Preparation method for slow-release-type nanometer zero-valent iron particles

Abstract

The invention discloses a preparation method for green slow-release-type nanometer zero-valent iron particles. The nanometer zero-valent iron particles serve as the core of a material, and the surface of the nanometer zero-valent iron particles is wrapped with polyaspartic acid (PASP). A reduction method is adopted, in a PASP aqueous solution, KBH4 or NaBH4 or other reducing agents are used for reducing Fe2+ to obtain Fe0. The preparation method is simple and free of secondary pollution. The obtained nanometer zero-valent iron particles have better dispersity and reactivity, and are higher than common iron powder by more than 174% and 148% respectively on the aspect of the effects of removing Cr6+ and hexachlorobenzene. The nanometer zero-valent iron particles have good stability in air, can be stored for a longer time, have good slow-release performance and can effectively control pollutants for a long time. Compared with common nanometer zero-valent iron, the action duration time can be improved by more than 40%, and the slow-release-type nanometer zero-valent iron particles have good market potentials.

Description

technical field [0001] This patent relates to nanomaterial preparation technology, especially a preparation method of slow-release nanometer zero-valent iron particles. Background technique [0002] Zero-valent iron is a material widely used in the treatment of polluted groundwater and soil. Due to its strong electronegativity and reducibility, it can react with a variety of pollutants, such as chlorobenzenes and heavy metals. So as to achieve the purpose of removing pollutants. Due to the unique nanoparticle structure of nano-zero-valent iron, it has the characteristics of large specific surface area and strong activity. It has a faster reaction rate in the process of interacting with the above pollutants, and the treatment effect is far better than that of ordinary zero-valent iron. Powder has a good market prospect. [0003] At present, the preparation methods of nano-zero-valent iron mainly include gas-phase method, liquid-phase method and solid-phase method. The nano...

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Problems solved by technology

The nano-zero-valent iron prepared by the gas-phase method has the advantages of small particle size and high purity, but this method requires relatively high equipment and is difficult to operate; the solid-phase method has a relatively simple process, but the prepared nano-zero-valent iron has poor dispersion and is prone to reunion

The liquid phase method is the most widely used, and can produce nano-zero-valent iron with good dispersion performance, but the stability of nano-zero-valent iron in the air before use has not been solved; at the same time, due to the adsorption of pollutants in groundwater and soil on soil particles On the surface, the release is relatively slow, and a large amount of nano-zero-valent iron is released at one time, resulting in waste of materials and unable to control the polluted site for a long time

In the previous research of this patent, natural polymer substances such as chitosan and guar gum were used to coat the surface of nano-zero-valent iron, which solved the stability problem of the material in the air and avoided the coating Secondary pollution of materials; however, the slow-release problem of nano-zero-valent iron has not been solved, and due to the limitation of the degree of polymerization of natural polymer substances, the application field of this nanocomposite material is relatively single

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