Method for determining the blue absorption of montmorillonite
The method of determining the blue absorption of montmorillonite by gravimetric analysis, combined with the dispersion of montmorillonite by a composite dispersant, solves the problems of large subjective error and high reagent toxicity in existing methods, and achieves high accuracy, low cost and safe detection of blue absorption of montmorillonite.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- 三明傲农生物科技有限公司
- Filing Date
- 2026-03-30
- Publication Date
- 2026-06-05
AI Technical Summary
Existing methods for determining the blue absorption capacity of montmorillonite have problems such as large subjective judgment errors, high reagent toxicity, and complex and unfriendly operation, making it difficult to guarantee the accuracy and safety of the test results.
The gravimetric method was used to determine the amount of methylene blue adsorbed by montmorillonite. By adding an excess of methylene blue solution to the pretreated sample, the amount of adsorbed methylene blue was measured. Montmorillonite was dispersed using a composite dispersant (sodium pyrophosphate and sodium citrate) to ensure uniformity and sufficient adsorption, avoid subjective errors, use non-toxic reagents, and simplify the operation process.
It significantly improves the accuracy and safety of the measurement results, reduces experimental costs, simplifies the operation steps, improves the repeatability and accuracy of the method, and ensures the reliability of the measurement results.
Smart Images
Figure CN122150052A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of chemical composition detection technology, and in particular to a method for determining the blue absorption capacity of montmorillonite. Background Technology
[0002] Montmorillonite is a hydrous aluminosilicate mineral with a layered structure. It consists of alternating layers of silicon-oxygen tetrahedra and aluminum-oxygen octahedra forming a TOT-type crystal structure, with exchangeable cations (such as Na+) existing between the layers. + Ca 2+ Methylene blue is a water-soluble cationic dye (with a positively charged molecule) that has a high affinity for the interlayer structure of montmorillonite. It replaces low-valent cations (such as Ca²⁺) in the interlayer structure of montmorillonite, thus giving it unique physicochemical properties. 2+ Methylene blue (MDB) is embedded in the interlayer through ion exchange and simultaneously fixed to the montmorillonite surface through physical adsorption (van der Waals forces) until the montmorillonite reaches adsorption saturation. When montmorillonite reaches saturation with MDB, excess MDB cannot be adsorbed, maintaining a stable blue color in the solution; if unsaturated, the solution color will lighten or disappear (due to adsorption by montmorillonite). "MDB adsorption capacity" is an indicator of the purity and adsorption strength of montmorillonite, expressed as the number of grams of MDB adsorbed per 100 grams of sample. This is not only a core method for determining the purity of montmorillonite in the laboratory but also a key standard for ensuring the quality of montmorillonite (such as in pharmaceuticals and environmental products) in industrial production, directly determining its application effectiveness.
[0003] Most existing methods for determining the blue absorption of montmorillonite use the halo method (GB / T20973-2020 "Bentonite"), which involves adding methylene blue solution, applying the solution to filter paper, and observing the pale blue halo to determine the endpoint. However, this method has several drawbacks: First, different personnel may interpret the halo differently, leading to significant subjective influence and reduced accuracy. Second, it requires numerous and highly toxic reagents (potassium dichromate is carcinogenic, and sulfuric acid can be used to manufacture toxins), and the standardization of methylene blue solution is complex, with the required reagents subject to control. Third, the properties of the filter paper can affect the halo, leading to experimental errors. Fourth, it is not user-friendly for beginners, as halo interpretation is challenging.
[0004] This invention innovates upon the halo method by adding excess methylene blue to the pretreated sample. After sufficient adsorption, the amount of adsorption is measured to obtain the blue adsorption amount. It offers significant advantages: it transforms into a gravimetric method, eliminating subjective influences, resulting in more accurate results; it requires fewer reagents and contains no toxic reagents, reducing costs and safety risks; it is simple to operate, requires no complex calibration, is easy to master, and exhibits good repeatability, precision, and accuracy. Summary of the Invention
[0005] The purpose of this invention is to provide a method for determining the blue absorption of montmorillonite, so as to solve the problems of difficulty in determining the detection endpoint and large titration error in the prior art mentioned in the background art.
