Method for detecting blue absorption amount of bentonite

Abstract

The invention relates to a method for detecting the blue absorption amount of bentonite. The method comprises the following steps: adding excessive methylene blue solution into a first solution added with a bentonite sample and an activating agent for reaction to obtain a second solution, carrying out solid-liquid separation on the second solution, and measuring the mass of a bentonite detection sample dried after solid-liquid separation, so as to directly calculate the blue absorption amount of the bentonite sample. According to the technical scheme, the error of judging the titration end point by observing whether a light blue halo appears or not by naked eyes can be reduced, and the observation error caused by human factors is reduced; common equipment and materials for the test are common equipment and common materials and are easy to obtain, and the test cost is low; excessive pipetting operation is not needed in the test process, so that the operation is convenient, and operation errors in the test process are reduced.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of chemical component detection, and particularly relates to a detection method for the methylene blue adsorption capacity of bentonite. BACKGROUND

[0002] Bentonite is a natural high-quality clay with montmorillonite as the main component, and is called "universal soil". It is widely used in many fields such as machinery, petroleum, metallurgy, chemical industry, papermaking, medicine and building materials. It has excellent properties such as swelling, binding, adsorption, catalysis, thixotropy, suspension and cation exchange. Methylene blue is a polar molecule. It produces a monovalent cation in aqueous solution, can replace bentonite and exchange cations, and can be adsorbed by bentonite in the form of hydroxide in alkaline medium. Therefore, bentonite dispersed in aqueous solution has the ability to adsorb methylene blue, and the amount of adsorbed methylene blue is the methylene blue adsorption capacity.

[0003] The existing detection method for the methylene blue adsorption capacity of bentonite is a method of observing with the naked eye. That is, after bentonite is dissolved in water, about two-thirds of the total amount of methylene blue solution is added dropwise, the bentonite and methylene blue in the solution are fully reacted by stirring for 2 minutes, then 1ml-2ml is added dropwise each time, and after stirring for 30 seconds, a drop of test solution is taken with a glass rod on a medium-speed quantitative filter paper, whether a light blue halo appears around the blue spot is observed, and the process is continued until the halo does not disappear. The methylene blue adsorption capacity of bentonite is calculated by the mass of the added methylene blue solution. However, the operation is complex near the titration endpoint, the timing of complete adsorption is not easy to achieve, and the endpoint is determined by observing with the naked eye whether a light blue halo appears, which can cause a large observation error. SUMMARY

[0004] To solve or partially solve the problems in the related art, the present application provides a detection method for the methylene blue adsorption capacity of bentonite, which can reduce the error of human judgment, reduce the operation error in the test process, and improve the detection efficiency and the accuracy of the detection result.

[0005] The first aspect of the present application provides a detection method for the methylene blue adsorption capacity of bentonite, comprising:

[0006] (1) weighing the mass of the bentonite sample to be detected, dispersing the bentonite sample to be detected in water, fully stirring, adding an activator for activating the bentonite, and obtaining a first solution;

[0007] (2) adding an excess amount of methylene blue solution to the first solution, fully stirring, and obtaining a second solution;

[0008] (3) performing solid-liquid separation on the second solution to obtain a bentonite detection sample;

[0009] (4) drying the bentonite test sample, weighing the mass of the dried bentonite test sample, and calculating the blue absorption of the bentonite test sample to be detected.

[0010] In an embodiment, the blue absorption of the bentonite test sample to be detected is calculated according to the following formula:

[0011]

[0012] wherein,

[0013] MBI is the blue absorption, in g / 100g;

[0014] m1 is the mass of the bentonite test sample to be detected, in g;

[0015] m2 is the mass of the dried bentonite test sample, in g.

[0016] In an embodiment, the step (3) comprises weighing the mass of the filter membrane, and placing the second solution on the filter membrane to perform vacuum filtration to obtain the bentonite test sample.

[0017] The step (4) comprises drying the filter membrane and the bentonite test sample, weighing the total mass of the dried filter membrane and the bentonite test sample, and calculating the blue absorption of the bentonite.

[0018] In an embodiment, the step (3) further comprises weighing the mass of the filter membrane, placing the second solution on the filter membrane to perform vacuum filtration, until the filtrate no longer shows blue color, and continuing the filtration for 1s-120s to obtain the bentonite test sample.

[0019] In an embodiment, the step (3) further comprises weighing the mass of the filter membrane, calculating the predetermined time of vacuum filtration according to the mass of the bentonite test sample to be detected, placing the second solution on the filter membrane and performing vacuum filtration for the predetermined time to obtain the bentonite test sample.

