A green preparation method and application of high-performance shaped sodalite

Abstract

The application discloses a green preparation method of high-performance shaped sodalite and application. Natural minerals, solid alkali and water are uniformly mixed to obtain a mixture; the mixture is extruded by using an extruder to obtain a shaped mixture; and then the shaped mixture is crystallized, filtered and washed to obtain high-performance shaped sodalite. The shaped sodalite prepared by the green preparation method has the characteristics of high mechanical strength, high water absorption and high maximum adsorption capacity of metal ions, can be used for adsorbing water and adsorbing metal ions, and is a material with excellent performance.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of green preparation and application of zeolite molecular sieve, and particularly relates to a green preparation method of high-performance shaped sodalite and application thereof. BACKGROUND

[0002] Sodalite, the framework type code of which is SOD according to the International Zeolite Association. The chemical formula of sodalite is 4Na2O·3Al2O3·6SiO2, the atomic ratio of silicon (Si) and aluminum (Al) is 1:1, and the content of sodium (Na) ion is high. Through ion exchange and electrostatic effect, sodalite has high industrial application prospect in adsorption dehydration and adsorption of metal ions. At present, the methods for preparing sodalite at home and abroad are divided into three types: 1, a method using chemical reagents as raw materials; 2, a method using natural minerals and sub-molten salt activation; and 3, a method using natural minerals and mechanical activation. In the method 1, the chemical reagents used are derived from natural minerals, and the overall preparation steps are more, the energy consumption and cost are high. The method 2 uses natural minerals, which can reduce the industrial production steps from natural minerals to chemical reagents to sodalite, but the sub-molten salt activation method uses more solid alkali, the cost is higher, and the secondary pollution of waste alkali to the environment is larger. The method 3 uses mechanical activation of natural minerals, which can appropriately reduce the amount of alkali used, reduce the cost of alkali use and the secondary pollution to the environment, but it is necessary to preheat and activate the natural minerals at high temperature; in addition, the intermediate after activation and molding needs to be heat treated, and finally needs to be hydrothermally crystallized in a high-concentration alkali solution, which has high energy consumption, high total amount of solid alkali, and large secondary pollution to the environment. The sodalite prepared by the above-mentioned three methods still needs to be shaped before it can be applied in industry, and even because of the low mechanical strength, it cannot be well applied in industry. Therefore, it is of great significance in industry to seek a green method for preparing high-performance shaped sodalite with low energy consumption, low material consumption and small secondary pollution to the environment.

[0003] N-methyl pyrrolidone can dissolve organic matter, so it is widely used as a cleaning agent in the electronics and battery industries. However, N-methyl pyrrolidone is also water-soluble, which can easily introduce water during the cleaning process, affecting the quality of electronic and battery products. Using high-performance shaped faujasite to adsorb N-methyl pyrrolidone before or after use (cleaning) can not only reduce water content, but also reduce metal ion content. When the heavy metal ion content of water (including domestic water, domestic sewage, industrial wastewater) is high, it cannot be directly used or discharged. The content of heavy metal ions in water can be reduced by chemical precipitation method, but when the content is reduced to a certain extent, the effect of chemical precipitation method is reduced, the cost is increased, and the secondary pollution to the environment is increased. At this time, using high-performance shaped faujasite for adsorption can further reduce the content of heavy metal ions, and even completely remove the heavy metal ions in water, ensuring human health, and also being beneficial to the recycling of industrial wastewater and the recovery of valuable heavy metal ions. SUMMARY

[0004] The purpose of the present application is to provide a green preparation method of high-performance shaped faujasite and its application in adsorbing water and metal ions.