[0006] To achieve the above objectives, the present invention provides the following technical solution: A method for determining the blue absorption capacity of montmorillonite includes the following steps: S1. Montmorillonite dispersion: Weigh 0.5-0.6 g of montmorillonite that has been dried at 102-108℃ for 2.0-2.5 h, place it in a 250 mL beaker, add 50 mL of water to fully wet it, and then stir and disperse it on a magnetic stirrer. Then add 20-25 mL of composite dispersant and continue stirring for 2-3 min. Subsequently, heat it on an electric furnace to a gentle boil and maintain it for 4-6 min. Remove it and cool it to room temperature to obtain a dispersed montmorillonite mixture. S2. Methylene blue adsorption: Slowly add 50 mL of excess methylene blue solution to the dispersed montmorillonite mixture using a burette while stirring. After the addition is complete, continue stirring for 15-17 min to allow for complete reaction. After the reaction is complete, filter the mixture using a No. 4 glass frit crucible that has been dried to constant weight at 102-108℃ to obtain a precipitate, and transfer all the precipitate to the glass frit crucible. S3. Dry to constant weight. Place the glass sand crucible containing the precipitate in an electrically heated drying oven for drying, then cool to room temperature and weigh it for the first time, accurate to 0.0001g. Then place the dried glass sand crucible containing the precipitate in the electrically heated drying oven for a second drying, then cool to room temperature and weigh it for the second time, accurate to 0.0001g. Continue until the difference between the two weighings is less than 0.0010g, which is considered constant weight. Substitute the mass of the first weighing into the calculation. At the same time, conduct a blank experiment, with all other treatments the same except without adding the sample.
[0007] As a preferred embodiment of the present invention, the blue absorption capacity of the montmorillonite is calculated according to the following formula: W=[(m1-m0)-(m 1-m 0)]×100 / m in: W represents the blue absorption capacity of montmorillonite, in g / 100g; m is the mass of the sample, in grams; m0 is the mass of the glass sand crucible after constant weight, in g; m1 is the mass of the glass sand crucible and the precipitate after constant weight, in g; m 0 represents the mass of the glass sand crucible after constant weight in the blank experiment, in g; m 1 represents the mass of the glass sand crucible and precipitate after constant weight in the blank experiment, in g; As a preferred embodiment of the present invention, the magnetic stirrer in S1 rotates at a speed of 500-700 rpm and the stirring time is 5-7 min.
[0008] As a preferred embodiment of the present invention, the composite dispersant in S1 is composed of sodium pyrophosphate and sodium citrate in a mass ratio of 3:1, with the concentration of sodium pyrophosphate being 30 g / L and the concentration of sodium citrate being 5 g / L.
[0009] As a preferred embodiment of the present invention, the concentration of the methylene blue solution in S2 is 10 g / L.
[0010] As a preferred embodiment of the present invention, the stirring speed in step S2 is 400~600 rpm.
[0011] As a preferred embodiment of the present invention, the temperature of the electric heating drying oven in S3 is 102~108℃ and the drying time is 3.0~4.0h; the temperature of the secondary drying is 102~108℃ and the drying time is 30~35min.
[0012] Compared with the prior art, the beneficial effects of the present invention are: 1. This method is an improvement and innovation based on the traditional halo method. During operation, an excess of methylene blue solution is added to the pretreated sample solution, and after thorough stirring, montmorillonite adsorption is completed. The amount of methylene blue adsorbed by the sample is then determined by measuring the adsorbed methylene blue content. Compared to the method for determining the amount of methylene blue adsorbed by montmorillonite in GB / T20973-2020 "Bentonite", replacing the conventional halo method with a gravimetric method completely avoids the interference of subjective factors on the results, significantly improving the accuracy of the experimental data. The experiment uses fewer reagents and excludes toxic and harmful reagents throughout the process, reducing experimental costs and significantly minimizing safety risks. Furthermore, the experimental procedure is simple to operate, eliminating complex steps such as solution calibration, allowing experimenters to quickly master the key points of operation. The method exhibits excellent repeatability, and its precision and accuracy are at a high level, stably ensuring the reliability of the measurement results.
