A dialysis machine is an example of which type of separation?

A dialysis machine is an example of which type of separation?

• A. Membrane Separation
• B. Distillation
• C. Adsorption
• D. Sedimentation

Answer: (A)

Membrane-based separation uses a semipermeable barrier to transport only certain species. In dialysis, blood flows on one side of a semipermeable membrane while the dialysis fluid sits on the other. Small solutes such as urea and excess water diffuse across the membrane toward the dialysate, driven by concentration and pressure differences, while larger components like blood cells and most proteins are retained in the blood. This selective transport via a membrane is the hallmark of membrane separation. Distillation relies on phase change and heating to separate components, so it isn’t the mechanism here. Adsorption involves sticking solutes to a solid surface, which isn’t how dialysis removes solutes. Sedimentation depends on gravity to settle particles, which also doesn’t describe this process.

Membrane-based separation uses a semipermeable barrier to transport only certain species. In dialysis, blood flows on one side of a semipermeable membrane while the dialysis fluid sits on the other. Small solutes such as urea and excess water diffuse across the membrane toward the dialysate, driven by concentration and pressure differences, while larger components like blood cells and most proteins are retained in the blood. This selective transport via a membrane is the hallmark of membrane separation.

Distillation relies on phase change and heating to separate components, so it isn’t the mechanism here. Adsorption involves sticking solutes to a solid surface, which isn’t how dialysis removes solutes. Sedimentation depends on gravity to settle particles, which also doesn’t describe this process.