Study the Process of Filtration


To separate solid particles from liquids and gases  



Filtration (Separating technique) 

Filtration is known as separating solid particles from a liquid or gaseous fluid using a filter medium that allows the fluid to pass through but retains the solid particles.  

Mechanism of filtration 

The mechanism of filtration is either physical, mechanical, or biological and the process is carried out by using a filter medium like filter paper, cloth, sintered glass, or asbestos. The pore size is larger than the solvent (liquid) but smaller than the solute (solid) resulting in the solvent being called filtrate and the solute being called residue. The pore size may vary depending on the solvent and solute. 

                                                                                                                      Fig.1 Process of filtration  

Steps in filtration  

  • Pour the mixture of solid and liquid through the filter paper in a funnel. 
  • The filter paper separates the solvent (liquid) from the solute (solid). 
  • The clear liquid (filtrate) is obtained in the beaker and the solid (residue) traps on the paper. 

Types of filtration  

The process of filtration applies based on two types of mixtures namely,  

  • Heterogenous mixture 
  • Homogenous mixture 

Heterogenous is a mixture of undistributed solute (solid) that is mixed with the solvent (liquid).  

Example: Sand in water, Concrete, Salad. 

                                                                                                            Fig.2 Sand in water 

In homogenous mixture, the solute (solid) is evenly distributed in the solvent (liquid). A homogeneous mixture is a uniformly composed gaseous, liquid, or solid sample with only one observed phase of matter. 

Example: Air, Sugar water, Vinegar. 


                                                                                                             Fig.3 Vinegar  

Applications of Filtration 

Water treatment: Wastewater treatment is crucial for environmental recycling and usage, using various filters to separate solvents (liquids) from sewage.  

Rainwater harvesting: The rainwater is stored in the tanks and filtered thoroughly before being disinfected and used for household purpose. 

Food applications 

Tea filtration: The prepared solvent (liquid tea) is separated using a filter or sieve from the solute (solid dust tea). 

Wine making:  The prepared mixture of grapevine is filtered to obtain the solvent of wine.   

Biological applications 

Kidney: As all know the kidney is working as a biological filter to clear out the urea and unwanted toxic particles from the blood.  


Learning Outcomes  

Student understands,  

  • The concept of filtration.  
  • The process of filtration.
  • The types and applications of filtration.