Flaky spherical manganous-manganic oxide as well as preparation method and application thereof

Abstract

The invention discloses flaky spherical manganous-manganic oxide and a preparation method and application thereof.The manganous-manganic oxide serves as an adsorption material to be used in a wastewater purification and solution impurity removal process, and the preparation method of the manganous-manganic oxide comprises the steps that 1, a mixed salt solution containing a manganese element and an A element is prepared or taken; (2) taking a mixture of ammonia water and water as a reaction base solution, adding the mixed salt solution, the ammonia water and caustic soda liquid into the reaction base solution for reaction, continuously introducing air and keeping stirring to obtain reaction slurry; and (3) carrying out post-treatment on the reaction slurry to obtain the flaky spherical manganous-manganic oxide. The flaky spherical manganous-manganic oxide disclosed by the invention can realize refined adsorption of impurities, is not easy to fall off and high in adsorption rate, and has very high application value as an adsorption material; the preparation method is easy to industrialize and low in cost, and physical indexes of a final product can be controlled through parameter adjustment.

Description

Technical Field

[0001] This invention relates to the field of materials technology, and in particular to a sheet-like spherical manganese tetroxide with uniform morphology, good adsorption effect on impurities, and the ability to achieve fine adsorption, as well as its preparation method and application. Background Technology

[0002] In the fields of wastewater purification and solution impurity removal, especially in the treatment of heavy metal wastewater, manganese tetroxide (MTO) is a commonly used adsorbent. Common methods for using MTO to adsorb impurities include: ① adding MTO to the adsorbent to improve adsorption performance, and ② utilizing the strong adsorption properties of in-situ generated MTO to remove impurity elements, such as patent CN105006263B which uses in-situ generated MTO to treat radioactive waste liquid from nuclear power plants.

[0003] Manganese tetroxide, as a conventional adsorbent material, is generally a porous form with high specific surface area and large particle size. However, the microscopic spacing between pores in this morphology is relatively large, resulting in low adsorption precision for impurity elements, low adsorption rate, and easy detachment of adsorbed impurities. In-situ generation of manganese tetroxide co-precipitation involves impurity removal during the generation of manganese tetroxide, which involves chemical precipitation, making the process more complex and costly. Summary of the Invention

[0004] This invention provides a manganese tetroxide with a sheet-like spherical morphology, its preparation method, and its application, in order to solve the technical problems of poor adsorption effect, low refinement level, poor economy, and complex process of existing manganese tetroxide adsorbent materials.

[0005] To solve the above-mentioned technical problems, the technical solution proposed by this invention is as follows: A method for preparing flake-shaped spherical manganese tetroxide includes the following steps: (1) Prepare or use a mixed salt solution containing manganese and element A, wherein element A includes at least one of aluminum, nickel, cadmium and cobalt; (2) Using a mixture of ammonia and water as the reaction base liquid, the mixed salt solution, complexing agent and alkaline substance are introduced into the reaction base liquid to carry out the reaction. During the reaction, air is continuously introduced into the reaction base liquid and stirring is maintained. After the reaction is completed, the reaction slurry is obtained. (3) The reaction slurry is post-treated to obtain the porous spherical manganese tetroxide.

[0006] The design concept of the above technical solution lies in using a solution co-precipitation method to allow the product to gradually grow from crystal nuclei into a uniformly sized, sheet-like spherical structure under high-magnification SEM. Compared to commonly used manganese tetroxide adsorbents, the product of this technical solution is easier to achieve refined adsorption, has a better adsorption effect on certain specific impurities, and allows impurities to penetrate into the sheet-like spherical layers upon contact with the product, making it easier to adsorb impurities. Furthermore, the sheet-like, spherical shape provides more adsorption space and prevents product detachment, resulting in a higher adsorption rate. Simultaneously, by controlling specific adjustments to conditions such as stirring, pH, temperature, amount of complexing agent, and reaction time during the reaction process, the physical properties of the final sample can be controlled. For different impurity removal situations and needs, manganese tetroxide materials with different properties can be produced for targeted adsorption and impurity removal.

