Preparation method of attapulgite-based magnesium silicate anthraquinone regenerative catalyst, anthraquinone regenerative catalyst and application thereof

Abstract

The application provides a palygorskite-based magnesium silicate anthraquinone regenerative catalyst and a preparation method thereof, the chemical formula of the anthraquinone regenerative catalyst is Mg4Si6O15(OH)2·6H2O, and the preparation method comprises the following steps: (1) obtaining a palygorskite-based SiO2 precursor through hydrothermal acidification of palygorskite; (2) uniformly mixing the palygorskite-based SiO2 precursor, an ammonium salt, a magnesium salt and ammonia water through ultrasonic mixing; and (3) transferring the mixed solution to a hydrothermal kettle to generate palygorskite-based magnesium silicate through hydrothermal reaction. The application takes palygorskite as a silicon source and a template, has the advantages of wide raw material source, simple preparation process, low production cost, green environmental protection and convenience for industrialized production, etc. The palygorskite-based magnesium silicate prepared by the application can be used as a solid alkali catalyst, and has the advantages of non-toxicity, environmental protection, high catalytic activity, long service life and the like.

Description

[0001] Field of study

[0002] This invention relates to a method for preparing an anthraquinone regeneration catalyst, the anthraquinone regeneration catalyst and its application, specifically to an attapulgite-based magnesium anthraquinone regeneration catalyst, its preparation method and application. Background Technology

[0003] In the anthraquinone process for producing H2O2, due to the uncontrollable nature of organic reactions, even with the most selective catalysts, some anthraquinone substances that lose their ability to produce H2O2 will still be generated. These substances are collectively referred to as anthraquinone degradation products. The formation of degradation products in the anthraquinone working solution gradually accumulates with continuous circulation. Excessive anthraquinone degradation product content not only severely affects the yield and quality of H2O2 and the catalytic efficiency of palladium-based catalysts, but also increases the viscosity of the working solution, increases the resistance of pipeline conveying devices, and leads to increased production costs. Faced with the ever-increasing demand for H2O2, the development of novel regenerators is receiving increasing attention. Because current catalysts suffer from high production costs and short service lives, there is an urgent need to develop a highly efficient and durable anthraquinone regeneration catalyst.

[0004] Magnesium silicate, with its abundant pores, stable structure, environmentally friendly properties, and tunable morphology, has been applied in various fields. The surface of magnesium silicate contains both basic and acidic active sites, possesses a high specific surface area and tunable pore size, exhibiting certain catalytic performance, making it a promising new catalytic material. Due to its unique structure and properties, magnesium silicate demonstrates good catalytic activity for the regeneration of anthraquinone degradation products, showing great promise for practical applications.

[0005] Natural attapulgite is inexpensive, possesses good thermal stability, chemical inertness, and a large specific surface area. Its abundant porous structure and diverse metallic composition endow it with strong adsorption properties and provide various catalytic active centers, making it a potentially valuable catalyst material applicable to different reaction systems. However, due to its complex composition, attapulgite cannot be directly used for the regeneration reaction of anthraquinone degradation products. Therefore, based on the unique porous and one-dimensional rod-like structure of attapulgite, this invention proposes purifying attapulgite before using it as a template and silicon source for preparing rod-shaped magnesium silicate anthraquinone regeneration catalyst. This not only saves on magnesium silicate preparation costs but also enhances the utilization value of attapulgite. Summary of the Invention

[0006] The present invention aims to provide an attapulgite-based magnesium silicate regeneration catalyst that is environmentally friendly, non-toxic, low-cost, long-lasting, and has high activity and selectivity for anthraquinone degradation products, as well as its preparation method.

[0007] This invention provides a method for preparing an attapulgite-based magnesium anthraquinone silicate regeneration catalyst, comprising the following steps: Step A: Dispersing attapulgite in a 1-4 mol / L HCl aqueous solution to form a suspension with a mass content of 5-15%, transferring the suspension to a hydrothermal reactor, and hydrothermally reacting at 100-180℃ for 3-6 hours, naturally cooling to room temperature to obtain a first precipitate, washing the first precipitate by centrifugation with deionized water 4-8 times, and drying to obtain a rod-shaped SiO2 precursor; Step B: Adding the rod-shaped SiO2 precursor to deionized water and ultrasonically dispersing for 10-30 minutes. n. Obtain rod-shaped SiO2 dispersion; Dissolve soluble magnesium salt and ammonium salt in deionized water to prepare a solution, then add ammonia water, stir evenly, and add the solution to the SiO2 dispersion, stir evenly to obtain a mixed system; Step C: Transfer the mixed system obtained in step B to a hydrothermal reactor, and hydrothermally react at 120-180℃ for 6-12h, and naturally cool to room temperature to obtain a second precipitate. The second precipitate is centrifuged and washed 4-8 times with deionized water, and the filter cake is dried in an oven at 90-120℃ for 6-10h. After thorough grinding, anthraquinone regeneration catalyst is obtained.

[0008] Furthermore, the magnesium salt is any one of magnesium chloride, magnesium nitrate, or magnesium sulfate.

