The process by which salt is separated from salty water is known as evaporation. To evaporate, a liquid needs latent heat of evaporation. As this energy is given to the liquid, the molecules on the top gain energy and escape the liquid as vapor. This process is known as evaporation. Sun is the source that provides this energy.
So, when salty water is exposed to sunlight, first the surface molecules would escape as they gain the latent heat of evaporation. Then, the layer below would evaporate and this would continue until gradually all the water in the solution evaporates. As the water has evaporated only salt is left behind.
In some countries, especially in the UAE, this phenomenon is used to extract drinking water from extremely saline seawater. They have specially designed beds for this purpose and have a mechanism to collect the water vapor through simple condensation. Condensation is a process by which a vapor changes into a liquid. When a vapor is released from water, it has a very high energy. When it touches a cold surface, it loses the energy and converts back into liquid. In this way salt-free water can be obtained from sea water.
So, when salty water is exposed to sunlight, first the surface molecules would escape as they gain the latent heat of evaporation. Then, the layer below would evaporate and this would continue until gradually all the water in the solution evaporates. As the water has evaporated only salt is left behind.
In some countries, especially in the UAE, this phenomenon is used to extract drinking water from extremely saline seawater. They have specially designed beds for this purpose and have a mechanism to collect the water vapor through simple condensation. Condensation is a process by which a vapor changes into a liquid. When a vapor is released from water, it has a very high energy. When it touches a cold surface, it loses the energy and converts back into liquid. In this way salt-free water can be obtained from sea water.
