One common method to remove salt from sea water chemically is through a process called desalination, specifically a technique called reverse osmosis. Here's how it works:
Pre-Treatment: Before the sea water can undergo reverse osmosis, it usually goes through a pre-treatment stage. This stage involves removing larger particles, such as debris, sediment, and algae, through processes like screening and filtration. Chemicals may also be added to prevent scaling and fouling of the reverse osmosis membranes.
Reverse Osmosis: In this step, the pre-treated sea water is forced through a semi-permeable membrane under high pressure. The membrane has extremely tiny pores that allow water molecules to pass through while blocking the larger salt particles and other impurities. As a result, fresh water is produced on one side of the membrane, while the concentrated saltwater, known as brine, is left on the other side.
Post-Treatment: The fresh water obtained from reverse osmosis still contains some dissolved salts and may require further treatment to meet the desired quality standards. This post-treatment can involve additional filtration, disinfection with chemicals like chlorine, pH adjustment, and remineralization if necessary.
It's important to note that while reverse osmosis is an effective method for desalination, it requires significant energy input due to the high pressure needed to push water through the membrane. Therefore, it is generally more feasible in areas where energy resources are abundant or in smaller-scale applications where energy efficiency is not a major constraint. Other desalination methods, such as distillation or electrodialysis, can also be used to remove salt from sea water, but they have different chemical processes involved.