Filtration is the process of separating solids in a suspension by means of a porous mechanical medium. The mechanical means that can be used for the separation of the solids is also called sieve, screen, sieve or filter.
If we make a suspension in a liquid medium, and we use a porous medium to filter it, we will be able to separate the smaller solids that will pass through the porous medium, and the larger solids that will be retained by the porous medium.
Filtration has been used over the years domestically. But filtration theory is also used for the interpretation of results at the scale of laboratory practices.
The major limitation with which it is found is that the interaction of the particles may vary depending on the characteristics of the solid particles and the fluid.
The variables influencing the filtration process are the pressure, the filter cake, the viscosity and temperature, the particle size and its concentration and the filter medium
Depending on the size and nature of the mixture we can talk about different ways of filtering. On the one hand, the filtrate itself, which separates the minute solid particles into a colloidal suspension.
On the other hand, casting, which separates large and visible particles with a strainer. And sieving, which separates particles of different sizes without the need for a liquid medium.
Featured filtration examples
Air filters
They can be used in enclosed spaces but also in mechanical applications such as car engines.
These filters serve to separate and brake the solid particles that are in the air preventing their entry.
Water filters
Like the previous example, these filters serve to separate the particles that float in the water and purify the water.
Stone Filters
These water filters from the colonial era served to purify water formerly through a porous stone. This stone served as a barrier to particles floating in the water.
Oil filters
Some combustion engines produce particles that are harmful to the engine, so that a filter is installed that retains them, keeping the engine oil clean and prolonging its useful life.
Filter paper
This type of paper is used mainly in laboratory processes to separate solutions. This paper retains the smallest particles but lets it pass into the water.
Coffee
The coffee brewing process is an example of filtration. The ground coffee is placed on a strainer, usually cloth or paper, and the boiling water is thrown over it.
In this way, the water dilutes and transports the flavor and properties of the coffee separating it from the solid particles.
Juices
In the manufacture of many fruit juices, the pulp is liquefied or squeezed, and sometimes strained to separate the liquid from solid pieces.
Infusions
The infusions are prepared by infusing the herbs in boiling water. They can be done in two ways, adding the herbs to the boiling water and then pouring them, or using a sachet of filter paper that retains the herbs and allows the water to pass through its properties and taste.
Pasta or rice
In the kitchen, the filtering technique is used for some dishes such as pasta and rice. These ingredients are cooked in water and then strained to remove excess liquid
Flour
In the confectionery sieve the flour and the sugar glas so that the particles of the ingredients are separated and using only the smaller ones that pass through the sieve, thus preventing lumps from appearing in the final preparations.
Wine and spirits
Wine and alcoholic beverages obtained through fruits need to undergo a filtration process to remove the solid substances from the final preparation, before allowing them to ferment to obtain the alcoholized process.
Sewer grates
In the streets we can see how some sewers have a piece that filters solid waste and separates them from rainwater so they do not enter the sewers.
Thus, in sewers only small particles can be easily carried without risk of obstruction
Sinks and Sinks
Increasingly, these grids prevent solid waste entering the pipes and pipes of our house, not only to avoid possible jams, but also to avoid the bad odors that occur from the decomposition state of organic waste.
Filtration of waste water
There are processes to clean the wastewater by filtering the solid particles that are in the water.
This filtration process makes the water reusable and does not contaminate so much seawater.
Cigarette filter
The filter of the cigarettes is an important part of the same, since it retains the most toxic and harmful substances preventing them from entering our system.
Cement
In the construction the process of sieving of some materials like the cement to create the mortar is followed.
This makes the cement powders well decomposed and can be mixed homogeneously with the water.
Failure to do so may result in non-homogeneous cement balls remaining that weaken the structure being built.
Kidneys, liver and lungs
The kidneys, liver and lungs function as the filters of the human body. In them are separated and filtered the materials that will go to the waste.
If the kidneys do not produce the filtrate as it should, it often requires the use of dialysis machines that perform the filtration process as if they were the kidneys themselves.
References
- KITTEL, Charles. Introduction to solid state physics . Wiley, 2005.
- VAN KAMPEN, Nicolaas Godfried; REINHARDT, William P. Stochastic processes in physics and chemistry.
- BENEFIELD, Larry D.; JUDKINS, Joseph F.; WEAND, Barron L. Process chemistry for water and wastewater treatment . Prentice Hall Inc, 1982.
- PRIMICERO, M.; GIANNI, Roberto. Filtration in porous media. Cuadernos of the Institut of mathematics"Beppo Levi"/ Univ. Nac. Of Rosario. Faculty of Exact Sciences and Engineering , 1989.
- MAFART, PierreBELIARD; MAFART, EMILEPierre; EMILE, Beliard. Food Industrial Engineering . Acribia, 1994.
- CONCHA, Fernando. Manual of filtration & separation . University of Conception, Department of Metallurgical Engineering, 2001.
- VAZQUEZ, Juan Luis. The equations of fluid filtration in porous media. Soc. Espanola Mat. Apps , 1999, vol. 14, p. 37-83.