Now there is a new water purification technology: put a ping-pong material into a bucket of water and shake it, so that salt and other impurities in the water can be sucked in and safe and drinkable water can be purified. Put some clean water in the sun for a few minutes and shake it. It can be used to purify water again.
This is "nature? The latest research published in August 10 by the journal of natural sustainable development. This study was developed by Wang Huanting, a professor at Monash University in Australia, and the first author of this study was Wen Ran, an associate professor and doctoral supervisor at Xiamen University. This is a photosensitive MOF material PSP-MIL-53. Through adsorption, seawater can be desalinated into safe and clean drinking water within 30 minutes, which is expected to solve the problem of safe drinking water in water-deficient areas and greatly benefit mankind.
The purified water is cleaner than the standards recommended by WHO.
MOF is a porous material, and its unit surface area exceeds all known materials. The surface area of a teaspoon volume of MOF material is equivalent to the size of a football field. On the other hand, MIL-53 is a special MOF. After PSP was added, it became a photosensitive MOF material named PSP-MIL-53.
The first authors of this study are Dr. Wen Ran and Professor Wang Huanting, associate professors of School of Environment and Ecology, Xiamen University.
The photosensitive m of material can continuously purify 40 gallons (about 65,438+0,565,438+0 liters) of drinking water per kilogram, and its water quality is even cleaner than the quality drinking water standard recommended by WHO, and the total dissolved solids (TDS) is less than 500(500ppm). According to WHO's recommendation, the total dissolved solids content of high-quality drinking water should be less than 600 parts per million (600(600ppm).
Another advantage of the above photosensitive MOF material is that it can be recycled. Wang Huanting told the Red Star journalist that when the sun is strongest at noon, the absorbed salt can be washed out by 4 minutes of light, so that it can be recycled. In addition, washing out salt does not necessarily depend on sunlight. Wang Huanting's team can also use the lights of the laboratory to clean up, but it takes a little longer, about 30 minutes to 1 hour.
How is this material designed? ? First applied, and then consciously designed this material. ? Wang Huanting told reporters that he has been studying the application of membrane materials and nano-materials in different fields, and has also done research on water for many years.
As early as two years ago (20 18), Wang Huanting and his team designed a temperature-sensitive porous material to absorb salt, and then washed it off with hot water to reuse the material. This breakthrough research is to put photoresponsive polymer materials into porous materials to realize the elution of salt by light. So Wang Huanting said, what is the result of this study? The results accumulated in the group for so many years are taken for granted. ?
The materials are efficient, energy-saving and sustainable.
In the past decades, scientists have been committed to solving the problem of safe drinking water for human beings, and have successfully developed some effective water purification methods, but these methods are difficult to popularize in some areas lacking stable power supply because of energy consumption problems.
Desalination and purification of seawater and brine is one of the ways to obtain clean fresh water. According to Wang Huanting, at present, the large-scale application of seawater desalination or low-concentration brine desalination is mainly through two methods, namely reverse osmosis membrane and thermal desalination. Among them, the method using reverse osmosis membrane has the problems of high energy consumption, environmental protection and high cost. This method of turning seawater into fresh water consumes a lot of electricity and can only get 40% fresh water. In terms of efficiency, when the concentration of salt is higher and higher, the energy consumption of desalination is greater. Therefore, the remaining 60% concentrated brine was put back into the sea. If the dispersion and backflow of concentrated brine are not done well, the concentration of surrounding seawater will increase, which will affect the growth of surrounding marine life.
Under dark and bright conditions, the material absorbed and washed out, according to the inverse.
In addition, this water purification method requires large equipment and the cost of building a factory is very high. The investment of a desalination plant of this kind in Melbourne is as high as A $33.4 billion, and this kind of water purification method involving large equipment has high maintenance cost.
Another large-scale application of hot seawater desalination in industry also consumes huge energy.
Compared with these methods, using photosensitive MOF materials to purify water? No equipment, no energy consumption and low maintenance cost. ? Wang Huanting pointed out that if this material can be truly industrialized, it can solve the water problem of some people.
It also has application potential in other fields.
It is understood that this research result has attracted a lot of attention once it was released. Wang Huanting told the Red Star journalist that several countries such as Saudi Arabia have contacted the team, and some people with drinking water problems in remote areas have also come to consult. Wang Huanting's team recently received a letter from a small island resident in the United States, asking when this material can enter the market for customers to buy.
However, there is still a process from the principle experiment in the laboratory to the products for industrial application. Wang Huanting said that at present, he has applied for a patent, and the next step is to test the stability and durability of materials in different environments.
There are still many specific problems in the practical application of new materials, such as what water to use for purification and whether there are other impurities besides salt in the water. And whether these impurities have an effect on the properties of the material. Wang Huanting estimated that? The problem should not be very big? However, we still have to draw conclusions from scientific research.
In addition, this photosensitive MOF material adsorbs? Salt? It's just a broad statement, but it actually has the ability to adsorb ions. Some elements harmful to human body, such as mercury and copper, also exist in the form of ions, which can be absorbed by it in principle, but how much can be absorbed has not been tested.
It is worth noting that the large-scale application of a material needs to consider how to make it cheaper and whether its cost can be accepted by the market. So in general, photosensitive MOF materials are far from application.
In addition to water purification, this material also has application potential in mining and other fields. Wang Huanting revealed to the Red Star journalist that the selective adsorption of a certain ion can be realized by some improvements to the material, which can be applied to other fields. For example, in mining, MOF materials can be used to extract lithium by adsorption. Some existing adsorbents in mining industry need to wash out lithium with chemicals after adsorption, which will lead to secondary pollution. If photosensitive or thermosensitive MOF materials are adsorbed, chemicals are not used in the cleaning process, which has great environmental protection value and lower cost.