A kind of modification method that iron ions promote the rapid formation of γ-feooh layer on the surface of iron filings

Abstract

The invention relates to a modification method for promoting the rapid formation of a γ-FeOOH layer on the surface of iron filings by iron ions, comprising the following steps: (1) selecting scrap iron filings of low carbon steel, medium carbon steel and low alloy structural steel, and carrying out pretreatment; (2) placing the iron filings obtained in step (1) in a mixed modification liquid containing an oxidant and a promoter for modification, and the modification liquid includes the following composition by mass percentage: 0.05% to 0.45% of the oxidant , accelerator 0.025~0.5%, polyvinyl butyral resin 0~2g / L, polyethylene glycol 0~1g / L, the balance is water, the pH of the modification solution is 2~4, and the temperature is 15-40℃ (3) After the modification in step (2) is completed, continue to add oxidant to the modification system to keep its mass concentration at 0.05% to 0.45%, and continue to modify for 20 to 60 min; (4) after the modification is completed, from The product is taken out from the above modification solution, air-dried naturally, and then the residual resin on the surface is cleaned. Compared with the prior art, the method of the invention can shorten the growth time of the γ-FeOOH layer, improve the modification efficiency, and the obtained product has stable catalytic performance and surface components.

Description

technical field [0001] The invention relates to the field of pollution control, in particular to a modification method for rapidly forming γ-FeOOH on the surface of iron filings. Background technique [0002] Ozone (O 3 ) has a history in the field of water pollution control. Due to its strong oxidizing property (2.07V) and special dipole structure, it has excellent treatment and disinfection effects on pollutants rich in electronic groups and pathogenic microorganisms in water. However, due to the selectivity of ozone oxidation, low mineralization rate and low utilization rate of ozone, its application is limited. By adding a catalyst, ozone can be adsorbed on the active sites on the catalyst surface and decompose to generate a large number of hydroxyl radicals. Hydroxyl radicals are active substances with strong oxidizing properties (2.33V), which can not only react with organics indiscriminately, but also improve the mineralization rate of organics. Among them, γ-FeOOH...

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Problems solved by technology

[0004] There are many preparation methods of γ-FeOOH, as the patent publication number CN106587164B discloses the use of FeSO 4 ·7H 2 The method for preparing γ-FeOOH nanopowder through precipitation reaction of O solution and amine-based compound; 2 , O 2 , FeSO 4 and methods for preparing γ-FeOOH catalysts from phosphate; however, these methods have complex preparation processes, long reaction times, and difficult control of reaction conditions, and the generated product is γ-FeOOH powder. If applied to the field of water pollution control, it also involves catalyst agglomeration, easy Loss, causing secondary pollution and other problems

[0005] Patent application CN110152667A discloses a method for modifying the surface of iron filings to form γ-FeOOH, including pretreating the iron filings, modifying them with a modifying solution, and air-drying the modified products to obtain surface modification. Iron filings forming γ-FeOOH showed good corrosion resistance after corrosion experiments, but this method needs to adjust the oxidation-reduction potential (ORP) of the modified solution through ozone aeration, and the modification conditions are difficult to control, and the modified solution It needs to be replaced every half an hour, and the modification fluid consumes a lot

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