[0005] To achieve the above purpose, the present application adopts the following technical solutions:

[0006] A green preparation method of high-performance shaped faujasite, comprising the following steps:

[0007] (1) uniformly mix natural minerals and solid alkali according to the proportion, then further mix with deionized water to obtain a mixture;

[0008] (2) extrude the mixture with double screw rods in the extruder at a speed of 35-45 revolutions per minute (according to the need, use a mold with a pore size of 1-10 mm) to obtain a shaped mixture;

[0009] (3) crystallize, filter, wash, then cut and crush the shaped mixture to obtain high-performance shaped faujasite with different shape requirements.

[0010] Further, the natural mineral in step (1) is diatomite or kaolin.

[0011] Further, the solid alkali in step (1) is sodium carbonate, sodium hydroxide or sodium bicarbonate.

[0012] Further, the mass ratio of solid alkali to natural mineral in step (1) is 0.001:1-1.500:1.

[0013] Further, the amount of deionized water added in step (1) is 5-50% of the total mass of natural minerals and solid alkali.

[0014] Further, the crystallization in step (3) is hydrothermal crystallization or thermal activation crystallization. o The hydrothermal crystallization process is as follows: the shaped mixture is dried at 40-160 o C for 0.1-4 h, and then the mixture is transferred to a hydrothermal kettle, sodium hydroxide solution is added, and hydrothermal reaction is performed at 60-170 o C for 0.1-6 h; the thermal activation crystallization process is as follows: the shaped mixture is heated at 40-160

[0015] The mass ratio of the sodium hydroxide solution to the mixture is 0.5:1-6:1, and the content of the alkali in the alkali solution is 0-12 mol / L.

[0016] Further, the number of times of suction filtration in step (3) is 1-6, and the mass ratio of the deionized water used for suction filtration to the product after crystallization is 1:1-600:1.

[0017] The high-performance shaped offretite can be used for adsorbing water or adsorbing metal ions.

[0018] The adsorption of water includes using the shaped offretite as a drying agent to reduce the humidity in a specific environment such as the interior of a Fourier transform infrared spectrometer, so as to ensure the stable and long-term normal operation of the instrument. The adsorption of water also includes using the shaped offretite to adsorb water in an organic substance, and the organic substance includes N-methyl pyrrolidone and the like.

[0019] The adsorption of metal ions includes using the shaped offretite to adsorb Cu 2+ , Zn 2+ and the like in N-methyl pyrrolidone, or adsorbing Co 2+ , Mn 2+ and the like in industrial wastewater, domestic sewage or domestic water. The industrial wastewater includes refined wastewater, oxidation mother liquor and oxidation residue (after treatment) generated in the production of purified terephthalic acid.

[0020] Compared with the existing preparation technology of shaped offretite, the green preparation method provided by the present application does not need the step of preheating and activating or sub-molten salt activating the natural mineral, the crystallization step is simple, the amount of alkali used is small, and it is a green preparation method with low energy consumption and low material consumption. The shaped offretite prepared has the characteristics of high mechanical strength, high water absorption rate and high maximum adsorption capacity of metal ions, can be used for adsorbing water and adsorbing metal ions, and is a material with excellent performance. BRIEF DESCRIPTION OF DRAWINGS

[0021] Figure 1 It is the XRD spectrum of the product S3 of Example 3.

[0022] Figure 2 The left image is a field emission transmission electron microscope (TEM) image of S3. Figure 2 The right image is the FFT image of the TEM image of S3.

[0023] Figure 3 To use S3 to Co 2+ and Mn 2+ The results of dynamic adsorption of simulated wastewater with an initial concentration of 50 mg / L. Detailed Implementation

[0024] To help understand the technical solution of the present invention, the present invention will be further described below in conjunction with specific embodiments, but the present invention is not limited thereto. Example 1

