Büchner Funnel - The Ultimate Guide: What It Is, How to Use It, and More!

In this article you will be able to know everything about a very important instrument in the laboratory, such as the “Büchner Funnel”, which has a very useful application that may interest you, so continue reading the article so that you can discover it.

✔ What is the büchner funnel?

The büchner funnel is an instrument that is commonly used in the laboratory to separate a solid-liquid mixture using vacuum filtration or assisted pressure filtration. It is usually made of porcelain, but it can also be presented in glass or plastic. This can be seen in Figure 1 below:

Who invented the Büchner funnel?

The aforementioned funnel was invented by the industrial engineer Ernest büchner in 1888, which is made of porcelain, since many laboratory instruments are made of that material, because it resists high temperatures, as well as various chemical substances that can be corrosive. That is why it is a very useful instrument for laboratory analyzes.

▶ Multipurpose

This funnel is used for the separation of a solid-liquid mixture by means of vacuum, since the liquid passes through the funnel, and the solid is retained in it, thus achieving separation.

It is important to know that said funnel should be used for solids that do not have very small dimensions, which could have the consequence that it manages to transfer the funnel accompanied by the liquid, so it would not perform the filtration properly. However, a filter paper can be placed on it, so that it can prevent the solid from passing through the funnel.

 

✔ Features of the büchner funnel

The büchner funnel has the following characteristics:

It is made of porcelain

Generally of this material since it is very characteristic of other laboratory materials. It can also be made of glass or plastic.

It has a base with small holes

In its center, it has a sheet with small holes through which the liquid of the mixture to be separated passes, thus making the funnel penetrate into the receiving container of this. Thus achieving the separation of the solid component.

It is circular in shape

This way is very easy to add the mixture that you want to filter, besides it is also useful because the filter paper can be placed to the funnel without any difficulty, so it could be said that it gives greater comfort for it.

It has a long neck

The neck is where the liquid circulates that was already
separated from the solid, towards the receiving container of said liquid.

✎Types of Büchner Funnels

There are different types of büchner funnels, including:

• Porcelain Büchner Funnels: These are the most durable and resistant to chemical corrosion. They are suitable for high-temperature applications and can be used with most solvents and acids.
• Glass Büchner Funnels: These are lightweight and transparent, making them ideal for observing the filtration process. They are not as durable as porcelain funnels and can break easily.
• Plastic Büchner Funnels: These are the most affordable and lightweight. They are suitable for most laboratory applications, but not for high-temperature or corrosive substances.

▶ Vacuum filtration

Be filtration is an instrumental technique used in laboratories for the separation of a solid into a fluid. This type of filtration is similar to gravity filtration, only which is assisted by vacuum pressure (suction).

First the mixture of the solid in liquid that you want to separate is poured, where it passes through the separation funnel with the help of vacuum so that the liquid passes more easily through the funnel and once this is finished, the mixture is completely separated, thus obtaining the solid and the liquid.

✎ How to use the büchner funnel

As mentioned above, this funnel is used to separate the solid from a solid-liquid mixture using vacuum filtration.

Initially the filtration assembly must be prepared, which consists of a Kitazate (similar to a fiola), which has an arm where the vacuum outlet is connected to it (where the vacuum pressure is given).

A plug is placed on the bottom of the büchner funnel to attach it to the top of the Kitazato, where the assembly similar to the following figure would then be obtained:

Once the assembly is done, a filter paper is placed on the funnel, so that it looks like a first mesh before the funnel, this serves to guarantee a better filtration of the mixture and prevent the solid from passing through the funnel, since, depending on the size of the particles, they could pass through the funnel if the filter paper were not. Then the vacuum is turned on, and the solid-liquid mixture is poured over the funnel.

At that moment, the liquid should be observed descending towards the kitazate, so the mixture should continue to be added as the liquid descends through the funnel. After the filtration has finished, the vacuum is closed, and the kitazate is disconnected from the vacuum inlet.

Then the büchner funnel is removed from the kitazate (which contains the liquid), where the filter paper is taken, which contains the separated solid.  And according to what is required, you can have both parts already separated.