[0007] As a further preferred embodiment of the above technical solution, in step (1), the concentration of manganese in the mixed salt solution is 60~130g / L, and the concentration of element A is 1~5g / L.

[0008] As a further preferred embodiment of the above technical solution, in step (1), the mixed salt solution is obtained by dissolving soluble manganese salt and soluble A salt in deionized water. The soluble manganese salt includes at least one of manganese sulfate, manganese nitrate and manganese chloride. The soluble A salt includes at least one of aluminum nitrate, aluminum sulfate, aluminum acetate, aluminum chloride, nickel nitrate, nickel sulfate, nickel acetate, nickel chloride, cadmium nitrate, cadmium sulfate, cadmium acetate, cadmium chloride, cobalt nitrate, cobalt sulfate, cobalt acetate and cobalt chloride.

[0009] As a further preferred embodiment of the above technical solution, in step (2), the complexing agent includes at least one of EDTA, ammonium chloride, ammonium sulfate and ammonia water, and the concentration of the complexing agent is 7%~15%; the alkaline substance includes at least one of liquid alkali, potassium hydroxide solution and lime milk, and the mass concentration of the alkaline substance is 20%~40%, and the concentration of ammonium in the reaction base liquid is 0.1~0.3mol / L.

[0010] As a further preferred embodiment of the above technical solution, in step (2), the flow rate of the mixed salt solution is 1~3 L / h, the flow rate of the complexing agent is 0.1~0.3 L / h, and the flow rate of the alkaline substance is 0.1~0.3 L / h.

[0011] As a further preferred embodiment of the above technical solution, in step (2), the air flow rate is 0.6~1.2m³. 3 / h.

[0012] As a further preferred embodiment of the above technical solution, in step (2), the pH of the reaction system is controlled at 8.5~11.0.

[0013] As a further preferred embodiment of the above technical solution, in step (2), the reaction temperature of the mixed salt solution, complexing agent and alkaline substance is 40~80℃, and the reaction time is 10~40h.

[0014] As a further preferred embodiment of the above technical solution, in step (3), the post-processing operation includes sequential filtration, washing and drying; the filtration process uses Buchner funnel filtration; the washing process involves adding deionized water to the solid obtained by filtration and washing; and the drying process uses a constant temperature oven for drying at a temperature of 90~120℃.

[0015] Based on the same technical concept, the present invention also provides a sheet-like spherical manganese tetroxide, which is prepared by the preparation method described in the above technical solution.

[0016] As a further preferred embodiment of the above technical solution, the particle size D50 of the flake-shaped spherical manganese tetroxide is 3~20μm, and the specific surface area is 3~20m². 2 / g.

[0017] Based on the same technical concept, the present invention also provides an application of the above-mentioned sheet-like spherical manganese tetroxide as an adsorbent material in wastewater purification and solution impurity removal processes.

[0018] Compared with the prior art, the beneficial effects of the present invention are as follows: The present invention will now be described in further detail with reference to the accompanying drawings. Attached Figure Description

[0019] The accompanying drawings, which form part of this application, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings: Figure 1 This is a process flow diagram of the preparation method in Example 1; Figure 2 This is a particle size distribution diagram of the flaky spherical manganese tetroxide product from Example 1; Figure 3 and Figure 4 SEM images of the sheet-like spherical manganese tetroxide product of Example 1 (at different magnifications). Figure 5 This is a particle size distribution diagram of the flaky spherical manganese tetroxide product from Example 2; Figure 6 and Figure 7 SEM images of the sheet-like spherical manganese tetroxide product of Example 2 (at different magnifications). Detailed Implementation

[0020] The embodiments of the present invention will be described in detail below with reference to the accompanying drawings, but the present invention can be implemented in many different ways as defined and covered by the claims.