[0013] 2. This invention utilizes a composite dispersant prepared by combining sodium pyrophosphate and sodium citrate. The two components work synergistically: sodium pyrophosphate effectively disrupts the agglomeration forces between montmorillonite particles, opening up their aggregated structures; while sodium citrate stabilizes the dispersed colloidal system through electrostatic repulsion, preventing particle re-agglomeration and significantly improving the uniformity of montmorillonite dispersion. This ensures sufficient exposure of adsorption sites, laying the foundation for complete methylene blue adsorption and reducing measurement errors caused by insufficient dispersion. Furthermore, the composite dispersant allows for easier concentration control compared to single dispersants, reducing interference from excess reagents on the adsorption reaction. It also eliminates the need for high-concentration single reagents, reducing reagent consumption and experimental costs. Combined with its stable dispersion effect, it further enhances the repeatability and accuracy of the measurement method, providing crucial support for the reliability of methylene blue adsorption measurement results. Attached Figure Description
[0014] Figure 1 This is a flowchart of the method for determining the blue absorption capacity of montmorillonite according to the present invention. Detailed Implementation
[0015] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.
[0016] To enable those skilled in the art to better understand the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings.
[0017] The halo method for determining the blue absorption of montmorillonite involves adding methylene blue standard solution dropwise to the sample solution using a burette while stirring. Initially, about 2 / 3 of the total methylene blue solution is added, and the mixture is stirred for 2 minutes to allow for complete reaction. Subsequent additions are 1-2 mL, stirred for 30 seconds, and then a drop of the solution is applied to medium-speed quantitative filter paper using a glass rod. The appearance of a pale blue halo around the blue spot is observed. Once a blue halo begins to appear, stirring is continued for 2 minutes, and another drop of the solution is applied to the medium-speed quantitative filter paper using a glass rod. If a pale blue halo still appears, this is the endpoint. However, determining the endpoint by observing whether a pale blue halo appears around the blue spot is problematic. Different experimenters interpret the halo method differently, and the results are heavily influenced by the experimenter's subjective judgment, thus affecting the accuracy of the results. Furthermore, the appearance of the pale blue halo is affected by the properties of the filter paper; different filter papers exhibit different phenomena, which can also lead to experimental errors. In addition, this method uses a variety of reagents, which are highly toxic. The standardization process for the methylene blue standard titration solution is complex, requiring two pre-standardized standard titration solutions: potassium dichromate and sodium thiosulfate. Potassium dichromate is toxic and classified as a Group 1 carcinogen. In addition, the sulfuric acid required for the experiment is also a precursor to toxic substances, and the procurement channels for these reagents are subject to control by relevant departments. Moreover, this method is not user-friendly for novice experimenters, as the interpretation of the halo is quite difficult.
[0018] This method is an improvement and innovation based on the traditional halo method. During operation, an excess of methylene blue solution is added to the pretreated sample solution, and after thorough stirring, montmorillonite adsorption is completed. The amount of methylene blue adsorbed by the sample is then determined by measuring the adsorbed methylene blue content. Replacing the conventional halo method with a gravimetric method completely eliminates the interference of subjective factors on the results, significantly improving the accuracy of the experimental data. Furthermore, the method uses fewer reagents and excludes toxic and harmful reagents throughout the process, reducing experimental costs and significantly minimizing safety risks. The experimental procedure is also simple to operate, eliminating complex steps such as solution standardization, allowing researchers to quickly master the key operational points. The method exhibits excellent repeatability, and its precision and accuracy are at a high level, consistently ensuring the reliability of the measurement results.
[0019] A composite dispersant was prepared by combining sodium pyrophosphate and sodium citrate. The two components work synergistically: sodium pyrophosphate effectively breaks down the agglomeration forces between montmorillonite particles, opening up their aggregated structures; while sodium citrate stabilizes the dispersed colloidal system through electrostatic repulsion, preventing particle re-agglomeration and significantly improving the uniformity of montmorillonite dispersion. This ensures sufficient exposure of adsorption sites, laying the foundation for complete methylene blue adsorption and reducing measurement errors caused by insufficient dispersion. Furthermore, the composite dispersant is easier to control in concentration compared to a single dispersant, reducing interference from excess reagents on the adsorption reaction. It also eliminates the need for high-concentration single reagents, reducing reagent consumption and experimental costs. Combined with its stable dispersion effect, it further improves the repeatability and accuracy of the measurement method, providing crucial support for the reliability of methylene blue adsorption measurement results.
