Dialysis, membrane market

Currently, the largest market for membranes is dialysis [56]. Driven by a global increase in the number of patients with end-stage renal disease, dialysis membranes are the leader in terms of surface area and sales revenue. Filtration membranes, ultrafiltration and microfiltration, are the next largest market with combined sales slightly less than that of dialysis membranes. Reverse osmosis and gas separation membranes round out the top five markets. 

Fig. 13.3 Worldwide changes of dialysis membrane properties observed between the years 2000 and 2013. Cellulose-based membranes have lost their importance and market share continuously. They are replaced by synthetic polymers as membrane materials. In addition flux has become an issue either. High-flux membranes, characterized by their ultraflltration coefficient to be UFC => 20 [ml/h-mmHg] are now used in more than two thirds of aU dialysis centers...

Already in 1972, Rhdne Poulenc introduced the first synthetic highly permeable dialysis membrane to the market. This membrane was made from a copolymer, the hydrophobic polyacrylo-nitrile (PAN) and the hydrophilic Na-MethaUyl-sulfonate and was called AN69 [31], Later, a PAN membrane, fabricated exclusively with the PAN-polymer was also offered by ASAHI Kasei Medical in Japan. 

Many industrial yams have specific surface function requirements. For technical yams the market share for composites or coated fabrics is almost 70%. Furthermore, textile applications also can benefit from a special surface treatment in order to improve the water repellency. Capillary membranes for dialysis, however, have totally different requirements enhanced biocompatibility of the membranes is needed.4-6... 

The first widespread use of polymeric membranes for separation applications dates back to the 1960-70S when cellulose acetate was cast for desalination of sea and brackish waters. Since then many new polymeric membranes came to the market for applications extended to ultrafiltration, miciofiltration, dialysis, electrodialysis and gas separations. So far ultrafiltration has been used in more diverse applications than any other membrane processes. The choice of membrane materials is dictated by the application environments, the separation mechanisms by which they operate and economic considerations. Table 1.4 lists some of the common organic polymeric materials for various membrane processes. They include, in addition to cellulose acetate, polyamides. 

Fig. 13.2 The standardly used artificial kidney is a dialyzer that contains more them 10,000 capillary membranes. Blood is guided through these hollow fibers whereas the dieilysis fluid is perfused in an opposite direction. Due to size, reproducibility and perfection of engineering features this type of dialyzer now dominates the dialysis market, mostly as a single-use device, since many years. The annual production capacity for hoUow fibers in 2013 made from different polymers is about 450,000,000 km. This figure is equivalent to three-times the distance between the Earth and the sun...

Membranes from polysulfone dominate the dialysis market since many years. Today, 93 % of all synthetic membranes stem from the parent polyarylethersulfone... 

Production of cuoxam fiber began to decline in the early 1960 s due to the success of synthetic alternatives, outdated equipment and unresolved ecological problems (copper). Research was then focussed successfully on membranes and hollow fibers, which are now the standard materials worldwide for blood dialysis in artificial kidneys. There are only a few production plants serving this important specialty market. 

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