You use distillation. Boil water and catch the subsequent steam. The steam will not contain the salt, which does not evaporate. Condense the steam and it will be pure water: 2 hydrogen, 1 oxygen.
To seperate muddy water from water, you could use a filter or a sieve. Or you could use distillation.
Through Evaporation. EASY DA!
God does not exist drawing a conclusion that that is a myth!
Your question is very vague. Anything can be separate from water. Perhaps you mean to ask what does not mix with water. Oil would be an example.