[0021] Example 1: The sheet-like spherical manganese tetroxide product of this embodiment, such as Figure 1 As shown, it is prepared by the following method: (1) Weigh out manganese sulfate and aluminum sulfate at a concentration of 80 g / L and 2 g / L respectively, dissolve them in deionized water to prepare a mixed salt solution, and label it as Agent A. Prepare a 32% liquid alkali and label it as Agent B. Prepare an 8% ammonia solution and label it as Agent C.

[0022] (2) Add deionized water to a 30L synthesis reactor, covering the upper edge of the stirring paddle. Add agent C dropwise to bring the pH to 9.3-9.5. Then turn on the stirring and heating, setting the stirring speed to 500 r / min. Heat to 50℃ and maintain a constant temperature. Then continuously introduce air into the liquid in the synthesis tank at a set air flow rate of 0.8 m³ / min. 3 / h.

[0023] (3) Pump agents A, B and C into the synthesis tank simultaneously using a peristaltic pump. The feed flow rate of agent A is 1.4 L / h; the feed flow rate of agent B is between 0.5 and 0.7 L / h, specifically to control the pH in the tank to 9.3 to 9.7; and the feed flow rate of agent C is 0.15 L / h.

[0024] (4) During the reaction, the pH of the slurry in the synthesis tank is controlled by controlling the flow rate of agent B. The pH is controlled between 9.3 and 9.7. The particle size growth of the slurry is monitored during the process. When the particle size grows to the required value and the reaction is stopped, the reaction slurry is obtained.

[0025] (5) The reaction slurry was subjected to solid-liquid separation (Buchner funnel filtration). The obtained solid portion was washed and dried in an oven at 100°C to obtain flaky spherical manganese tetroxide product. This product can be used as an adsorbent material in wastewater and solution purification processes. The specific surface area of ​​the product was tested and found to be 12 m². 2 / g, particle size distribution diagram as shown Figure 2 As shown, the particle size D50 is 6.5 μm, and the SEM image is as follows. Figure 3 , Figure 4 As shown.

[0026] Example 2: The flake-shaped spherical manganese tetroxide product of this embodiment is prepared by the following method: (1) Weigh out manganese sulfate and aluminum sulfate at a concentration of 120 g / L and 3 g / L respectively, dissolve them in deionized water to prepare a mixed salt solution, and label it as Agent A. Prepare a 32% potassium hydroxide solution and label it as Agent B. Prepare a 10% ammonia solution and label it as Agent C.

[0027] (2) Add deionized water to a 30L synthesis reactor, covering the upper edge of the stirring blades. Add agent C dropwise to bring the pH to 9.5-10. Then turn on the stirring and heating, setting the stirring speed to 600 r / min. Heat to 70℃ and maintain a constant temperature. Then continuously introduce air into the liquid in the synthesis tank at a set air flow rate of 1.2 m³ / min. 3 / h.

[0028] (3) A, B and C agents are simultaneously pumped into the synthesis tank by a peristaltic pump. The feed flow rate of agent A is 1.0 L / h; the feed flow rate of agent B is between 0.3 and 0.6 L / h, specifically to control the pH in the tank to 9.5 to 9.7; and the feed flow rate of agent C is 0.12 L / h.

[0029] (4) During the reaction, the pH of the slurry in the synthesis tank is controlled by controlling the flow rate of agent B. The pH is controlled between 9.5 and 9.7. The particle size growth of the slurry is monitored during the process. When the particle size grows to the required value and the reaction is stopped, the reaction slurry is obtained.

[0030] (5) The reaction slurry was subjected to solid-liquid separation (Buchner funnel filtration). The obtained solid portion was washed and dried in an oven at 120°C to obtain a flaky spherical manganese tetroxide product. The product was tested and found to have a specific surface area of ​​20 m². 2 / g, particle size distribution diagram as shown Figure 5 As shown, the particle size D50 is 5 μm, and the SEM image is as follows. Figure 6 , Figure 7 As shown.