[0020] Please see Figure 1 This application provides a method for determining the blue adsorption capacity of montmorillonite, comprising the following steps: S1. Montmorillonite dispersion: Weigh 0.5-0.6 g of montmorillonite that has been dried at 102-108℃ for 2.0-2.5 h, place it in a 250 mL beaker, add 50 mL of water to fully wet it, and then stir and disperse it on a magnetic stirrer. Then add 20-25 mL of composite dispersant, continue stirring for 2-3 min, and then heat it on an electric furnace to a slight boil and maintain it for 4-6 min. Remove it and cool it to room temperature to obtain a dispersed montmorillonite mixture. S2. Methylene blue adsorption: Slowly add 50 mL of excess methylene blue solution to the dispersed montmorillonite mixture with a burette while stirring. After the addition is completed, continue stirring for 15-17 min to allow it to react fully. After the reaction is completed, filter the mixture using a No. 4 glass sand crucible that has been dried to constant weight at 102-108℃ to obtain a precipitate, and transfer all the precipitate to the glass sand crucible. S3. Dry to constant weight. Place the glass sand crucible containing the precipitate in an electrically heated drying oven for drying, then cool to room temperature and weigh it for the first time, accurate to 0.0001g. Then place the dried glass sand crucible containing the precipitate in the electrically heated drying oven for a second drying, then cool to room temperature and weigh it for the second time, accurate to 0.0001g. Continue until the difference between the two weighings is less than 0.0010g, which is considered constant weight. Substitute the mass of the first weighing into the calculation. At the same time, conduct a blank experiment, with all other treatments the same except without adding the sample.
[0021] All raw materials used in this invention are commercially available.
[0022] In the embodiments listed in this invention, the requirements for the instruments, equipment, and environment used are as follows: 1. Instruments and equipment Analytical balance (accurate to 0.0001g), electric drying oven, magnetic stirrer, electric furnace, vacuum pump, and commonly used laboratory glassware, etc.
[0023] 2. Environmental Requirements Room temperature.
[0024] Example 1: A method for determining the blue absorption capacity of montmorillonite includes the following steps: S1. Montmorillonite dispersion: Weigh 0.6 g of montmorillonite that has been dried at 108℃ for 2.0 h, place it in a 250 mL beaker, add 50 mL of water to fully wet it, and then stir and disperse it on a magnetic stirrer at 500 rpm for 7 min. Then add 25 mL of composite dispersant (composed of sodium pyrophosphate and sodium citrate in a mass ratio of 3:1, with a sodium pyrophosphate concentration of 30 g / L and a sodium citrate concentration of 5 g / L), continue stirring for 3 min, and then heat it on an electric furnace to a slight boil and maintain it for 6 min. Remove it and cool it to room temperature to obtain the dispersed montmorillonite mixture.
[0025] S2. Methylene blue adsorption: While stirring at 400 rpm, 50 mL of excess 10 g / L methylene blue solution was slowly added dropwise to the dispersed montmorillonite mixture using a burette. After the addition was completed, stirring was continued at 400 rpm for 17 min to allow the reaction to proceed fully. After the reaction was completed, the precipitate was obtained by vacuum filtration using a No. 4 glass sand crucible that had been dried to constant weight at 108 °C. All the precipitate was then transferred to the glass sand crucible. S3. Dry to constant weight. Place the glass sand crucible containing the precipitate in an electrically heated drying oven at 108℃ for 3.0 h. After drying, cool to room temperature and weigh for the first time, accurate to 0.0001 g. Then, place the dried glass sand crucible containing the precipitate in the electrically heated drying oven again for a second drying at 108℃ for 30 min. Then, cool to room temperature and weigh for the second time, accurate to 0.0001 g. Continue until the difference between the two weighings is less than 0.0010 g, which is considered constant weight. Substitute the mass of the first weighing into the calculation. At the same time, conduct a blank experiment, with all other treatments the same except without adding the sample.
[0026] Example 2: A method for determining the blue absorption capacity of montmorillonite includes the following steps: S1. Montmorillonite dispersion: Weigh 0.5 g of montmorillonite that has been dried at 102℃ for 2.5 h, place it in a 250 mL beaker, add 50 mL of water to fully wet it, and then stir and disperse it on a magnetic stirrer at 700 rpm for 5 min. Then add 20 mL of composite dispersant (composed of sodium pyrophosphate and sodium citrate in a mass ratio of 3:1, with a sodium pyrophosphate concentration of 30 g / L and a sodium citrate concentration of 5 g / L), continue stirring for 2 min, and then heat it on an electric furnace to a slight boil and maintain it for 4 min. Remove it and cool it to room temperature to obtain the dispersed montmorillonite mixture.
