UBC Theses and Dissertations
Development and evaluation of UV-LED coupled ceramic-based photocatalytic membrane reactor for water treatment Sakhaie, Sahar
The increasing water crisis urges the investigation of new methods of water and wastewater treatment. As a green and sustainable method, photocatalytic membranes (PMs) have been investigated in various studies; however, they have not yet been industrialized despite their high efficiency in removing various organic contaminants. Some of the key obstacles to commercialization are (i) shape restrictions of UV lamps, inhibiting their application, (ii) low attachment stability of the photocatalyst (PC) particles, and (iii) initial permeability loss due to PC immobilization and the consequent pore blockage, which imposes operational and capital costs on water treatment plants. In this study, we presented the following solutions to the aforementioned problems to pave the way for practical applications of the PM. First, custom-made photocatalytic membrane reactors (PMRs) were designed, fabricated, and coupled with ultraviolet light-emitting diodes (UV-LEDs) for a thorough evaluation of developed PMs in degrading rhodamine B (RhB) and humic acid (HA) as model pollutants. UV-LEDs, owing to their small size, offer the adaptability to be inserted in membrane systems without further modification. Moreover, their flexibility in the arrangement can be beneficial to uniformly irradiate the PM surface, increasing photocatalytic efficiency. Second, we introduced a novel method of synthesizing a Zr/TiO2 coated silicon carbide-based PM; the developed PM not only showed high HA removal efficiency (up to 86% in 3 h), but also exhibited high stability of the attached PC particles to the membrane surface. Furthermore, different synthesis and operating parameters, namely, Zr molar ratio, PC loading, UV wavelength and irradiance, etc., were examined and optimized. The results indicated that Zr incorporation at 10% molar ratio and 3.8–4.5 mg/cm2 PC loading resulted in the highest removal efficiency. Finally, the method of immobilization was improved to reduce initial pore blockage and enhance long-term permeability; the results showed that the UV-irradiated PM tended to have higher permeability compared with the bare membrane after 1.5 h of operation. In addition, the PM tended to form reversible fouling, which was easily removed during the cleaning step. All the results found in this study reinforce the high potential of the proposed PM for industrial applications.
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