Water desalination removes minerals from sea or brackish water through processes including reverse osmosis, thermal distillation, and electrodialysis. These processes use membranes, heat, or electrical charges to trap unwanted salt and minerals, leaving fresh water behind. Other processes include solar humidification, membrane distillation, and freezing.
Water desalination is the process of removing minerals from sea or brackish water. It works by removing the salt from the water, leaving clean water behind. There are several types of water desalination processes, including reverse osmosis, thermal distillation, and electrodialysis.
Reverse osmosis pushes water through a membrane while trapping unwanted salt and minerals. It is said to remove 95-99% of unwanted materials. Before the process, the water is pre-treated and sent through microfilters to remove larger particles and help protect the membrane. The water is then pushed through membranes that trap salt or minerals to produce fresh water.
Thermal distillation uses heat to remove minerals. Bringing the salted water to a boil evaporates the water leaving the salt. The vapor is then condensed in a second container and collected. The process of boiling water can consume a lot of fuel, so to keep costs down, other processes can be used. These processes are called multistage flash distillation, multiple effect distillation, and vapor compression distillation. They all have to do with reducing the vapor pressure of water to lower its boiling point, so less energy can be used.
Electrodialysis uses the electrical charge of salt ions to separate them from water. In this process, water is pre-treated and then sent to a membrane stack. Two electrodes, a positive one on one side of the battery and a negative one on the other, pass an electric current through the water. The ions are attracted to the oppositely charged electrodes and flow through membranes designed to trap anions, which are negatively charged ions, or cations, which are positively charged ions. Once the ions are trapped, fresh water is left behind.
Other types of desalination processes include solar humidification, membrane distillation, and freezing. Freezing takes advantage of the fact that salt is not included in the formation of ice crystals when water freezes, so this mineral can be washed away when the water is nearly frozen. Solar humidification uses the sun’s energy to vaporize water. The water is then allowed to condense on another surface, where it is collected.
In membrane distillation, water is first vaporized. It is then sent through membranes which allow the vapor to pass but not the liquid. Salt and other substances are captured in the membrane and trapped there, and water vapor is condensed onto a surface on the other side. Once liquid, fresh water cannot flow back through the membrane and is free to collect.
Protect your devices with Threat Protection by NordVPN