[0027] S2. Methylene blue adsorption: While stirring at 600 rpm, 50 mL of excess 10 g / L methylene blue solution was slowly added dropwise to the dispersed montmorillonite mixture using a burette. After the addition was completed, stirring was continued at 600 rpm for 15 min to allow for complete reaction. After the reaction was completed, the precipitate was obtained by vacuum filtration in a No. 4 glass sand crucible that had been dried to constant weight at 102 °C. All the precipitate was then transferred to the glass sand crucible. S3. Dry to constant weight. Place the glass sand crucible containing the precipitate in an electrically heated drying oven at 102℃ for 4.0 h. After drying, cool to room temperature and weigh for the first time, accurate to 0.0001 g. Then, place the dried glass sand crucible containing the precipitate in the electrically heated drying oven again for a second drying at 102℃ for 35 min. Then, cool to room temperature and weigh for the second time, accurate to 0.0001 g. Continue until the difference between the two weighings is less than 0.0010 g, which is considered constant weight. Substitute the mass of the first weighing into the calculation. At the same time, conduct a blank experiment, with all other treatments the same except without adding the sample.
[0028] Example 3: A method for determining the blue absorption capacity of montmorillonite includes the following steps: S1. Montmorillonite dispersion: Weigh 0.55 g of montmorillonite that has been dried at 105℃ for 2.2 h, place it in a 250 mL beaker, add 50 mL of water to fully wet it, and then stir and disperse it on a magnetic stirrer at 500 rpm for 6 min. Then add 22 mL of composite dispersant (composed of sodium pyrophosphate and sodium citrate in a mass ratio of 3:1, with a sodium pyrophosphate concentration of 30 g / L and a sodium citrate concentration of 5 g / L), and continue stirring for 2.5 min. Then heat it on an electric furnace to a slight boil and maintain it for 5 min. Remove it and cool it to room temperature to obtain the dispersed montmorillonite mixture.
[0029] S2. Methylene blue adsorption: 50 mL of excess 10 g / L methylene blue solution was slowly added dropwise to the dispersed montmorillonite mixture using a burette while stirring at 500 rpm. After the addition was completed, stirring was continued at 500 rpm for 16 min to allow for complete reaction. After the reaction was completed, the precipitate was obtained by vacuum filtration in a No. 4 glass sand crucible that had been dried to constant weight at 105 °C. All the precipitate was then transferred to the glass sand crucible. S3. Dry to constant weight. Place the glass sand crucible containing the precipitate in an electrically heated drying oven at 105℃ for 3.5 hours. After drying, cool to room temperature and weigh for the first time, accurate to 0.0001g. Then, place the dried glass sand crucible containing the precipitate in the electrically heated drying oven again for a second drying at 105℃ for 32 minutes. Then, cool to room temperature and weigh for the second time, accurate to 0.0001g. Continue until the difference between the two weighings is less than 0.0010g, which is considered constant weight. Substitute the mass of the first weighing into the calculation. At the same time, conduct a blank experiment, with all other treatments the same except without adding the sample.
[0030] Example 4: A method for determining the blue absorption capacity of montmorillonite includes the following steps: S1. Montmorillonite dispersion: Weigh 0.52 g of montmorillonite that has been dried at 104℃ for 2.3 h, place it in a 250 mL beaker, add 50 mL of water to fully wet it, and then stir and disperse it on a magnetic stirrer at 550 rpm for 5.5 min. Then add 25 mL of composite dispersant (composed of sodium pyrophosphate and sodium citrate in a mass ratio of 3:1, with a sodium pyrophosphate concentration of 30 g / L and a sodium citrate concentration of 5 g / L), and continue stirring for 2.3 min. Then heat it on an electric furnace to a gentle boil and maintain it for 4.5 min. Remove it and cool it to room temperature to obtain the dispersed montmorillonite mixture.
