Colloids play an important role in our daily life. Some important applications of colloids are:
The medicines used in the form of colloids are more effective on account of their easy adsorption and assimilation. Colloidal sulphur, colloidal calcium etc. are used as medicines for different diseases. Antibiotics are mostly used in colloidal form.
(2)MOST OF OUR FOOD HAS COLLOIDAL NATURE
Important examples of such foods are milk, ice-cream, butter, fruit jellies etc.
(3) PURIFICATION OF WATER
The water obtained from natural sources often contains colloidal particles such as bacteria and clay. For the purification of such water, alum and lime are added which fcrm a precipitate of aluminium hydroxide.
Al2(SO43 + 3Ca(OH)2 _______> 3CaSO4 + 2A1(OH)3
This precipitate of Al(OH)3 has the ability to adsorb bacteria and clay particles and thus make them to settle.
(4)REMOVAL OF SMOKE
The air near the factories and industrial plants is usually contaminated with smoke and other gases. The colloidal particles of carbon, arsenic compounds; cement dust and metallic powder, are irritating and even poisonous. The apparatus used for the removal of such particles from the air is called Cottrell Precipitator which has a number of wires. The contaminated air is passed over the wires maintained at high voltage, when the colloidal particles present in air acquire electric charge. A collecting plate of opposite charge attracts the charged particles which lose their charge and fall to the bottom. The air pollution is thus reduced to a minimum.
(5)FORMATION OF DELTA
The river water contains colloidal particles of sand and clay, which carry negative charge. The sea water, on the other hand, contains positive ions such as Na+, Mg+2, Ca+2 etc. As the river water meets the sea water, the negative charge present on clay and sand particles is discharged. As a result, these clay and sand particles are deposited in the form of a delta.
Artificial rain can be caused by throwing electrified sand on the clouds by means of an aero plane. Clouds contain charged colloidal particles. Electrified sand helps to neutralize this charge. As a result, water molecules become dense and result in rainfall.