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Electrodialysis and Reverse Osmosis as a Regeneration System for Hemofiltrate
Author(s) -
Hintzen K.,
Stiller S.,
Brunner H.,
Rautenbach R.,
Mann H.
Publication year - 1983
Publication title -
artificial organs
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.684
H-Index - 76
eISSN - 1525-1594
pISSN - 0160-564X
DOI - 10.1111/j.1525-1594.1983.tb04183.x
Subject(s) - electrodialysis , reverse osmosis , chemistry , urea , dialysis , chromatography , electrolyte , regeneration (biology) , adsorption , osmosis , membrane , ion exchange , chemical engineering , process engineering , ion , surgery , engineering , biochemistry , organic chemistry , electrode , medicine , biology , microbiology and biotechnology
The separation of urea from the hemofiltrate (or from spent dialysis fluid) must be considered the critical step in all regeneration systems. A promising solution for this problem is the combination of electrodialysis and reverse osmosis. A mathematical simulation of the process and in vitro experiments have been carried out in order to determine operating conditions and design specifications. The experiments confirmed the predicted performance of the regeneration system with respect to the separation of urea and the recovery of electrolytes. As expected, some ionic toxins, such as uric acid, and some middle molecules are recovered also. These substances, however, can be easily removed by a small adsorption cartridge. A combination of ED and RO is a promising solution for the regeneration of hemofiltrate. The separation of neutral uremic toxins, such as urea and creatinine, and the recovery of water and electrolytes are satisfactory. Ionic toxins such as uric acid and some middle molecules will be recovered, i.e., not separated to a certain degree. These substances, however, can be easily separated by adsorption. Trivalent ions like phosphate will be partly separated by the regeneration system, because in ED their rate of transport is lower than that of mono and bivalent ions. The experiments indicate that the ED unit has to be optimized. It would need ˜ 5.7 m 2 of membrane area in order to achieve the desired removal. It could be demonstrated, however, that with improved flow conditions in the ED unit, a membrane area of ˜ 1 m 2 may be sufficient. A detailed flow diagram of the complete regeneration system is shown in Fig. 9. The ED‐RO system in principle can also be used for regeneration of dialysate.