Catalytic membrane based advanced oxidation processes for micropollutant removal

Abstract

Given the wide spread of organic micropollutants (MPs) in our surface waters and their toxicities, MPs pose a significant threat, not only to aquatic organisms but also to human beings. In this thesis, catalytic membranes, which can successfully integrate membrane separation and sulfate radicals-based advanced oxidation processes (SR-AOPs) are developed and then immediately applied to treat water streams containing organic MPs. Indeed, the membrane is very suitable as a substrate for required small-sized catalysts, avoiding the difficulties of reusing and recycling them. Meanwhile, through activating the oxidants by the catalysts embedded within the membrane structure, the reactive species generated can degrade MPs when the solution passes through the membrane structure. In this case, not only the MP concentrations in the permeate are reduced but also the rejected MPs can be degraded, preventing the formation of the highly concentrated retentate. This thesis highlights the possibility of utilizing SR-AOPs-based catalytic membranes to treat MPs. Based on the position where the catalysts are introduced, different fabrication methods are demonstrated, which can be found in Chapter 2 and 5. Meanwhile, the significant roles of the residence time (Chapter 2), pH (Chapter 3), and concentration polarization (Chapter 4) in the SR-AOPs-based membrane processes are also revealed. To further push forward the application of the SR-AOPs-based membrane, the possible future work is discussed in Chapter 6 and more relevant work can be done by exploring the effects of complex water matrices, upscaling with hollow fiber geometry, and developing new types of membranes. With the development of catalytic membranes and a good understanding of the AOPs-coupled membrane process, the combination of membrane separation and AOPs can significantly improve the quality of the wastewater, possibly helping to alleviate the global shortage of water resources.