Method for preparing iron-manganese catalyst by using solid waste and application device thereof

Abstract

The invention provides a method for preparing an iron-manganese catalyst by using solid wastes and an application device thereof. The preparation method of the iron-manganese catalyst comprises the following steps: carrying out drying and sieving pretreatment on waste raw materials; preparing an iron-manganese mixed solution, and adding the pretreated raw material into the mixed solution to obtain a precursor; performing high-temperature curing on the precursor to obtain a cured product; cleaning, centrifugally separating and drying to obtain a catalyst precursor; and roasting and activating at high temperature to obtain the catalyst. And putting the obtained iron-manganese catalyst into an application device for continuously and circularly feeding wastewater for application. The catalyst and the application device thereof have the advantages of high catalytic efficiency, good stability and low production cost.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of wastewater treatment, and particularly relates to a method for preparing an iron-manganese catalyst by using solid waste and an application device thereof. BACKGROUND

[0002] With the rapid development of industrialization, the treatment of refractory organic pollutants (such as dyes, antibiotics, pesticides, etc.) in water bodies has become an important challenge in the environmental field. The advanced oxidation technology based on persulfate activation has attracted much attention due to its high efficiency in degrading organic pollutants. Iron-manganese bimetallic catalysts have shown great potential in this field due to their synergistic effect of multiple valence states and electron transfer advantage. However, existing iron-manganese catalysts are mostly prepared from pure chemical reagents, which has high production cost and high risk of metal leaching. Moreover, the traditional hydrothermal synthesis method has high energy consumption, which restricts its large-scale application. At the same time, industrial solid waste such as lithium slag, fly ash, steel slag and manganese slag contains rich iron and manganese oxides and porous silicon-aluminum matrix. The disposal of such solid waste not only occupies land resources, but also has the risk of heavy metal leaching. Therefore, how to realize the high-value utilization of such solid waste has become an industry pain point.

[0003] Currently, some studies have attempted to use solid waste as a catalyst carrier, but there are still some technical bottlenecks in practical application: (1) the active sites of the solid waste-based catalyst are not fully exposed, and the uneven distribution of iron and manganese components leads to low electron transfer efficiency; (2) the traditional impregnation method cannot achieve stable combination between the active components and the carrier, and the metal may be dissolved and detached in the persulfate system; (3) the supporting reaction device mostly adopts a fixed bed or batch reaction mode, which has low mass transfer efficiency and poor light energy utilization, and the treatment effect of wastewater containing humic acid and other light shielding substances is significantly reduced.

[0004] In view of the above problems, the present application innovatively proposes a three-in-one technical route of "solid waste in-situ reconstruction-active site directional anchoring-photocatalytic synergistic activation". By precisely controlling the interface reaction process of iron and manganese salts and solid waste matrix, a Fe-O-Mn heterostructure is formed in the high-temperature curing stage, and a stable skeleton is constructed by using the silicon-aluminum network of solid waste. The photocatalytic circulation device is designed to cooperate with the central ultraviolet / visible light source and the light reflection channel to strengthen the chain reaction of persulfate hydrogen peroxide activation and pollutant degradation. This system not only reduces the production cost of the catalyst, but also significantly improves the mineralization efficiency of organic pollutants, realizing the synergistic effect of solid waste resource utilization and wastewater deep treatment. SUMMARY

[0005] In view of the deficiencies in the prior art, the present application provides a method for preparing an iron-manganese catalyst by using solid waste and an application device thereof, which provides an efficient, environmentally friendly and low-cost technology for organic wastewater treatment.

[0006] In one aspect of the present application, a method for preparing an iron-manganese catalyst using solid waste is provided, characterized in that the method comprises the following steps:

[0007] S1, pretreatment: using one of lithium slag, fly ash or iron-manganese tailings as a solid waste raw material, drying and sieving the raw material to obtain pretreated raw material;

[0008] S2, preparation of a precursor: FeCl3 and MnCl2 are configured into solutions of the same volume in a certain mass ratio, and are fully mixed by stirring for 1-12 h; under stirring, an alkaline solution of the same volume as the mixed solution is added at a uniform speed, and after the addition is completed, stirring is continued for 30 min to obtain a precursor.

