A method for treating steel cold rolling pickling wastewater
A microemulsion process recovers iron ions from steel cold rolling pickling wastewater, forming photocatalytically active iron oxide particles that address environmental pollution and resource waste by transforming waste into valuable products.
Patent Information
- Application Number
- CN202410780766.X
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2024-06-18
- Publication Date
- 2024-12-17
- Estimated Expiration
- 2044-06-18
AI Technical Summary
The discharge of steel cold rolling pickling wastewater, rich in iron ions, poses environmental pollution and resource waste issues due to direct discharge, necessitating an effective treatment method.
A method involving the use of surfactants, precipitants, and morphology control agents in a microemulsion process to recover iron ions from the wastewater, producing iron oxide particles with controlled morphology, which are then calcined to form photocatalytically active particles.
The method recovers iron ions as valuable iron oxide particles with petal-like morphology, preventing pollution and enabling resource recycling, and demonstrates good photocatalytic properties for organic pollutant degradation.
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Figure CN118791049B_ABST
Abstract
Description
Technical Field
[0001] The invention relates to the technical field of sewage treatment, in particular to a method for treating steel cold rolling pickling sewage. Background Art
[0002] Steel cold rolling pickling wastewater is the waste liquid produced by steel mills using sulfuric acid, hydrochloric acid and other acidic liquids as cleaning agents for surface treatment in order to improve the surface quality of steel. With the vigorous development of my country's steel industry, the discharge of steel pickling wastewater has increased rapidly. Steel cold rolling pickling wastewater is rich in iron ions. Direct discharge will not only cause environmental pollution, but also waste resources. Summary of the invention
[0003] Purpose of the invention: In view of the above technical problems, the present invention proposes a method for treating steel cold rolling pickling wastewater.
[0004] The technical solutions adopted are as follows:
[0005] A method for treating steel cold rolling pickling wastewater is as follows:
[0006] S1: adding a surfactant to a mixed solution of cyclohexane and ethylene glycol to obtain solution A, dividing solution A into two parts, adding a precipitant to one part to obtain solution B, and adding steel cold rolling pickling wastewater and a morphology control agent to the other part to obtain solution C;
[0007] S2: Mixing solution B and solution C to obtain solution D;
[0008] S3: transferring solution D to a sealed autoclave, collecting the product after the reaction, washing it, and drying it to obtain a precursor;
[0009] S4: Finally, the precursor is calcined.
[0010] Further, the surfactant includes Triton X-100 and sodium lauryl sulfate;
[0011] The mass ratio of Triton X-100 to sodium dodecyl sulfate is 1-5:1-5.
[0012] Furthermore, the mass ratio of cyclohexane to ethylene glycol is 1-10:1-10.
[0013] Furthermore, the precipitant is any one or more combinations of urea, ammonia water, sodium hydroxide and potassium hydroxide.
[0014] Furthermore, the morphology control agent is urotropine quaternary ammonium salt.
[0015] Further, the preparation method of the urotropine quaternary ammonium salt is as follows:
[0016] Under nitrogen protection, add urotropine and sodium bicarbonate to methanol and mix well, then add halogenated hydrocarbon, heat the reaction solution to 50-60°C and react for 5-10 hours, return to room temperature and collect the product, and then purify it with fresh methanol.
[0017] Furthermore, the carbon number of the halogenated hydrocarbon is ≥4.
[0018] Furthermore, the molar ratio of hexamethylenetetramine to halogenated hydrocarbon is 1:1-2.
[0019] Furthermore, in S3, the reaction temperature is 120-140° C., and the reaction time is 5-10 h.
[0020] Furthermore, in S4, the calcination temperature is 400-600° C., and the calcination time is 1-5 h.
[0021] Beneficial effects of the present invention:
[0022] The present invention provides a method for treating steel cold rolling pickling wastewater, which uses a microemulsion method to recover iron ions in the wastewater to prepare iron oxide particles with special morphology, thereby avoiding direct discharge to cause heavy metal pollution and turning waste into treasure to achieve resource recycling.
