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Sulfide or thiosulfate catalytic air complete oxidation at normal temperature and pressure

A thiosulfate, catalytic oxidation technology, applied in the direction of sulfate preparation, etc., can solve the problems of inability to oxidize, slow oxidation reaction, high operating costs, etc., and achieve the effects of cost saving, easy separation, and simple operation

Active Publication Date: 2010-08-11
西安德兴环保科技有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0006] However, using the high temperature and high pressure oxidation method can obtain good oxidation treatment effect, but the engineering investment of the device is large, the operating cost is high, and the system operation and management are complicated.
[0007] On the other hand, a large amount of sulfur-containing wastewater or waste lye produced in the field of environmental engineering can also be treated by air oxidation, but under normal temperature and pressure conditions, the oxidation reaction is slow, and there are a large number of Thiosulfate, incomplete oxidation reaction
In addition, a large odor is generated during the treatment process, which pollutes the air environment
Under normal temperature and pressure conditions, traditional catalysts, such as catalysts containing iron, manganese, zinc or cobalt, and catalysts containing other materials can improve the utilization rate of air, speed up the reaction speed, and reduce the thiosulfate. Concentration of by-products, but still not fast enough to completely oxidize sulfide or thiosulfate to stable sulfate

Method used

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  • Sulfide or thiosulfate catalytic air complete oxidation at normal temperature and pressure
  • Sulfide or thiosulfate catalytic air complete oxidation at normal temperature and pressure
  • Sulfide or thiosulfate catalytic air complete oxidation at normal temperature and pressure

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0043] Catalyst preparation:

[0044] Weigh 7.5 g Bi(NO 3 ) 3 ·5H 2 O in a beaker, add 200ml of water, then add NaOH and stir, and adjust the pH of the resulting mixed solution to be 7.0, thereby obtaining the catalyst Bi(OH) 3 .

[0045] 1. S 2- Oxidation of ions:

[0046] Weigh 50g of Na 2 S·9H 2 O is mixed with the obtained catalyst and put into a 2000ml beaker, and about 1600ml of water is added, and the aeration oxidation reaction is carried out at a temperature of 50°C to make the free S 2- All converted to SO 4 2- , S 2 o 3 2- or Bi 2 S 3 ; During the reaction, adjust the pH of the reaction mixture by adding sodium hydroxide solution to make it more than 8.5.

[0047] The reaction equation is:

[0048] Bi 2 S 3 + air (O 2 , CO 2 )+OH - →Bi(OH) 3 / Bi(OH)CO 3 +SO 4 2- +S 2 o 3 2-

[0049] Bi(OH) 3 / Bi(OH)CO 3 +S 2- → Bi 2 S 3 (black precipitate)

[0050] S 2- detection of:

[0051] After 24 hours of reaction, about 50 ml of the reactio...

Embodiment 2

[0067] Choose 0.8g Bi(NO 3 ) 3 ·5H 2 O as a catalyst, adding Na 2 CO 3 and stirring, the pH of the resulting mixed solution was adjusted to be 7.0, thereby obtaining the catalyst Bi(OH)CO 3 .

[0068] Weigh 15 grams of Na 2 S·9H 2 O was dissolved in 700 milliliters of water and mixed with the catalyst, and the sulfide content of the resulting mixture was about 2800 mg / L.

[0069] The reaction temperature in step 1 is 20° C., and the reaction time is 65 hours.

[0070] The reaction temperature in step 2 is 20°C, the supplementary catalyst is bismuth hydroxide, the pH of the reaction mixture is adjusted to 1.5-4.0 with dilute phosphoric acid, and the reaction is carried out with aeration for 20 hours.

[0071] After the reaction is completed, the pH is adjusted to 6.5-7.5 with sodium carbonate, and the solid-liquid separation is carried out.

[0072] A part of the separated liquid was taken, and the COD value of the separated liquid was measured to be 27.5 mg / L.

Embodiment 3

[0074] Weigh 15 g Bi(NO 3 ) 3 ·5H 2 O, in the beaker of 2000 milliliters, add water and stir, and add sodium hydroxide, the pH value of mixture is adjusted to about 7.0.

[0075] Weigh 8.4 g Na 2 S·9H 2 O, add it to the above mixture, add water to the mark of 1400 ml, stir the reaction, make S 2- complete reaction to form Bi 2 S 3 Precipitation (due to excess bismuth nitrate, S 2- have all been precipitated, so it can be considered that a desulfurization reaction has been completed).

[0076] The above-mentioned beaker was placed in a water bath at 50° C. for aeration, and the pH value of the reaction mixture was adjusted to a range of 1-4 with dilute hydrochloric acid.

[0077] After 6 hours of aeration reaction, take a part of the mixed liquid, add sodium hydroxide to adjust its pH value to about 7.0, then filter, take a part of the filtrate, add dilute hydrochloric acid to it, and then add BaCl 2 2H 2 O, in the range of pH value 1~2, stir the reaction, white turbi...

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Abstract

The invention relates to a catalysis and oxidation treatment method for wastewater containing sulfide or thiosulfate, which is used for completely oxidizing sulfide and / or thiosulfate into sulfate at normal temperature and pressure by using gas as an oxidant and using a compound containing trivalent bismuth as a catalyst. The catalyst used in the invention can be recycled, which not only solves the problem that sulfide and / or thiosulfate can not be oxidized into stable sulfate by using a traditional catalytic air oxidation method, but also is beneficial to environmental protection, decreasing the investment, saving the operation cost, and realizing simple operation. Therefore, the invention can be widely applied to treatment on wastewater containing sulfide and / or thiosulfate or alkali waste liquid.

Description

technical field [0001] The invention relates to a method for catalytically oxidizing sulfide and / or thiosulfate into sulfate, specifically at normal temperature and pressure, using air as an oxidant and a compound containing trivalent bismuth as a catalyst to sulfide And / or the method that thiosulfate is thoroughly oxidized into stable sulfate belongs to the field of chemical engineering. Background technique [0002] At present, sulfur-containing wastewater mainly comes from catalytic cracking, coking, hydrocracking and other production units of refineries, and high-sulfur waste caustic mainly comes from refining and separation production units of petrochemical products. This type of wastewater has a high pollution concentration. In addition to sulfide or thiosulfate, it also contains pollutants such as phenolic compounds and oils, which has a strong odor, is extremely corrosive to equipment, and seriously pollutes the surrounding environment. Therefore, these wastewaters ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C01B17/96
Inventor 罗德春
Owner 西安德兴环保科技有限公司
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