Process dialysis

Klein, Ward, and Lacey, Membrane Processes—Dialysis and Electro-Dialysis in Rousseau, Handbook of Sepaiation Piocess Technology, Wiley, 1987. 

The membrane separation processes described above represent the bulk of the industrial membrane separation industry. Another process, dialysis, is not used industrially but is used on a large scale in medicine to remove toxic metabolites from blood in patients suffering from kidney failure. The first successful artificial kidney was based on cellophane (regenerated cellulose) dialysis membranes and was developed in 1945. Over the past 50 years, many changes have been made. Currently, most artificial kidneys are based on hollow-fiber membranes formed into modules having a membrane area of about 1 m2 the process is illustrated in Figure 1.7. Blood is circulated through the center of the fiber, while isotonic... 

Dialysis continues to meet certain specialized applications, particularly those in biotechnology and the life sciences. Delicate substances can be separated without damage because dialysis is typically performed under mild conditions ambient temperature, no appreciable transmembrane pressure drop, and low-shear flow. While slow compared with pressure-driven processes, dialysis discriminates small molecules from large ones reliably because the absence of a pressure gradient across the membrane prevents convective flow through defects in the membrane. This advantage is significant for two... 

Electrodialysis In this process, dialysis is carried out under the influence of electric field (figure 3) Potential is applied between the metal screens supporting the membranes. This speeds up the migration of ions to the opposite electrodes. So, dialysis is greatly accelerated. 

The diameter or the radius of the pores is one of the most important geometric characteristic of porous solids. In terms of lUPAC nomenclature, we can have macropores (mean pore size greater than 5 x 10 m), mesopores (between 5 x 10 and 2 x 10 m) and micropores (less than 2 x 10 m). The analysis of species transport inside the porous structure is very important for the detailed description of many unit operations or applications among them we can mention suspension filtration, solid drying and humidification, membrane processes (dialysis, osmosis, gaseous permeation. ), flow in catalytic beds, ion exchange, adsorp-... 

Klein E, Ward RA, and Lacey RE. Membrane processes—dialysis and electrodialysis. In Rousseau RW, Ed. Handbook of Separation Process Technology, John Wiley Sons, Wiley-Interscience, New York, 1987, pp. 954-981. 

Dialysis is not used very often in environmental applications, but a brief discussion is useful to compare it to other types of membrane processes. Dialysis separates solutes of different ionic or molecular size in a solution. The driving force is a difference in solute concentration across the membrane. The smaller ions and molecules will pass through the membrane, but the bigger particles cannot make it through the pore openings. 

The metabolic changes observed in uremia result from the decline in renal excretory function, hence the retention of a legion of substances the loss of vital renal hormones (e.g., erythropoietin) and enzymes (e.g., la-hydroxylase) the effect of the uremic environment on organ function, intermediary metabolism, and transport processes dialysis-related problems and exogenous toxins. 

Ethyl xanthate Ore flotation process Dialysis UV-Vis 0.3 pmol L"1 Flow injection system sodium hydroxide solution as the acceptor stream manual sample filtration not required even for sludge suspension samples [535]... 

This part, on applications, covers the following unit operations 8. Evaporation 9. Drying of Process Materials 10. Stage and Continuous Gas-Liquid Separation Processes (humidification, absorption) 11. Vapor-Liquid Separation Processes (distillation) 12. Liquid—Liquid and Fluid-Solid Separation Processes (adsorption, ion exchange, extraction, leaching, crystallization) 13. Membrane Separation Processes (dialysis, gas separation, reverse osmosis, ultrafiltration) 14. Mechanical-Physical Separation Processes (filtration, settling, centrifugal separation, mechanical size reduction). 

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