Method for pretreatment on industrial wastewater by nascent state ferrous iron reduction

A technology for industrial wastewater and new ecology, applied in chemical instruments and methods, multi-stage water/sewage treatment, water/sludge/sewage treatment, etc., can solve problems such as increased treatment costs, difficult-to-treat wastewater, and poor regulation effects. Achieve the effect of optimizing coagulation and sedimentation conditions, improving reducing ability, and improving biodegradability

Active Publication Date: 2012-08-08
TONGJI UNIV
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  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Some chemical wastewater is often strongly acidic and difficult to treat.
At present, the conventional method of treating acid wastewater is to use the "lime neutralization method", which is widely used because of the low price of lime; however, there are many problems in the lime method, such as high calcium content, which is easy to scale in the pipeline and form sediments , blockage of pipelines, less and less used in actual projects, and the addition of a large amount of alkaline substances such as lime increases the processing cost
The Chinese patent "A Treatment Method for Industrial Acidic Wastewater" (CN101891294A) discloses the use of strong alkaline industrial waste barium slag to treat acidic industrial wastewater. Disadvantages of often containing a large amount of toxic substances
The Chinese patent "Treatment Process and Equipment for Acid-Alkaline Wastewater" (CN19511839A) mentions adding alkaline actual wastewater to neutralize acidic wastewater to adjust the pH of the mixed solution, flocculation and sedimentation, but the effect of adjusting the alkalinity of alkaline wastewater is poor, or requires a lot of Ratio of alkaline wastewater dosing
However, the suitable pH of the iron-carbon internal electrolysis method is 3 to 5, and there are application problems such as easy clogging and material hardening, and due to the use of oxygenation methods such as aeration, the large amount of ferrous iron produced cannot be fully utilized.

Method used

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  • Method for pretreatment on industrial wastewater by nascent state ferrous iron reduction
  • Method for pretreatment on industrial wastewater by nascent state ferrous iron reduction

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0018] Take 1L of acidic chemical wastewater (water quality conditions as shown in the table below), add 2g of reduced iron powder and CuCl 2 Aqueous solution, Cu / Fe mass ratio is 0.5%, stirring reaction for 2h, regular sampling and centrifugation, analysis of ferrous concentration, chroma, pH, COD of supernatant Cr 、BOD 5 . Table 1 shows that after acidic chemical wastewater is treated with iron powder, the pH is significantly improved, the chroma is significantly removed, and the BOD of the wastewater 5 / COD Cr The improvement effect is remarkable, and the toxic pollutants in the waste water can be reduced and transformed by the iron powder, thereby improving the biodegradability of the waste water. And the dissolved ferrous iron of 1384mg / L was produced after reacting 2h.

[0019] Table 1 Effect of iron powder on acid wastewater treatment

[0020] pH Fe 2+ Concentration / mg.L -1 Chroma COD Cr / mg.L -1 BOD 5 / COD Cr raw wastewater 1.5 ...

Embodiment 2

[0022] Take 1L of acidic wastewater with different initial pH, add 2g / L reduced iron powder, and CuCl 2 Aqueous solution, Cu / Fe mass ratio is 0.3%, stirring reaction for 6h, regular sampling analysis of ferrous concentration, chroma, pH in wastewater. Table 2 shows that when the initial pH is greater than or equal to 1.5, a good pH adjustment effect can be achieved, and a large amount of new ecological ferrous iron can be generated under low pH conditions.

[0023]Table 2 The effect of iron powder on acidic wastewater with different initial pH

[0024] initial pH 1.25 1.5 1.75 2 pH after reaction 1.7 5 6 6.7 Fe 2+ Concentration / mg.L -1 1976 1734 1384 716

Embodiment 3

[0026] A: Take 2L of acidic wastewater with an initial pH value of 2.5 (600 times the initial chromaticity), add 0.5g / L reduced iron powder, and CuCl 2 Aqueous solution, Cu / Fe mass ratio is 1%, stirring reaction for 1h, regular sampling analysis of ferrous concentration and chromaticity in wastewater.

[0027] B: Take 2L of acidic wastewater with an initial pH value of 2.5 (600 times the initial chromaticity), add 0.5g / L reduced iron powder, stir and react for 1 hour, and regularly take samples to analyze the ferrous concentration and chromaticity in the wastewater.

[0028] Table 3 shows the concentration of ferrous iron in the wastewater after the reaction and the chromaticity of the wastewater, and the results show that CuCl 2 The addition of can significantly promote the dissolution of iron powder and the formation of ferrous iron.

[0029] Table 3 Cu 2+ Effect on dissolution of iron powder

[0030] Fe 2+ Concentration / mg.L -1 Wastewater color A 2...

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Abstract

The invention belongs to the technical field of environmental protection and especially relates to a method for pretreatment on industrial wastewater by nascent state ferrous iron reduction. The method is characterized in that acidic wastewater and zero-valent iron undergo a reaction in the presence of a catalyst to produce a large amount of high-activity nascent state ferrous iron and the acidity of the acidic wastewater is eliminated and a pH value of the acidic wastewater is improved; the high-activity nascent state ferrous iron and alkaline wastewater are mixed according to a certain ratio so that nascent state ferrous iron ions form a high-activity structural-state ferrous complex under alkaline conditions; through negative and positive ions and the catalyst in the wastewater, reduction performances of structural-state ferrous iron are improved; and through addition of a trace amount of an oxidizing agent, catalytic oxidation effects of residual ferrous iron are performed so that a ferrous iron structural form is changed and coagulating precipitation effects of ferrous iron are improved. The method realizes preparation of nascent state ferrous iron from acidic waste water, utilizes reduction effects of zero-valent iron and ferrous iron, realizes synchronous treatment on acidic wastewater and alkaline wastewater, realizes treatment of wastes with processes of wastes against one another and saves a treatment cost.

Description

Technical field [0001] The invention is a field of environmental protection technology, which involves a method of wastewater treatment. Background technique [0002] During the difficulty of degrading industrial wastewater, due to the complex ingredients, it contains toxic and harmful pollutants, and has poor biochemical performance, which has become a problem for my country's water pollution control.The governance of toxic and difficult to degrade industrial wastewater has also been established as a research topic in China in the future.Due to its simple craftsmanship and low cost, the current water treatment technology in my country is mainly based on biological methods. However, for the increasingly difficult to degrade industrial waste water, due to poor biodegradation, traditional biological treatment technology is difficult to solve.Generally, pre -processing methods need to be added, and the composite process of materialized pre -processing and then connecting biological ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C02F9/04
Inventor 吴德礼冯勇王权民马鲁铭
Owner TONGJI UNIV
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