Preparation method of bentonite adsorption material

Abstract

The invention discloses a preparation method of a bentonite adsorption material, which comprises the following steps: firstly preparing bentonite suspension to completely disperse the bentonite suspension, then mixing the bentonite suspension with polyethyleneimine (PEI), inducing the bentonite to form adsorption particles with completely exposed crystal faces (100) through the polyethyleneimine (PEI), and drying the adsorption particles to obtain the bentonite adsorption material. The unique structure greatly enhances the adsorption capacity of the material. Meanwhile, in the mixing process, PEI is adsorbed on the surface of bentonite through electrostatic interaction, a stable layer stacking structure is formed, generation of fine dust is effectively avoided through the strong interlayer acting force of layer-by-layer stacking, and finally wet granulation is conducted on the bentonite. The bentonite adsorption material prepared by the invention has excellent water absorption and deodorization functions, and also has the advantages of low dust content and environmental protection.

Description

Technical Field

[0001] The present invention belongs to the technical field of the process of adsorption materials, and particularly relates to a production process of bentonite adsorption materials. Background Art

[0002] As a medium for burying and absorbing liquids, adsorption materials are widely used in occasions where it is necessary to keep the environment clean and dry. Early adsorption materials were mainly of the non-coagulating type, and their functions were limited to basic liquid absorption. With the progress of technology, various improved adsorption materials have emerged on the market, such as tofu adsorption materials, bentonite adsorption materials, crystal adsorption materials, etc. These new materials can not only quickly absorb liquids, but also effectively control odors, thus greatly improving the convenience of use and hygienic conditions.

[0003] In order to improve the performance of adsorption materials, the prior art has adopted various means to optimize the water absorption, deodorization effect and reduce dust generation of products. For example, tofu adsorption materials utilize the combination of natural minerals and plant fibers to provide good water absorption and easy handling characteristics; bentonite adsorption materials prepare macroporous adsorption material particles with microporous and mesoporous structures by selecting clay particles of specific particle sizes and adding organic modifiers and carboxymethyl cellulose as binders, enhancing the selective adsorption ability for water molecules and odor-emitting gases such as hydrogen sulfide and ammonia; crystal adsorption materials achieve efficient water absorption and low dust generation due to their unique crystal structures. In addition, some manufacturers have also explored the possibility of using biodegradable materials or renewable resources to manufacture environmentally friendly adsorption materials.

[0004] Despite the adoption of the above various technical means, the existing adsorption materials still have some deficiencies. First of all, the water absorption performance of many adsorption materials is not strong enough, resulting in an increased replacement frequency, causing waste of resources and rising labor costs. Secondly, some types of adsorption materials are prone to generating a large amount of dust during use. These fine particles are not only easily scattered into the surrounding environment, but may also remain on the surface or in the gaps and are difficult to clean. More importantly, the dust problem may affect air quality and pose a potential threat to the health of the respiratory system. Therefore, although significant progress has been made in adsorption material technology, there is still room for improvement, especially in improving the water absorption efficiency, reducing dust emissions, and ensuring the economy and environmental protection of long-term use. Summary of the Invention

[0005] The object of the present invention is to provide a production process of hierarchical bentonite adsorption materials for bentonite adsorption materials prepared by traditional processes with insufficient excellent performance, which is suitable for exhibiting more excellent water absorption and deodorization performance in various occasions and environments.

[0006] To achieve the above object, the present invention adopts the following technical solutions: A preparation method of a bentonite adsorption material, comprising the following steps:

[0007] (1) Prepare a bentonite suspension by mixing 90 - 95 parts by weight of bentonite with 900 - 1000 parts by weight of deionized water, add 3 - 5 parts by weight of sodium carbonate, stir and react at 80 °C for 2 h, with a stirring speed of 150 r / min, and then centrifuge and wash the precipitate to obtain sodium-modified bentonite;

[0008] (2) Disperse 80 - 100 parts by weight of the sodium-modified bentonite into deionized water, add 4 - 5 parts by weight of polyethyleneimine, and stir and react for 30 min; Filter the reaction solution, and send the obtained filter residue to a dryer for drying at a drying temperature of 280 - 330 °C for 2 h. After drying, put it into a grinder for grinding and pulverization to obtain an organically modified bentonite powder; During the mixing process, the electrostatic interaction adsorbs the positively charged (100) plane of bentonite around the negatively charged PEI, making the (100) plane completely exposed, forming a stable layer stacking structure, as Figure 1 shown.

[0009] (3) Perform wet granulation to form small particles with a layer stacking shape, and finally, under the action of the binder carboxymethyl cellulose, bond multiple small particles into large particles through wet granulation. Specifically, first use the organically modified bentonite powder obtained in step (2) to perform wet granulation through a disk granulator to obtain adsorption material particles with a particle size of 0.5 - 4 mm; Screen and classify, and select adsorption material balls with a particle size of 0.5 - 1 mm; Then mix the adsorption material balls obtained in step (3) and the coating material according to a mass ratio of 10:1 to obtain bonded macroporous adsorption material particles; After drying, screen and classify, and select macroporous adsorption material particles with a particle size of 3 mm, where the drying temperature is 250 - 300 °C and the drying time is 2 h; The coating material is composed of the modified bentonite powder obtained in step (2) and carboxymethyl cellulose mixed according to a mass ratio of 99:1.

[0010] Further, in step (2), the organically modified bentonite is ground to 200 meshes, and the mesopore size in the organically modified bentonite is 2 - 5 nm.

[0011] Further, when performing wet granulation through a disk granulator in step (3), the water content is about 30 wt%.

[0012] Further, the obtained adsorption material in step (4) is dried to a water content of ≤ 3.0%, and the macropore size in the adsorption material is 50 - 100 nm.

[0013] The beneficial effects of the present invention are as follows: By using polyethyleneimine (PEI) to induce bentonite to form adsorption particles with the (100) crystal plane completely exposed, this unique structure greatly enhances the adsorption capacity of the material. At the same time, the strong interlayer forces of the layer-by-layer stacking effectively avoid the generation of fine dust, thereby providing a new type of adsorption material that is efficient, low-dust and environmentally friendly, significantly improving the user experience and environmental friendliness. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 is the formation process of the organically modified bentonite powder of the present invention;

[0015] Figure 2 is the XRD pattern of the organically modified bentonite powder and the bentonite powder without organic modification;

[0016] Figure 3 , Figure 4 , Figure 5 is the scanning electron micrograph of the bentonite adsorption material obtained in Examples 1-3;

[0017] Figure 6 a is the absorbance curve of Example 1 and Comparative Example 1, Figure 6 b is the working curve of absorbance vs. ammonium ion concentration (mg·L -1 );

[0018] Figure 7 is the adsorption effect diagram of the blank control, Example 1 and Comparative Example 1. DETAILED DESCRIPTION OF THE INVENTION

[0019] The present invention will be further clarified below with reference to specific embodiments. It should be understood that these embodiments are only used to illustrate the present invention and not to limit the scope of the present invention. In addition, it should be understood that after reading the content taught by the present invention, those skilled in the art make various changes or modifications to the present invention, and these equivalent forms also fall within the scope defined by the appended claims of this application.

[0020] In the following examples, the performance characterization is carried out according to the following scheme:

[0021] 1. Water absorption rate test

[0022] The water absorption rate is the amount of clear water that a certain mass of adsorbent material can absorb and dry within a certain period of time. The experimental instruments used include: a 100 ml glass measuring cup, an electronic scale, and a 50 m separating funnel. Weigh 10 g of the material to be tested and place it in a 100 ml glass measuring cup. Slowly drip 50 ml of warm water into the cup using the separating funnel. After standing for 5 minutes, slowly pour out the suspended liquid in the glass measuring cup and weigh the weight of the liquid. Conduct the test three times and take the average value. The water absorption rate of the material to be tested is calculated as mass fraction A, expressed as a percentage: A = (50 - m) / 10 × 100%, where m is the weight of the poured-out suspended liquid, with the unit of (g).

[0023] 2. Test on the agglomeration strength of the material particles to be tested

[0024] Lay 1 Kg of the material to be tested flat in a container with dimensions of 25×12×8 cm (length × width × height). Each time, use a syringe to draw 10 ml of physiological saline containing 0.1 g / ml urea at a temperature of 37°C and vertically add it to the material to be tested from a height of 2.5 cm. After 10 s, take out the agglomerate and weigh it, and let the agglomerate freely fall from a height of 15 cm until it breaks. Record the number of times the agglomerate falls, and this number is the agglomeration strength. Repeat the test 3 times for each group.

[0025] 3. Test on the hardness of the material particles to be tested

[0026] Test device: An automatic particle hardness detector or a device with the same function, with a resolution of at least 0.1 N. Take 10 particles of different materials to be tested for hardness testing and take the average value.

