What physiological process does dialysis utilize to remove waste products from the blood?

Dialysis uses the physiological process of diffusion to remove waste products from the blood. During dialysis, particularly hemodialysis, blood flows past a semipermeable membrane that separates it from a dialysate solution. Waste products and excess ions in the blood move across the membrane into the dialysate solution, driven by the concentration gradient—this movement is known as diffusion.

As the blood has a higher concentration of waste products compared to the dialysate, the substances naturally diffuse from the blood into the less concentrated dialysate until equilibrium is reached, effectively cleansing the blood of harmful substances. This mechanism is crucial for those with impaired kidney function, allowing for the removal of toxins and waste products that the kidneys would typically filter out.

Osmosis, while related to diffusion, specifically refers to the movement of water across a semipermeable membrane and is not the primary process used for the removal of solutes in dialysis. Similarly, absorption and filtration describe different mechanisms that do not apply to the primary process used in dialysis for waste removal.