The best method is fractional distillation.
distillation
Separation of pure components from a mixture.
Allow the water to evaporate, leaving behind the salt would be effective for separating salt and water in a mixture.
Filtering
The process is distillation.
You wouldn't end up separating different kinds of water, you would boil off the pure water leaving its impurities behind.
it is not too pure but is a compound
isolation done with column chromatography fractionation method
By separating the compounds into separate dots on the plate. It is pure if the only dot showing up is that of the tested product
A method is repeated processes of crystallization/recrystallization, for a supplementary refining.But it is a nonsense in your question: salt or pure salt are both sodium chloride, supposed to be pure.
Cryogenic distillation of air is a method to obtain pure noble gases.
gasoline is from crude oil so it's not a pure substance