A new desalination method is able to remove salts from the water with less energy than is required for other methods
[Translation by Dr. Nachmani Moshe]
According to researchers from the Pennsylvania State University, a new desalination method is able to remove salts from the water with less energy than required by other methods. "From a global point of view, there is a decreasing and decreasing accessibility to fresh drinking water," says the main researcher. "More and more water sources used by humanity are becoming damaged, both due to rising salinity and the presence of other pollutants, and the result of this is the need to rely on water sources that are not optimal."
In order to combat the situation, the researchers developed a new desalination method known as 'battery electrode deionization, BDI'. This method improves the usual method accepted today for desalination - CDI (capacitive deionization) - by omitting the regeneration step and while reducing the electrical voltage required to complete the process. The conventional method (CDI) prays water by separating the ions in the water. A typical CDI cell consists of two electrodes attached to opposite ends of a flow channel. The electrodes trap the salt ions through electrical conversions that occur when an electric current is applied to the cell. In the next step, the cell regenerates by releasing the salt ions in a second cycle by reversing the direction of the applied current. Since this method does not need filter membranes and has lower energy requirements than other methods, it becomes a competitive method for the removal of salt from water. The problem with this method lies in the fact that it is limited by the adsorption of a small amount of salt when using the typical electrical voltage of 1.2 volts.
Increasing the applied voltage does improve salt adsorption, but it also increases the chance of getting unwanted side reactions that waste unnecessary energy, with the possibility of permanent consumption of the electrode. In the new system developed by the researchers, a specially manufactured flow cell is used which consists of two channels. The channels are separated by a membrane and two identical electrodes are located at each end. In order to test the efficiency of the cell, the team of researchers fed the channel with a salt solution at a defined flow rate while applying a constant electric current. The researchers measured several current densities, depending on the number of membranes in each stack. The researchers next reversed the cell voltage flow when the current reached a minimum level of minus 0.6 volts or a maximum level of plus 0.6 volts. The research team found that the new system effectively removed the salt at levels similar to those of the previous method (CDI), using a low voltage of only 0.6 volts. Moreover, the low current applied and the materials used helped prevent unwanted side reactions, while achieving better desalination performance while utilizing a smaller amount of energy.
Since the researchers simultaneously created desalinated water and concentrated water in two separate channels, the system also bypasses the two-cycle approach, so the cell regeneration phase is no longer needed. In addition, the researchers found that adding membranes between the electrodes reduced energy consumption even more. "Many researchers discuss the possibility of capturing energy from the second CDI cycle, but this possibility is very difficult to the point of impractical," says the researcher. "Our system avoids this second regeneration step simply by replacing the trapping current by changing the direction of the applied electric current. This step is very simple, and it requires the use of little energy."
Although the current configuration is not suitable for the desalination of particularly saline water, such as seawater, the results show that the new method could be effective as a low-energy method for low-level saline water, such as groundwater, or for the preliminary desalination of water before entering treatment facilities. The researchers now intend to improve the system and make it more suitable for large scale. The research findings have long been published in the scientific journal Environmental Science & Technology Letters.
The new desalination system consisting of two channels and two identical electrodes that produces two streams: concentrated water and desalinated water.
10 תגובות
Isn't it easier to spray the clouds with water?
The drops of water that land on the clouds from above will get bigger as they go down. So that the cloud will drop its showers near the sowing area.
As far as I know, "silver iodide" is not effective enough to bring down rain,
Already about 20 years ago, attempts were made to spray clouds with salt water pumped from the sea. This is because the salt absorbs a large amount of water, its weight increases rapidly and it brings down the rain in the desired place. However, using sea water to bring down the rain, will cause salty rain to fall, the salt in which will accumulate on the ground, which is not desirable at all.
As a principle, any sowing of water on the clouds will result in a large amount of rain falling.
Eyal Moorg Shalom
I have the production file on the technology of the late Prof. Dan Zaslavsky. He managed to give it to me before he passed away, with clear instructions. At the time, the faculty had a desktop proof of feasibility that was lost. It is very easy to restore it. As of today, I intend to revive the project even though those interested at the time tried to torpedo it throughout the period. There was no secret here, just stupidity.
If there are other interested parties who wish to take up the project, they should leave details by SMS to the number 0543336888.
Good day, drive carefully.
Life
· Prof. Dan Zaslavsky, the former water commissioner spoke about a new and more efficient desalination method than reverse osmosis, only he kept it a secret. until finding money for development and patent registration.
Another point that can be problematic is the low temperatures at these altitudes. According to what I understand, starting at an altitude of about 2 km, the temperatures drop below zero degrees Celsius and drop rapidly as you increase in altitude, the question is how this will affect the network's water output.
Another problem in the same context, this may also cause the accumulation of ice on the net and turn it into a heavy and useless weight. In such a case, a possible solution is perhaps to wrap a thin copper wire around the net through which an electric current will flow that will come from the ground through the mooring cable, which will heat the net (to an optimal temperature) and prevent the accumulation of ice.
