# Exploring Nanofiltration for Transport of Small Molecular Species for Application in Artificial Kidney Devices to Treat End-Stage Kidney Disease

## TL;DR

This study explores nanofiltration for separating small molecules like glucose and urea, aiming to improve artificial kidney devices for treating kidney failure.

## Contribution

The study identifies key operational and feed conditions affecting nanofiltration performance for glucose and urea separation under physiological conditions.

## Key findings

- Glucose rejection increased significantly above 20 psi, while urea rejection remained stable.
- Divalent ions were more strongly rejected than monovalent ions and were more affected by feed conditions.
- Temperature slightly increased flux but decreased divalent ion rejection.

## Abstract

End-stage renal disease occurs when there is permanent loss of the kidney’s ability to filter toxins from the blood. Due to the limited number of transplants, dialysis is currently the most common treatment, but it significantly limits a patient’s lifestyle and has significant side effects. One solution is an artificial kidney, but significant challenges remain in its development. One challenge is the separation of glucose from urea. Nanofiltration is ideal for this separation; however, there is little understanding of the important parameters for this separation under physiological conditions. In this study, operating parameters (pressure and temperature) as well as feed conditions (increased glucose/salt) were explored for their effects on the separation of glucose from urea in six commercial membranes. The rejection of monovalent and divalent ions was also characterized. While increasing pressure increased flux, it had little effect on metabolite rejection, except for glucose, which increased above 20 psi. Increasing temperature led to a slight increase in flux and a slight decrease in the rejection of divalent ions. Glucose rejection was sensitive to feed conditions, while urea rejection was less affected. Divalent ions were rejected more strongly than monovalent ions and were also more affected by feed conditions.