Maximizing the Efficiency of 'Seawater Desalination' Using Magnesium

[Asia Economy Reporter Junho Hwang] Domestic researchers have discovered a method to suppress fouling of membranes used in seawater desalination technology, which removes salt and dissolved substances from seawater to obtain drinking water, domestic water, and industrial water.

The Korea Institute of Science and Technology (KIST) announced on the 6th that the research team led by Dr. Seongpil Jeong and Dr. Seokheon Lee at the Water Resources Circulation Research Center developed a magnesium dosing pretreatment process that prevents membranes applicable to the membrane distillation process, one of the seawater desalination technologies, from fouling or wetting.

The membrane distillation process, one of the seawater desalination technologies, produces freshwater by heating seawater to generate steam, passing it through a hydrophobic membrane, and condensing it. However, this process has the disadvantage of reduced efficiency or increased costs due to membrane fouling on the membrane surface or membrane wetting phenomena.

The research team conducted a study to solve this drawback. Through this, they confirmed that the main cause of membrane fouling is the formation of calcium carbonate (CaCO3) and calcium sulfate (CaSO4) crystals on the membrane surface. Calcium carbonate forms from the early stages of operation, causing partial membrane wetting, while calcium sulfate causes complete membrane wetting, leading to operational shutdowns.

Additionally, the research team developed a pretreatment process that doses magnesium chloride into seawater to address membrane fouling and wetting. Magnesium binds with carbonate and sulfate ions present in seawater. Accordingly, the formation of calcium carbonate and calcium sulfate can be prevented. The research team demonstrated that the magnesium chloride pretreatment process effectively delays membrane fouling and also secures resistance to membrane wetting.

Dr. Seongpil Jeong of KIST said, "With the stability of hydrophobic membranes secured, desalination efficiency is expected to increase, and the lifespan of membranes can be extended," adding, "This inorganic-based eco-friendly pretreatment can be applied not only to membrane distillation processes but also to various seawater desalination processes."

This content was produced with the assistance of AI translation services.