기계공학부 구성원들의 많은 관심과 참여 부탁드립니다.

[The link to the lecture] [Posting duration: 4/16 ~ 4/26]

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▣ Title: Physicochemical Hydrodynamics for Engineering Better Electro-membrane Processes

▣ Speaker: Rhokyun Kwak (Assistant Professor)

▣ Affiliation: Dept. of Mechanical Engineering, Hanyang University

▣ Date: 2021. 4. 23.(Fri) 13:00

▣ Venue: Online(Zoom)

▣ Host: Prof. Jongsup Hong

▣ Abstract

Electrodialysis(ED) is one of the membrane-based desalination processes utilizing ion exchange membranes and electricity. Although ED has important advantages such as scalability and portability, it becomes a niche technology with lower salt removal than other desalination methods. Previous research have tried to improve membranes’ performance, but the technology of ion exchange membrane is often considered mature (96–99% ion selectivity), and it is unlikely to produce any further improvement of ED process. In this talk, ED technology will be revisited with transport phenomena, i.e. ion concentration polarization (ICP) and electroconvection. Departing from previous focuses on membranes, we will explore these phenomena between the membranes, and describe how this opens the door for enhancing salt removal. The focus will be mainly on two subjects: First, a miniaturized ED platform will be presented, which can visualize in situ concentration profiles and fluid flows. This allows us to characterize ICP and electroconvection in ED, and to verify the possible improvement of salt removal with electro convection. At a second, a novel desalination process−ICP desalination−will be introduced by conducting only cation (or anion) with only cation (or anion) exchange membranes; conventional ED removes one pair of cation and anion simultaneously with both cation and anion exchange membranes. In this new method, we will demonstrate that such unipolar ion conduction with ICP is enough to remove salts, and conspires with salts’ inherent asymmetry (e.g. diffusivities of NaCl: DNa+=1.33, DCl- =2.03 [10-9m2s-1]) to enhance salt removal up to 20% than conventional ED. In parallel, a brief overview will be offered of other research efforts utilizing ICP and electroconvection.