The salt water can be purified by:
Filtering it through a cloth.
Heating it and thus condensing steam which will give fresh water.
Stirring it for half an hour.
Salt water cannot be purified.
Salt get dissolved in water, so filtering it will not purify water. But since salt doesn't evaporate on heating so heating salt water purify it.
Impure compounds of copper sulphate or salt from sea water can be purified using the method called: