Dialysate diffusive resistance

Thus, the resistance lo mass transfer from ihe bulk feed stream to the bulk dialysate stream can be considered the sum of three terms concentration polarization on the feed and dialysate sides of the membrane and the resistance to diffusion in the membrane itself. For laminar flow devices, these resistaoces... 

A cellulosic membrane with a thic.kness of 20 am is used in hemodialysis to remove urea from blood at 37°C. The concentradon of urea (mol. weight 60 g/mol) in blood is 0.2 g/1 whereas the concentration in the dialysate can be assumed to be negligible. The diffusion coefficient of urea in the cellulosic membrane is 4.5 10 " mVs and the distribution coefficient is 1.5. The mass transfer coefficient at the blood side is 10 m/s and in the dialysate 4 lO tn/s. Calculate the urea flux and indicate the influence of the boundary layer resistance. 

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