[0020] In an embodiment,

[0021] The blue absorption of the bentonite is calculated according to the following formula:

[0022]

[0023] wherein,

[0024] MBI is the blue absorption, in g / 100g;

[0025] m1 is the mass of the bentonite test sample to be detected, in g;

[0026] m3 is the mass of the filter membrane, in g;

[0027] m4 - the total mass of the dried bentonite test sample and the filter membrane, in g.

[0028] In an embodiment, the filter membrane is a water-based filter membrane or an organic filter membrane.

[0029] In an embodiment, the pore size of the filter membrane is 0.2 um to 1 um.

[0030] In an embodiment, the step (1) further comprises:

[0031] adding an activator and then performing ultrasonic treatment to obtain a first solution;

[0032] or, adding an activator and then performing heating treatment to obtain a first solution.

[0033] In an embodiment, the activator is a sodium pyrophosphate solution or a sodium thiosulfate solution.

[0034] In an embodiment, the concentration of the methylene blue solution is 0.00312 mol / L to 0.0312 mol / L.

[0035] The technical solution provided in the present application can include the following beneficial effects:

[0036] The technical solution of the present application can reduce the error of determining the titration endpoint by observing whether a light blue halo appears with the naked eye, and reduce the observation error of human factors. The commonly used equipment and materials for the test are easy to obtain, and the test cost is low. The test process does not require excessive pipetting operation, is easy to operate, and reduces the operation error in the test process.

[0037] It should be understood that the above general description and the following detailed description are only exemplary and explanatory, and cannot limit the present application. DETAILED DESCRIPTION

[0038] The terms used in the present application are only for the purpose of describing specific embodiments, and are not intended to limit the present application. The singular forms "a", "an" and "the" used in the present application and the appended claims are also intended to include the plural forms, unless the context clearly indicates otherwise. It should also be understood that the term "and / or" used herein means and includes any or all possible combinations of one or more associated listed items.

[0039] It should be understood that although the terms "first", "second", "third", etc. can be used in this application to describe various information, these information should not be limited to these terms. These terms are only used to distinguish the same type of information from each other. For example, the first information can also be referred to as the second information, and similarly, the second information can also be referred to as the first information without departing from the scope of the application. Therefore, the features defined as "first", "second" can explicitly or implicitly include one or more features. In the description of this application, the meaning of "multiple" is two or more, unless otherwise specifically limited.

[0040] The physical and chemical properties of bentonite are mainly determined by the structure of its main component montmorillonite, that is, the content of montmorillonite determines the quality and quality of bentonite. The crystal structure unit of montmorillonite is composed of two layers of [SiO4] tetrahedron and [AlO2(OH)4] octahedron in the middle. The oxygen atoms at the top of each tetrahedron point to the center of the structure layer and share with the octahedron. Therefore, determining the content of montmorillonite in bentonite is a very important detection content in the application of bentonite. In the prior art, the methods for detecting the content of montmorillonite mainly include: blue absorption method, spectrophotometer method, oscillopolarographic method and X-ray diffraction method. Among these methods, the blue absorption method is the simplest and the most convenient device is used, which is widely used in daily work.

[0041] The current national standard "Bentonite" 20973-2020 uses a manual method to detect the blue absorption of bentonite, and takes the blue absorption as an important detection index to evaluate the quality of bentonite. The specific detection steps are: after dissolving bentonite in water, about two-thirds of the total amount of methylene blue solution is added, and the bentonite and methylene blue in the solution are fully reacted by stirring for 2 minutes, then 1ml~2ml is added each time, and after stirring for 30 seconds, a drop of test solution is taken on the quantitative filter paper at medium speed with a glass rod, and whether a light blue halo appears around the blue spot is observed, until the halo does not disappear. The blue absorption of bentonite is calculated by the mass of the added methylene blue solution. However, this detection method is complex in operation near the titration end point, and the complete adsorption time is not easy to achieve, and the end point is determined by observing whether a light blue halo appears with the naked eye, which can cause a large observation error. For example:

[0042] (1) The test needs to dip a drop of reagent on the quantitative filter paper with a glass rod at moderate speed near the titration end point, and observe whether there is a light blue halo around the central dark blue spot. If not, continue to add methylene blue solution. Repeat the operation until a light blue halo appears. Then, after 1 min, dip a drop of reagent with a glass rod. If there is no light blue halo around, it means that the end point has not been reached, and the methylene blue solution should be added again until a clear light blue halo appears. The operation is complex, and it is difficult to determine how many times the operation needs to be repeated to produce a light blue halo. The timing of complete adsorption needs to be observed by the naked eye to determine whether a halo appears. It is not easy to determine the timing of complete adsorption.

