Analysis of a hollow-fibre artificial kidney performing simultaneous dialysis and ultrafiltration

Two-Dimensional Theoretical Analysis and Experimental Study of Mass Transfer in a Hollow-Fiber Dialysis Module Coupled with Ultrafiltration Operations

This research theoretically and experimentally develops a hollow-fiber dialysis module coupled with ultrafiltration operations by introducing a trans-membrane pressure during the membrane dialysis process, which can be applied to the waste metabolic end products in the human body for improving the dialysis efficiency. The solutes were transported by both diffusion and convection from the concentration driving-force gradient between retentate and dialysate phases across the membrane, compared to the traditional dialysis processes by diffusion only. A two-dimensional modeling of such a dialysis-and-ultrafiltration system in the hollow-fiber dialysis module was formulated and solved using the stream function coupled with the perturbation method to obtain the velocity distributions of retentate and dialysate phases, respectively. The purpose of the present work is to investigate the effect of ultrafiltration on the dialysis rate in the hollow-fiber dialyzer with ultrafiltration operations. A highest level of dialysis rate improvement up to about seven times (say 674.65% under Va=20 mL/min) was found in the module with ultrafiltration rate Vw=10 mL/min and membrane sieving coefficient θ=1, compared to that in the system without operating ultrafiltration. Considerable dialysis rate improvements on mass transfer were obtained by implementing a hollow-fiber dialysis-and-ultrafiltration system, instead of using the hollow-fiber dialyzer without ultrafiltration operation. The experimental runs were carried out under the same operating conditions for the hollow-fiber dialyzers of the two experimental runs with and without ultrafiltration operations for comparisons. A very reasonable prediction by the proposed mathematical model was observed.

A prototype model for renal vasculature and its application in haemodialyser miniaturization

At present, little information and few models are available to describe either renal haemodynamics or the structure of the kidney. By modelling renal haemodynamics, more information about flow behaviour and efficiency can be obtained, thus leading to the modelling of the human kidney and enabling comparisons with dialysis haemodynamics to be made. This paper examines a prototype model of renal vasculature and remarks upon comparisons drawn from data from human kidneys, as an introduction to those interested in replicating the functions of the kidney by using a miniature haemodialyser.

Biochemical engineering of biocatalysts immobilized on cellulosic materials

Complete design of the optimum immobilized biocatalyst seems to still be a matter of the future. To be successful, it would require numerical determination of all significant parameters at each enzyme engineering phase, that is at the design of the carriers, immobilized biocatalysts and immobilized reactors. Future research trends should follow this strategy. For processing, cellulosic materials have been considered carriers that fulfill requests to an example model: they represent a unique family of carriers that cover a broad variety of physical and chemical properties, immobilizing techniques, and immobilized reactors as well. The reason for writing this review article was to test the reliability of such a processing and subsequently, to confront theoretical considerations with practical applications of biocatalysts immobilized on cellulose materials.