William H. Van Geertruyden

Evaluation of Nano-porous Alumina Membranes for Hemodialysis Application

Globally, kidney failure has consistently been a major health problem. The number of patients suffering from kidney failure is radically increasing. Some studies forecast an exponential growth in the number of kidney failure patients during the coming years. This emphasizes the importance of hemodialysis (HD) membranes. Current dialysis membranes (cellulose based and synthetic polymer membranes) have irregular pore shapes and sizes, nonuniform pore distribution and limited reusable capability, which leads to low efficiency of toxin removal. New alumina membranes with uniform, controllable and well-structured nanoscale pores, channeled pores aligned perpendicular to the membrane plane, high porosity, high thermal and chemical resistance, and better mechanical properties are certainly preferable to currently used membranes. Determination of transport properties of alumina membranes will assist in the development of the alumina membranes for enhancing hemodialysis. Experiments were performed to evaluate hydraulic permeability, solute diffusive permeability, sieving coefficient, and clearance of four solutes (urea, creatinine, Vancomycin, and inulin) for alumina membrane. Based on comparison of these values against those of polyethersulfone (PES) membranes, transport performance of alumina membrane was determined. Hydraulic conductivity of the alumina membrane was approximately twice that of the PES membrane and inulin sieving coefficient for alumina membrane is approximately 21% higher than that for PES membrane. Alumina membrane has higher solute clearances and no albumin leakage, which makes it an effective replacement for current dialysis membranes.

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

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.Copyright