What Do You Mean by Vacuum Filtration?

As a technique widely used in organic chemistry labs, not only removing solid impurities from an organic solution but also isolating an organic solid, filtration can be found in two types, gravity filtration, and vacuum filtration. Hawach vacuum filtration have Stainless Steel Single-Branch Vacuum Filtration Manifold, Glass Triple-Branches Vacuum Filtration System.

Compare to gravity filtration, vacuum filtration allows for a greater and faster rate of filtration. In normal filtration, it is the gravity that provides the force and makes the liquid draw through the filter paper. But in vacuum filtration, a pressure gradient helps to perform the filtration with the advantage of offering a greater rate depending on the vacuum force from the pump to extract air from the Büchner flask.
Three-Branches Vacuum Filtrations
After you set up the vacuum filtration set, it is time to filter your sample. First, you can pour the solvent into the center of the filter paper very slowly and carefully, When you find the collection of the solid is desired, you can use a more clean solvent to rinse your beaker, helping all the solid to be collected. Keeping on drawing the air through the solid, to evaporate the remains of the solvent in the sample. Break the vacuum connection from the arm of the flask, when you are done, and don’t forget to turn off the vacuum.

You need to pay more attention to not using such a strong vacuum that might rip the filter paper. As a result, the solid will be lost into the solvent back again, and the glass flask might break.

Hawach vacuum filtration work as a separation method, which is commonly used to remove a solid from a liquid, that is, the solids are dissolved or filtrated in a solution. The solution can be applied in different situations such as saturated, unsaturated, or supersaturated conditions, and the difference depends on the concentration of the solid. In general, a special filter will be applied to separate the samples from the solution, and a vacuum pump will be applied to make the liquid through the filter.

In cases, Hawach vacuum filtration can be used to collect various particles. Such particles will dissolve in the solvent, be recovered, recrystallized, heated, and evaporated in the final process. After the solvent has been evaporated, filter paper will be used to deposit the flask. Filter flask is connected to the funnel to suck the air out with a rubber tube attached to a vacuum.

Components of Vacuum Filtration Setup:

  1. Filter Flask (Filtering Flask): This is a round-bottomed flask with an opening at the top. It is often connected to a sidearm to attach a vacuum source.
  2. Filter Funnel: The filter funnel is placed inside the neck of the filtering flask. It contains a filter medium (usually filter paper or a membrane filter) that allows the liquid to pass through while retaining the solid particles.
  3. Filtering Medium: The choice of the filtering medium depends on the nature of the sample. It can be filter paper, filter membrane, or other specialized filter materials.
  4. Rubber Stopper or Adapter: Used to secure the filter funnel to the neck of the filtering flask, creating a vacuum-tight seal.
  5. Vacuum Tubing: Connects the sidearm of the filtering flask to a vacuum source. The vacuum helps pull the liquid through the filter medium, speeding up the filtration process.


  1. Assembly: Set up the filtration apparatus by placing the filter funnel in the neck of the filtering flask. Ensure a tight seal using a rubber stopper or adapter.
  2. Pre-wet the Filter: If using filter paper, wet it with the solvent or liquid being filtered. This helps to prevent the filter paper from absorbing the liquid being filtered.
  3. Add the Sample: Pour the liquid sample containing the solid particles onto the filter medium in the filter funnel.
  4. Apply Vacuum: Turn on the vacuum source, creating a pressure difference. The reduced pressure on one side of the filter medium allows the liquid to pass through, leaving the solid particles behind.
  5. Wash and Collect: Optionally, wash the retained solid with a solvent to remove any impurities. Collect the filtrate in the filtering flask.
  6. Disassembly: Turn off the vacuum source, disconnect the apparatus, and remove the filter funnel with the solid residue.

Specific separation process of vacuum filtration

The whole separation process is as followed: if suction or particles occurred at one end of the tube, the filter flask will collect and suck it. With the particles are poured onto the filter paper, the solvent will deposit in the filter flask. Finally, the remaining particles will be collected and weighed again in the next process.

Principle of filtration cycle of vacuum filtration

First of all, we must divide the filter medium into the upper and lower chambers, which is a simple filter. The upper chamber is designed to filter residues or solid particles with suspension, and the filter medium will enter the lower chamber under the action of this pressure, and then the residues or the solid particles will leave in the filter. The phenomenon of filter residue formed on the surface of the medium. Of course, during this filtration process, the filter residue on the surface of the filter medium will gradually increase, and residues or solid particles will gradually pile up, and then the filtering speed will be affected greatly.

Filter residue of vacuum filtration

When filter residue blocks the chamber, the filtering speed of vacuum filtration will become very low. At this time, you should better remove the filter residue, and regenerate the filter medium. If you operate as instructed, the filtration process will be done successfully. The intermittently operated vacuum filter can filter suspensions of various concentrations, and the continuously operated vacuum filter is suitable for filtering thick suspensions containing more solid particles.