[0043] (2) The halo needs to be observed by the naked eye, which is highly subjective and can easily cause large observation errors.

[0044] (3) Without knowing the quality of the bentonite, it is impossible to determine how much montmorillonite is contained in the bentonite. The total amount of methylene blue added is assumed to be all pure montmorillonite crystals. During the test, it is possible that about two-thirds of the total amount of methylene blue solution has been added, and the methylene blue solution has reacted completely or has been added in excess. Therefore, it is difficult to determine the amount of methylene blue to be added. The test operation of adding methylene blue to the bentonite sample has a large error.

[0045] (4) The appearance of a light blue halo around the blue spot will cause a large calculation error when the amount of methylene blue solution added is used to calculate the blue adsorption of the bentonite, as observed from the actual test results. When the light blue halo appears, the methylene blue solution has been added in excess. At this time, using the mass of the added methylene blue solution to calculate the blue adsorption of the bentonite will cause a large calculation error.

[0046] In another detection method, the liquid spot image acquisition and image processing method can be used to measure the blue value of bentonite, wherein the liquid spot is the light blue halo near the blue spot. The method generally includes: mixing bentonite sample, sodium pyrophosphate and distilled water to obtain a bentonite sample solution, transferring a 0.2% methylene blue solution to the bentonite sample solution and stirring to form a mixed solution, and the transfer amount is 85% of the daily test volume of the blue value of bentonite. According to the preset algorithm, the amount of methylene blue is calculated, 0.1 mL of the mixed solution is titrated to the medium-speed quantitative filter paper to form a drop spot, the drop spot image is collected by an industrial camera, and the drop spot image is processed by digital image processing. The essence of this detection method is to use the gray value digital analysis method of RGB to determine the titration end point. The accuracy of this method is more accurate than manual visual judgment, but the solution processing step, the mixed solution forming step and the quantitative reagent transfer step in this detection method are all completed manually, and operation errors are easy to occur in the experimental process. In addition, in the step of transferring a 0.2% methylene blue solution to the bentonite sample solution and stirring to form a mixed solution, the transfer amount is 85% of the daily test volume of the blue value of bentonite. However, the daily test volume of the blue value of bentonite is not a fixed value, and the transfer volume of the methylene blue solution cannot be determined in each test process, and the quantitative detection cannot be achieved.

[0047] In another test method, the method generally includes: using a solution injection system to inject the to-be-detected solution in the solution storage system into a titration pool system, and then pretreating the to-be-detected solution in the titration pool system; titration step: using a solution injection system to inject methylene blue solution and flocculating agent in the solution storage system into the titration pool system to form a mixed solution; detection step: using a detection system to determine the titration end point of the methylene blue solution, the detection system includes a color recognition detector and a plurality of glass capillaries, and the blue value of bentonite is determined according to the titration amount of the methylene blue solution. This method can determine whether the titration end point is reached by using a color recognition detector, i.e. the color recognition detector includes a light source for irradiating the glass capillary. According to the test detection, the glass capillary stores methylene blue solution with different concentrations, and the result can be determined according to the color depth. However, the concentration of the methylene blue solution will change under the irradiation of light, resulting in deterioration, and the color of the methylene blue solution will change constantly, especially the color change of the methylene blue solution with low concentration will be very obvious, so that the operator cannot determine when the titration end point is reached according to the color change of the methylene blue solution. Therefore, a variable color value cannot be used to determine the quantitative test result.

[0048] In order to solve the problems of the detection method of the blue absorption of the bentonite in the prior art, the embodiment of the present application provides a detection method of the blue absorption of the bentonite, which can reduce the error of the artificial judgment, reduce the operation error in the test process, and improve the detection efficiency and the accuracy of the detection result.

[0049] In order to make the present application more easily understood, the present application will be further described in detail below with reference to the embodiments, which are only illustrative and not limited to the application. The raw materials or components used in the present application can be prepared by commercial channels or conventional methods if not otherwise specified.

