Figure 1. Flat Sheet Test Unit
Figure 2. Single Element Test Unit
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| Membrane Research One of ESEI's primary interests involves the characterization of the nature and performance of various membranes used in drinking water treatment processes. Specific applications of this interest include assessing the efficiency with which a particular choice of membrane is capable of removing selected physical and/or chemical contaminants, such as DBP precursors. A study such as this usually involves acquiring samples of the membrane of interest from the manufacturer, and then conducting laboratory scale filtration tests with them. ESEI is capable of testing membranes of interest on various small scales, in order to “approximate” the performance of a full-scale element in a full-sized water treatment plant. Flat-sheet testing is done with a small portion of membrane material that is cut from a large element and mounted into a testing apparatus capable of holding it in place while challenging it with water at selected hydraulic conditions (pressure, flow, etc.). Single element testing is done using a pilot membrane plant and an individual (but complete) membrane provided by the manufacturer. In either case, samples of permeate, concentrate, and feed water are collected and analyzed for water quality.
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Figure 1. Flat Sheet Test Unit
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Figure 2. Single Element Test Unit
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Then, the surface of the membrane sample itself is studied to determine its morphology (surface charge, etc.) before, during, and after fouling. This morphology can be assessed in one way by conducting a surface analysis using an electrokinetic analyzer (EKA). This apparatus determines the charge density or distribution over a membrane surface at the interface between that surface and the liquid it is in contact with. This measurement provides information on the characteristics of that surface, such as the chemical and/or physical structure and composition of the surface and of the liquid itself. This information then provides insights on what chemical processes are going on at the interface, such as adsorption of a film onto the surface, ionic interactions, and others. These processes are used to deduce mechanisms of the filtration process, such as membrane fouling.
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Figure 3. Electrokinetic Analyzer (EKA)
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Last update: June 20, 2005 |
Maintained by: Drinking Water Research Team |
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Copyright 2005. University of Central Florida |
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