What are the major uses of colloids in daily life industry and medicine
Colloids are also called colloidal solutions or even colloidal systems. They are mixtures wherein microscopically dispersed insoluble particles of one particular substance are suspended in the other. The size of these suspended particles in colloids tends to range from 1 to 1000 nm. A mixture is classified as a colloid only when the suspended particles in it do not settle at the bottom of the container when they are left undisturbed.
Colloidal solutions tend to exhibit the Tyndall effect, wherein a beam of leam that is incident on colloids tends to scatter because of the interaction occurring between the light and colloidal particles. Today, we will learn about the examples of colloids, application of colloids in food and medicine, the protective action of colloids and the different uses of colloids in different industries. Let us first take a look at some of the examples of colloids.
Examples of Colloids
1) Blood
Blood is a respiratory pigment that contains the protein albumin in water. The pigment part consists of albumin which acts as a dispersed phase in the dispersion medium, which is water. This is a hydrosol.
2) Cloud
Clouds consist of air that is a dispersion medium and the droplets of water act as a dispersed phase. They are aerosols.
3) Gold Sol
Gold sol is a metallic sol wherein the gold particles are dispersed in water. The food products that we eat in our day to day lives are all colloids. For example, dairy products, fruit juices, cake, bread, butter, cream, milk, whipped cream, etc. are all colloidal.
The natural phenomena occurring around us like clouds, fog, mist, rain, etc. are colloids as well but in different forms. Dust and smoke and colloidal nature too.
The blue colour of the sky is due to the suspended dust and water particles in the air that tends to scatter blue light more than any other light. Similarly, the seawater seems blue in colour due to the colloidal matter present in it that scatters the blue light.
Fertile soil consists of colloids as well in the form of humus and clay which plays an essential role for storing and exchanging minerals.
Application of Colloids
Let us now learn about the application of colloids in food and medicine.
Colloids are used widely in several different industries and have domestic and medical applications.
Food Items: Day to day food items like soup, syrup, dairy products, etc.
Medicine: Colloidal silver named Arygyrols which acts as an antiseptic for several eye infections.
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Let us take a look at some of the other applications of colloidal dispersion.
Purification of Air Via Cottrell Precipitator
The process of purification of air via Cottrell precipitator consists of coagulation of the solution particles. Smoke is dust that is allowed to pass through the electrified chamber inlet that has a centralised electrical plate. This is provided with an opposite charge of the smoke particles. When dust is allowed to pass, these particles tend to coagulate and purified air passes through the other outlet.
Leather Tanning
Animal skin is quite soft and when it is immersed in the tannin solution having an opposite charge to that of the animal skin, particles tend to get coagulated. In turn, skin tends to become harder and the process is called tanning of leather.
Delta Formation
Delta formation consists of coagulation of the river particles with the help of the seawater electrolyte.
Protective Action of Colloids
The protective action of different colloids is to be compared regarding the gold number.
A lyophobic colloid is protected from the coagulation when a protective lyophilic colloid is used. The protection power is expressed in regards to the gold number, which determines the amount of protective colloid in milligrams which is required for preventing the coagulation of a 10mL standard gold sol when 1mL 10% NaCl solution gets added to it. The smaller the gold number is, the higher the protection power would be.
FAQs on Applications of Colloids in Chemistry and Real World Uses
1. What are colloids and why are they important in chemistry?
A colloid is a heterogeneous mixture in which particles of size 1–1000 nm are dispersed in another medium and do not settle under gravity. Colloids are important because they bridge the properties of true solutions and suspensions and have wide industrial and biological applications.
- Dispersed phase: particles present in small amount.
- Dispersion medium: continuous phase in larger amount.
- Show Tyndall effect and Brownian motion.
- Examples: milk (emulsion), fog (aerosol), starch solution (sol).
2. What are the main applications of colloids in daily life?
Colloids are used in food, medicine, cosmetics, water purification, and industrial processes due to their unique surface and stability properties. Key applications include:
- Food industry: milk, butter, ice cream, and jellies are colloidal systems.
- Medicines: colloidal silver and gold are used for therapeutic purposes; drug delivery systems use colloidal carriers.
- Cosmetics: creams, lotions, and gels are emulsions.
- Water purification: removal of colloidal impurities by coagulation using alum.
- Industrial uses: rubber latex, paints, inks, and photographic films.
3. How are colloids used in water purification?
Colloids are removed from water by coagulation, where an electrolyte like alum neutralizes the charge on colloidal particles causing them to aggregate and settle. In water treatment:
- Impurities are often negatively charged colloids.
- Addition of Al2(SO4)3 (alum) forms Al(OH)3 precipitate.
- Reaction: Al2(SO4)3(aq) + 6H2O(l) → 2Al(OH)3(s) + 3H2SO4(aq)
- The gelatinous Al(OH)3 traps colloidal particles and settles down.
4. What are the applications of colloids in medicine?
Colloids are used in medicine for drug delivery, plasma expanders, and antimicrobial agents due to their small particle size and high surface activity. Important examples include:
- Colloidal gold and silver for diagnostic and antimicrobial purposes.
- Plasma expanders like dextran (a colloidal solution) to maintain blood volume.
- Drug delivery systems using liposomes (colloidal dispersions).
- Antacids such as milk of magnesia are colloidal dispersions.
5. How are colloids used in the food industry?
Colloids are widely used in the food industry to improve texture, stability, and appearance of products. Common examples include:
- Emulsions: milk (liquid in liquid), mayonnaise.
- Gels: jelly, cheese, custard.
- Foams: whipped cream, bread.
- Stabilizers like starch and gelatin maintain colloidal structure.
6. What is the role of colloids in industry?
Colloids play a crucial role in industries such as paint, rubber, textiles, and metallurgy due to their dispersing and stabilizing properties. Major industrial applications include:
- Paints and inks: pigments dispersed as sols.
- Rubber industry: latex is a colloidal dispersion of rubber particles.
- Textile industry: dyeing involves adsorption of colloidal particles.
- Metallurgy: froth flotation process for ore concentration uses colloidal principles.
7. What is the application of colloids in the purification of air?
Colloidal particles in air are removed using a Cottrell precipitator, which applies electrostatic precipitation to eliminate smoke and dust. In this method:
- Smoke particles are charged electrically.
- Charged particles move toward oppositely charged plates.
- Particles get neutralized and settle down.
8. How are colloids applied in the froth flotation process?
The froth flotation process uses colloidal principles to concentrate sulphide ores by selectively adsorbing collectors on ore particles. The steps include:
- Ore is powdered and mixed with water to form slurry.
- Collectors like xanthates selectively make ore particles hydrophobic.
- Air is bubbled; hydrophobic particles attach to froth and rise.
- Impurities remain in water.
9. What is the importance of colloids in biological systems?
Biological systems are largely colloidal in nature because many body fluids and tissues exist as colloidal dispersions. Key examples include:
- Blood as a colloidal dispersion of proteins in plasma.
- Protoplasm of cells is a complex colloidal system.
- Enzymes and proteins function effectively due to colloidal properties.
10. What is the role of colloids in the formation of clouds and fog?
Clouds and fog are examples of aerosols, where tiny liquid water droplets are dispersed in air as a colloidal system. In this case:
- Dispersed phase: water droplets.
- Dispersion medium: air.
- Droplet size falls within colloidal range (1–1000 nm).
