Permeability polysulfone membranes

In hemodialysis, blood from the patient flows on one side of a membrane and a specially prepared dialysis solution is fed to the other side. Waste material in the blood such as urea, excess acids, and electrolytes diffuse into the dialysate the blood is then returned to the patient, as shown in Fig. 48. A patient typically undergoes dialysis three times per week in sessions lasting several hours each. Modern dialysis systems combine sophisticated monitoring and control functions to ensure safe operation. Regenerated cellulose was the first material used in hemodialysis membranes because of its biocompatibility and low cost it remains the most popular choice. Subsequently, high-permeability dialysis membranes derived from cellulose esters, modified polysulfone, or polyacrylonitrile copolymers have also gained wide acceptance because of the shorter sessions they make possible. 

Steam sterilization of medical devices Is used In Japan. It has the advantage of facilitating removal of water soluble residues left after membrane manufacturing, but requires that the device be shipped filled with water. Steam sterilization appears to alter the pore structure of hydrophobic membranes, despite the fact that their glass transition temperatures may be quite high, for example, the permeability of polysulfone membranes Is altered above 70°C. Literature Cited... 

Non-celluloslc Membranes. While the development of CA gas permeation membranes can be directly attributed to the development of water desalination membranes, the Invention of modified silicone membranes and polysulfone membranes was more Influenced by the extension of knowledge of transport, sorption and diffusion of gases In polymers (24-27). In principle, rubbery polymers exhibit the highest gas permeabilities at the lowest selectlvitles, and. 

As indicated in Figure 10b, this membrane proved quite easy to clean. In contrast to the polysulfone membranes used in the cell separation step, the spiral ultrafilter showed 100% recovery of hydraulic permeability with a minimum effort to clean (i.e., no extra cleaning steps were ever used). Again, the ease of cleaning is related to both the nature of the process stream to which the unit was exposed, and the properties of the membrane itself. In the enzyme concentration step, solids load was very low (compared to the original cell broth). The membrane itself, on the other hand, exhibits much less tendency to adsorb protein than polysulfone because of the hydrophilic nature of regenerated cellulose. 

Based on the dual-mode transport model, calculate the pure component and mixtures permeability of CO2 and CH4 using a polysulfone membrane. The gas pressure is 10 atm for each component. 

A commercial composite polyamide/polysulfone membrane for reverse osmosis (HR95) from DSS (Denmark). The characteristic membrane parameters, such as total thickness, hydraulic permeability, and rejection, are Ax = (165 5) pm, = 8.5 x 10 m/(sec Pa), and a = 99.5%, respectively (Jonsson and Benavente 1992). 

A hollow fibber polysulfone membrane with an effective area of 0.42 m was used throughout this study. The internal diameter of the fibers is 0.5 mm. The membrane molecular weight cut-off is 500 kDalton to completely retain suspended solids, supracolloidal material, and micro-organisms. The hydraulic permeability of the membrane at 28°C is 875 L/m h bar. 

Reid B D, Ruiz-Trevino F A, Musselman I H, Balkus Jr K J, Ferrari P (2001) Gas Permeability Properties of Polysulfone Membranes Containing the Mesoporous Molecular Sieve MCM-41. Chemistry of materials 13 2366-2373. 

MF and UF membranes can be polymeric or inorganic. Membrane materials must be chemical resistant to both feed and cleaning solutions, mechanically and thermally stable, and characterized by high selectivity and permeability. Polysulfone (PS), polyethersulfone (PES), polyamide (PA), cellulose acetate (CA), polyacrylonitrile (PAN), polytetrafluoroethylene (PTFE), poly(vinylidene F ) (PVDF) and polypropylene (PP) are typical materials commonly used to cast the membrane. Alumina, zirconia and ceramic materials are usually used as inorganic materials. 

We have prepared pH/temperature-sensitive polymer membranes by grafting AAc or NIPAAm or AAc and NIPAAm on the surface of polyamide and polysulfone membranes, utilizing plasma and UV radiation teehniques. The structure of the graft chain was confirmed by XPS and ATR-FTIR spectra. Through this study, we investigated the morphology and permeability of the riboflavin of the unmodified and modified polymer membranes. AAe or NIPAAm or AAc and NIPAAm-grafted polymer membranes showed the pH or temperature and pH-dependent permeation behaviours of riboflavin, respectively. 

There are several kinds of membrane characterization, depending on the information and knowledge required (morphological structure, chemical properties, permeability, selectivity, etc.). In this case, we focused on the morphological characterization of polysulfone membranes by using the SEM technique. 

A commercial composite polyamide/polysulfone membrane for reverse osmosis (HR95) and an ultrafiltration polysulfone membrane (PS-Uf) similar to the porous support of the composite membrane, both from DDSS (Denmark). Both membranes present similar thickness, Axm = 165 + 5 pm and the hydraulic permeability is Lp = 10.0 x 10 °m/s Pa and Lp =8.5 x 10 m/ s Pa, for the PS-Uf and the HR95, respectively, while the rejection coefficient for the reverse osmosis HR95 membrane is = 99.5% [7]. 

Consider the composite "PRISM-type membrane illustrated in Example 6.3.14. For such a polysulfone membrane having a thin coating of silicone rubber, the values of the permeability coefficients through layers A and B for a H2-CO mixture are ... 

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