Here are the steps to using a büchner funnel:

1. Set up the vacuum filtration apparatus by connecting the büchner funnel to the vacuum flask with a rubber stopper or adapter.
2. Place a filter paper in the funnel, making sure it is snug against the walls.
3. Wet the filter paper with a solvent or solution to help it adhere to the funnel.
4. Pour the mixture to be filtered into the funnel.
5. Turn on the vacuum pump to create a vacuum, which pulls the liquid through the filter paper and into the flask.
6. Once the filtration is complete, turn off the vacuum pump and carefully remove the funnel from the flask.

Tips for Using a Büchner Funnel

• Always use a filter paper that is the right size and shape for the funnel.
• Wet the filter paper with a solvent or solution to help it adhere to the funnel and prevent tearing.
• Never let the funnel run dry, as this can damage the filter paper and reduce the efficiency of the filtration.
• Use a clean funnel and flask for each filtration to avoid contamination.
• Dispose of the filtered material properly.

✎ Precautions to take

This instrument, despite being small and easy to use, can be somewhat fragile, so precautions must be taken according to its handling, in order to avoid possible falls and that this leads to it being fractured or broken, and consequently affecting the analysis.

That is why it is recommended to take the funnel very carefully, and when placing it in the kitazate for filtration, adjust it in such a way that it does not separate from it.

🎯 Büchner funnel price

The prices of such a funnel may vary according to the dimensions that are required. When consulting with various suppliers, it was found that the price of the büchner funnel ranges from (1,0 – 130,0) $.  So it can be said that its cost is affordable and it is worth investing in it, since it is an instrument that can last for a long time (depending on the use it has).

▶ Importance of the büchner funnel

This funnel is a very useful instrument, used in laboratory analysis for the separation of solid-liquid mixtures by means of vacuum filtration, which thanks to the vacuum makes the separation of the mixture be carried out more quickly. And it also provides greater safety due to the fact that a filter paper can be placed on it, ensuring that the solid of the mixture is retained, thus achieving a successful separation.

In conclusion, it can be argued that the büchner funnel is an instrument whose purpose is relevant for the analyses involved in the separation processes of mixtures containing a solid in a liquid by means of vacuum filtration, whose method is very simple and safe to perform.

FAQs

What is the purpose of a büchner funnel?

A büchner funnel is used for vacuum filtration, which separates solid material from a liquid mixture.

What is the difference between a büchner funnel and a regular funnel?

A regular funnel is used to transfer liquids from one container to another, while a büchner funnel is used for vacuum filtration.

How do you clean a büchner funnel?

To clean a büchner funnel, rinse it with water or a solvent, and then soak it in a cleaning solution. Scrub the funnel with a brush or sponge to remove any remaining residue.

Büchner funnel manufacturers

• Manufacturer: Kimble Chase
  • Description: Kimble Chase is a leading manufacturer of laboratory glassware and equipment, including büchner funnels. Their büchner funnels are made of high-quality porcelain, with a glazed surface for easy cleaning and resistance to chemical corrosion. They are available in various sizes and styles to meet the needs of different laboratory applications.
  • Web link: https://www.kimble-chase.com/
• Manufacturer: Eisco Labs
  • Description: Eisco Labs is a supplier of laboratory equipment and supplies, including büchner funnels. Their büchner funnels are made of high-quality glass, with a heavy-wall construction for durability and resistance to chemical corrosion. They are available in various sizes and styles to meet the needs of different laboratory applications.
  • Web link: https://www.eiscolabs.com/
• Manufacturer: Bel-Art Products
  • Description: Bel-Art Products is a manufacturer of laboratory equipment and supplies, including büchner funnels. Their büchner funnels are made of high-quality plastic, with a durable construction for resistance to most laboratory applications. They are available in various sizes and styles to meet the needs of different laboratory applications.
  • Web link: https://www.belart.com/

Conclusion

In conclusion, a büchner funnel is an essential piece of laboratory equipment for vacuum filtration. By following the tips and techniques outlined in this guide, you can ensure that you use your büchner funnel effectively and safely. Whether you are a seasoned chemist or a beginner, understanding how to use a büchner funnel is a valuable skill to have in the laboratory.

 

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