[0009] Furthermore, the ammonium salt is any one of ammonium chloride, ammonium nitrate, or ammonium sulfate.

[0010] Furthermore, in step B, the mass content of SiO2 is 1-5%, and the molar ratio of Si to Mg is 1-1.5:1.

[0011] Furthermore, the molar solubility of the ammonium salt in step B is 0.1-0.5 mol·L⁻¹. -1 The molar concentration of ammonia water is 0.2-1 mol·L⁻¹. -1 .

[0012] This invention also provides an attapulgite-based magnesium anthraquinone silicate regeneration catalyst, prepared by the above-described method for preparing the attapulgite-based magnesium anthraquinone silicate regeneration catalyst, the chemical formula of which is: Mg4Si6O 15 (OH)2·6H2O.

[0013] The present invention also provides an application of an attapulgite-based magnesium anthraquinone silicate regeneration catalyst, wherein the catalyst is prepared from the above-mentioned attapulgite-based magnesium anthraquinone silicate regeneration catalyst and is used for the regeneration of anthraquinone degradation products.

[0014] The beneficial effects of the present invention are as follows: Compared with the prior art, the present invention has the following significant advantages: (1) The present invention uses natural one-dimensional porous attapulgite, which is extremely abundant and inexpensive in my country, as a silicon source and template to prepare porous rod-shaped magnesium silicate. It has the advantages of wide availability of raw materials, simple preparation process, no use of organic reagents, green and environmentally friendly, low production cost, and easy industrial production; (2) The attapulgite-based magnesium silicate material prepared by the present invention is green, environmentally friendly, non-toxic and harmless. As a solid base catalyst for the regeneration of anthraquinone degradation products, it has the advantages of high catalytic activity and selectivity, long service life, etc. The regeneration capacity of anthraquinone degradation products can reach 6.19 g / L within 72 h. Attached Figure Description

[0015] Figure 1 The X-ray diffraction pattern of the attapulgite-based magnesium anthraquinone silicate regenerated catalyst prepared in Example 1;

[0016] Figure 2 This is a scanning electron microscope image of the attapulgite-based magnesium anthraquinone silicate regeneration catalyst prepared in Example 1;

[0017] Figure 3 The diagram shows the regeneration performance of the attapulgite-based magnesium anthraquinone silicate regeneration catalyst prepared in Example 1. Detailed Implementation

[0018] To enable those skilled in the art to better understand the technical solution of the present invention, a solid base catalyst and its preparation method provided by the present invention are described in detail below with reference to embodiments. The following embodiments are for illustrative purposes only and are not intended to limit the scope of the present invention.

[0019] Example 1

[0020] This invention provides an attapulgite-based magnesium anthraquinone silicate regeneration catalyst and its preparation method. The chemical formula of the attapulgite-based magnesium anthraquinone silicate regeneration catalyst is Mg4Si6O15(OH)2·6H2O. The specific preparation steps are as follows:

[0021] (1) Disperse 10g of attapulgite in 100mL of 1mol / L HCl aqueous solution, stir ultrasonically for 30min to form a uniform suspension, transfer the suspension to a hydrothermal reactor, and hydrothermally react at 100℃ for 3h. After naturally cooling to room temperature, centrifuge and wash the precipitate 5 times, and dry it at 60℃ to obtain the rod-shaped SiO2 precursor.

[0022] (2) Add 6g of rod-shaped SiO2 to 150mL of deionized water and sonicate for 10min to obtain rod-shaped SiO2 dispersion; dissolve 15.36g of magnesium nitrate and 7.35g of ammonium nitrate in 150mL of deionized water to prepare a solution, then add 15mL of concentrated ammonia water, stir for 20min, add the solution to the SiO2 dispersion, and sonicate for 30min.

[0023] (3) The mixture obtained in step 2 is transferred to a 1L hydrothermal reactor and hydrothermally reacted at 120°C for 6 hours. After cooling naturally to room temperature, the precipitate is centrifuged and washed 6 times with water. Then it is dried in an oven at 90°C for 6 hours and thoroughly ground to obtain attapulgite-based magnesium silicate powder, which is the anthraquinone regeneration catalyst to be prepared in this embodiment.

[0024] The powder XRD diffraction pattern of the attapulgite-based magnesium silicate prepared in this embodiment is as follows: Figure 1 As shown in the figure, its XRD diffraction peaks correspond to the standard card (JCPDS:29-1492) of Mg4Si6O15(OH)2·6H2O.

[0025] The morphology of the attapulgite-based magnesium silicate prepared in this embodiment is as follows: Figure 2 As shown, it exhibits a multi-level structure assembled from nanosheets.

[0026] The regeneration catalytic performance of the anthraquinone degradation product of attapulgite-based magnesium silicate prepared in this embodiment was tested, and the results are as follows: Figure 3 As shown in the figure. The test procedure is as follows: 5g of attapulgite-based magnesium silicate was added to 50mL of working solution. After 72h, 50μL of anthraquinone regeneration solution was taken and placed in a 10mL volumetric flask and diluted to volume with anhydrous methanol. The anthraquinone regeneration amount was tested by liquid chromatography. The test results show that the prepared attapulgite-based magnesium silicate anthraquinone regeneration catalyst has high regeneration performance for anthraquinone degradation products, and the regeneration amount reaches 6.19g / L within 72h.

