There are [multiple desalination methods](https://en.wikipedia.org/wiki/Desalination https://en.wikipedia.org/wiki/Desalination). My favourite is [reverse osmos

There are [multiple desalination methods](https://en.wikipedia.org/wiki/Desalination https://en.wikipedia.org/wiki/Desalination). My favourite is [reverse osmosis](https://en.wikipedia.org/wiki/Reverse_osmosis https://en.wikipedia.org/wiki/Reverse_osmosis), though it does cost about $1.2 per cubic meter of water. To answer your question, ion exchangers do what you ask, using sulfuric acid and sodium hydroxide, and produce a ton of sodium sulfate in the resulting desalinated water.