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In an effort to curb global climate change, scientists are competing with the mastery of designing more efficient systems to capture carbon dioxide to reduce its concentration in the atmosphere. In a joint effort, manufacturers have begun equipping themselves with air management centers, particularly so -called direct air capture (DAC) systems, to reduce their carbon footprint. However, the latter remains limited in terms of capacity. The cost of surgery is also a brake, because chemical reactions are very energy efficient. The new Japanese carbon capture system aims to overcome these barriers, using “liquid-solid phase separation” technology, which directly removes CO2 from the atmosphere. 99% efficient with short CO2 concentrations and twice as fast as current DACs, this new system is the fastest in the world.
Many scientists believe that the effects of climate change have reached the point of no return. These consequences are already being felt in many countries around the world, where the damage is severe. Countries like India and Pakistan, for example, have recently made headlines with severe and unusual temperature rises. In other countries, thousands of acres of forest have been lost to make way for deserts. Without a sustainable solution, this type of disaster risks affecting many countries.
In an attempt to mitigate these harmful effects, technologies for reducing carbon emissions (one of the major anthropogenic factors of climate change) have been developed. In addition to reducing atmospheric carbon, scientists have seen opportunities for reusing captured CO2. Current technologies make it possible to extract, store and convert CO2 into other industrial reusable chemical compounds.
However, many obstacles still need to be overcome before current DAC technologies (such as potassium hydroxide and calcium hydroxide) can be used on a large scale. One of the challenges is efficiency, since CO2 concentrations in the air allow only very slow chemical reactions with the components obtained. In addition, the extracted CO2 is difficult to extract and reuse, if the chemical reactions that allow desorption are very energy intensive.
A new study led by Tokyo Metropolitan University relates to liquid-solid phase separation system DACs. Typically, this type of separation must operate on the basic principle of sedimentation, which is to say that in a liquid-solid mixture, the densest bodies accumulate at the bottom of the container, by the effect of gravity. But in a liquid-solid separation that is in continuous operation, the solid particles have no time to fully sediment, and the liquid thus remains with the solids at the outlet of the system.
On the other hand, most DACs pass air through a liquid, where a chemical reaction takes place between the liquid and the CO2. As the reaction progresses, more reaction products accumulate in the liquid, making subsequent reactions slower and slower.
The new liquid-solid phase separation system, presented in the study published in the journal ACS Publications, allows insoluble and solid reaction products to come out of the solution. Therefore there is no accumulation of solid particles in the liquid and the reaction rate does not slow down.
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In their new carbon capture system, the researchers modified the structure of liquid amine compounds to optimize the speed and efficiency of the chemical reaction, with high concentrations of CO2 in the air (up to 400ppm). ).
They then discovered that one of their aqueous solutions, especially isophorone diamine (IPDA), can capture and convert 99% of CO2 from the air into a solid precipitate of carbamic acid. In addition, it is sufficient to heat the dispersing solid in the solution to 60 ° C to reverse the reaction, and thus re-release the CO2 while recovering the original liquid.
In addition, the CO2 removal rate is at least twice as high as conventional laboratory DAC systems, making it the fastest of its class in the world, even at low CO2 concentrations.
The Japanese team also believes its new process will eventually be applicable to a large extent. The use of extracted carbon for industries and the manufacture of household products will also be studied, making this new capture system a versatile solution.