[0009] S3, loading and maturation: under continuous stirring, the pretreated raw material obtained in S1 is added to the precursor solution prepared in S2, and high-temperature maturation is performed to obtain a maturation product;

[0010] S4, separation and purification: the maturation product obtained in S3 is washed with a water / ethanol mixture, and a catalyst precursor is obtained by centrifugal separation and drying.

[0011] S5, high-temperature activation: the catalyst precursor obtained in S4 is calcined and activated at high temperature to obtain a catalyst.

[0012] Further, in step S2, the mass ratio of FeCl3 to MnCl2 is 1:0.25-1:2, and the concentration is 0.01-0.3 mol / L.

[0013] Further, in step S2, the alkaline solution used is NaOH solution, the concentration is 1 mol / L, and the dropwise addition speed is 2.5 mL / min.

[0014] Further, in step S3, the high-temperature maturation temperature is 95 ℃, and the maturation time is 1-12 h.

[0015] Further, in step S5, the high-temperature activation temperature is 200-800 ℃, and the activation time is 0.5-3 h.

[0016] In another aspect of the present application, an application device for an iron-manganese catalyst prepared from solid waste is provided, which comprises the use of the above catalyst.

[0017] Further, the application comprises the following steps:

[0018] The iron-manganese catalyst is put into an application device for continuously circulating wastewater, and after adsorption equilibrium, persulfate is added to the water body, and the central lamp is turned on for irradiation reaction.

[0019] Further, the dosage of the iron-manganese catalyst in the wastewater in the above step is 0.01-6 g / L.

[0020] Further, the dosage of the persulfate in the above step is 0-6 g / L, and the mass ratio of the dosage of the iron-manganese catalyst to the persulfate is 0.5:1-10:1.

[0021] Further, the application device center is a lamp tube, and the wavelength is 10-760 nm.

[0022] Further, the application device is preferably funnel-shaped, including a water inlet 1 located at the lower part of the reactor, an ascending cylinder 2, a descending cylinder 3, an inclined plate 4, a catalytic reaction light source 5, a water outlet collection channel 6, a water inlet jet device 7, a reactor shell 8, a catalyst recovery pipe 9, a water outlet pipe 10, and a catalyst 11.

[0023] Further, the application device preferably connects the ascending cylinder 2 and the descending cylinder 3 at the bottom through the water inlet jet device 7 to realize circulation in the reactor, thereby realizing automatic recovery.

[0024] Further, the application device recycles the catalyst in the reactor in the form of powder, recovers the catalyst through the bottom catalyst recovery pipe 9, and regenerates the catalyst.

[0025] Further, the catalyst of the application device can be fixed in the ascending cylinder 2 in the form of a column or other shapes.

[0026] Further, the light source of the application device exists in the ascending cylinder 2 in single or multiple.

[0027] Further, the ascending cylinder 2 of the application device is transparent tempered glass. The light source can be directed to the descending cylinder 3 through the ascending cylinder 2, thereby realizing full utilization of the light source. Preferably, a light-reflecting material is coated on the inner wall of the ascending cylinder, thereby realizing more sufficient light source in the ascending cylinder 2, thereby realizing strengthened reaction efficiency of the ascending cylinder 2.

[0028] Further, the catalyst 11 of the application device can be returned to the ascending cylinder 2 through a water pump or other ways.