[0031] S2. Methylene blue adsorption: 50 mL of excess 10 g / L methylene blue solution was slowly added dropwise to the dispersed montmorillonite mixture using a burette while stirring at 550 rpm. After the addition was completed, stirring was continued at 550 rpm for 15.5 min to allow the reaction to proceed fully. After the reaction was completed, the precipitate was obtained by vacuum filtration using a No. 4 glass sand crucible that had been dried to constant weight at 104 °C. All the precipitate was then transferred to the glass sand crucible. S3. Dry to constant weight. Place the glass sand crucible containing the precipitate in an electrically heated drying oven at 104℃ for 3.6 hours. After drying, cool to room temperature and weigh for the first time, accurate to 0.0001g. Then, place the dried glass sand crucible containing the precipitate in the electrically heated drying oven again for a second drying at 104℃ for 34 minutes. Then, cool to room temperature and weigh for the second time, accurate to 0.0001g. Continue until the difference between the two weighings is less than 0.0010g, which is considered constant weight. Substitute the mass of the first weighing into the calculation. At the same time, conduct a blank experiment, with all other treatments the same except without adding the sample.
[0032] Example 5: A method for determining the blue absorption capacity of montmorillonite includes the following steps: S1. Montmorillonite dispersion: Weigh 0.58 g of montmorillonite that has been dried at 107℃ for 2.1 h, place it in a 250 mL beaker, add 50 mL of water to fully wet it, and then stir and disperse it on a magnetic stirrer at 650 rpm for 6.5 min. Then add 25 mL of composite dispersant (composed of sodium pyrophosphate and sodium citrate in a mass ratio of 3:1, with a sodium pyrophosphate concentration of 30 g / L and a sodium citrate concentration of 5 g / L), and continue stirring for 2.8 min. Then heat it on an electric furnace to a gentle boil and maintain it for 5.5 min. Remove it and cool it to room temperature to obtain the dispersed montmorillonite mixture.
[0033] S2. Methylene blue adsorption: 50 mL of excess 10 g / L methylene blue solution was slowly added dropwise to the dispersed montmorillonite mixture using a burette while stirring at 570 rpm. After the addition was completed, stirring was continued at 570 rpm for 16.5 min to allow the reaction to proceed fully. After the reaction was completed, the precipitate was obtained by vacuum filtration using a No. 4 glass sand crucible that had been dried to constant weight at 107 °C. All the precipitate was then transferred to the glass sand crucible. S3. Dry to constant weight. Place the glass sand crucible containing the precipitate in an electrically heated drying oven at 107℃ for 3.1 hours. After drying, cool to room temperature and weigh for the first time, accurate to 0.0001g. Then, place the dried glass sand crucible containing the precipitate in the electrically heated drying oven again for a second drying at 107℃ for 31 minutes. Then, cool to room temperature and weigh for the second time, accurate to 0.0001g. Continue until the difference between the two weighings is less than 0.0010g, which is considered constant weight. Substitute the mass of the first weighing into the calculation. At the same time, conduct a blank experiment, with all other treatments the same except without adding the sample.
[0034] Montmorillonite samples from Examples 1, 2, 3, 4, and 5 were used to determine the blue absorption using the existing national standard halo method, serving as control groups 1, 2, 3, 4, and 5. The results of the blue absorption measurements of the same montmorillonite samples using these two methods were compared, and the relative deviations were calculated. The results are shown in Table 1. Table 1: Results of blue absorption measurement of the same montmorillonite sample in the example group and the control group.
[0035] The experimental results show that the relative deviation between the blue absorption capacity determination results of montmorillonite in the embodiments of the present invention and the results determined by the halo method according to the national standard is between 0.35 and 0.85, which meets the requirement of no more than 2% allowable difference in GB / T20973-2020 "Bentonite", indicating that the determination method is effective and feasible. Therefore, the determination method of the present invention can be used to determine the blue absorption capacity of montmorillonite.
[0036] To further verify the repeatability of the method of the present invention, the blue absorption of the same montmorillonite sample was measured five times in parallel, and the relative standard deviation was calculated. The repeatability results of measuring the blue absorption of the same montmorillonite sample are shown in Table 2: Table 2: Results of parallel tests on the blue absorption capacity of montmorillonite in the same sample
[0037] The results in the table show that the relative standard deviation is small when the same sample is measured in parallel 5 times, indicating that the method has good repeatability.