[0023] Surfactants have an important influence on the particle size and morphology of microemulsions and their performance. The present invention controls the composition of surfactants to affect the size and shape of micelles, thereby achieving the synthesis of nanometer-level particles with uniform particle size.
[0024] At present, there are reports that quaternary ammonium salt compounds guide the synthesis of metal oxides with special morphologies. Inspired by this, the inventors tried to make urotropine into quaternary ammonium salts and use urotropine to control the morphology of the reaction products. Unexpectedly, iron oxide particles with a petal-like microscopic morphology were obtained. Moreover, tests have verified that the iron oxide particles prepared by the present invention have good photocatalytic properties and can be used for photocatalytic degradation of organic pollutants. BRIEF DESCRIPTION OF THE DRAWINGS
[0025] Figure 1 This is a microscopic morphology of the iron oxide particles prepared in Example 1. DETAILED DESCRIPTION
[0026] If the specific conditions are not specified in the examples, the experiments were carried out under conventional conditions or the conditions recommended by the manufacturer. If the manufacturer of the reagents or instruments is not specified, they are all conventional products that can be purchased commercially. The techniques not mentioned in the present invention are all referenced to the prior art. Unless otherwise specified, the following examples and comparative examples are parallel experiments, using the same processing steps and parameters.
[0027] Embodiment 1:
[0028] A method for treating steel cold rolling pickling wastewater:
[0029] 17g of Triton X-100 and 50g of sodium dodecyl sulfate were added to a mixed solution consisting of 400g of cyclohexane and 80g of ethylene glycol to obtain solution A, solution A was divided into two equal parts, 2.25g of sodium hydroxide was added to one part to obtain solution B, and 250ml of steel cold rolling pickling wastewater (ferrous iron content 6.8%, pH=1.5) and 1g of urotropine quaternary ammonium salt were added to the other part to obtain solution C, solution B was mixed with solution C to obtain solution D, solution D was transferred to a polytetrafluoroethylene-lined autoclave, sealed and heated to 125°C for reaction for 8h, the product was collected and repeatedly washed with deionized water and ethanol, and then dried at 80°C for 10h to obtain a precursor, and the precursor was heated to 550°C in an air atmosphere and calcined for 3h to obtain iron oxide particles with a yield of 68.3%, a product purity of ≥99%, and a petal-like micromorphology.
[0030] Wherein, the preparation method of urotropine quaternary ammonium salt is as follows:
[0031] Under nitrogen protection, add 2.8g (0.02mol) of urotropine and 0.5g of sodium bicarbonate to 50ml of methanol and mix well, then add 4.11g of 1-bromobutane (0.03mol), heat the reaction solution to 55°C for 8h, return to room temperature and filter out the product, add it to 50ml of fresh methanol, stir and slurry for purification for 30min, filter out the product and dry it at 60°C for 10h.
[0032] Embodiment 2:
[0033] A method for treating steel cold rolling pickling wastewater:
[0034] 17g of Triton X-100 and 50g of sodium dodecyl sulfate were added to a mixed solution consisting of 400g of cyclohexane and 80g of ethylene glycol to obtain solution A, solution A was divided into two equal parts, 2.25g of sodium hydroxide was added to one part to obtain solution B, and 250ml of steel cold rolling pickling wastewater (ferrous iron content 6.8%, pH=1.5) and 1g of urotropine quaternary ammonium salt were added to the other part to obtain solution C, solution B was mixed with solution C to obtain solution D, solution D was transferred to a polytetrafluoroethylene-lined autoclave, sealed and heated to 140°C for reaction for 10h, then the product was collected and repeatedly washed with deionized water and ethanol, and then dried at 80°C for 10h to obtain a precursor, and the precursor was heated to 600°C in an air atmosphere and calcined for 5h to obtain iron oxide particles with a yield of 67.7%, a product purity of ≥99%, and a petal-like micromorphology.
[0035] Wherein, the preparation method of urotropine quaternary ammonium salt is the same as that in Example 1.
