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Trixie Ruth Nunez DY

Doctor Candidate in Chemical and Biomolecular Engineering (Nanotechnology Concentration)

Supervisor: Prof. King Lun YEUNG

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Research Topic

Pulsed Electric Field (PEF) Microreactor for Water Disinfection

Abstract

“Worldwide, one out of every five deaths of children under five is due to a water-related disease.” (The Water Project, 2016). Most, if not all, of these diseases are due to presence of bacteria and virus from lack of proper water sanitation. The need for clean water in drinking and food production cannot be overstated given the growing human population. Hence, clean water research must be a prime benefactor of new and cutting edge technologies.

The use of pulsed electric field (PEF) to inactivate bacterial cells via electroporation were proven to be effective by several studies (Fox M. B., et al., 2006). This technology was used in designing point-of-use water disinfection devices that can achieve up to 98% bacterial reduction in a 10-minute treatment of a 100-volt PEF (Lee, 2014; Hung, 2015). This same study suggested that lowering the gap distance between electrodes to nanoscale will increase the electric field and lower the exposure time.

In the early years of 2000, technological advances allowing miniaturization of materials and processes gave way to PEF microreactors for cell electroporation. PEF microreactors provide advantages such as (a) fast heat removal due to higher surface to volume ratio, (b) lower voltage requirement and better control of electric pulse—both brought by the small electrode distance, and (c) in situ visualization of electroporation because of the use of clear glass wafers as reactor material. However, bringing the technology to microscale also induce problems like (a) electrode damage via electrolysis due to high current densities, (b) contamination of loaded material with degraded electrode components, (c) arcing due to gas formation from the electrolysis of water, and (d) low throughput. (Fox M. B., et al., 2006)

Understanding the micro phenomena during operation is vital in developing microreactor designs that efficiently serve their purpose. It is the desire of this study to develop a novel flow-through water disinfection device by investigating on the effects of different design and operating parameters on the electric field density distribution in a microreactor utilizing nano-sized electrodes. Validations shall be done through computer simulations and actual experiments.

Journal Publication


Zhan, Ning; Dy, Trixie Ruth Nunez; Kwan, Joseph Kai Cho; Yeung, King Lun, "Bactericidal activity and design of low voltage Pulsed-Electric Field (PEF) device for water disinfection", (2017)