Osmosis membrane technology: the latest development of desalination

A few days ago a United Nations study predicts that by 2025, two-thirds of the world's population will be facing a water crisis. Population growth and changes in rainfall patterns will make the ocean as a potential source of drinking water in many countries. But due to huge demand for energy, in the process of seawater desalination technology is still unable to solve the problem of people is imminent. And according to new scientist reported, compared with traditional reverse osmosis technology, the researchers found the alternative energy efficiency is relatively high - — Is penetration technology.

the modern energy consumption effect of reverse osmosis desalination plants than decades ago has improved, but 一座 1 year production. 500 million cubic meters of water desalination plant will consume 90 megawatts, peak output is equivalent to 20 offshore wind turbines. Reverse osmosis is a inner energy intensive process, the process of natural water by light salty, and reverse osmosis process is just the opposite. If high concentrations in seawater injection of absorbing liquid, fresh water can be extracted easily, and this is what some are already starting to appear experimental 'leaking' the principle behind the factory.

hydration technology innovation of companies in the United States ( HydrationTechnologyInnovations) In 2004, introduced a portable water filter is based on the osmosis principle. Is permeable membrane is small, sealed plastic bag, sealed in the package also includes source as absorbing liquid sugar and spices. But the high cost of the filter to produce clean drinking water, can only be used for emergency, thus unable to cope with global water crisis.

is also 2004, the United States by menachem yili miller (Yale university MenachemElimelech) , Jeffrey McCarty piano ( JeffreyMcCutcheon) , Robert McGinnis ( RobertMcGinnis) Team is composed of penetrating ideas to further advance. The team used an absorbing liquid based on ammonium bicarbonate, ammonium ions and bicarbonate ions can attract water molecules through the membrane, and then heating solution to 40 degrees Celsius, ammonia and carbon dioxide discharge, leaving the pure fresh water, and exhaust gas can be reused after capture. Team said, if we can take advantage of the power plant waste heat evaporating gases, the method of energy consumption is only 20% of the desalination plants, but the technology higher requirements for the plant's location.

is infiltration technology faced another challenge is to find the right film, let water through and out of salt. 'Water desalination report' edit Tom carat, pan ( TomPankratz) Said: 'this is the main obstacle is penetrating industry faces. 'Are permeable membrane needs not only the thickness of thin as far as possible, so that the water of the sea close to attract solution, maintain a high osmotic pressure; At the same time also need to be strong enough, but resistance to penetration of water.

hydration technology innovation of the company has developed a cellulose film, the film could not resist ammonium bicarbonate alkaline solution. In order to withstand the high pressure reverse osmosis process, reverse osmosis membrane 'support' is needed to strengthen its toughness, but if used in penetration, the membrane is too thick.

Yale university research team realized that if the support layer to go out, you can get appropriate is permeable membrane. Through the test of different polymer solution, the team found a way to use alternative support layer of thin film method. In addition to the new film, thin and toughness, permeability is very good also. Experiment, up for osmosis membrane flux is traditional 9 times that of the reverse osmosis membrane, can filter 97% of salt. Yili miller said the test USES is 'manual lab version of' the new film, if the new film in industrial scale production, its performance will be better.