A kind of nano zero-valent iron stable in air and preparation method thereof

Abstract

The invention discloses nanoscale zero-valent iron stable in air, wherein nanoscale zero-valent iron is taken as a core, and silicon dioxide is covered on the surface thereof. The preparation method comprises the following steps of: (1) adding isopropanol aqueous solution in ferrous sulphate, charging nitrogen, mechanically stirring for 15 to 30 minutes, dropping sodium borohydride solution containing sodium hydroxide while stirring, after that, adding polyethylene glycol, and continuing to react for 0.5 to 1 hours while stirring; (2) adding tetraethoxysilane in the solution, controlling the molar ratio of the sodium hydroxide to the sodium borohydride in the solution to be in a certain range, continuously stirring, and continuously charging nitrogen, after the reaction is finished, staying, vacuum-filtrating, then washing by absolute ethyl alcohol and deionized water respectively; and (3) vacuum-drying the obtained nano-iron to obtain the stable nanoscale zero-valent iron. The nanoscale zero-valent iron has a good inoxidizability in air; and the whole reaction process has the advantages of low material price, simple device, convenient operation, and easily-controlled and safe process condition.

Description

technical field [0001] The invention relates to nanometer zero-valent iron and a preparation method thereof, belonging to the field of nanotechnology. In particular, it relates to a nanometer zero-valent iron stable in air and a preparation method thereof. Background technique [0002] In recent years, the application of nano-zero-valent iron in environmental restoration and the degradation of environmental pollutants has become a new hot spot. Compared with ordinary iron powder, nano-zero-valent iron has the characteristics of small particle size, large specific surface area, and large surface energy. , has high activity when reacting with other substances, and the treatment effect is far superior to that of ordinary iron powder. Coupled with its excellent reduction effect, nano-zero-valent iron has a wide range of applications in the field of environmental protection. For the ecological environment It is of great significance to restore and protect the water environment. ...

AI Technical Summary

Problems solved by technology

In order to improve the stability of nano-zero-valent iron in the air so as to improve the anti-oxidation performance of nano-iron powder, the main anti-oxidation modification methods currently used are: (1) Surface micro-oxidation method, exposing nano-zero-valent iron to a micro-oxygen environment Among them, the method of slowly oxidizing the surface will reduce the use efficiency of nano-iron; (2) organic matter coating method, generally using high-molecular organic matter to modify nano-iron, but high-molecular organic matter usually brings secondary pollution to the environment , and the operation is more complicated; (3) polymer coating method, generally using polymer to modify nano-iron, but this method has complicated steps, complicated operation, and will cause certain pollution to the environment; (4) alloying method, that is, noble metal coating Coated on the surface of nano-zero-valent iron to improve its oxidation resistance, but precious metal materials are expensive and not suitable for mass production

The above-mentioned methods all have the disadvantages of expensive equipment, complex operation process, complicated steps, low product purity and low yield to varying degrees.

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