Abstract
Membranes are widely used in industries, agriculture, and medicine fields. Currently, the dominant NIPS method for membrane preparation relies on unsustainable organic solvents, using polyelectrolytes as membrane materials can eliminate the use of these organic solvents. Polyelectrolyte complexes (PECs) are formed in aqueous solutions and have unique properties for membrane preparation. Aqueous phase separation (APS) and hot-pressing methods have been developed to utilize polyelectrolyte solutions and bulk PECs to prepare porous membranes and dense saloplastics. In this thesis, we aim to prepare and functionalize membranes with enzymes in a sustainable fashion.
In Chapter 2, sustainable pH change-induced APS approach was successfully utilized to prepare bio-based PEC membranes using cationic CS and anionic CMC. The influence of pH and concentration of the acetate buffer were studied, and the obtained membranes demonstrated tunable structures and microfiltration performance.
In Chapter 3 and 4, we successfully prepared biocatalytic PEI-PSS membranes via the pH change-induced APS. The effects of casting solution pH were investigated in Chapter 3 and the lysozyme-functionalized membranes showed temperature-dependent enzymatic activities. In Chapter 4, the polyelectrolytes mixing ratio and lysozyme concentration were varied to tune the membrane structure and the enzymatic activity. Besides, the enzyme laccase was successfully introduced and showed the versatility of the APS approach for preparing biocatalytic membranes.
In Chapter 5, biocatalytic membranes were prepared via lysozyme-functionalized saloplastics through salt annealing. PDADMAC-PSS saloplastics were prepared via hot-pressing. Then the changes in KBr concentration were used for annealing and curing the saloplastics where the temporary opening of pores allowed lysozyme loading. This chapter provides new possibilities for sustainable saloplastics as a straightforward method for functionalization.
Chapter 6 discusses the findings and remaining problems in this thesis and gives approaches to solve the problems and improve the membranes’ performance. Moreover, this chapter provides clear outlook for future work.
In Chapter 2, sustainable pH change-induced APS approach was successfully utilized to prepare bio-based PEC membranes using cationic CS and anionic CMC. The influence of pH and concentration of the acetate buffer were studied, and the obtained membranes demonstrated tunable structures and microfiltration performance.
In Chapter 3 and 4, we successfully prepared biocatalytic PEI-PSS membranes via the pH change-induced APS. The effects of casting solution pH were investigated in Chapter 3 and the lysozyme-functionalized membranes showed temperature-dependent enzymatic activities. In Chapter 4, the polyelectrolytes mixing ratio and lysozyme concentration were varied to tune the membrane structure and the enzymatic activity. Besides, the enzyme laccase was successfully introduced and showed the versatility of the APS approach for preparing biocatalytic membranes.
In Chapter 5, biocatalytic membranes were prepared via lysozyme-functionalized saloplastics through salt annealing. PDADMAC-PSS saloplastics were prepared via hot-pressing. Then the changes in KBr concentration were used for annealing and curing the saloplastics where the temporary opening of pores allowed lysozyme loading. This chapter provides new possibilities for sustainable saloplastics as a straightforward method for functionalization.
Chapter 6 discusses the findings and remaining problems in this thesis and gives approaches to solve the problems and improve the membranes’ performance. Moreover, this chapter provides clear outlook for future work.
| Original language | English |
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| Qualification | Doctor of Philosophy |
| Awarding Institution |
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| Supervisors/Advisors |
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| Award date | 16 Jan 2025 |
| Place of Publication | Enschede |
| Publisher | |
| Print ISBNs | 978-90-365-6429-8 |
| Electronic ISBNs | 978-90-365-6430-4 |
| DOIs | |
| Publication status | Published - 16 Jan 2025 |