Microfluidic Seawater Desalination Device Using Ion Concentration Polarization

  • 羅 浩恩

Student thesis: Master's Thesis

Abstract

The shortage of fresh water is a serious problem in the world today Climate change is leading to vanishing glaciers and reduced precipitation which threatens the water supply of more than one-sixth of the Earth’s population Our device is advantageous because it has a small footprint is portable scalable consumes little power and is highly energy efficient In this study we manufactured a microfluidic seawater desalination device using microelectromechanical systems (MEMS) fabrication techniques and the self-sealed Nafion junction method The ion concentration polarization (ICP) effect occurs at the junction of the micrometer and ion-selective nanometer channels when an electric field is applied across the channels Both cations and anions are enriched at the cathode end and depleted at the anode end of a micro/nanojunction The ion concentration is very low in the depletion zone; thus the depletion zone repels charged particles and no ions can pass through this region This phenomenon is the principle underlying the ICP seawater desalination method used in this experiment In seawater desalination experiments we applied 100 V to the microfluidic chip with One Nafion Junction and introduced a (Q = 5 ?l/min) solution of 0 5 M NaCl and 10–5 M fluorescein into the chip Seawater desalination was observed at the eighth minute after the voltage was applied We discuss the desalination effect of several types of seawater desalination devices These devices exhibit a different design of Nafion nanochannels We could not produce a steady seawater desalination phenomenon The major defect in this experiment lies in the fabrication of the nanochannel We used the self-sealing method to produce micro/nanojunctions in our device; however nonuniform Nafion sediment resulted in unsealed gaps We will discuss these problems in more detail in chapter 5
Date of Award2014 Sep 10
Original languageEnglish
SupervisorRuey-Jen Yang (Supervisor)

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