An Experimental Study of Transport Properties of Ceramic Membranes for Use in Hemodialysis

2008 ◽  
Author(s):  
Zhonping Huang ◽  
Anil C. Attaluri ◽  
Amit Belwalkar ◽  
William Van Geertruyden ◽  
Dayong Gao ◽  
...  
Keyword(s):  
Mass Transfer ◽  
Molecular Weight ◽  
Pore Size ◽  
Pore Distribution ◽  
Hydraulic Permeability ◽  
High Flux ◽  
Convective Mass Transfer ◽  
Diffusive Mass Transfer ◽  
Solute Clearance ◽  
Uniform Pore Size

Hemodialysis (HD) remains the primary treatment modality for the management of renal failure patients. Hemodialysis membranes play an important role in renal replacement therapy (RRT). HD is an extracorporeal blood clean process where the major mass transfer mechanism is diffusion. This therapy is mainly effectual for low molecular weight (LMW) solutes (such as urea and creatinine) removal or clearance for which diffusive mass transfer is a swift process. There is an increase in the removal of middle molecular weight (MMW) solutes (such as β2-microglobulin) when high flux membranes are available. Hemodiafiltration (HDF) is a treatment where the convective mass transfer accolades with diffusive mass transfer to increase the solute clearance efficacy, specifically for MMW solutes. The convective mass transfer is reliant on the amount of fluid exchanged. Toxin removal efficiency of HDF significantly depends on the porosity, pore size, pore distribution and surface area of the membrane [1, 2]. Although newly developed high flux polysulfone membranes have high MMW solute clearance, the non-uniform pore size and pore distribution is the main contributors to the albumin loss. Previous studies by Huang et al.[3], showed that nanoporous alumina sheet membranes have uniform pore size (∼ 10nm), high hydraulic permeability, uniform pore distribution and excellent pore structure with uniform channels. It was predicted that these membranes would have high molecular removal capacity. Therefore, in this study, experiments were performed to generate the data of intrinsic membrane properties such as hydraulic permeability, sieving coefficient and solute diffusive permeability for the alumina tubular membranes. Results were also compared to current polyethersulfone (PES) dialysis membranes.

Effect of Membrane Pore Size and Membrane-Solute Interactions on Lysozyme Ultrafiltration

2006 ◽  
Vol 514-516 ◽  
pp. 1483-1487
Author(s):  
Vitor Magueijo ◽  
Viriato Semião ◽  
Maria Norberta de Pinho
Keyword(s):  
Molecular Weight ◽  
Pore Size ◽  
Pore Radius ◽  
Double Layers ◽  
Hydraulic Permeability ◽  
Average Pore ◽  
Average Pore Radius ◽  
Electric Double Layers ◽  
Membrane Pore ◽  
Cellulose Acetate Membranes

A model based on steric hindrance mechanisms [1] is used to determine the pore sizes of two ultrafiltration (UF) membranes. The lysozyme rejection coefficients of those membranes are predicted through the same model after modification of the pore size and solute radius by taking into account the development of electric double layers. Two asymmetric cellulose acetate membranes M1 and M2 were prepared and characterized. Membrane M1 has an hydraulic permeability of 2.1x10-6 m/s/bar, a molecular weight cut-off (MWCO) of 30,000 Da and an average pore radius of 2.6 nm. Membrane M2 has an hydraulic permeability of 5.9x10-6 m/s/bar, a molecular weight cut-off (MWCO) of 60,000 Da and an average pore radius of 5.3 nm. Aqueous solutions of lysozyme containing a NaCl concentration of 0.1M were ultrafiltrated through membranes M1 and M2. The predicted lysozyme rejections considering the development of electric double layers on the protein and membrane pore surfaces, are in good agreement with the experimental results.

scholarly journals MHD on Convective Mass Transfer in Annular Flow: Catheter Based Drug Release

2021 ◽  
Vol 12 (5) ◽  
pp. 6699-6709
Keyword(s):  
Magnetic Field ◽  
Drug Delivery ◽  
Mass Transfer ◽  
Biomedical Applications ◽  
The Body ◽  
Convective Mass Transfer ◽  
Diffusive Mass Transfer ◽  
Tissue Region ◽  
Physical Phenomena ◽  
The Magnetic Field

In the present study, convective diffusive mass transfer is considered, along with effects of particle drag under the influence of a magnetic field concerning drug delivery in the presence of the catheter. A concentric annular region is created by the presence of a catheter, and the effects of which on mass transfer are considered. A model on the hydrodynamics of the fluid, blood flow, and convective diffusive mass transfer of the species is presented. Here, an attempt is made to analyze a drug delivery method for delivering a drug to a specific site in the body and for this analysis, considered a channel bounded by the tissue region where the drug is targeted. The magnetic field induces pulsatile flow, which affects the mass transfer. The graphs predict that the mass transfer increases from the lumen region to the tissue region. Peclet number and magnetic parameter are the parameters that significantly affect carrying drugs towards the tissue. The results are well agreed with the physical phenomena of the problem as well as many biomedical applications.

