Piezodialysis
黃意軒 49940050
一、原理說明
A membrane or, more properly, a semipermeable membrane, is a thin layer of
material capable of separating substances when a driving force is applied across
the membrane. Once considered a viable technology only for desalination,
membrane processes are increasingly employed for removal of bacteria
and other microorganisms, particulate material, and natural organic material,
which can impart color, tastes, and odors to the water and react with
disinfectants to form disinfection byproducts (DBP). As advancements are made
in membrane production and module design, capital and operating costs
continue to decline.
When hydraulic pressure is applied to one surface of an ion exchange membrane
immersed in a salt solution, water permeates through the membrane due to
exclusion of salt by the membrane, and salt rejection increases with increasing
fixed ion concentration of the membrane. However, the flux of water through the
membrane is extremely low though the flux changes slightly with species of ion
exchanged ions due to differences in their hydration.The transport of ions
through a mosaic ion exchange membrane in the presence of a concentration
gradient of salt.Also,
piezodialysis using a mosaic ion exchange membrane may possibily desalinate
saline water with a high water flux and high salt rejection.
二、應用/用途
電透析離子交換薄膜應用在飲用水的製造、食品加工製程、製藥工業
及纖維工業等。近期有機酸的製造更利用雙性離子交換薄膜配合電透
析，直接由其鹽類中取得，而這樣的技術甚至使用於維他命Ｃ的萃取
而製成生物可分解塑膠，以配合目前環境保護意識的需求。
三、參考文處
1. Toshikatsu Sata，Ion Exchange Membranes: Preparation, Characterization,
Modification and Application，Chapter6.5
2. Membrane filtration
3. 張淑貞，探討電透析技術於海水淡化處理的特點及其處理效能，p.38