[0050] An embodiment of the present application provides a detection method of the blue absorption of the bentonite, comprising:

[0051] (1) weighing the mass of the bentonite sample to be detected, dispersing the bentonite sample in water, fully stirring, adding an activator for activating the bentonite to obtain a first solution;

[0052] (2) adding an excess amount of methylene blue solution to the first solution, fully stirring to obtain a second solution;

[0053] (3) performing solid-liquid separation on the second solution to obtain a bentonite detection sample;

[0054] (4) drying the bentonite detection sample, weighing the mass of the dried bentonite detection sample, and calculating the blue absorption of the bentonite sample.

[0055] The bentonite sample to be detected in step (1) is a dried detection sample.

[0056] The mass of the bentonite sample to be detected weighed in step (1) is accurate to 0.0001 g.

[0057] The fully stirring in step (1) means that the bentonite sample to be detected is added to water and stirred until there is no particle agglomeration.

[0058] The activator in step (1) can be a sodium pyrophosphate solution or a sodium thiosulfate solution. After mixing with the bentonite, the sodium pyrophosphate reacts with the bentonite to form a colorless and solid-free solution.

[0059] The amount of the activator in step (1) is obtained according to the mass of the bentonite sample.

[0060] The concentration of the methylene blue solution in step (2) is 0.00312 mol / L to 0.0312 mol / L.

[0061] The excess methylene blue solution in step (2) is determined according to the mass of the bentonite sample, i.e. the mass of the bentonite sample is assumed to be pure montmorillonite crystal structure without any impurities, the amount of methylene blue reagent adsorbed is theoretically calculated as the minimum amount of methylene blue reagent to be added, and the excess methylene blue solution is required during the test.

[0062] The solid-liquid separation method in step (3) can be precipitation, filtration or centrifugation. The precipitation method is to let the mixed solution stand for a period of time, so that the solid particles precipitate to the bottom of the solution, and then the supernatant is separated. The filtration method is to use a filter such as filter paper or filter membrane to filter the mixed solution, and the solid particles are filtered out. The centrifugation method is to put the mixed solution into a centrifuge, use the centrifugal force to make the solid particles precipitate to the bottom of the tube, and then separate the supernatant.

[0063] The bentonite sample in step (4) is dried at (105±10)℃ until the mass is constant, i.e. the mass does not change after multiple weighings.

[0064] In one embodiment, step (1) further comprises ultrasonic treatment after adding the activator. Ultrasonic treatment of the solution can improve the reaction efficiency of the activator and the bentonite sample. Compared with heating treatment of the solution, the solution does not need to be heated to boiling and then cooled, which saves test time. In one embodiment, the ultrasonic frequency during ultrasonic treatment is in the range of 20KHz-100KHz.

[0065] In one embodiment, step (1) further comprises heating treatment after adding the activator. Heating treatment of the solution can improve the reaction efficiency of the activator and the bentonite sample, and save test time.

[0066] In one embodiment, the activator is sodium pyrophosphate solution or sodium thiosulfate solution. The sodium pyrophosphate solution or sodium thiosulfate solution can form a cation exchange reaction with montmorillonite in the bentonite, and the reaction product can react with methylene blue molecules.

[0067] In an embodiment, the concentration of the methylene blue solution is 0.00312 mol / L-0.0312 mol / L, and the mass of the bentonite sample is the same (generally, the mass of the bentonite sample is 0.2 g-1 g), i.e., the adsorbed methylene blue organic matter is a determined value. The concentration of the methylene blue solution is directly related to the size of the test volume, thereby affecting the size of the reading error. The smaller the volume, the greater the reading error. Therefore, according to the different concentrations of the methylene blue solution, the volume range of the methylene blue solution can be set to 10 ml-100 ml, which can better reduce the reading error. In an embodiment, preferably, the mass of the bentonite sample is 0.2 g, the concentration of the methylene blue solution is 0.00625 mol / L, and the volume of the methylene blue solution is 20 ml, which can reduce the reading error in the titration process.

[0068] In an embodiment, the blue adsorption capacity of the bentonite is calculated according to the following formula:

[0069]

[0070] Wherein:

[0071] MBI is the blue adsorption capacity, in units of g / 100 g;

[0072] m1 is the mass of the bentonite sample to be detected, in units of g;

[0073] m2 is the mass of the dried bentonite sample, in units of g.

[0074] Through this calculation method, the value of the blue adsorption capacity of the bentonite can be directly calculated, and there is no need to observe the appearance of the halo, and there is no subjective judgment step, thereby reducing human error.

[0075] Wherein, m1 can be 0.2 g-1 g.