[0038] By ensuring strict control over key parameters, operational fluctuations are reduced. Furthermore, the constant weight judgment is rigorous (difference < 0.0010g), blank experiments eliminate systematic errors, composite dispersants ensure uniform dispersion and sufficient adsorption of montmorillonite, and standardized filtration and transfer reduce losses. Subjective errors are avoided, the procedures are simple and easy to master, and the repeatability, accuracy, and applicability are all superior to traditional methods.
[0039] In summary, this invention replaces the common halo method with a gravimetric method for measurement. This method is not affected by personal subjective consciousness, and the results obtained by this measurement method have good repeatability and high accuracy.
[0040] The above are merely specific embodiments of the present invention, but the technical features of the present invention are not limited thereto. Any simple changes, equivalent substitutions, or modifications made based on the present invention to solve essentially the same technical problems and achieve essentially the same technical effects are all covered within the protection scope of the present invention.
Claims
1. A method for determining the blue absorption capacity of montmorillonite, characterized in that, Includes the following steps: S1. Montmorillonite dispersion: Weigh out montmorillonite that has been dried at 102~108℃ for 2.0~2.5h. 0.5~0.6g was placed in a 250mL beaker, and 50mL of water was added to fully wet it. The mixture was then stirred and dispersed on a magnetic stirrer. 20~25mL of the composite dispersant was added and the mixture was stirred for 2~3min. The mixture was then heated on an electric furnace to a slight boil and held for 4~6min. The mixture was then removed and cooled to room temperature to obtain the dispersed montmorillonite mixture. S2. Methylene blue adsorption: 50 mL of excess methylene blue solution was slowly added dropwise to the dispersed montmorillonite mixture with stirring using a burette. After the addition was completed, stirring was continued for 15-17 min to allow the reaction to proceed fully. After the reaction was completed, the precipitate was obtained by vacuum filtration using a No. 4 glass sand crucible that had been dried to constant weight at 102-108℃. All of the precipitate was then transferred to the glass sand crucible. S3. Dry to constant weight. Place the glass sand crucible containing the precipitate in an electrically heated drying oven for drying, then cool to room temperature and weigh it for the first time, accurate to 0.0001g. Then place the dried glass sand crucible containing the precipitate in the electrically heated drying oven for a second drying, then cool to room temperature and weigh it for the second time, accurate to 0.0001g. Continue until the difference between the two weighings is less than 0.0010g, which is considered constant weight. Substitute the mass of the first weighing into the calculation. At the same time, conduct a blank experiment, with all other treatments the same except without adding the sample.
2. The method for determining the blue absorption capacity of montmorillonite according to claim 1, characterized in that... It lies in, The amount of blue absorption by montmorillonite is calculated according to the following formula: W=[(m1-m0)-(m,1-m,0)] ×100 / m in: W represents the blue absorption capacity of montmorillonite, in g / 100g; m is the mass of the sample, in grams; m0 is the mass of the glass sand crucible after constant weight, in g; m1 is the mass of the glass sand crucible and the precipitate after constant weight, in g; m,0 is the mass of the glass sand crucible after constant weight in the blank experiment, in g; m,1 represents the mass (in grams) of the glass sand crucible and precipitate after constant weight in the blank experiment.
3. The method for determining the blue absorption capacity of montmorillonite according to claim 1, characterized in that, The magnetic stirrer in S1 operates at a speed of 500-700 rpm and a stirring time of 5-7 minutes.
4. The method for determining the blue absorption capacity of montmorillonite according to claim 1, characterized in that, The composite dispersant in S1 is composed of sodium pyrophosphate and sodium citrate in a mass ratio of 3:1, with the concentration of sodium pyrophosphate being 30 g / L and the concentration of sodium citrate being 5 g / L.
5. The method for determining the blue absorption capacity of montmorillonite according to claim 1, characterized in that, The concentration of the methylene blue solution in S2 is 10 g / L.
6. The method for determining the blue absorption capacity of montmorillonite according to claim 1, characterized in that, The stirring speed in S2 is 400~600 rpm.
7. The method for determining the blue absorption capacity of montmorillonite according to claim 1, characterized in that, The temperature of the electric heating drying oven in S3 is 102~108℃, and the drying time is 3.0~4.0h; the temperature of the secondary drying is 102~108℃, and the drying time is 30~35min.