Today, more than a third of the world's population already lives in areas where they struggle to meet the demand for clean water. By 2025 this number will almost double. Several countries have faced the challenge by installing pipes in natural sources of clean water, but in many such examples this method is not sufficient.
In a new study conducted at Yale University, it is claimed that desalination of seawater should play an important role in helping the fight against the global shortage of clean water - after conservation, reuse and other methods have been perfected. Also, the research provides insights into the process by which more energy efficient and economic desalination technologies can be developed.
"The oceans on Earth are actually an inexhaustible source of water, but the process to remove the salts from them is expensive and consumes energy," said Menachem Elimelech, professor of chemical and environmental engineering at Yale University and the lead author of the article published in the prestigious scientific journal Science.
Reverse osmosis - the process by which seawater is forced to pass through a membrane that filters out the salt - is currently the leading method in the world for seawater desalination. For many years, scientists have focused on increasing the flow of water through the membrane using innovative materials, such as carbon nanotubes, in order to reduce the amount of energy required to push the water through the membrane.
In the new study, the scientists demonstrated that reverse osmosis requires a minimal amount of energy that cannot be exceeded, and that existing technologies are already beginning to approach this limit. Instead of a higher water flow, the researchers suggested that a real gain in efficiency could be obtained during the pre- and post-desalination treatment stages.
Seawater contains organic matter and particulate matter that exists in nature, and they must be filtered before passing through the membrane that removes the salt. Chemical substances are added to the water in order to clean it and help turn these into larger particles that can be removed before the treatment stage. However, if organic matter does not accumulate on the surface of the membrane, then most, if not all, of the early treatment can be dispensed with - this is in accordance with the research findings. In addition, the researchers calculated and found that a membrane capable of filtering out borax and chlorine would result in significant energy and cost savings.
Seventy percent of the world's water is used in agriculture, but water containing even low concentrations of boron and chlorine - minerals found naturally in seawater - cannot be used for this purpose. Instead of removing them during a separate post-treatment step, the scientists believe it would be possible to develop a membrane that could filter them out more efficiently at the same time as the salt removal step.
Elimelech warns and says that desalination should be the last resort in efforts to provide clean water to the world's population, and he explains that long-term research is needed to determine the effect of seawater desalination on the marine environment, but he believes that desalination has an important role already now and in the future come.
"All this will require the development of new materials and improved chemistry, but we believe that this is where we should focus our efforts," Elimelech adds. "The problem of water scarcity will only get worse, and we need to be ready to face the challenge of developing improved and sustainable technology."
5 תגובות
In the United Arab Emirates, water is desalinated with electricity generated from solar panels. It's always better. Even over biodiesel. Biodiesel should be used, for example, in airplanes.
On the one hand, I see a lot of articles here about bio fuel, on the other hand, I now see an article about water desalination.
It is clear that the main requirement for water desalination is energy and one of the main requirements for biofuel is water.
The question is whether bio fuel can provide enough energy for desalination of water that will be consumed for growing it?
If so, then water desalination and growing biofuels seem logical from this point of view (and I emphasize from this point of view)
But if the answer is negative, then only one of the two makes sense to exist, so you have to decide why there is priority for water or energy.
I would be happy if someone who understands can answer me whether bio-fuels can cover the energy cost for desalination of water they will consume in their cultivation, I have been trying to find out for a long time.
This is my brother, well done
In my opinion (and I have expressed it before) the water problem is only an indirect matter. The problem is energy. Once the price of energy is cheap enough, it will be possible to return to wasteful and low-tech processes to convert seawater into drinking water for the masses. For example, if there is still a certain ion in the treated seawater, with the help of an electric electrode it is certainly possible to invest it and remove it from the water.
When we reach efficient and mass energy harvesting technologies, a great many of the problems of the third world will be reduced. Of course, this is about renewable energy and harvesting facilities that are always coupled to sister technologies that consume heat. For example, in solar boiler panels that only use heat, you can also place a panel that harvests the sun's energy. Heat utilization technology combined with light energy harvesting technologies are a key interest in the development of the human race.
To be honest, the article did not innovate anything and I did not see any method of improving water desalination.
We will wait for the next article
Good night
Sabdarmish Yehuda