[0029] Compared with the prior art, the application has the following beneficial effects:

[0030] The application uses industrial waste lithium residue as raw material, prepares an iron-manganese catalyst with stable structure by accurately regulating and controlling the interface reaction process of the iron-manganese salt and the solid waste substrate, and matches a photocatalytic circulating device to strengthen the degradation reaction of the catalyst on pollutants. The system reduces the production cost of the catalyst while significantly improving the mineralization efficiency of organic pollutants, realizing the synergistic effect of solid waste resource utilization and wastewater deep treatment. BRIEF DESCRIPTION OF DRAWINGS

[0031] Figure 1 A structural schematic diagram of an application device of the iron-manganese catalyst provided by the present application.

[0032] Figure 2 is Figure 1 A structural schematic diagram of the top of the application device.

[0033] Figures 1-2 In the figure, 1 is an inlet pipe, 2 is an ascending cylinder, 3 is a descending cylinder, 4 is an inclined plate, 5 is a lamp tube, 6 is an outlet water collecting channel, 7 is an inlet water jet device, 8 is a reactor shell, 9 is a catalyst recovery pipe, 10 is an outlet pipe, and 11 is a catalyst.

[0034] Figure 3 A scanning electron microscope analysis diagram of the iron-manganese catalyst and lithium slag in Test Example 1 of the present application, (a) is the lithium slag, and (b) is the iron-manganese catalyst.

[0035] Figure 4 A catalytic performance diagram of the catalyst prepared in Scheme H of Example 1 and Comparative Examples 1-5 of the present application on tetracycline simulated wastewater in an application device. DETAILED DESCRIPTION

[0036] The technical solutions in the present application will be further described below in combination with the drawings and examples.

[0037] Example 1 Preparation of iron-manganese catalyst using solid waste

[0038] The lithium slag was dried at 105°C for 24h and sieved through a 200-mesh sieve to obtain a pretreated raw material.

[0039] A 0.2 mol / L FeCl3 solution and a 0.1 mol / L MnCl2 solution were prepared using distilled water, and then 25 mL of the FeCl3 and MnCl2 solutions were taken and mixed, stirred on a magnetic stirrer for 1 h, and then added to a 50 mL NaOH (1 mol / L) solution at a rate of 2.5 mL / min at room temperature and a rotation speed of 350 r / min, and stirring was continued for 30 min after the addition was completed to obtain a precursor. Then 2 g of the pretreated raw material was added to the precursor mixture, and placed in a heat collecting constant temperature heating magnetic stirrer, and continuously stirred at 95°C for 8 h to perform high temperature curing to obtain a cured product. After the stirring was completed, the cured product was washed with a mixture of distilled water and anhydrous ethanol (0.85V / 1V), and then separated by a high speed centrifuge until it was neutral, and the collected solid was placed in a freeze dryer to dry to a constant weight to obtain a catalyst precursor. Finally, the catalyst precursor was placed in a box type resistance furnace and calcined at 600°C for 1 h to perform high temperature activation, and after the calcination was completed and cooled to room temperature, it was sieved through a 200 mesh sieve to obtain the iron manganese catalyst. The iron manganese ratio, iron manganese loading, and volume of the FeCl3 and MnCl2 solutions are shown in Table 1.

[0040] Table 1 Iron manganese ratio, iron manganese loading, and volume of the FeCl3 and MnCl2 solutions

[0041]

[0042] Example 2 Preparation of an iron manganese catalyst using solid waste

[0043] Similar to the scheme H of Example 1, except that the curing stirring time was 10 h, and the high temperature activation temperature was 400°C.

[0044] Example 3 Preparation of an iron manganese catalyst using solid waste

[0045] Similar to the scheme H of Example 1, except that the curing stirring time was 10 h, and the high temperature activation time was 0.5 h.

[0046] Test Example 1 Scanning electron microscope analysis

[0047] The catalyst prepared in Example 1 and lithium slag were compared and analyzed by scanning electron microscopy, and the results are shown in Figure 1

[0048] As can be seen from the results, the surface of the lithium slag is covered with many iron manganese particles, which are uniformly distributed.

