One is distillation, that is, seawater is heated into steam, and then steam is cooled into fresh water. One distillation won't work, and it can be distilled many times.
Another is reverse osmosis. A thin porous "reverse osmosis membrane" is used as the core component. Under pressure, the membrane can only let water pass through, keep salt substances out of the membrane, and separate fresh water from salt.
The shortage of fresh water resources in the world has become an increasingly worrying problem, which has also affected the economic development of some countries. 1In March, 1997, the World Meteorological Organization and UNESCO, in the document prepared for the World Water Forum held in Morocco, exclaimed that "water may become a rare thing by 2 1 century". Of course, the water mentioned here refers to fresh water. Fresh water on the earth is very limited, accounting for less than 3% of the total water on the earth. Moreover, about 2/3 of them are stored in the thick snow and ice in the mountains and polar regions, and nearly 1/3 are buried deep in the stratum. The fresh water that can really be used by us only accounts for about 0.26% of the total water of the earth. It is this small part of fresh water resources that is facing serious human pollution today, making it even more stretched and increasingly scarce. Therefore, saving water and protecting precious fresh water resources have become a top priority all over the world.
In addition to the above two seawater desalination methods, people are still exploring other seawater desalination technologies with higher efficiency and lower cost.