[0031] Example 3: (1) Weigh out manganese sulfate and nickel sulfate with a concentration of 80 g / L and 5 g / L respectively, dissolve them in deionized water to prepare a mixed salt solution, and label it as Agent A. Prepare a 32% liquid alkali and label it as Agent B. Prepare an 8% ammonia solution and label it as Agent C.

[0032] (2) Add deionized water to a 30L synthesis reactor, covering the upper edge of the stirring paddle. Add agent C dropwise to bring the pH to 9.3-9.5. Then turn on the stirring and heating, setting the stirring speed to 500 r / min. Heat to 50℃ and maintain a constant temperature. Then continuously introduce air into the liquid in the synthesis tank at a set air flow rate of 0.8 m³ / min. 3 / h.

[0033] (3) Pump agents A, B and C into the synthesis tank simultaneously using a peristaltic pump. The feed flow rate of agent A is 1.4 L / h; the feed flow rate of agent B is between 0.5 and 0.7 L / h, specifically to control the pH in the tank to 9.3 to 9.7; and the feed flow rate of agent C is 0.15 L / h.

[0034] (4) During the reaction, the pH of the slurry in the synthesis tank is controlled by controlling the flow rate of agent B. The pH is controlled between 9.3 and 9.7. The particle size growth of the slurry is monitored during the process. When the particle size grows to the required value and the reaction is stopped, the reaction slurry is obtained.

[0035] (5) The reaction slurry was subjected to solid-liquid separation (Buchner funnel filtration). The obtained solid portion was washed and dried in an oven at 100°C to obtain flaky spherical manganese tetroxide product. This product can be used as an adsorbent material in wastewater and solution purification processes. The specific surface area of ​​the product was tested and found to be 15 m² / g. 2 / g, particle size follows a normal distribution.

[0036] Comparative Example 1: The preparation of the manganese tetroxide adsorbent material in this comparative example differs from that in Example 1 in that agent A in step (1) of this comparative example is only prepared from manganese sulfate, without the addition of aluminum sulfate.

[0037] Comparative Example 2: The preparation of the manganese tetroxide adsorbent material in this comparative example differs from that in Example 2 in that, in step (1) of this comparative example, agent A is prepared only by manganese sulfate, without the addition of aluminum sulfate.

[0038] Comparative Example 3: The preparation of the manganese tetroxide adsorbent material in this comparative example differs from that in Example 3 in step (1) of this comparative example, agent A is prepared only by manganese sulfate, without the addition of aluminum sulfate.

[0039] No nickel sulfate is added.

[0040] The oil absorption performance of the manganese tetroxide materials in Examples 1-3 and Comparative Examples 1-3 was tested, and the adsorption amount of oily substances by the manganese tetroxide materials was detected. The results are shown in Table 1.

[0041] Table 1 shows the adsorption test results of manganese tetroxide materials for oily substances in each embodiment and comparative example.

[0042] Wastewater was treated with manganese tetroxide materials from Examples 1-3 and Comparative Examples 1-3, and the reduction rates of COD and SS in the water were measured. The results are shown in Table 2.

[0043] Table 2 shows the adsorption test results of manganese tetroxide materials on wastewater in each embodiment and comparative example.

[0044] The results showed that the sheet-like spherical manganese tetroxide materials prepared in Examples 1-3 of the present invention had a better purification effect on wastewater, with a reduction rate of more than 85% for COD and a reduction rate of more than 70% for SS, which was better than the manganese tetroxide materials prepared in Comparative Examples 1-3.

[0045] The above are merely preferred embodiments of this application and are not intended to limit this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application. The above are merely preferred embodiments of the present invention, and the protection scope of the present invention is not limited to the above embodiments. For those skilled in the art, improvements and modifications obtained without departing from the technical concept of the present invention should also be considered within the protection scope of the present invention.