[0027] 4. Test on the ammonia absorption rate of the material particles to be tested

[0028] Add ammonium chloride solution to a 50 ml colorimetric tube, add 1.0 ml of 50% potassium sodium tartrate solution, and mix well. Then add 2.0 ml of Nessler's reagent and shake well. Let it stand for 1 h. Use a 1 cm colorimetric cell, with water as the reference, and measure the absorbance at a wavelength of 420 nm.

[0029] In a set of 50 ml colorimetric tubes, add ammonium chloride standard solutions respectively: Pipette 0.00 ml, 0.50 ml, 1.00 ml, 2.00 ml, 3.00 ml, 5.00 ml, 7.00 ml, and 10.00 ml, add water to the mark, add 1.0 ml of potassium sodium tartrate solution, and mix well. Add 1.5 ml of Nessler's reagent and mix well. After standing for 1 h, at a wavelength of 420 nm, with water as the reference, measure their absorbances respectively. Plot the working curve of absorbance against ammonium ion concentration (mg·L -1 ).

[0030] 5. Hydrogen sulfide removal rate of the material particles to be tested

[0031] Prepare hydrogen sulfide gas with a concentration of 500 ppm to fill the gas tank. Take 1 g of the adsorption material to be tested and put it into the tank to fully absorb for 24 h. Use a hydrogen sulfide gas detection tube to detect the concentration of hydrogen sulfide after adsorption, and calculate the hydrogen sulfide removal rate.

[0032] 6. Testing the bactericidal performance of the material particles to be tested

[0033] Inoculate the frozen-preserved bacteria by streaking on a plate medium and culture at 37 °C for 24 h; pick a single colony and inoculate it into 100 mL of liquid medium, and culture overnight on a shaker at 37 °C and 200 r / min. The bacterial solution is reserved. First, inoculate 1 mL of the bacterial solution into the sterilized plate, and then pour about 20 mL of the plate medium that has been cooled to about 50 °C, mix evenly, and let it stand horizontally to solidify for later use. Add the material to be tested into it and detect the bactericidal performance.

[0034] Example 1

[0035] (1) Prepare a bentonite suspension by mixing 90 g of bentonite with 900 ml of deionized water, stir it evenly on a magnetic stirrer, then add 3 g of sodium carbonate, put it into an oil bath for heating and stirring reaction, the heating temperature is 80 °C, the stirring time is 2 h, the stirring speed is 150 r / min. After stirring evenly, centrifuge and wash the precipitate 3 times.

[0036] (2) Disperse 80 g of the sodium-modified bentonite obtained by centrifugal precipitation in 200 ml of water, add 4 g of polyethyleneimine, and stir for 30 min; filter the reaction solution, send the obtained filter residue to a dryer for drying, the drying temperature is 280 °C, the drying time is 2 h. After drying, put it into a grinder for grinding and crushing to 200 mesh, and obtain the organically modified bentonite powder with a mesopore size of 2 - 5 nm;

[0037] Perform XRD characterization on the organically modified bentonite powder, and the results are as Figure 2 shown. It can be seen from the figure that the peak intensity of the (100) plane of the bentonite after sodium modification in step 1 is significantly lower than that of the (001) plane, the (100) plane is more exposed and the (001) plane is less exposed. After the charge regulation of bentonite by PEI in step 2, the peak corresponding to the (001) plane disappears, and the peak intensity of the (100) plane increases, making the (100) plane fully exposed.

[0038] (3) The obtained organically modified bentonite powder is wet granulated by a disk granulator to obtain adsorption material particles with a particle size of 0.5 - 4 mm. When wet granulating by a disk granulator, the water content is about 30 wt%. The obtained adsorption material is sieved and classified, and the adsorption material balls with a particle size of 0.5 - 1 mm are selected.

[0039] (4) Mix the adsorbent material spheres obtained in step (3) and the coating material at a mass ratio of 10:1 to obtain macroporous adsorbent material particles in a bonded state; after drying, sieve and classify them, and select macroporous adsorbent material particles with a particle size of 3 mm, as Figure 3 shown, where the drying temperature is 250 °C and the drying time is 2 h; the coating material is composed of the modified bentonite powder obtained in step (2) and carboxymethyl cellulose mixed at a mass ratio of 99:1. It can be seen from Figure 3 that the surface of the macroporous adsorbent material particles is rough, and adsorbent material spheres with a size of 0.5 - 1 mm can be clearly observed.

