Colloids

Colloids: Introduction

The microscopic, distributed insoluble particles of one material suspended in another are colloids (colloidal solutions and colloidal systems). Particles suspended in a colloid vary in size from one to a thousand nanometers (10-9 metres). The suspended particles of a combination must not sink to the bottom of the container to be considered a colloid (in the manner that the particles of suspensions settle at the bottom of the container if left undisturbed). When light strikes colloidal particles, it is known as the Tyndall Effect, and this scattering occurs as a result of interactions between light and particles in the solution.

IUPAC defines colloidal state as “the state of subdivision in which molecules or polymolecular particles having at least one dimension in the range of 1 nanometre and 1 micrometre, are scattered in some medium.”. Substances uniformly scattered in one another are common in colloids. The scattered phase is referred to as such in mixes, whereas the continuous phase describes the dispersed phase.

In the thick fog, have you seen any water droplets? Yeah! Colloidal substances, such as fog, are also found in the atmosphere. Water molecules abound in the thick mist. In the same way, you’re certain to come into contact with a slew of colloids in your daily life. As a result, the focus of this article will be on colloids’ many uses and properties.

Overview of Colloids

There are two substances in a colloidal combination, and one of them has tiny particles in it. It is the dispersion medium that holds the dispersed phase in place, whereas the dispersed phase is the material that holds the dispersed phase in place. Water (liquid) is the dispersed phase in fog, whereas other gases make up the dispersion medium. Dispersed phase particles in colloids are so small that we can’t see them with the naked eye.

Examples of Colloids

There are several colloidal solutions to be found in our surroundings. There are several colloids in foods including cakes, breads, butter and ice cream. This is only a small sample of the colloids that make up the environment. Examples of colloidal dispersion are shown in the following list.

Unique Characteristics of Colloids

• It’s a fleeting concoction.
• Colloidal particles are very small. Their particles range in size from one to a thousand nanometers.
• Effect of Tyndall shown. To show the course of the light, it scatters and reflects it
• Colloidal solutions are very stable because they do not settle after being left undisturbed for an extended period of time.
• They cannot be separated by filtration.
• Centrifugation is one option for separating them.
• The brownian motion may be seen in colloidal particles.

Colloids: Their Use and Benefits

Colloids are vitally important because of their ubiquitous presence in nature and our everyday lives. Some of the most important uses of colloids are discussed in the following sections:

Industrial Uses of Colloids

Pharmaceuticals: Because the body’s tissues more easily absorb them, colloidal medicines are more effective.

Wastewater treatment: When sewage water is run over plates with high potential, the colloidal particles of dirt, muck, and other organic materials congeal, and the suspended stuff is removed.

Water purification: Alum and other electrolytes may precipitate colloidal contaminants in water. Negatively charged contaminant colloidal particles are neutralised by Al3+ ions and sink to the bottom, enabling for the decantation of clean water.

Soap’s ability to clean surfaces: A colloidal soap solution has a high surface area to volume ratio. Adsorbing or emulsifying the oily material that has been attached to the fabric, it eliminates dirt particles.

The Delta: Clay, sand, and a variety of other substances may be found in river water in colloidal particles. Electrolytes are dissolved in seawater at a high concentration. When river water’s colloidal particles contact saltwater, they thicken and settle at the point of contact. As a result, the riverbed rises in height. A delta forms as a result of the change in the water flow direction.

Smoke Precipitation: Smoke particles are colloidal carbon particles that have been charged with electricity. The electrophoresis-based Cottrell precipitator is used to precipitate smoke particles. A metal wire connects a high-potential source to a series of metal plates in a chamber, allowing smoke to pass through. Electrodes with opposing charges attract charged particles of smoke that exit via the chimney. This process also eliminates dust particles. Consequently, large industrial cities will be spared the stench of smoke.

Photographic methods: Glass plates, celluloid films, or paper are coated with a colloidal solution of silver bromide in gelatin to create sensitive plates for photography.

Human-induced rain: It can make rain by spraying colloidal dust or sand particles with opposing charges over a cloud. Artificial rain will result because of the neutralisation and coagulation of colloidal water droplets in the cloud.

The manufacture of rubber: Latex is composed of rubber particles with a negative charge suspended in a colloidal fluid. The process may make rubber of latex coagulation.

Rubber-plated things are created by using the rubber-plated object as an anode in a rubber plating solution and depositing negatively charged rubber particles on it.

Smokescreens are utilised in warfare because they are nothing more than a colloidal dispersion of several chemicals in the air.

Colloids may be used in a variety of ways.

Particles that are smaller than the wavelength of light cause light to be scattered. The blue colour of the sky is caused by tiny particles in the atmosphere scattering light (dust and water particles). According to Rayleigh’s rule, the intensity of scattered light is inversely proportional to the fourth power of the wavelength. This is because red light has a longer wavelength than blue thus, it is more easily absorbed, whereas blue has a shorter one. Dispersed blue light reaches the eye, and a blue sky is seen in its reflection.

Fog, mist, and rain are colloidal. Microdroplets form when moisture in the air condenses on dust particles during the winter. When these droplets condense as mist or fog because of their colloidal nature, they float in the air.

Millions of tiny water droplets float through the air in clouds, making them a kind of aerosol (aerosols). When it comes to clouds, they’re the answer. As they condense in the high atmosphere, colloidal water droplets grow larger and larger until they finally fall as rain. They have electricity flowing through them. Condensation happens when dust particles are subjected to temperatures lower than their dew point. Occasionally, rain falls when two types of clouds collide.

Colloidal dust, sand particles, or silver iodide precipitates make fake rain by spraying them into the clouds. It is via this spraying technique that water droplets are made to thicken and fall as rain, so neutralising the cloud’s charge.

Due to their smaller size than the wavelength of light, colloidal pollutants in seawater scatter blue light. The blue colour of the ocean is due to colloids scattering light.

Conclusion

A colloid is a combination of tiny particles of one substance spread in a different substance’s dispersion medium. The lubricants, lotions, toothpaste, and coatings are just a few of the many commercial products that employ colloids as thickening agents.

Furthermore, painting and ink manufacturing relies on colloids. Pens with ballpoint refills employ gel ink (liquid-solid colloid). Using aluminium sulphates (alum) and iron sulphates, coagulation removes suspended contaminants from natural water (ferric sulphates).

Most medications are colloidal. Colloidal gold and calcium are infused into the body to keep muscles alive. Topical eye ointment, Argyrol (silver sol). Other colloids used in medicine include albumin, hetastarch, and dextran.