Polycarbonates, membrane technology

At the Eotvos Lorand University - Department of Chemical Technology and Environmental Chemistry, a coupled Eulerian photochemical reaction-transport model and a detailed ozone dry-deposition model for the investigation of ozone fluxes over Hungary have been developed and are used in collaboration with Leeds University of the UK. As part of a research project with Ghent University, aerosol samples were collected using several filter-based devices (Nuclepore polycarbonate membrane. Teflon membrane and quartz fibre filters) over... 

Speciation of airborne chromium also has been investigated. Alkaline extraction of polycarbonate membrane filters was used to leach chromium which was subsequently determined by CFAAS. The National Institute of Standards and Technology has a standard reference material (SRM) 2584 - Trace Elements in Indoor Dust. Chromium in this SRM was successfully determined using high-resolution ICP-MS (Yu et al. 

The formation of open and porous structures with extremely large surface area is of high technological significance, because this structure type is very suitable for electrodes in many electrochemical devices, such as fuel cells, batteries and sensors [1,2], and in catalysis applications [3]. The template-directed synthesis method is most commonly used for the preparation of such electrodes. This method is based on a deposition of desired materials in interstitial spaces of disposable hard template. When interstitial spaces of template are filled by deposited material, the template is removed by combustion or etching, and then the deposited material with the replica structure of the template is obtained [4, 5]. The most often used hard templates are porous polycarbonate membranes [6, 7], anodic alumina membrane [8-10], colloidal crystals [11, 12], echinoid skeletal stractures [13], and polystyrene spheres [14, 15]. 

Since the early 1980s, membrane technology has advanced rapidly and continues to advance. In addition to cellulose acetate and polysulfone, the polymers used in making gas separation membranes include polyimides, polyamides, polyaramid, polydimethylsiloxane, silicon polycarbonate, neoprene, silicone rubber, and others. Today membranes can be designed to withstand a 2,000 psi pressure differential. Membranes used in hydrogen or carbon dioxide applications operate at temperatures up to 200°F, while those used in solvent applications can operate at temperatures up to about 400°F (Baker, 1985). 

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