Filtration

Filtration is a method to separate the components of a mixture of a liquid and an insoluble substance. In simple words, filtration can be defined as a physical process that separates the solid matter from liquid from a mixture using filter paper (or filter medium) that allows the liquid to pass through it except the solid particles. The term “filtration” involves in a field depending on whether the filter is mechanical, biological, or physical. The liquid filtrate and the solid filtration process are recovered in several chemical manufacturing processes. You can filter out other types of media as well, including electricity, light, and sound. Let’s learn more about filtration in this article, by understanding the filtration definition, types, examples, applications, etc. 

What is Filtration?

Filtration is a separation technique that uses a porous medium that retains the solid substance but allows the fluid to penetrate through it. It is the process of removing insoluble substances from the solution. 

This process is carried out using a filter medium, for instance, filter paper. The pores of the used filter medium are lesser in comparison to the size of the particles to be extracted. This process can generally be used for the separation of any heterogeneous mixture. The principle of filtration is the difference in sizes between the particles. It chooses a solvent so that one substance dissolves in the solvent and the other does not. Therefore, the latter is collected as a residue over the chosen filter media. 

Filtration Process

A heterogeneous mixture is deposited throughout a filter membrane during the filtration process. The pores in the filter medium or membrane of a specific size. Particles larger than the membrane holes are unable to pass through the membrane and are instead trapped on top of the filter membrane. Smaller particles will also move through the membrane pores simultaneously with the fluid. The liquid will pass through the filter membrane while the larger particles are deposited as a residue on top of the membrane. removing the fluid and solid from the heterogeneous mixture in the process. The term slurry is used for the mixture of the solid and liquid to be filtered.

Here is the filtration diagram, that will ease understanding the filtration process:

Filter medium refers to the porous material that is utilized to hold onto the solids. The filter cake is the buildup of solids on the filter. The filtrate is the clear liquid that emerges from the filter. Tea-making provides a clear illustration of this in the most basic terms. Using a sieve, we separate the prepared tea from the tea leaves. Tea leaves would be kept above the sieve while the tea and sugar would readily pass through the sieve’s pores. Another illustration of filtration is the removal of dust particles from the air in an air conditioner.

With this knowledge, the following components make up a basic assembly of filtration systems:

• Filter Medium (Filter Paper),
• Slurry or Residue (fluid with suspended solids),
• Filtration driving force (pressure, force, gravity, etc), and 
• Filtration device that holds the filter medium and filtrate.

Filtration Example

Filtration is one of the most important techniques for the Separation of Mixtures in a laboratory, it is also a common process happening in our everyday life like:

• When making coffee, hot water is filtered through the ground coffee and a coffee bean. The filtrate is the coffee in liquid form. Using a tea ball or a tea bag (paper filter) for brewing tea is very similar (usually, a metal filter).
• A biological filter is an example of the kidneys. The glomerulus filters the blood. The blood is reabsorbed with necessary chemicals.
• HEPA filters are used by various vacuum cleaners and air conditioners to filter out dust and pollen from the air.
• Filters with particulate-capturing fibers are commonly used in aquariums.
• During mining, belt filters extract precious metals.
• Sand and permeable rock in the ground have filtered the water in an aquifer, making it comparatively pure.

Applications of Filtration

Some applications of separation by filtration method are:

• Preparing coffee and tea: The hot coffee is obtained as the filtrate while the coffee beans remain as residue on the top of the filter.
• This technique can separate a mixture of chalk powder and water.
• Vacuum cleaners are fitted with filters in order to absorb dust particles.
• Filtration of sand particles from water or chalk powder.
• Effluents and wastewater treatment: Filtration is a useful technique to simulate the process of water treatment, however, the process is costly and cumbersome.
• Used by furnaces to simulate the prevention of furnace elements from fouling with particulates.
• Air filters are used to weed out airborne particulate matter in building ventilation systems and combustion engines.
• Potable wastewater treatment is carried out using biofilm filtration in slow sand filters.
• Blood filtering in kidneys.

FAQs on Filtration

Question 1: Define Filtration.

Answer:

Filtration is a separation technique that uses a porous medium that retains the solid substance but allows the fluid to penetrate through it. It is the process of removing insoluble substances from the solution. 

Question 2: Which type of mixture can be Separated by Filtration?

Answer:

A mixture that contains a liquid and an insoluble solid can be Separated by Filtration.

Question 3: What is the principle of Filtration?

Answer:

The principle of filtration is the difference in sizes between the particles. It chooses a solvent so that one substance dissolves in the solvent and the other does not. Therefore, the latter is collected as a residue over the chosen filter media. 

Question 4: Which water treatment process is done after the Filtration of Water?

Answer:

Disinfection is the process used to treat water after filtration.

Question 5: Name the basic Filtration unit present in the Kidney.

Answer:

The basic filtration unit of the kidney is called the nephron.

Question 6: What is Slurry?

Solution:

The slurry is basically a liquid-solid fluid mixture with a value of specific gravity greater than 1. The slurry is made to pass through each of the filtration chambers, under pressure delivered by a slurry pump.

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