Claims

1. A method for preparing flaky spherical manganese tetraoxide, characterized in that: The following steps are involved: (1) preparing or taking a mixed salt solution containing manganese and element A, wherein element A includes at least one of aluminum, nickel, cadmium and cobalt; (2) using a mixture of ammonia water and water as a reaction base liquid, introducing the mixed salt solution, the complexing agent and the alkaline substance into the reaction base liquid for reaction, continuously introducing air into the reaction base liquid during the reaction and maintaining stirring, and obtaining a reaction slurry after the reaction is completed; (3) The reaction slurry is post-treated to obtain the flaky spherical manganese tetraoxide.

2. The method for preparing flaky spherical manganese tetraoxide according to claim 1, characterized in that: In step (1), the concentration of manganese element in the mixed salt solution is 60-130 g / L, and the concentration of A element is 1-5 g / L.

3. The method for preparing flaky spherical manganese tetraoxide according to claim 2, characterized in that: In step (1), the mixed salt solution is obtained by dissolving a soluble manganese salt and a soluble A salt in deionized water, wherein the soluble manganese salt includes at least one of manganese sulfate, manganese nitrate and manganese chloride, and the soluble A salt includes at least one of aluminum nitrate, aluminum sulfate, aluminum acetate, aluminum chloride, nickel nitrate, nickel sulfate, nickel acetate, nickel chloride, cadmium nitrate, cadmium sulfate, cadmium acetate, cadmium chloride, cobalt nitrate, cobalt sulfate, cobalt acetate and cobalt chloride.

4. The method for preparing flaky spherical manganese tetraoxide according to claim 1, characterized in that: In step (2), the complexing agent includes at least one of EDTA, ammonium chloride, ammonium sulfate and ammonia water, and the concentration of the complexing agent is 7% to 15%; the alkaline substance includes at least one of liquid caustic soda, potassium hydroxide solution and lime milk, and the mass concentration of the alkaline substance is 20% to 40%, and the concentration of ammonium in the reaction base liquid is 0.1 to 0.3 mol / L.

5. The method for preparing flaky spherical manganese tetraoxide according to claim 4, characterized in that: In step (2), the flow rate of the mixed salt solution is 1-3 L / h, the flow rate of the complexing agent is 0.1-0.3 L / h, and the flow rate of the alkaline substance is 0.1-0.3 L / h.

6. The method for preparing flaky spherical manganese tetraoxide according to claim 1, characterized in that: In step (2), the air flow rate is 0.6~1.2m 3 / h.

7. The method for preparing flaky spherical manganese tetraoxide according to claim 1, characterized in that: In step (2), the pH of the reaction system is controlled at 8.5-11.

0.

8. The method for preparing flaky spherical manganese tetraoxide according to claim 1, characterized in that: In step (2), the reaction temperature of the mixed salt solution, the complexing agent and the alkaline substance is 40-80° C., and the reaction time is 10-40 hours.

9. The method for preparing flaky spherical manganese tetraoxide according to any one of claims 1 to 8, characterized in that: In step (3), the post-treatment operation includes filtering, washing and drying in sequence; the filtering process adopts Buchner funnel filtration; the washing process is to add deionized water to the solid obtained by filtration for extraction and washing; the drying process is to dry in a constant temperature oven at a drying temperature of 90-120°C.

10. A flaky spherical manganese tetraoxide, characterized in that: The method is prepared by the method according to any one of claims 1 to 9.

11. The flaky spherical manganese tetraoxide according to claim 10, characterized in that: The particle size D50 of the flaky spherical manganese tetraoxide is 3-20 μm, and the specific surface area is 3-20 m 2 / g.

12. Use of the flaky spherical manganese tetraoxide according to claim 11 or 12, characterized in that: The flaky spherical manganese tetraoxide is used as an adsorption material in wastewater purification and solution impurity removal processes.

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