Osmosis Vs Reverse Osmosis: Differences & Similarities

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Water filtration systems come in two main types: osmosis and reverse osmosis. Both work well, but there are differences between the two.

In this article, I’ll explain the differences between osmosis and reverse osmosis and why you should choose one over the other.

I’ll also compare the benefits and drawbacks of each system and tell you which one is best for your home water filtration needs.

Osmosis Vs Reverse Osmosis

What is Osmosis?

Osmosis is a naturally occurring phenomenon that takes place regularly in all living organisms.

Water moves from an area where there is a lot of water (a high water potential) to an area where there isn’t much water (a low water potential).

Osmosis requires no input of external force. It happens because there is a difference in concentrations between two solutions.

Osmotic pressure is caused by differences in concentrations of solutes (such as salt) between two solutions separated by a semipermeable membrane. And since it happens passively, it’s a passive process.

Osmosis is one of the mechanisms by which plant and animal tissues exchange fluids.

Since the cell membrane acts as a selectively permeable membrane allowing certain molecules to pass through it, only via osmotic pressure can water molecules move in and out of the cell?

So if you want to know more about osmosis, keep reading!

What is Reverse Osmosis?

Reverse osmosis is a method used to purify water. Water passes through a semipermeable membrane, where it becomes concentrated.

Then, the concentrated water is forced through a second membrane, where it is purified again. This process removes impurities from the water, leaving pure water behind.

This method is commonly used to remove contaminants from drinking water. However, reverse osmosis systems are expensive and require large amounts of electricity.

As a result, they are typically found in commercial applications, such as desalination plants or food processing facilities.

Similarities Between Osmosis and Reverse Osmosis?

Both osmosis and reverse osmosis involve moving water through a semi permeable membrane, but there are differences between the two.

Both processes require the movement of mostly liquid molecules through the membrane.

However, in reverse osmosis, only water passes through the membranes. And in osmosis, both water and dissolved substances move across the membrane.

Both processes prevent solutes from crossing the cell membrane.

But in reverse osmosis, the solutes stay behind the membrane. And in the process of osmosis, the solutes pass through the membrane.

Furthermore, the osmotic pressures affect both processes. But in reverse osmosis, the osmotic force pushes the solution away from the membrane. Whereas in osmosis, the osmotic forces pull the solution towards the membrane.

So, although both processes are similar, there are still differences between the two.

Difference Between Osmosis and Reverse Osmosis?

This infographic explains how osmosis works and why it differs from reverse osmosis. You’ll find out that there are several differences between osmosis and osmosis.

Osmosis occurs passively when there is a difference in concentrations between two solutions. Reverse osmosis occurs actively when there is a difference between two solutions.

Another difference is that osmosis doesn’t require any energy to work while reverse osmosis needs the energy to provide pressure.

So if you’re interested in learning more about osmosis and reverse osmosis, then this infographic will be helpful. It gives you a detailed explanation of the differences between osmosis versus reverse osmosis.

Here are some of the main distinctions between osmosis and Reverse Osmosis:

OsmosisReverse Osmosis
Solvent diffusion is the process by which solvents move across a semi-permeable barrier from regions of low concentration to high concentrations.When a solvent passes through a semipermeable membrane from a region of high concentration to one of low concentration, the solvent moves because there is a difference in solute concentrations between the two sides of the membrane.
It’s a natural process.It’s an artificial process.
Occurs along the potential gradient.Occurs against the potential gradient.
During the opening of the stoma and the absorption of moisture from the soil by the root system, these processes occur.This is used in water purification systems.


Reverse osmosis (RO) is an advanced water filtration system that uses pressure to force water molecules through membranes. This method has been proven effective in removing impurities from drinking water. However, RO systems are expensive and require regular maintenance.

On the other hand, osmosis (OSM) is a natural phenomenon that occurs when two solutions of differing concentrations are separated by a semi permeable membrane. OSM does not require any energy input and works without any maintenance. In fact, OSM is often referred to as passive reverse osmosis because it requires no power source. It simply relies on the difference between the concentration of salt in the seawater and the fresh water.