Question

How can dissolved impurities be removed from water?

Answer 1

There are many ways by which dissolved impurities can be removed from the water. This is usually done based upon the type of impurities whether soluble or insoluble. There are different types of impurities also and their separation is indifferent.

Complete answer: Water impurities are the unwanted substances present in the water. These impurities are of two types: the dissolved impurities and the suspended solids. The dissolved impurities include salts and minerals. These minerals are not important and are harmful to organisms. Dissolved impurities may also include organic and inorganic salts as well as gases. The suspended solid consists of algae, sand, bacteria, and viruses which can cause several diseases e.g. gastroenteritis, diarrhea, malaria, etc.
Separation of the impurities depends on the kind of impurity, the concentration of the impurity. There are several processes by which impurities can be removed.
The dissolved impurities can be removed by the process of distillation. Distillation is the process of separation of impurities from the liquid mixture by evaporation and then condensing that vapor into liquid. Distillation will result in the complete separation of the impurities and the water. The best example for the distillation process is the conversion of seawater to freshwater which is done in many countries to remove the dissolved impurities from the seawater. Temperature plays a very important role in the process of distillation.

Note:
In distillation, there is a change of state from liquid to gas and then again to liquid. Reverse osmosis can also be used as one way to remove the impurities but the most effective way is distillation. Some impurities are insoluble; they are removed by the process of filtration and sedimentation.