[0040] Example 2

[0041] (1) Prepare a bentonite suspension by mixing 95 g of bentonite with 1000 ml of deionized water, stir it evenly on a magnetic stirrer, then add 5 g of sodium carbonate, and place it in an oil bath for heating and stirring reaction. The heating temperature is 80 °C, the stirring time is 2 h, the stirring speed is 150 r / min. After stirring evenly, centrifuge and wash the precipitate 3 times.

[0042] (2) Disperse 100 g of the sodium-modified bentonite obtained by centrifugal precipitation in 200 ml of water, add 5 g of polyethyleneimine, and stir for 30 min; filter the reaction solution, send the filter residue obtained to a dryer for drying, the drying temperature is 330 °C, the drying time is 2 h. After drying, put it into a grinder and grind it to 200 mesh to obtain the organically modified bentonite powder; the XRD characterization results show that for the bentonite in this example after charge regulation by PEI, the peak corresponding to the (001) plane disappears, and the peak intensity of the (100) plane increases, making the (100) plane fully exposed.

[0043] (3) The obtained organically modified bentonite powder is wet granulated by a disk granulator to obtain adsorbent material particles with a particle size of 0.5 - 4 mm. When wet granulating by a disk granulator, the water content is about 30 wt%. The obtained adsorbent material is sieved and classified, and adsorbent material spheres with a particle size of 0.5 - 1 mm are selected.

[0044] (4) Mix the adsorbent material spheres obtained in step (3) and the coating material at a mass ratio of 10:1 to obtain macroporous adsorbent material particles in a bonded state; after drying, sieve and classify them, and select macroporous adsorbent material particles with a particle size of 3 mm, as Figure 4 shown, where the drying temperature is 300 °C and the drying time is 2 h; the coating material is composed of the modified bentonite powder obtained in step (2) and carboxymethyl cellulose mixed at a mass ratio of 99:1. It can be seen from Figure 4 that the surface of the macroporous adsorbent material particles is rough, and adsorbent material spheres with a size of 0.5 - 1 mm can be clearly observed.

[0045] Example 3

[0046] (1) Prepare a bentonite suspension by mixing 92 g of bentonite with 1000 ml of deionized water, stir it evenly on a magnetic stirrer, then add 5 g of sodium carbonate, place it in an oil bath and heat it with stirring. The heating temperature is 80 °C, the stirring time is 2 h, the stirring speed is 150 r / min. After stirring evenly, centrifuge and wash the precipitate 3 times.

[0047] (2) Disperse 90 g of the sodium-modified bentonite obtained by centrifugal precipitation in 200 ml of water, add 5 g of polyethyleneimine, and stir for 30 min; filter the reaction solution, and send the obtained filter residue to a dryer for drying. The drying temperature is 300 °C, the drying time is 2 h. After drying, put it into a grinder and grind it to 200 mesh to obtain the organically modified bentonite powder; the XRD characterization results show that the peak corresponding to the (001) plane of the bentonite after charge regulation by PEI in this example disappears, and the peak intensity of the (100) plane increases, making the (100) plane fully exposed.

[0048] (3) The obtained organically modified bentonite powder is wet granulated by a disk granulator to obtain adsorption material particles with a particle size of 0.5 - 4 mm. When wet granulating by a disk granulator, the water content is about 30 wt%. The obtained adsorption material is sieved and classified, and the adsorption material balls with a particle size of 0.5 - 1 mm are selected.

[0049] (4) Mix the adsorption material balls obtained in step (3) and the coating material according to a mass ratio of 10:1 to obtain the bonded macroporous adsorption material particles; after drying, sieve and classify them, and select the macroporous adsorption material particles with a particle size of 3 mm, as Figure 5 shown, where the drying temperature is 280 °C, the drying time is 2 h, and the material is dried to a moisture content of ≤ 3.0%; the coating material is composed of the modified bentonite powder obtained in step (2) and carboxymethyl cellulose mixed according to a mass ratio of 99:1. It can be seen from Figure 5 that the surface of the macroporous adsorption material particles is rough, the macropore size in the adsorption material is 50 - 100 nm, and the adsorption material balls with a size of 0.5 - 1 mm can be clearly observed.

