A kind of sulfurized nano zero-valent iron particles and its preparation method and application

Abstract

The invention discloses a sulfurized nano-zero-valent iron particle and its preparation method and application. The preparation method of the sulfurized nano-zero-valent iron particle comprises the following steps: 1) ferrous salt and NaBH 4 react to prepare nanometer zero-valent iron particles; 2) coat nanometer zerovalent iron particles with elemental sulfur powder to prepare elemental sulfur-coated nanometer zerovalent iron particles. The present invention uses elemental sulfur powder as a sulfur source to coat and modify nanometer zero-valent iron particles. The reaction conditions are mild, the operation is simple, the production cost is low, and it is convenient for large-scale production, and the prepared vulcanized nanometer zerovalent iron particles will pollute the target. It has high selectivity and high reduction conversion efficiency, and can be widely used in the remediation of contaminated groundwater or soil.

Description

Technical field [0001] The present invention relates to a sulfide nano zero-valent iron particle and a preparation method thereof and a method thereof. Background technique [0002] Nano-zero-ferrous iron particles are widely used in pollution of groundwater and soil, which) has the following advantages: Heavy reduction ability; 2) After the pollutant treatment, it will turn itself into iron oxide, and the effect is small. ; 3) Small particle size, uniform particle size, large specific surface area; 4) Easy to use, injecting the in-situ repair by injection into contaminated groundwater or soil, and can be contaminated with aqueous layer, contaminated water Purification is more thorough. [0003] However, the nano-zero-coated iron particles still have the following defects and lack of deficiency in the actual application: 1) is affected by the surface role of Van Dehua, magnetic force, and the nano-zero-valent iron particles are easy to collect into larger particles, reaction. The...

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Problems solved by technology

[0003] However, there are still the following defects and deficiencies in the practical application of nano-zero-valent iron particles: 1) Under the influence of van der Waals force, magnetic force and other surface forces, nano-zero-valent iron particles are easy to aggregate into particles with larger particle sizes, and the reaction The activity is greatly reduced; 2) In the actual pollution remediation process, the reactivity of nano-zero-valent iron particles is high, and electrons can be arbitrarily transferred to H 2 O, dissolved oxygen (DO) and nitrate (NO 3 - ) and other electron acceptors will consume a large amount of reducing power, reducing its selectivity to target pollutants and reduction conversion efficiency

[0008] At present, the vulcanization reagents used in the synthesis of vulcanized nano-zero-valent iron particles include Na 2 S 2 o 4 and Na 2 S, but Na 2 S 2 o 4 It has certain oxidative properties, which will cause a large amount of Fe(0) to be converted into FeS, which greatly consumes the initial reducing power provided by Fe(0), while Na 2 S is easy to deliquesce in the air and absorb CO 2 and deteriorate, and will continue to release toxic and harmful H 2 S gas, so the large-scale production and application of sulfide-type nano zero-valent iron particles are greatly restricted

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