[Chemistry Class Notes] on Coagulation of Colloidal Solutions Pdf for Exam

Define Coagulation in Chemistry?

In general, we can define coagulation in chemistry as it is one of the various properties exhibited by the colloidal solutions. Where, a colloid is a heterogeneous mixture of one single substance of very fine particles (a dispersed phase) dispersed into another substance (a dispersion medium).

Few substances such as metals, and their sulfides, etc. cannot simply be mixed with the dispersion medium to produce a colloidal solution. Some special methods are used to develop their colloidal solutions. Solutions of this type are known as lyophobic solutions. This kind of colloidal solution carries some charge on them always. The charge present on the colloidal solutions indicates their stability. By any chance, if we can remove the charge present on the solution, the particles get closer to each other and accumulate to produce precipitate and aggregates under the gravity action. The accumulation and settling down of the particle process is further referred to as precipitation or coagulation.

Coagulation Techniques

Since the process of coagulation can be carried out in a few ways, such coagulation techniques are defined below in a brief manner. Let us look at it.

1. By Electrophoresis

The colloidal particles are compelled to move towards the oppositely charged particles in this method, and later they are discharged and collected at the bottom.

2. By Mixing Two Oppositely Charged Solutions

In this type of coagulation technique, an equal amount of oppositely charged particles are mixed, and they precipitate by canceling out their charges.

The below representation shows the coagulation technique by mixing two oppositely charged solutions.

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3. By Boiling

Whenever we boil a solution, the molecules of the dispersion medium start colliding with each other and with the surface, and resultantly this disturbs the adsorption layer. This reduces the charge on the solution because of which the particles settle down.

4. By Persistent Dialysis

Under the persistent dialysis parts, the electrolytes are removed completely, and the solution loses its stability and coagulates ultimately.

The below representation shows the coagulation by persistent dialysis.

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Coagulation of Lyophilic Solutions

The lyophilic solution’s stability depends on the below two factors.

When these two factors are removed, then only the lyophilic solutions can be coagulated. And, it can be done either by adding an electrolyte or a suitable solvent.

Coagulation Process

The coagulation process in chemistry can be explained by taking an example of drinking water treatment, which is provided in a brief way below.

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• Solids are removed by the sedimentation (settling) process, followed by filtration. The small particles are not removed by sedimentation efficiently because they settle very slowly, and they may also pass through filters. If they clumped together (coagulated), it would be easier to remove to form larger particles. But they don’t because they repel each other (like two north poles of a magnet) due to the reason they have a negative charge.

• We add a chemical in coagulation, such as alum, produces positive charges to neutralize the negative charges on the particles. Then, the respective particles can stick together, forming larger particles that are removed more easily.

• The coagulation process includes the addition of chemicals (for example, alum), and then, a rapid mixing occurs to dissolve the chemical and distribute it throughout the water evenly.

Coagulation Tests

Clotting prevents excessive bleeding when anyone cuts themselves. But the blood moving through our vessels should not clot. If any such clots form, they can travel through our bloodstream to the lungs, brain, and heart. This may cause a heart attack, stroke, or even death.

Coagulation tests measure our blood’s clotting ability, and how long it takes to get a clot. Testing can help the doctor to assess our risk of excessive bleeding or clot developing (thrombosis) somewhere in our blood vessels.

Coagulation tests are the same as most blood tests. There is a minimal chance of side effects and risks. A professional medical representative will collect a blood sample and send it to a laboratory for tests and analysis.

Types of Coagulation Tests

There are various types of coagulation tests. A few of them are explained below.

The doctor may suggest a complete blood count (CBC) as part of our routine physical. This test result can alert our doctor if we have a low platelet count or anemia, which can interfere with our ability to clot.

This test measures the V Factor, a substance that is involved in clotting. An abnormally low level can be indicative of primary fibrinolysis (a breakdown of clots), liver disease, or disseminated intravascular coagulation (DIC).

Fibrinogen is a protein made by the human liver. This test measures how much fibrinogen is present in our blood. The abnormal results may result in a sign of hemorrhage or excessive bleeding, fibrinolysis, or placental abruption, which is a placenta separation from the uterine wall.

Other names for this test include hypofibrinogenemia test and factor I.