[0049] Test Example 2 Catalytic performance of the catalyst on tetracycline simulated wastewater in an application device

[0050] ​The catalytic performance of the catalyst in the application device on tetracycline simulated wastewater was studied at room temperature. The application device was filled with 5 L of tetracycline (20 mg / L) simulated wastewater, and the wastewater was circulated in and out of the water. 0.1 g / L iron-manganese catalyst was added to the device, and after adsorption equilibrium, 0.2 g / L of peroxymonosulfate was added and the catalytic reaction was carried out under light. Samples were collected at time intervals of 5 min, 10 min, 20 min, 30 min, 45 min, and 60 min, and the residual tetracycline concentration was determined.

[0051] Comparative Example 1

[0052] Similar to Scheme H of Example 1, except that the reaction solution did not contain FeCl3 and MnCl2. The prepared lithium slag catalyst was used to detect the catalytic performance on tetracycline simulated wastewater in the application device. The application device was filled with 5 L of tetracycline (20 mg / L) simulated wastewater at room temperature, and the wastewater was circulated in and out of the water. 0.1 g / L lithium slag catalyst was added to the device, and after adsorption equilibrium, 0.2 g / L of peroxymonosulfate was added and the catalytic reaction was carried out under light. Samples were collected at time intervals of 5 min, 10 min, 20 min, 30 min, 45 min, and 60 min, and the residual tetracycline concentration was determined.

[0053] Comparative Example 2

[0054] Similar to Scheme H of Example 1, except that the reaction solution did not contain FeCl3. The prepared catalyst was used to detect the catalytic performance on tetracycline simulated wastewater in the application device.

[0055] Comparative Example 3

[0056] Similar to Scheme H of Example 1, except that the reaction solution did not contain MnCl2. The prepared catalyst was used to detect the catalytic performance on tetracycline simulated wastewater in the application device.

[0057] Comparative Example 4

[0058] Similar to Scheme H of Example 1, except that the reaction solution did not contain lithium slag and FeCl3. The prepared catalyst was used to detect the catalytic performance on tetracycline simulated wastewater in the application device.

[0059] Comparative Example 5

[0060] Similar to Scheme H of Example 1, except that the reaction solution did not contain lithium slag and MnCl2. The prepared catalyst was used to detect the catalytic performance on tetracycline simulated wastewater in the application device.

[0061] The catalytic performance of the iron-manganese catalyst prepared in Scheme H of Example 1 was compared with the application, and the results are shown in Table 1. Figure 2 As shown in Table 1, the catalytic performance of the iron-manganese catalyst prepared in Scheme H of Example 1 was better than that of the catalyst prepared in Comparative Examples 1-5.Figure 2 It can be seen that the catalytic application performance of the iron-manganese catalyst prepared by the method of Example 1 Scheme H is obviously higher than the catalytic performance of the catalyst prepared by Comparative Examples 1-5.

[0062] Finally, it should be pointed out that the above examples are only used to illustrate the technical solutions of the present application and are not limiting. Although the present application has been described in detail with reference to the preferred embodiments, it should be understood by those skilled in the art that the technical solutions of the present application can be modified or replaced by equivalents without departing from the purpose and scope of the technical solutions of the present application, and they should all be covered in the scope of the claims of the present application.

Claims

1. A method for preparing iron-manganese catalysts from solid waste and its application apparatus, characterized in that: The method for preparing iron-manganese catalysts using solid waste includes the following steps: S1 Pretreatment: Using one of the solid wastes, such as lithium slag, fly ash, or iron-manganese tailings, as raw material, the raw material is dried and sieved to obtain pretreated raw material; S2 Preparation of precursor: FeCl3 and MnCl2 are prepared into solutions of equal volume according to a certain mass ratio and thoroughly mixed by stirring for 1~12h; while stirring, an alkaline solution of equal volume to the mixture is added dropwise at a uniform rate, and stirring is continued for 30min after the addition is completed to obtain the precursor. S3 Loading and maturation: Under continuous stirring, the pretreated raw material obtained in S1 is added to the precursor solution prepared in S2 and maturated at high temperature to obtain the maturation product. S4 Separation and Purification: The ripening product obtained from S3 was washed with a water / ethanol mixture, and the catalyst precursor was obtained by centrifugation and drying. S5 High-Temperature Activation: The catalyst precursor obtained in S4 is activated by calcination at high temperature to obtain the catalyst.

