Method for testing specific surface area of white carbon black

Abstract

The invention provides a method for testing the specific surface area of white carbon black. The testing method comprises the following steps: S1, taking a part of white carbon black to be tested as a white carbon black sample, testing the specific surface area of the white carbon black sample by a nitrogen adsorption method, and calculating according to a formula (I) to obtain a sample weighing amount: (I); wherein x is the specific surface area, measured by a nitrogen adsorption method, of the white carbon black sample, and the unit is m < 2 > / g; y is the sample weighing amount, and the unit is g; s2, weighing the other part of white carbon black to be detected according to the sample weighing amount, and mixing the white carbon black to be detected with a hexadecyl trimethyl ammonium bromide solution to obtain a turbid liquid; s3, carrying out solid-liquid separation treatment on the turbid liquid to obtain supernate; and S4, diluting the supernatant, carrying out potentiometric titration by adopting a sodium sulfosuccinate dioctyl ester solution, recording the volume consumption of the sodium sulfosuccinate dioctyl ester solution after a titration end point is reached, and calculating to obtain the specific surface area of the white carbon black to be detected, which is recorded as SCTAB.

Description

Technical Field

[0001] This invention relates to the specific surface area of ​​silica, and more specifically, to a method for testing the specific surface area of ​​silica. Background Technology

[0002] In recent years, with the development of green tires, the application of silica has increased. Depending on the specific surface area, there are also more and more types of silica. In order to improve the wear resistance of tires, many silicas with high specific surface area have emerged, with a specific surface area of ​​up to three or four hundred square meters per gram or even higher.

[0003] Currently, the testing principle for CTAB in silica involves adding a hexadecyltrimethylammonium bromide (CTAB) solution to the precipitated hydrated silica sample. Mechanical agitation is used to disperse the CTAB until equilibrium is reached, allowing the sample to adsorb it and form a suspension. After centrifugation, the amount of unadsorbed CTAB is titrated using a turbidimeter, and the specific surface area of ​​the dried sample can be calculated. However, the sample quantity requirements for CTAB testing in related technologies no longer meet the requirements for CTAB specific surface area testing of precipitated silica with high specific surface area.

[0004] Furthermore, the measurement of CTAB specific surface area depends on an appropriate sample weight. If the sample weight is too high, all or most of the added CTAB macromolecules will be adsorbed on the surface of silica, while the remaining CTAB macromolecules that react with the OT (sodium dioctyl sulfosuccinate) solution will be very low or almost non-existent, leading to abnormal test results. If the sample weight is too low, fewer CTAB macromolecules will be adsorbed on the silica surface, and most will react with the OT solution after separation, resulting in a higher OT consumption per test, longer test time, and potentially affecting the results. Therefore, a reasonable sample weight ensures both rapid testing and accurate results.

[0005] Based on this, it is of great significance to research and develop a method that can improve the accuracy of the specific surface area test results of silica. Summary of the Invention

[0006] The main objective of this invention is to provide a method for testing the specific surface area of ​​silica, so as to solve the problem that the accuracy of the specific surface area test results of silica in the prior art needs to be improved.

[0007] To achieve the above objectives, the present invention provides a method for testing the specific surface area of ​​silica, the method comprising: step S1, taking a portion of the silica to be tested as a silica sample, testing its specific surface area using nitrogen adsorption method, and calculating the sample weight according to formula (I): (I); where x is the specific surface area of ​​the silica sample measured by nitrogen adsorption method, in m³. 2 / g; y is the sample weight in g; Step S2: Weigh another portion of the silica to be tested using the sample weight, mix it with hexadecyltrimethylammonium bromide solution to obtain a suspension; Step S3: Perform solid-liquid separation on the suspension to obtain the supernatant; Step S4: Dilute the supernatant and perform potentiometric titration with sodium dioctyl sulfosuccinate solution. After reaching the titration endpoint, record the volume consumption of sodium dioctyl sulfosuccinate solution. Calculate the specific surface area of ​​the silica to be tested, denoted as S. CTAB .

[0008] Furthermore, x≥60m 2 / g.

[0009] Furthermore, x ≥ 250m 2 / g.

[0010] Furthermore, x is taken as 250–420m. 2 Any value in / g.

[0011] Furthermore, in step S2, the volume of the hexadecyltrimethylammonium bromide solution is 30 mL, and the molar concentration is 0.0151 mol / L.

[0012] Furthermore, during the mixing process in step S2, stirring is carried out for 35 to 50 minutes at a stirring speed of 400 to 600 r / min.

[0013] Furthermore, the solid-liquid separation process is centrifugation, preferably with a rotation speed of 4000–9000 r / min and a time of 20–60 min.

[0014] Furthermore, step S3 also includes a filtering process.

[0015] Further, step S4 includes: taking 5 mL of supernatant, diluting it with water to 25–70 mL to obtain the test solution; titrating the test solution with a portion of sodium dioctyl sulfosuccinate solution until the titration endpoint, and recording the volume consumption V in mL; taking 2.5 mL of cetyltrimethylammonium bromide solution, diluting it with water to 25–70 mL to obtain the blank control solution; titrating the blank control solution with the remaining portion of sodium dioctyl sulfosuccinate solution until the titration endpoint, and recording the volume consumption V0 in mL; calculating the specific surface area of ​​the silica to be tested using formula (II): (II), where y is the sample weight in g, X is the percentage of mass lost by the tested silica after heating to constant weight at 105℃ in 1g, and S CTAB The unit is m 2 / g.

