Chinese researchers propose a new method for desalination of brackish water at low cost using new materials

The reporter learned from Hohai University on the 11th that the young teacher and student team of the School of Hydrology and Water Resources of the school proposed a new method of desalinating brackish water at low cost based on the "metal-organic" framework materials
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Related results have recently been published in the international academic journal "Materials Horizon"
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? According to the first author of the paper, Dr.
Xingtao Xu, there are two common water purification methods: one is adsorption filtration, and the other is reverse osmosis
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"Under the natural state, water molecules diffuse from fresh water to salt water through a semi-permeable membrane.
This is osmosis
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To achieve the separation of salt and water in saline water with reverse osmosis, it not only requires an osmotic membrane, but also consumes a lot of energy
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"? Xu Xingtao told reporters that although reverse osmosis is the current mainstream method for desalination of brackish water, it has disadvantages such as high energy consumption, high permeable membrane cost, and difficulty in waste liquid treatment.
The scientific community has also been trying more energy-saving and environmentally friendly desalination technologies.
"Capacitive deionization" is one of them
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Lin Peng, a core member of the team and a 2018 graduate student in the School of Hydrology and Water Resources of Hohai University, introduced that "capacitive deionization" is also known as the electrosorption method.
When the electrodes in the salt solution are energized, the anions and cations of the salt will be adsorbed separately The positive and negative poles of the electrode achieve the purpose of desalination
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? "The advantage of this technology is that it requires a very small voltage, which is equivalent to the voltage of an ordinary dry cell
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Moreover, as long as the voltage is reversed, the salt adsorbed on the electrode will return to the solution, and the electrode will also be regenerated
"Xu Xingtao said, the key problem of "capacitive deionization" is that the current mainstream carbon adsorption materials have poor performance, are susceptible to corrosion by dissolved oxygen, shorten their lifespan, and increase costs in disguise
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? "We pyrolyzed the'metal-organic' framework material in nitrogen to obtain a carbon material doped with iron and nitrogen
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" Lin Peng said, the team put the electrode made of this new material into oxygen saturation In the salt solution, the test results show that the electrode not only maintains good corrosion resistance, but also significantly increases the amount of salt adsorption
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? Yang Tao, Dean of the School of Hydrology and Water Resources of Hohai University, said that at present, the brackish water desalination equipment trial-produced by the institute using this new material has completed the laboratory stage test.
The next step will be to carry out the test in the water-scarce area of ​​Northwest China.
Achieving the set goals will be of great significance to solving the problem of clean drinking water for local residents
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