Why is it impossible to purify sea-water?

Question

We humans have so advanced technology at our disposal and still we are unable to purify sea-water even though it only has salt in excess quantity. That is, we have technology to remove all those harmful bacteria etc., but no technology for removing salinity.

So what is the problem in purifying such sea water?

Answer 1

It is not impossible. The problem is that in order to purify water we need a lot of energy more than what we would gain from the water made. Another thing is that in order to have water for all the population in earth again excessive use of energy would be used an that is what is imppossible to gain all of that energy

Answer 2

There are two useful processes for getting drinking water from sea water.   Desalinization is basically distilling the water by evaporating it and condensing the vapor.    The other process is called reverse osmosis.    The US Naval base in Guantanamo, and a number of other places on Earth use the processes.  

Since you asked, the problem is that it is more expensive than just taking water from a river or lake, and treating it.

Answer 3

As others said, it's possible and practical.  It's just expensive.  But then, God is doing it for us for free by distillation.  The sun evaporates it from the oceans, transports it as clouds, condenses it as rain/snow, and delivers it to us in underground aquifers.  What more do you want?

Answer 4

Sea water can be purified and salts can be removed from sea water so you are incorrect. This can be done by a process known as electrolysis. The problem with that is that it's expensive to use electrical energy to separate salts from water so we don't invest much money into it. Ores are a much more efficient source of salts.