Matthew, thank you, I will consider your offer.
Miracles,
I am aware of all the points you raised and I addressed some of them in the original message:
1. Indeed, the intention is that the net will be spread between two balloons that will be anchored to the ground with the help of cables, similar to the IDF observation balloons. To avoid entanglement between cables of different networks, it will be necessary to ensure a sufficiently large safety margin between them.
2. True, there will be winds, they will constantly flow new clouds saturated with water into the network that you can "squeeze" them, this will only increase the yield of water, which I also estimate will be high in a rain cloud. If you place the net at the average height of the rain clouds (their base starts at a height of 2-3 km and they can reach heights of 20-30 km) then most of the time it will be inside the cloud even if the wind moves it a little to the right and left. It will also be possible to control the height of the network in real time with the help of the cables, that is, to raise or lower it according to the height of the clouds.
3. There is a problem of wear and tear and these nets wear out and tear over time due to the winds, but I still think that in terms of cost/benefit it will be more effective than desalination plants even if you have to change to a new net every two weeks. I also saw that there is a company called cloudFisher that makes much more durable fog nets that don't wear out as quickly.
4. As you said, these nets are very useful in foggy conditions, and in my opinion they will be much more effective in a rain cloud and produce much larger amounts of water there compared to the morning fog, this is actually the main thing in my idea.
5. There is another possibility of deploying the network between two mountain peaks, but I am less connected to this idea and I am not sure that it will be as effective as a network that will be uploaded directly into the cloud. Even from a technical point of view it seems more complicated to me, and in addition it is not certain that the mountains around the Kinneret are high enough for this need.
In my opinion, the simplest thing is to perform an experiment (as I suggested in the first message) and check in practice how much water is produced using this method. You just have to wait for winter for rain clouds to arrive with lots of water 🙂
You will have at least one big problem - the location of the network within the cloud. The clouds are in motion most of the time, unlike fog. The wind gets stronger as you get higher - so the net will not be able to stay inside a cloud. I don't know if it drops the efficiency below the threshold of viability, but I believe it will have a big impact.
You will also need cables to hold the network in place, so it will be a problem to set up a cave of several networks.
I'm not dismissing the idea, God forbid, and from what I've read about fog nets, they are definitely useful.
Looks like a cool idea, contact Mekorot's engineers with the idea, maybe you can solve Israel's water problem..
Haim,
Using a fog net to extract water from the moisture in the air at ground level is not a new idea, but my innovation is to take such a fog net and raise it (with the help of observation balloons, weather balloons, aircraft, etc.) straight into the rain clouds. Intuition tells me that each volume of air inside a rain cloud contains a much larger amount of water compared to the same volume of air at ground level, therefore a fog net placed inside a rain cloud will produce a much larger amount of water compared to an identical net at ground level. If several such networks are installed above the Sea of Galilee, the water produced from them will flow directly to the Sea of Galilee, and there is no need to build a special and expensive pipeline.
Something like sowing clouds with silver iodide, but in my opinion in a much more effective way (it's just a gut feeling, and this of course requires a test which I think is quite simple to perform).
You said that the idea I brought up has been known for a long time, I am not aware of such a thing. Can you direct me to any article that mentions my idea?
An excellent idea that has been known for a long time. The trouble with the dream sages around us who care only about the good and not about the right things.
Hello, I've had an idea for a long time (I call it a "cloud squeezer") that unfortunately I don't have the time or resources to test it in practice, but I would be very happy if someone knowledgeable in the field would give their professional opinion on the subject or even test it practically. My idea is to take a large fog net (of the type used in many places in the world to extract water directly from the moisture in the air, especially in remote villages where there is no access to water infrastructure) and raise it to the height where the rain clouds are. For example, it can be placed between two large balloons of the type used by the IDF to observe the border areas.
My intuition says that such a fog network placed inside a water-saturated rain cloud will produce a much larger amount of water than a fog network that produces water from the moisture in the air at ground level. Clouds contain huge amounts of tiny water droplets floating in the air, and I think the mesh will cause them to condense quickly and drip down as rain. It is possible, for example, to place several such large nets above the Kinneret so that all the water that they "squeeze" from the clouds will drip straight into the Kinneret (it is desirable to direct the net so that it is always perpendicular to the wind so that as many clouds as possible pass through it, this is possible perhaps by using a large rear fin as is present in windbreaks on House roofs Alternatively you can use maybe one single balloon that carries a long and wide strip of fog net with a small weight at the end.
As a start, you can perform a simple feasibility experiment - take two fog nets of the same size that drain the water that condenses in them into a small plastic container, leave one net at ground level as a control experiment, and raise the other net into the rain clouds. Now it is possible to check if the tank in the cloud fills significantly faster compared to the control tank that remains at ground level. As soon as you perform this (relatively simple) experiment and see how much water was produced from the network in the cloud and at what speed it is easy to calculate whether it will be economical or not, and what is the desired size of the network (of course also depends on the weight the balloons can carry).
I would love to hear a professional opinion about the idea,
Thanks in advance.