Difference Between Osmosis and Dialysis

The key difference between osmosis and dialysis is that the osmosis refers to the movement of water or solvent molecules from high concentration area to low concentration area through a semi-permeable membrane while the dialysis refers to the process of separating solute molecules in a solution by the difference of their diffusion rates through a semi-permeable membrane.

Diffusion, osmosis, dialysis, and active transport, etc. are processes that describe the movements of molecules from one area to another area. Some movements require energy supply while some occur passively without energy consumption. When the molecules move from higher concentration to lower concentration, it does not use energy. However, when the opposite movement occurs; the molecules move from a low concentration area to high concentration area, the process uses energy since it takes place against the concentration gradient. These movements are important in order to filter substances, to maintain osmosis balance, to move ions and other substances in and out across the cell membranes, etc. Among the different movements, osmosis and dialysis are two important processes. Also, both osmosis and dialysis have two types; endosmosis and exosmosis are the two types of osmosis, and the two main types of dialysis are hemodialysis and peritoneal dialysis.

CONTENTS

1. Overview and Key Difference
2. What is Osmosis
3. What is Dialysis
4. Similarities Between Osmosis and Dialysis
5. Side by Side Comparison – Osmosis vs Dialysis in Tabular Form
6. Summary

What is Osmosis?

Osmosis is a type of diffusion in which water molecules or solvent molecules move from a higher concentration region to a low concentration region through a semi-permeable membrane. This process continues till the solute concentration equalizes in both areas.

However, in osmosis, the semi-permeable membrane does not allow solutes to move across the membrane. Since water molecules or solvent molecules move along the concentration gradient, it does not require energy. Hence, it is a passive process that occurs spontaneously.

Osmosis is an important biological process going on inside the cells of all plants and animals. In fact, it is the primary process by which water is transported into and out of cells.

What is Dialysis?

Dialysis is a process that separates solutes in a solution based on their diffusion rates. It also occurs via a semi-permeable membrane. Solutes move from higher concentration to lower concentration along the concentration gradient through a selective membrane. Dialysis is mostly used to help patients who suffer from kidney failure as their kidneys cannot perform blood purification on their own. Hence, dialysis can be performed in order to treat acute kidney failure, to remove drug, toxins, poisons from our body, etc.

Dialysis has two main types. Hemodialysis is one type, and it uses a machine called dialyzer. In hemodialysis, blood comes from the arteries of the patient to the machine (artificial kidney). Then the machine removes impurities and waste material from the blood and purifies the blood. Finally, purified blood provides back to the arteries of the patient. Peritoneal dialysis is another type of dialysis which does not use a machine, instead, use a membrane lining of the abdomen (peritoneum), and a cleaning solution called dialysate to clean the blood.

What are the Similarities Between Osmosis and Dialysis?

• Osmosis and dialysis describe the movement of molecules across a semi-permeable
• They are types of diffusion.
• In both processes, molecules move from high concentration area to low concentration area.
• Also, both are passive processes.
• Furthermore, both occur continuously until it reaches the equilibrium.

What is the Difference Between Osmosis and Dialysis?

Osmosis is the movement of water across a semi-permeable membrane while the dialysis is the movement of solute molecules across a semi-permeable membrane. Therefore, this is the key difference between osmosis and dialysis. Moreover, osmosis equalizes the solute concentration in both sides while dialysis separates small solute molecules from larger solute molecules. Accordingly, osmosis facilitates the movement of water in and out of the cells while dialysis helps to purify blood and remove waste and toxins in peoples who suffer from kidney failures. Thus, this emphasizes another difference between osmosis and dialysis.

Furthermore, osmosis has two types; namely, endosmosis and exosmosis while dialysis has two main types namely hemodialysis and peritoneal dialysis. Also, there is a difference between osmosis and dialysis based on their movements as well. More details are presented in the infographic on the difference between osmosis and dialysis

Summary – Osmosis vs Dialysis

Osmosis and dialysis are two processes that relate to movements of molecules across a semi-permeable membrane. In osmosis, water molecules or solvent molecules move from higher concentration to low concentration along the concentration gradient through a semi-permeable membrane. On the other hand, in dialysis, small solute molecules separate from larger solute molecules by moving from higher concentration to lower concentration via a semi-permeable membrane. Therefore, this is the key difference between osmosis and dialysis.

Furthermore, osmosis can be endosmosis or exosmosis while dialysis can be hemodialysis or peritoneal dialysis. Osmosis is a type of diffusion that occurs passively. On the other hand, dialysis can occur through diffusion or filtration. All the information mentioned above summarizes the difference between osmosis and dialysis.

Reference:

1.Britannica, The Editors of Encyclopaedia. “Osmosis.” Encyclopædia Britannica, Encyclopædia Britannica, Inc., 19 Sept. 2017. Available here   
2.“What Is Dialysis?” The National Kidney Foundation, 2 July 2018. Available here  

Image Courtesy:

1.”0307 Osmosis”By OpenStax  (CC BY 4.0) via Commons Wikimedia  
2.”Blausen 0313 Dialysis”By Blausen.com staff (2014). “Medical gallery of Blausen Medical 2014”. WikiJournal of Medicine 1 (2). DOI:10.15347/wjm/2014.010. ISSN 2002-4436. – Own work, (CC BY 3.0) via Commons Wikimedia