[0036] Embodiment 3:
[0037] A method for treating steel cold rolling pickling wastewater:
[0038] 17g of Triton X-100 and 50g of sodium dodecyl sulfate were added to a mixed solution consisting of 400g of cyclohexane and 80g of ethylene glycol to obtain solution A, solution A was divided into two equal parts, 2.25g of sodium hydroxide was added to one part to obtain solution B, and 250ml of steel cold rolling pickling wastewater (ferrous iron content 6.8%, pH=1.5) and 1g of urotropine quaternary ammonium salt were added to the other part to obtain solution C, solution B was mixed with solution C to obtain solution D, solution D was transferred to a polytetrafluoroethylene-lined autoclave, sealed and heated to 120°C for reaction for 5h, then the product was collected and repeatedly washed with deionized water and ethanol, and then dried at 80°C for 10h to obtain a precursor, and the precursor was heated to 500°C in an air atmosphere and calcined for 2h to obtain iron oxide particles with a yield of 65.2%, a product purity of ≥99%, and a petal-like micromorphology.
[0039] Wherein, the preparation method of urotropine quaternary ammonium salt is the same as that in Example 1.
[0040] Comparative Example 1:
[0041] The method is basically the same as Example 1, except that no urotropine quaternary ammonium salt is added, and the obtained product is iron oxide particles with a yield of 62.8%, a product purity of ≥99%, and a spherical microscopic morphology.
[0042] Performance Testing:
[0043] The iron oxide particles prepared in Examples 1-3 and Comparative Example 1 and commercially available α-Fe2O3 (Ningbo Beijiaer New Materials Co., Ltd.) were used as samples for performance testing;
[0044] Using a 300W xenon lamp equipped with a 420nm filter as the light source, 30mg of the sample and 100ml of a 20mg / L Rhodamine B aqueous solution were added into a 250ml reactor respectively, stirred for 30min in the dark, hydrogen peroxide was added dropwise, and the xenon lamp was turned on for illumination. 5ml of the solution was taken out from the reaction solution every 30min, and the supernatant was taken by centrifugation. The mass concentration of Rhodamine B in the solution before and after the reaction was measured with a UV-visible spectrophotometer, and the corresponding absorbance was detected at a wavelength of 553nm. The corresponding mass concentration was calculated according to the relationship between absorbance and mass concentration, and the degradation rate was calculated.
[0045] The test results are shown in Table 1 below:
[0046] Table 1:
[0047]
[0048] It can be seen from Table 1 above that the iron oxide particles prepared in the present invention have good photocatalytic performance and can be used for photocatalytic degradation of organic pollutants.
[0049] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features may be replaced by equivalents. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.
Claims
1. A method for treating steel cold rolling pickling wastewater, characterized in that: The details are as follows: S1: adding a surfactant to a mixed solution of cyclohexane and ethylene glycol to obtain solution A, dividing solution A into two equal parts, adding a precipitant to one part to obtain solution B, and adding steel cold-rolled pickling wastewater and a morphology control agent to the other part to obtain solution C; S2: Mixing solution B and solution C to obtain solution D; S3: transferring solution D to a sealed autoclave, collecting the product after the reaction, washing it, and drying it to obtain a precursor; S4: finally calcining the precursor; The surfactants are Triton X-100 and sodium lauryl sulfate; The mass ratio of Triton X-100 to sodium dodecyl sulfate is 1-5:1-5; The mass ratio of cyclohexane to ethylene glycol is 1-10:1-10; The precipitant is any one or more combinations of urea, ammonia water, sodium hydroxide and potassium hydroxide; The morphology control agent is urotropine quaternary ammonium salt; The preparation method of the urotropine quaternary ammonium salt is as follows: Under nitrogen protection, add urotropine and sodium bicarbonate to methanol and mix well, then add 1-bromobutane, heat the reaction solution to 50-60°C for 5-10 hours, return to room temperature and collect the product, then stir and slurry it with fresh methanol for purification; The reaction temperature in S3 is 120-140°C and the reaction time is 5-10h.
2. The method for treating steel cold rolling pickling wastewater according to claim 1, characterized in that: In S4, the calcination temperature is 400-600°C and the calcination time is 1-5h.