Hexavalent chromium reducing agent and preparation method thereof

A reducing agent, hexavalent chromium technology, applied in the field of building materials, can solve problems such as poor high temperature resistance, achieve the effects of preventing oxygen oxidation, solving high temperature resistance and poor stability

Active Publication Date: 2018-04-17
DONGYUAN HONGCHAO TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] In order to solve the problem of poor high temperature resistance of the hexavalent chromium reducing agent in the prior art, the present invention proposes a hexavalent chromium reducing agent and its preparation method

Method used

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  • Hexavalent chromium reducing agent and preparation method thereof
  • Hexavalent chromium reducing agent and preparation method thereof
  • Hexavalent chromium reducing agent and preparation method thereof

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preparation example Construction

[0026] The present invention also provides a kind of preparation method of hexavalent chromium reducing agent, comprises the following steps:

[0027] In step a, 10-30 parts of dispersant are dissolved in 47-85 parts of water at 30°C-90°C, stirred and left for a period of time, 40-60 parts of iron-containing compound are dissolved in the solution, and stirred again.

[0028] Preferably, the temperature of the water is 50°C-80°C. In this step, the dispersant can be left for 1-2 hours after dissolving to remove air bubbles in the solution.

[0029] In step b, after dissolving 3 to 5 parts of reducing agent in 3 to 5 parts of water to prepare a reducing agent solution, slowly add the reducing agent solution dropwise to the solution prepared in step a, and continue stirring to obtain a dispersed nanometer zero-valent iron agent solution.

[0030] During specific implementation, since the reducing agent solution is added to the solution prepared in step a and stirred, a large num...

Embodiment 1

[0036] Dissolve 15 g of sodium carboxymethyl cellulose in 85 g of water at 40° C., and place it for 1 hour to completely remove the air bubbles to obtain an aqueous solution of sodium carboxymethyl cellulose. 5 g of sodium borohydride was dissolved in 5 g of water to obtain an aqueous solution of sodium borohydride.

[0037] Dissolve 50 g of ferrous sulfate into the above-mentioned sodium carboxymethyl cellulose aqueous solution, then gradually add the above-mentioned sodium borohydride aqueous solution dropwise, and stir for 1 hour to obtain an aqueous sodium carboxymethyl cellulose solution containing 10 g of nanometer zero-valent iron.

[0038] Mix 10 g of sodium carboxymethyl cellulose solution of nano zero-valent iron with 90 g of ferrous sulfate heptahydrate and stir for 3 hours, and dry in an oven at 50°C for 8 hours under nitrogen protection to prepare nano-zero-valent iron particles and carboxymethyl Sodium cellulose coated hexavalent chromium reducing agent.

Embodiment 2

[0040] Dissolve 10 g of sodium alginate in 47 g of water at 30° C., and place it for 2 hours to completely remove air bubbles to obtain an aqueous solution of sodium alginate. 3 g of sodium borohydride was dissolved in 3 g of water to obtain an aqueous solution of sodium borohydride.

[0041] Dissolve 40g of ferrous sulfate into the above-mentioned sodium alginate aqueous solution, then gradually add the above-mentioned sodium borohydride aqueous solution dropwise, and after stirring for 1 hour, an aqueous sodium alginate solution containing 8g of nanometer zero-valent iron is obtained.

[0042] Mix 15 g of sodium alginate solution of nano-zero-valent iron with 60 g of ferrous sulfate heptahydrate and stir for 2.5 hours, and dry in an oven at 30°C for 48 hours under nitrogen protection to prepare nano-zero-valent iron particles and sodium alginate-wrapped Hexavalent chromium reducing agent.

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Abstract

The invention provides a hexavalent chromium reducing agent and a preparation method thereof. The reducing agent contains the following components in parts by weight: 50-90 parts of an iron-based reducing agent, 0.57-3.6 parts of nanometer zero-valent iron and 0.9-7.1 parts of a dispersing agent. According to the hexavalent chromium reducing agent provided by the invention, an iron-based reducingagent is uniformly packaged by a dispersing agent solution containing nanometer zero-valent iron particles, and very high reaction activity is achieved by mixing nanometer zero-valent iron with the iron-based reducing agent, so that hexavalent chromium in the reducing agent solution can be rapidly reduced; dispersing agent molecules are capable of stabilizing nanometer zero-valent iron and packaging the iron-based reducing agent, so that the oxidation of the iron-based reducing agent by oxygen in the air is prevented, the hexavalent chromium reducing agent has a moisture preserving function, and the situations that because the partial water-entraining iron-based reducing agent is dehydrated under a high temperature condition, the solubleness is reduced, and the iron-based reducing agent isunlikely to participate in the reducing reaction of hexavalent chromium are prevented.

Description

technical field [0001] The invention relates to the technical field of building materials, in particular to a hexavalent chromium reducing agent and a preparation method thereof. Background technique [0002] Hexavalent chromium is introduced into the calcining link in the cement clinker manufacturing process. Hexavalent chromium has high water solubility and strong permeability, and can easily penetrate into human tissues, causing diseases such as dermatitis and ulceration. After long-term rain or immersion in concrete, hexavalent chromium is dissolved and brought into the reservoir or underground to cause chromium pollution in drinking water sources. In order to reduce the harm of hexavalent chromium to the human body, the European Union issued Directive 2003 / 53 / EC , it is stipulated that the hexavalent chromium in cement should not exceed 2.0mg / kg. my country's regulations on the content of hexavalent chromium in cement started relatively late. According to GB 31893-2015...

Claims

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Application Information

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IPC IPC(8): C04B7/42
CPCC04B7/425C04B7/428
Inventor 蔡洪
Owner DONGYUAN HONGCHAO TECH
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