[0025] 66.6 g of kaolin was heated at 700°C. o Calcined at C for 4 h, mixed with 48 g of sodium hydroxide, and then mixed thoroughly with 39 g of deionized water. The thoroughly mixed mixture was further processed on an extruder, and extruded using a twin-screw extruder at 40 rpm. The extruded mixture was then heated at 110 °C. o Dry at C for 4 h, then place in a hydrothermal reactor, add 154 g of deionized water, and heat at 150 °C. o The crystallization reaction was carried out at C for 4 h. The crystallized product was filtered (three times, with a deionized water to crystallized product mass ratio of 200:1), washed, and then subjected to a 110°C solution. o Drying at C for 1 h yields shaped sodalite. Example 2

[0026] Mix 66.6 g of kaolin with 40 g of sodium hydroxide, then mix thoroughly with 43 g of deionized water. Further mix the above mixture on an extruder, extruding the mixture at 35 rpm using a twin-screw extruder. The extruded mixture is then heated at 110°C. o Dry at C for 4 hours, then place in a hydrothermal reactor, add 150 g of deionized water, and heat at 150°C. o The crystallization reaction was carried out at C for 4 h. The crystallized product was filtered (filtered twice, with a deionized water to crystallized product mass ratio of 300:1), washed, and then subjected to a 110°C solution. o Drying at C for 1 h yields shaped sodalite. Example 3

[0027] Mix 66.6 g of kaolin clay with 32 g of sodium hydroxide, and then mix with 39 g of deionized water. Further mix the uniformly mixed mixture on an extruder, and extrude the mixture with a double screw of the extruder at a speed of 45 rpm. Dry the extruded mixture at 110 o C for 4 h, and then put into an autoclave, add 140 g of deionized water, and crystallize the mixture at 150 o C for 2 h. Filter the crystallized product (the filtering is performed 3 times, and the mass ratio of deionized water used for filtering to the crystallized product is 350:1), wash, and dry at 110 o C for 1 h to obtain a shaped sodalite (denoted as S3). Example 4

[0028] Mix 66.6 g of kaolin clay with 64 g of sodium hydroxide, and then mix with 55 g of deionized water. Further mix the uniformly mixed mixture on an extruder, and extrude the mixture with a double screw of the extruder at a speed of 40 rpm. Dry the extruded mixture at 110 o C for 4 h, and then put into an autoclave, add 185 g of deionized water, and crystallize the mixture at 100 o C for 4 h. Filter the crystallized product (the filtering is performed 4 times, and the mass ratio of deionized water used for filtering to the crystallized product is 400:1), wash, and dry at 110 o C for 1 h to obtain a shaped sodalite. Example 5

[0029] Mix 66.6 g of kaolin clay with 44 g of sodium hydroxide, and then mix with 45 g of deionized water. Further mix the uniformly mixed mixture on an extruder, and extrude the mixture with a double screw of the extruder at a speed of 40 rpm. Dry the extruded mixture at 110 o C for 4 h, and then put into an autoclave, add 150 g of 8 mol / L sodium hydroxide solution, and crystallize the mixture at 100 o C for 4 h. Filter the crystallized product (the filtering is performed 4 times, and the mass ratio of deionized water used for filtering to the crystallized product is 400:1), wash, and dry at 110 o C for 1 h to obtain a shaped sodalite. Example 6

[0030] Mix 66.6 g of kaolin clay with 44 g of sodium hydroxide, and then mix with 45 g of deionized water. Further mix the uniformly mixed mixture on an extruder, and extrude the mixture with a double screw of the extruder, and dry the extruded mixture at 150o Heating at C for 6 h, the resulting product was filtered (the filtration was performed 4 times, and the mass ratio of deionized water to crystallized product used for filtration was 400:1), washed, and then heated at 110 °C. o Drying at C for 1 h yields shaped sodalite.

[0031] Application Example 1

[0032] Using product S3 from Example 3 to treat Co 2+ and Mn 2+ Simulated wastewater with an initial concentration of 50 mg / L was subjected to dynamic adsorption. The specific operation was as follows: S3 was crushed to obtain particles between 20 and 40 mesh. These particles were then packed into a dynamic adsorption bed. The simulated wastewater was flowed through the particles in the dynamic adsorption bed at a rate of 5 BV / h. The breakthrough point was set at Co. 2+ and Mn 2+ The concentration was 2 mg / L, which was used to determine the penetration treatment quality of S3 particles on simulated wastewater.