Diffusive mass transfer in island films

1978 ◽  
Vol 125 (7) ◽  
pp. 489-525 ◽  
Author(s):  
Ya.E. Geguzin ◽  
Yu.S. Kaganovskii
Keyword(s):  
Mass Transfer ◽  
Diffusive Mass Transfer ◽  
Island Films

Experimental Study of Natural Convective Mass Transfer from Downward Pointing Conical Surfaces in Porous Media

2007 ◽  
Vol 10 (3) ◽  
pp. 277-286 ◽  
Author(s):  
Martin J. Garland ◽  
S. U. Rahman ◽  
K. A. Mahgoub ◽  
Ahmad Nafees
Keyword(s):  
Mass Transfer ◽  
Experimental Study ◽  
Porous Media ◽  
Convective Mass Transfer ◽  
Conical Surfaces

Free Convective Mass Transfer at Isosceles Triangular Surfaces of Varying Inclination

2003 ◽  
Vol 68 (11) ◽  
pp. 2080-2092 ◽  
Author(s):  
Martin Keppert ◽  
Josef Krýsa ◽  
Anthony A. Wragg
Keyword(s):  
Mass Transfer ◽  
Transfer Rate ◽  
Mass Transfer Rate ◽  
Mass Transfer Process ◽  
Sulfate Solution ◽  
Convective Mass Transfer ◽  
Varying Length ◽  
Inclined Surface ◽  
Vertical Case ◽  
Limiting Diffusion Current

The limiting diffusion current technique was used for investigation of free convective mass transfer at down-pointing up-facing isosceles triangular surfaces of varying length and inclination. As the mass transfer process, copper deposition from acidified copper(II) sulfate solution was used. It was found that the mass transfer rate increases with inclination from the vertical to the horizontal position and decreases with length of inclined surface. Correlation equations for 7 angles from 0 to 90° were found. The exponent in the ShL-RaL correlation ranged from 0.247 for the vertical case, indicating laminar flow, to 0.32 for inclinations of 60 to 90°, indicating mixed or turbulent flow. The general correlation ShL = 0.358(RaL sin θ)0.30 for the RaL sin θ range from 7 × 106 to 2 × 1011 and inclination range from 15 to 90° was obtained.

Convective mass transfer around a dissolving bubble

2017 ◽  
Vol 2 (11) ◽  
Author(s):  
Jerome Duplat ◽  
Mathieu Grandemange ◽  
Cedric Poulain
Keyword(s):  
Mass Transfer ◽  
Convective Mass Transfer

scholarly journals Randomised trial on clinical performances and biocompatibility of four high-flux hemodialyzers in two mode treatments: hemodialysis vs post dilution hemodiafiltration

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Marion Morena ◽  
Caroline Creput ◽  
Mouloud Bouzernidj ◽  
Annie Rodriguez ◽  
Lotfi Chalabi ◽  
...  
Keyword(s):  
Primary Outcome ◽  
Randomised Trial ◽  
High Flux ◽  
Β2 Microglobulin ◽  
Inflammatory Parameters ◽  
Large Size ◽  
Significant Difference ◽  
Good Biocompatibility ◽  
Very High ◽  
Solute Clearance

AbstractThis prospective multicenter randomized comparative cross-over trial aimed at evaluating the influence of hemodialysis vs post-dilution hemodiafiltration with high-flux dialyzers in solute clearance and biocompatibility profile. 32 patients were sequentially dialyzed with Leoceed-21HX, Polypure-22S+, Rexsys-27H and VIE-21A. Primary outcome was β2-microglobulin removal. Secondary outcomes were (i) extraction of other uremic solutes (ii) parameters of inflammation and nutrition and (iii) comparative quantification of perdialytic albumin losses (using total ‘TDC’ vs partial ‘PDC’ collection of dialysate). Significant increases in removal rates of β2-microglobulin (84.7 ± 0.8 vs 71.6 ± 0.8 mg/L), myoglobin (65.9 ± 1.3 vs 38.6 ± 1.3 µg/L), free immunoglobulin light chains Kappa (74.9 ± 0.8 vs 55.6 ± 0.8 mg/L), β-trace protein (54.8 ± 1.3 vs 26.8 ± 1.4 mg/L) and orosomucoid (11.0 ± 1.1 vs 6.0 ± 1.1 g/L) but not myostatin (14.8 ± 1.5 vs 13.0 ± 1.5 ng/mL) were observed in HDF compared to HD when pooling all dialyzers. Rexsys and VIE-A use in both HD and HDF subgroups was associated to a better removal of middle/large-size molecules compared to Leoceed and Polypure, except β2-microglobulin for Rexsys. Inflammatory parameters were unchanged between dialyzers without any interaction with dialysis modality. Mean dialysate albumin loss was comparable between TDC and PDC (1.855 vs 1.826 g/session for TDC and PDC respectively). In addition, a significant difference in albumin loss was observed between dialyzers with the highest value (4.5 g/session) observed using Rexsys. Use of all dialyzers was associated with good removals of the large spectrum of uremic toxins tested and good biocompatibility profiles, with an additional gain in removal performances with HDF. Larger surface area, thinner wall and resultant very high ultrafiltration coefficient of Rexsys should be taken into account in its clear performance advantages.

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