https://ris.utwente.nl/ws/files/6775659/Witte96phase.pdf

Phase-Separation Processes in Polymer-Solutions in Relation to Membrane Formation

Membrane-based gas separation

Two of the greatest challenges facing the 21st century involve providing sustainable supplies of clean water and energy, two highly interrelated resources, at affordable costs. Membrane technology is expected to continue to dominate the water purifica- tion technologies owing to its energy efficiency. However, there is a need for improved membranes that have higher flux, are more selective, are less prone to various types of fouling, and are more resistant to the chemical environment, especially chlorine, of these processes. This article summarizes the nature of the global water problem and reviews the state of the art of membrane technology. Existing deficiencies of current membranes and the opportunities to resolve them with innovative polymer chemistry and physics are identified. Extensive background is provided to help the reader understand the fundamental issues involved. V C 2010 Wiley Periodi- cals, Inc. J Polym Sci Part B: Polym Phys 48: 1685-1718, 2010

Water Purification by Membranes: The Role of Polymer Science

https://academiccommons.columbia.edu/doi/10.7916/D8708CCQ/download

Relating performance of thin-film composite forward osmosis membranes to support layer formation and structure

Pressure retarded osmosis has the potential to produce renewable energy from natural salinity gradients. This work presents the fabrication of thin-film composite membranes customized for high performance in pressure retarded osmosis. We also present the development of a theoretical model to predict the water flux in pressure retarded osmosis, from which we can predict the power density that can be achieved by a membrane. The model is the first to incorporate external concentration polarization, a performance limiting phenomenon that becomes significant for high-performance membranes. The fabricated membranes consist of a selective polyamide layer formed by interfacial polymerization on top of a polysulfone support layer made by phase separation. The highly porous support layer (structural parameter S = 349 μm), which minimizes internal concentration polarization, allows the transport properties of the active layer to be customized to enhance PRO performance. It is shown that a hand-cast membrane that bal...

/pdf/thin-film-composite-pressure-retarded-osmosis-membranes-for-2tpf45bjdv.pdf

Thin-Film Composite Pressure Retarded Osmosis Membranes for Sustainable Power Generation from Salinity Gradients

Pervaporation is carried out primarily with homogeneous membranes. An improvement in permeation rate can be achieved by using asymmetric or composite membranes. In order to maintain a high selectivity, very dense top layers are needed. The formation of asymmetric pervaporation membranes will be discussed in terms of the model proposed by our group: formation of the top layer by gelation; formation of the porous sublayer by liquid-liquid phase separation followed by gelation of the concentrated polymer phase. To obtain very dense top layers the following factors are important: the ratio of nonsolvent inflow and solvent outflow, polymer concentration, location of the liquid-liquid demixing gap, and location of the gel region. Asymmetric membranes have been prepared by varying these factors, and the obtained membranes have been tested on ethanol/water mixtures.

/pdf/a-rationale-for-the-preparation-of-asymmetric-pervaporation-3mlvel8i6t.pdf

J. Oude Hendrikman

Papers

A rationale for the preparation of asymmetric pervaporation membranes