Pervaporative transport of water across ionic membranes for desalination
Date
2019
Authors
Journal Title
Journal ISSN
Volume Title
Publisher
University of Delaware
Abstract
Water scarcity is one of the major challenges facing mankind that motivates the search for more effective methods to produce pure water. Seawater desalination is a common method for obtaining pure water. One of the desalination processes is pervaporation where water is purified by partial vaporization through a membrane. In this thesis, we investigate the pervaporative transport of water across two ionic membranes (Nafion 115 and an Xergy membrane). Tests were conducted using 60ml acrylic jars partially filled with water whose mouths were tightly sealed by the membrane, both in upright (non-water contact with the membrane) and inverted (water contact with the membrane) configurations. Water transport was measured under ambient pressure and under a vacuum at three different temperatures (22, 30 and 40°C). The effect of convective airflow (at 0.7 and 1.4 m/s) across the membrane surface was also studied under ambient conditions for both ionic membranes. In all cases, the moisture vapor transmission rate (MVTR) was calculated to assess water transport. In addition, MVTR of various concentrations of potassium acetate solutions (20, 40, and 60% PA in water) was also measured. Finally, modeling based on Henry’s law, Fick's law, and Darcy’s law was conducted for both the upright and inverted configurations to gain insight into the underlying transport mechanisms.
Description
Keywords
Pervaporative transport, Water, Ionic membrane, Desalination