2. The method for preparing iron-manganese catalyst from solid waste as described in claim 1, characterized in that: In step S2, the mass ratio of FeCl3 to MnCl2 is 1:0.25-1:2, and the concentration is 0.01~0.3 mol / L.

3. The method for preparing iron-manganese catalyst from solid waste as described in claim 1, characterized in that: In step S2, the alkaline solution used is NaOH solution with a concentration of 1 mol / L and a dropping rate of 2.5 mL / min.

4. The method for preparing iron-manganese catalyst from solid waste as described in claim 1, characterized in that: In step S3, the high-temperature curing temperature is 95 ℃ and the curing time is 1-12 h.

5. The method for preparing iron-manganese catalyst from solid waste as described in claim 1, characterized in that: In step S5, the high-temperature activation temperature is 200-800 ℃, and the activation time is 0.5-3h.

6. An application device for an iron-manganese catalyst, characterized in that: This includes applications using the catalyst described in any one of claims 1-5.

7. Add the iron-manganese catalyst to the application device that continuously circulates wastewater. After the adsorption reaches equilibrium, add persulfate to the water and simultaneously turn on the central lamp to irradiate the reaction.

8. The application device for an iron-manganese catalyst as described in claims 6 and 7, characterized in that: The dosage of iron-manganese catalyst in wastewater is 0.01-6 g / L.

9. An application device for an iron-manganese catalyst as described in claims 6 and 7, characterized in that: The dosage of persulfate is 0-6 g / L, and the mass ratio of the dosage of iron-manganese catalyst to persulfate is 0.5:1-10:

1.

10. An application device for an iron-manganese catalyst as described in claims 6 and 7, characterized in that: The central component of the device is a light source tube with a wavelength of 10~760nm.

11. An application device for an iron-manganese catalyst as described in claims 6 and 7, characterized in that: The device is preferably funnel-shaped, including an inlet 1 located at the bottom of the reactor, an ascending cylinder 2, a descending cylinder 3, an inclined plate 4, a catalytic reaction light source 5, an outlet water collection channel 6, an inlet water jet 7, a reactor shell 8, a catalyst recovery pipe 9, an outlet water pipe 10, and a catalyst 11.

12. The application device for an iron-manganese catalyst as described in claims 6 and 7, characterized in that: Preferably, the bottom of the rising cylinder 2 and the falling cylinder 3 are connected, and the water is circulated in the reactor through the water inlet jet 7, thereby achieving automatic recovery.

13. The application device for an iron-manganese catalyst as described in claims 6 and 7, characterized in that: The catalyst is automatically recovered and reused in the reactor in solid form. The catalyst is recovered and regenerated through the bottom catalyst recovery pipe 9.

14. An application device for an iron-manganese catalyst as described in claims 6 and 7, characterized in that: The catalyst can be fixed in the rising cylinder 2 in a columnar or other shape.

15. An application device for an iron-manganese catalyst as described in claims 6 and 7, characterized in that: The light source exists in one or more units within the rising cylinder 2.

16. An application device for an iron-manganese catalyst as described in claims 6 and 7, characterized in that: The ascending cylinder 2 is made of transparent tempered glass. The light source can shine through the ascending cylinder 2 onto the descending cylinder 3, thus maximizing the utilization of the light source. Preferably, a reflective material is coated on the inner wall of the ascending cylinder to further enhance the light source's illumination within the ascending cylinder 2, thereby improving its reaction efficiency.

17. An application device for an iron-manganese catalyst as described in claims 6 and 7, characterized in that: Catalyst 11 can be returned to the riser 2 via a water pump or other means.

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