis for optimizing SLM properties. To ensure sustained membrane performance, a method for real-time, non-destructive monitoring of SLM degradation using electrochemical impedance spectroscopy (EIS) is introduced. This approach provides insights into structural changes in SLMs over time and correlates these changes with performance metrics. EIS is validated as a tool for diagnosing membrane integrity and predicting degradation before significant failure. A comprehensive mass transfer model is developed to account for various degradation stages of SLMs, incorporating structural parameters obtained via EIS. The model predicts mass transfer dynamics for both intact and degraded membranes, highlighting the importance of maintaining an optimal effective area and thickness of SLMs to sustain high recovery rates and selectivity. To enhance the practical application of SLMs, stability improvements are achieved through tailored thin polymeric layers via interfacial polymerization. This method creates a dense, thin polymeric barrier on the SLM surface, improving membrane stability without compromising MCFA transfer rates. Optimal conditions for interfacial polymerization are identified, leading to SLMs with enhanced stability and long-term applications. Overall, this thesis advances SLM technology for efficient and sustainable MCFA recovery, integrating novel monitoring techniques, comprehensive mass transfer models, and innovative fabrication methods. The findings support developing scalable processes for resource recovery, promoting environmental sustainability and economic viability.

Text

2024-09-19

Attribution-NonCommercial-NoDerivatives 4.0 International

http://hdl.handle.net/2429/89267

Civil Engineering

University of British Columbia

UBCV

http://creativecommons.org/licenses/by-nc-nd/4.0/