[0076] For example, when m1 is 0.2 g, it is calculated that 20 ml of activator, i.e., methylene blue solution (concentration of 0.00625 mol / L) is needed. At this time, when the activator is added to the solution, the cations in the bentonite are replaced to form a colorless and solid-free solution. When the methylene blue is added to the colorless and solid-free solution, it can react with the bentonite. After the reaction is complete, solid-liquid separation is performed, and the bentonite adsorbed with methylene blue is obtained after drying.

[0077] It should be noted that the bentonite blue absorption detection method of the present application first reacts the bentonite sample with the activator to obtain the product after the first reaction, then reacts the product after the first reaction with the methylene blue solution, and obtains the bentonite detection sample after drying treatment. Compared with the bentonite sample, the bentonite detection sample has undergone cation exchange, so the bentonite sample and the bentonite detection sample are no longer the same substance, and there is a difference in quality. The test process of the bentonite blue absorption test is to obtain the blue absorption of the bentonite by the transformation of the substance.

[0078] In another embodiment, the solid-liquid separation method can be performed by vacuum filtration. Specifically:

[0079] Step (3) includes weighing the mass of the filter membrane, placing the second solution on the filter membrane to perform vacuum filtration to obtain the bentonite detection sample; step (4) includes drying the filter membrane and the bentonite detection sample, weighing the total mass of the dried filter membrane and the bentonite detection sample, and calculating the blue absorption of the bentonite. The solid-liquid separation of the second solution by vacuum filtration can effectively save the separation time and improve the test efficiency.

[0080] The blue absorption in the bentonite is calculated according to the following formula:

[0081]

[0082] Wherein:

[0083] MBI—blue absorption, unit: g / 100g;

[0084] m1—mass of the bentonite sample to be detected, unit: g;

[0085] m3—mass of the filter membrane, unit: g;

[0086] m4—total mass of the dried bentonite detection sample and filter membrane, unit: g; In the process of vacuum filtration, there will be residual reaction substances on the filter membrane, so the mass of the filter membrane needs to be measured in advance. Finally, the dried filter membrane and the bentonite detection sample are measured, and the mass of the filter membrane measured in advance needs to be subtracted in the calculation to reduce the test error and obtain more accurate blue absorption of the bentonite; The solid-liquid separation of the second solution by vacuum filtration can effectively save the separation time and improve the test efficiency. Step (3) further includes: weighing the mass of the filter membrane, placing the second solution on the filter membrane to perform vacuum filtration, until the filtrate no longer shows blue, continuing to filter for 1s~2min to obtain the bentonite detection sample. When vacuum filtration is performed, pure water can be continuously injected into the funnel until the filtrate no longer shows blue, so as to ensure that the methylene blue can be completely separated and reduce the test error.

[0087] In this step, the determination of no longer showing blue color can be made by naked eye observation, etc. When naked eye observation is used, the difference from the blue ring determination is that, for the determination of whether the filtrate shows blue color, only the color change needs to be identified, while for the determination of the blue ring, a drop of the solution is dropped on the medium-speed quantitative filter paper with a glass rod, and the presence or absence of a light blue halo around the central dark blue point is observed. Not only the presence or absence of the blue ring needs to be determined, but if the blue ring does not appear, the methylene blue solution needs to be added again, and the above steps need to be repeated, which requires additional operation steps. After the methylene blue solution is added again next time, the methylene blue solution may be added in excess, causing test errors. Directly judging by the color of the solution can reduce the operation steps and reduce the test errors.

[0088] Step (3) can also be weighing the mass of the filter membrane, calculating the predetermined time of vacuum filtration according to the mass of the bentonite sample to be detected, placing the second solution on the filter membrane and performing vacuum filtration for the predetermined time to obtain a bentonite detection sample. The predetermined time can ensure that the second solution is completely separated, and the naked eye observation of whether the second solution shows blue color is no longer needed to determine complete separation. During the water adding process, there are no free methylene blue molecules on the filter membrane, which reduces the test errors.

[0089] The predetermined time can be determined according to the experience of the tester and recorded. When the weighed sample is of the same mass, the historical predetermined time can be used.

[0090] In addition, the predetermined time can be expressed as the time of 2s to 120s after no longer showing blue color before adding again.

[0091] In step (3), the filter membrane is a water-based filter membrane or an organic filter membrane. The water-based filter membrane can be selected from filter membranes made of polypropylene, polyamide, polycarbonate, polyethylene, etc. The organic filter membrane can be selected from filter membranes made of polyamide or polytetrafluoroethylene, etc. The filter membranes are distinguished according to the type of the solvent to be filtered.