[0050] Comparative Example 1

[0051] (1) Prepare a bentonite suspension by mixing 90 g of bentonite with 900 ml of deionized water, stir it evenly on a magnetic stirrer, then add 3 g of sodium carbonate, place it in an oil bath and heat it with stirring. The heating temperature is 80 °C, the stirring time is 2 h, the stirring speed is 150 r / min. After stirring evenly, centrifuge and wash the precipitate 3 times.

[0052] (2)The obtained sodium bentonite powder is wet granulated by a disk granulator to obtain adsorbent material particles with a particle size of 0.5 - 4 mm. When wet granulating by the disk granulator, the water content is about 30 wt%. The obtained adsorbent material is sieved and classified to select adsorbent material balls with a particle size of 0.5 - 1 mm.

[0053] (3)The adsorbent material balls obtained in step (2) and the coating material are mixed in a mass ratio of 10:1 to obtain macroporous adsorbent material particles in a bonded state; after drying, they are sieved and classified to select macroporous adsorbent material particles with a particle size of 3 mm, where the drying temperature is 250 °C and the drying time is 2 h; the coating material is composed of the sodium bentonite powder obtained in step (1) and carboxymethyl cellulose mixed in a mass ratio of 99:1.

[0054] Examples 1 - 3 and Comparative Example 1 were subjected to performance tests. Figures 6 - 7 The test data graphs of Example 1 and Comparative Example 1 are given. The absorbance measured at a wavelength of 420 nm in Example 1 is significantly higher than that in Comparative Example 1. After conversion, its ammonia absorption rate is about 75%. The test analysis results of each example are as follows:

[0055] The results are shown in the following table

[0056] Comparative Example 1 Example 1 Example 2 Example 3 Water Absorption Rate 320% 345% 366% 353% Agglomeration Strength 10 Times Crushing 16 Times Crushing 15 Times Crushing 17 Times Crushing Hardness 8.9N 11.2N 13.6N 12.7N Ammonia Absorption Rate 40% 75% 78% 74% Hydrogen Sulfide Removal Rate 40% 80% 83% 78% Sterilization Performance None ≥97% ≥97% ≥97%

[0057] Although the embodiments of the present invention are disclosed for illustrative purposes, those skilled in the art can understand that: without departing from the spirit and scope of the present invention and the appended claims, various substitutions, changes, and modifications are possible. Therefore, the scope of the present invention is not limited to the content disclosed in the embodiments.

Claims

1. A method for preparing a bentonite adsorption material, characterized in that: The following steps are involved: (1) 90-95 parts by weight of bentonite and 900-1000 parts by weight of deionized water are prepared into a bentonite suspension, 3-5 parts by weight of sodium carbonate are added, and the mixture is stirred at 80° C. for 2 h at a stirring speed of 150 r / min, and then the precipitate is centrifuged and washed to obtain sodium-modified bentonite; (2) dispersing 80-100 parts by weight of sodium modified bentonite into deionized water, adding 4-5 parts by weight of polyethyleneimine, and stirring for 30 minutes; filtering the reaction solution and obtaining a filter residue which is sent to a dryer for drying at a temperature of 280-330° C. for a drying time of 2 hours. After drying, the residue is put into a grinder for grinding and pulverization to obtain an organic modified bentonite powder; (3) using the organic modified bentonite powder obtained in step (2) to perform wet granulation with a disc granulator to obtain adsorption material particles with a particle size of 0.5 to 4 mm; sieving and grading to select adsorption material balls with a particle size of 0.5 to 1 mm; (4) The adsorbent material balls obtained in step (3) and the coating material are mixed in a mass ratio of 10:1 to obtain macroporous adsorbent material particles in a bonded state; after drying, the particles are sieved and classified to select macroporous adsorbent material particles with a particle size of 3 mm, wherein the drying temperature is 250-300° C. and the drying time is 2 h; the coating material is prepared by mixing the modified bentonite powder obtained in step (2) and carboxymethyl cellulose in a mass ratio of 99:

1.

2. The method according to claim 1, characterized in that: In the step (2), the organic modified bentonite is ground to 200 mesh, and the mesopore size of the organic modified bentonite is 2-5 nm.

3. The method according to claim 1, characterized in that In the step (3), the water content during wet granulation by the disc granulator is about 30 wt%.

4. The method according to claim 1, characterized in that The adsorbent material obtained in step (4) is dried to a moisture content of ≤3.0%, and the macropore size of the adsorbent material is 50-100 nm.

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