[0027] Example 2

[0028] (1) Disperse 15g of attapulgite in 150mL of 2mol / L HCl aqueous solution, stir ultrasonically for 30min to form a uniform suspension, transfer the suspension to a hydrothermal reactor, and hydrothermally react at 140℃ for 2h. After naturally cooling to room temperature, centrifuge and wash the precipitate 5 times, and dry it at 80℃ to obtain the rod-shaped SiO2 precursor.

[0029] (2) Add 5g of rod-shaped SiO2 to 100mL of deionized water and sonicate for 10min to obtain rod-shaped SiO2 dispersion; dissolve 12.28g of magnesium nitrate and 7.35g of ammonium nitrate in 100mL of deionized water to prepare a solution, then add 18mL of concentrated ammonia water, stir for 20min, add the solution to the SiO2 dispersion, and sonicate for 30min.

[0030] (3) The mixture obtained in step 2 is transferred to a 1L hydrothermal reactor and hydrothermally reacted at 140°C for 5 hours. After cooling naturally to room temperature, the precipitate is washed 6 times by centrifugation with deionized water. The filter cake is dried in an oven at 100°C for 6 hours and then thoroughly ground to obtain attapulgite-based magnesium silicate powder, which is the anthraquinone regeneration catalyst to be prepared in this embodiment.

[0031] Example 3

[0032] (1) Disperse 20g of attapulgite in 180mL of 3mol / L HCl aqueous solution, stir ultrasonically for 30min to form a uniform suspension, transfer the suspension to a hydrothermal reactor, and hydrothermally react at 150℃ for 3h. After naturally cooling to room temperature, centrifuge and wash the precipitate 6 times, and dry it at 80℃ to obtain the rod-shaped SiO2 precursor.

[0033] (2) Add 8g of rod-shaped SiO2 to 200mL of deionized water and sonicate for 10min to obtain rod-shaped SiO2 dispersion; dissolve 10.24g of magnesium nitrate and 7.35g of ammonium nitrate in 200mL of deionized water to prepare a solution, then add 12mL of ammonia water, stir for 20min, add the solution to the SiO2 dispersion, and sonicate for 30min.

[0034] (3) The mixture obtained in step 2 was transferred to a 1L hydrothermal reactor and hydrothermally reacted at 150°C for 4 hours. After cooling naturally to room temperature, the precipitate was washed 6 times by centrifugation with deionized water. The filter cake was dried in an oven at 100°C for 6 hours and then ground thoroughly to obtain attapulgite-based magnesium silicate powder, which is the anthraquinone regeneration catalyst to be prepared in this embodiment.

[0035] The embodiments of the present invention have been described in detail above. However, the present invention is not limited to the above embodiments. Various changes that can be made within the scope of knowledge possessed by those skilled in the art without departing from the spirit of the present invention should also be considered within the scope of protection of the present invention.

Claims

1. A method for preparing an attapulgite-based magnesium anthraquinone silicate regeneration catalyst, characterized in that, The preparation method specifically includes the following steps: Step A: Disperse attapulgite in a 1-4 mol / L HCl aqueous solution to form a suspension with a mass content of 5-15%. Transfer the suspension to a hydrothermal reactor and perform a hydrothermal reaction at 100-180℃ for 3-6 hours. Allow it to cool naturally to room temperature to obtain the first precipitate. Wash the first precipitate with deionized water by centrifugation 4-8 times and dry it to obtain the rod-shaped SiO2 precursor. Step B: Add the rod-shaped SiO2 precursor to deionized water and ultrasonically disperse for 10-30 min to obtain a rod-shaped SiO2 dispersion; dissolve the soluble magnesium salt and ammonium salt in deionized water to prepare a solution, then add ammonia water, stir evenly, and add the solution to the SiO2 dispersion, and stir thoroughly to obtain a mixed system; Step C: Transfer the mixture obtained in step B to a hydrothermal reactor and hydrothermally react at 120-180℃ for 6-12 hours. After naturally cooling to room temperature, a second precipitate is obtained. The second precipitate is centrifuged and washed 4-8 times with deionized water. The filter cake is dried in an oven at 90-120℃ for 6-10 hours and then thoroughly ground to obtain the anthraquinone regenerated catalyst.

2. The preparation method according to claim 1, characterized in that: The magnesium salt is any one of magnesium chloride, magnesium nitrate, or magnesium sulfate.

3. The preparation method according to claim 1, characterized in that: The ammonium salt is any one of ammonium chloride, ammonium nitrate, or ammonium sulfate.

4. The preparation method according to claim 1, characterized in that: The mass content of SiO2 in step B is 1-5%, and the molar ratio of Si to Mg is 1-1.5:

1.

5. The preparation method according to claim 1, characterized in that: The molar concentration of the ammonium salt in step B is 0.1-0.5 mol·L⁻¹. -1 The molar concentration of ammonia water is 0.2-1 mol·L⁻¹. -1 .

Images