Difference Between Osmosis and Dialysis (With Table)

Though both Osmosis and Dialysis methods involve the movements of fluids crosswise semi-permeable membranes, many consider they are similar processes that can sometimes even be used alternatively. But actually, they have vast differences amongst them. Both of these methods have their own share of importance as they are receptive transportation systems.

Osmosis vs Dialysis

The main difference between Osmosis and Dialysis is that water flows from a low solute concentration zone to a high solute concentration area via a semipermeable membrane in the case of osmosis, whereas Dialysis, on the other hand, is a method that distinguishes small molecules from large ones. These two methods both have vast distinctions amongst them, especially under the criteria of types of solvent, types of molecules, etc.

Osmosis is the process where the passage of water molecules travels from low pressure to the high-pressure area via a semipermeable membrane. The compulsion of osmosis causes the water to flow through the clefts or gaps. It does not, though, have the strength to prevent particular molecules like salt or glucose.

Dialysis is the most used and popular method that is undertaken by medical professionals across the globe to treat and help the patients who are having or suffering from one or various problems of the kidney that prevents the latter from carrying out the natural processes on their own. It is an artificial measure to assist the doings of the kidney.

Comparison Table Between Osmosis and Dialysis

Parameters of Comparison




Osmosis is the terminology used to define the process where liquid molecules (water) travel via a semi-permeable membrane.

Dialysis is the therapeutic purification of blood to restore the kidney’s natural activity but in an artificial manner.


The movement of the flow is from a less saturated zone to a more intense saturation.

Diffusion or filtration are two methods for dialysis.

Molecule Types

Only water molecule.

Water molecules, solutes, toxins, and metabolic excesses.

Types of Processes

Ex-osmosis and End-osmosis

Peritoneal dialysis and Hemo-dialysis

Types of Solvents

a. Extra-cellular fluid
b. Cytosol

a. Dialysate
b. Blood

What is Osmosis?

Osmosis is the terminology that is used to identify the persistent net movement of water molecules via a selectively permeable membrane. This movement of the liquid molecules happened into a higher solute concentration area from the lower saturation area, in a direction that resembles standardizing the solute concentrations on both sides.

It may also refer to a physical phase in which any liquid passes through a selectively permeable membrane that separates two distinct amounts of solutions. It is possible to make osmosis work.

The exterior pressure must be exerted in such a way that there is no absolute movement of a solvent through the membrane that is known as osmotic pressure. Osmotic pressure is a phenomenon that possesses a colligative property. This means that it is determined by the solute’s molar concentration rather than its identity.

Osmosis is a very crucial part of the method during the biochemical processes since biological membranes, by nature, are semipermeable. Huge and extreme molecules like ions similar to the ones of polysaccharides and proteins are impermeable to these membranes. Although non-polar or hydrophobic molecules like lipids, as well as small molecules like Nitrogen, Carbon Dioxide, oxygen, and nitric oxide, are permeable.

The movement of a liquid via a semipermeable membrane from a region of low saturation to the zone with a higher concentration of the solute is defined as osmosis. On the contrary, water is the most typical and the most popular solvent in biological environments. Osmosis can also transpire in other liquids or supercritical liquids, and sometimes even in gases.

What is Dialysis?

The very first dialysis that is recorded to be a successful one was recorded in the year 1943. In medical terminology, dialysis is the process that is used to remove excess water, solutes, also toxins from the blood of people whose kidneys cannot function the normal process naturally.

When there is an unexpected sudden failure of kidney function, known as an Acute Kidney injury. The phenomenon was earlier known as acute renal failure. Moreover, when a progressive deterioration in kidney function, known as chronic kidney disease, hits stage 5, dialysis may be needed.

When the glomerular filtration valuation is 10–15% of normal, the creatinine allowance is less than 10 ml per minute, and if that of uremia is present, it is recognized as stage 5 chronic renal failure.

Dialysis can also be a course of treatment for those who are waiting for a kidney transplant. Moreover, the latter can be the treatment or a permanent measure in cases where a transplant is not known or necessary.

The governments of countries like Australia, the United Kingdom, the United States of America, and Canada tend to help in covering the bills of the patients who are required to take the dialysis treatment and qualify the categorical criteria.

Main Differences Between Osmosis and Dialysis

  1. By definition and the basic difference amongst these two beings, Osmosis is the terminology that is used to define the process where liquid molecules (water) travel via a semi-permeable membrane.se solution, whereas in the case of Dialysis is the therapeutic purification of blood to restore the kidney’s natural activity but in an artificial manner.
  2. The movement of the flow is from a less saturated zone to a more intense saturation, whereas Diffusion or filtration are two methods for dialysis.
  3. The type of molecules in osmosis is only the water molecules. But in Dialysis, the type of molecules involved are Water molecules, solutes, toxins, and metabolic excesses.
  4. The types of processes undertaken under Osmosis are Ex-osmosis and End-osmosis, whereas, under Dialysis, it is Peritoneal dialysis and Hemo-dialysis.
  5. The types of solvents that are involved in osmosis are Extra-cellular fluid and Cytosol, whereas, in the case of dialysis, the types associated are Dialysate and blood.


The migration of water molecules through a possible gradient of water through the cell membrane is known as osmosis. Dialysis, on the other hand, is a surgical treatment that replaces the kidney’s natural activity by removing extra water, solutes, and metabolic wastes from the blood. The method and relevance of osmosis and dialysis are the key differences.

Osmosis and dialysis are two of the body cycles that exist within our bodies. Dialysis is a term that all of us are acquainted with, and we might have friends who are on dialysis for medical reasons. This time, though, things are different. This is the dialysis that takes place on a molecular basis in our bodies. Osmosis, on the other hand, is not a well-known word, nor does the name ring a bell. Let’s look at both terms to see if they vary.


  1. https://www.cabdirect.org/cabdirect/abstract/19710402674
  2. https://link.springer.com/chapter/10.1007/978-3-642-86414-8_1