[0092] Compared with the traditional paper membrane, the water-based filter membrane and the organic filter membrane are thinner, and the water-based filter membrane and the organic filter membrane have less water absorption, which can reduce the test errors.

[0093] In step (3), the pore size of the filter membrane is 0.2um to 1um. The uniform pore size of the filter membrane can avoid the loss of the bentonite sample, better separate the second solution, and reduce the test errors. Compared with the traditional filter membrane such as medium-speed quantitative filter paper, the organic filter membrane or the water-based filter membrane in this pore size range has square holes and is orderly distributed, while the traditional filter membrane has circular holes and is disorderly distributed, so that the bentonite is more likely to pass through the traditional filter membrane and is not easy to achieve the purpose of solid-liquid separation.

[0094] The technical scheme of the present application can reduce the error of judging the titration end point by observing whether a light blue halo appears or not through naked eyes, and reduce the observation error of human factors; the commonly used equipment and materials in the test are common equipment and common materials, which are easy to obtain and have low test cost; the test process does not need too much pipetting operation, is convenient to operate, and reduces the operation error in the test process.

[0095] The above has described the embodiments of the present application, and the above description is exemplary, not exhaustive, and is not limited to the disclosed embodiments. Many modifications and changes are obvious to those skilled in the art without departing from the scope and spirit of the described embodiments. The selection of the terms used herein is intended to best explain the principles, practical application or improvement of the technology in the market of the embodiments, or to enable other ordinary skilled in the art to understand the embodiments disclosed herein.

Claims

1. A method for detecting the blue adsorption amount of bentonite, characterized by, The method comprises the following steps: (1) weighing the mass of the bentonite sample to be detected, dispersing the bentonite sample to be detected in water, fully stirring, and adding an activator for activating the bentonite to obtain a first solution; (2) adding an excess amount of methylene blue solution to the first solution, fully stirring to obtain a second solution; (3) performing solid-liquid separation on the second solution to obtain a bentonite detection sample; (4) drying the bentonite detection sample, weighing the mass of the dried bentonite detection sample, and calculating the blue absorption amount of the bentonite sample to be detected.

2. The method of claim 1, wherein, The blue absorption amount of the bentonite sample to be detected is calculated according to the following formula: Wherein, MBI is the blue absorption amount, and the unit is g / 100g; m1 is the mass of the bentonite sample to be detected, and the unit is g; m2 is the mass of the dried bentonite detection sample, and the unit is g.

3. The method of claim 1, wherein, The step (3) comprises the following steps: weighing the mass of the filter membrane, placing the second solution on the filter membrane to perform vacuum filtration to obtain the bentonite detection sample; The step (4) comprises the following steps: drying the filter membrane and the bentonite detection sample, weighing the total mass of the dried filter membrane and the bentonite detection sample, and calculating the blue absorption amount of the bentonite sample to be detected.

4. The method of claim 3, wherein, The step (3) further comprises the following steps: weighing the mass of the filter membrane, placing the second solution on the filter membrane to perform vacuum filtration until the filtrate no longer shows blue, and continuing to perform filtration for 1s-120s to obtain the bentonite detection sample.

5. The method of claim 3, wherein, The step (3) further comprises the following steps: weighing the mass of the filter membrane, calculating the predetermined time of vacuum filtration according to the mass of the bentonite sample to be detected, placing the second solution on the filter membrane and performing vacuum filtration for the predetermined time to obtain the bentonite detection sample.

6. The method of claim 3, wherein, The blue absorption amount of the bentonite sample to be detected is calculated according to the following formula: Wherein, MBI is the blue absorption amount, and the unit is g / 100g; m1 is the mass of the bentonite sample to be detected, and the unit is g; m3 is the mass of the filter membrane, and the unit is g; m4 is the total mass of the dried bentonite detection sample and the filter membrane, and the unit is g.

7. The method of claim 3, wherein, The filter membrane is a water-based filter membrane or an organic filter membrane, and the pore size of the filter membrane is 0.2μm-1μm.

8. The method according to any one of claims 1 to 7, characterized in that, The step (1) further comprises the following steps: After adding the activator, ultrasonic treatment is performed to obtain the first solution; Or, after adding the activator, heating treatment is performed to obtain the first solution.

9. The method according to any one of claims 1 to 7, characterized in that, The activator is a sodium pyrophosphate solution or a sodium thiosulfate solution.

10. The method according to claim 1, wherein the concentration of the methylene blue solution is 0.00312mol / L-0.0312mol / L. ​

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