[0033] Figure 1 The image shows the XRD pattern of product S3 from Example 3. Figure 1 It can be seen that 2 θ =14.0, 19.8, 24.3, 31.6, 32.6, 34.6, 37.4 and 42.7 o At that time, diffraction peaks were present, which belong to the characteristic diffraction peaks of sodalite, corresponding to the (1 1 0), (2 1 1), (3 1 0), (2 2 2), (3 2 1) and (411) crystal planes, respectively, indicating that sodalite was indeed prepared using Example 3. The shaped sodalite prepared by the green preparation method of the present invention all have obvious characteristic diffraction peaks of sodalite.

[0034] Figure 2 The left image is a field emission transmission electron microscope (TEM) image of S3. Figure 2 The right image is the FFT image of the TEM image of S3. From Figure 2 As can be seen in the left image, S3 has lattice fringes; from Figure 2 The right-hand image shows the diffraction spots corresponding to the crystal planes (1 1 0), (2 11), (3 1 0), (2 2 2), (3 2 1), and (411), which are related to... Figure 1 The characteristic diffraction peaks in the XRD pattern are consistent with the crystal plane assignments. Figure 2 The results further confirm from a microscopic perspective that the method provided by this invention can produce shaped sodalite in a green manner.

[0035] Figure 3 To use S3 particles with particle sizes between 20 and 40 mesh for Co 2+ and Mn2+ Results of dynamic adsorption of simulated wastewater with initial content of 50 mg / L, respectively. From Figure 3 It can be seen that the breakthrough treatment quality of S3 is 155.1 BV, which represents that using 1 g of S3 particles for adsorption, 155.1 g of simulated wastewater can be used to remove Co 2+ and Mn 2+ content to <2 mg / L.

[0036] The above description is only the preferred embodiment of the present application, and any equivalent changes and modifications made within the scope of the patent application of the present application shall be covered by the scope of the present application.

Claims

1. A green preparation method for high-performance molded sodalite, characterized in that, Includes the following steps: (1) Mix natural minerals, solid alkali and water evenly to obtain a mixture; The natural mineral is diatomaceous earth or kaolin, and the solid alkali is sodium carbonate, sodium hydroxide, or sodium bicarbonate; the mass ratio of solid alkali to natural mineral is 0.661:1 to 1.500:1, and the amount of water added is 5% to 50% of the total mass of natural mineral and solid alkali. (2) The mixture is extruded using an extruder to obtain a shaped mixture; (3) The shaped mixture is crystallized, filtered and washed to obtain high-performance shaped sodalite; The crystallization is thermally activated crystallization, and the thermally activated crystallization process is as follows: the shaped mixture is heated at 150-160℃ for 6-8 hours.

2. The green preparation method of high-performance molded sodalite according to claim 1, characterized in that, The number of times the filtration is performed in step (3) is 1-6 times, and the mass ratio of the deionized water used for filtration to the crystallized product is 1:1 to 600:

1.

3. A high-performance molded sodalite obtained by the green preparation method according to claim 1 or 2.

4. The application of high-performance molded sodalite obtained by the green preparation method according to claim 1 or 2 in the adsorption and removal of water or the adsorption of metal ions.

5. The application according to claim 4, characterized in that, The aforementioned adsorption and dehydration method involves using shaped sodalite as a desiccant to reduce ambient humidity; or, using shaped sodalite to adsorb water from organic matter.

6. The application according to claim 4, characterized in that, The adsorption of metal ions refers to the adsorption of metal ions in N-methylpyrrolidone using shaped sodalite, or the adsorption of metal ions in industrial wastewater, domestic sewage, or domestic water.

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