[0016] Furthermore, the molar concentration of the sodium dioctyl sulfosuccinate solution is 0.00389 mol / L.

[0017] Further, in step S4, the volume of the test solution obtained after dilution is 60 mL; and / or, the volume of the blank control solution obtained after dilution is 60 mL.

[0018] By applying the technical solution of this invention, an appropriate sample weight can avoid the situation where excessively large sample weight leads to the adsorption of all CTAB molecules in the CTAB solution, making subsequent potentiometric titration impossible. Conversely, insufficient sample weight can prevent the unadsorbed CTAB molecules in the CTAB solution from being absorbed by the silica, resulting in excessive consumption of OT solution and excessively long titration time, leading to inaccurate test results. Compared to directly weighing a certain weight of silica for the CTAB solution adsorption step and the OT solution potentiometric titration step, the test method of this application establishes a relationship between the specific surface area of ​​the silica sample measured by the nitrogen adsorption method (BET method) and the sample weight, calculating an appropriate sample weight of silica to be tested. This ensures that the subsequent adsorption of silica with CTAB and the potentiometric titration with the OT solution can proceed smoothly, thereby improving the accuracy of the specific surface area test results of the silica. This is of great value for the quality control and performance optimization of silica. Attached Figure Description

[0019] The accompanying drawings, which form part of this application, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings:

[0020] Figure 1 The graph shows the relationship between the specific surface area (x) and the sample weight (y) of the silica sample measured by the nitrogen adsorption method in this application. Detailed Implementation

[0021] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. The present invention will now be described in detail with reference to the embodiments.

[0022] As described in the background section, existing methods for testing the specific surface area of ​​silica have limitations in terms of accuracy. To address these issues, this application provides a method for testing the specific surface area of ​​silica, comprising: step S1, taking a portion of the silica to be tested as a sample, performing a specific surface area test using nitrogen adsorption, and calculating the sample weight according to formula (I): (I); where x is the specific surface area of ​​the silica sample measured by nitrogen adsorption method, in m³. 2 / g; y is the sample weight in g; Step S2: Weigh another portion of the silica to be tested using the sample weight, mix it with hexadecyltrimethylammonium bromide solution to obtain a suspension; Step S3: Perform solid-liquid separation on the suspension to obtain the supernatant; Step S4: Dilute the supernatant and perform potentiometric titration with sodium dioctyl sulfosuccinate solution. After reaching the titration endpoint, record the volume consumption of sodium dioctyl sulfosuccinate solution. Calculate the specific surface area of ​​the silica to be tested, denoted as S. CTAB .

[0023] The sample weight y is calculated using the above formula (I). This weight of the silica to be tested is weighed and mixed with CTAB solution. During this process, the silica to be tested adsorbs CTAB until adsorption saturation is reached, resulting in a suspension. The suspension is then subjected to solid-liquid separation to obtain a supernatant containing unadsorbed CTAB. This supernatant is then diluted and potentiometrically titrated with OT solution. The volume of OT solution consumed at the titration endpoint is recorded, thus obtaining the amount of remaining unadsorbed CTAB. The specific surface area (S) of the silica to be tested is then calculated. CTAB ).

[0024] An appropriate sample weight can prevent the complete adsorption of CTAB molecules in the CTAB solution due to excessive weight, thus hindering subsequent potentiometric titration. Conversely, an insufficient sample weight can lead to unadsorbed CTAB molecules, excessive consumption of OT solution, and prolonged titration time, resulting in inaccurate test results. Compared to directly weighing a certain weight of silica for the CTAB adsorption step and the OT solution potentiometric titration step, the test method described in this application establishes a relationship between the specific surface area of ​​the silica sample measured by the nitrogen adsorption method (BET method) and the sample weight. This allows for the calculation of an appropriate sample weight of silica, ensuring the smooth execution of subsequent CTAB adsorption and OT solution potentiometric titration steps. Consequently, the accuracy of the specific surface area test results for silica is improved, which is of significant value for silica quality control and performance optimization.

[0025] BET method, usually referring to nitrogen adsorption, is based on the theory of multilayer adsorption. At low temperatures (approximately -196°C), nitrogen molecules form monolayers or multilayers of adsorption on the sample surface. The adsorption capacity varies with the relative pressure P / The change in the ratio of actual pressure to saturated vapor pressure forms an adsorption isotherm. Based on the BET theory, the total specific surface area can be calculated by analyzing the amount of adsorption under different relative pressures. In this application, the specific surface area of ​​the silica sample tested by the nitrogen adsorption method (BET method) can be determined with reference to GB / T17022-2014.

[0026] The relationship between the specific surface area (x) and sample weight (y) of the silica sample measured by nitrogen adsorption method is shown in the figure below. Figure 1 As shown in the diagram, those skilled in the art can substitute the known values ​​of x into the diagram to find the corresponding vertical coordinate, thus obtaining the sample quantity y.

[0027] The test methods provided in this application are applicable to silica. In a preferred embodiment, x ≥ 60m 2 / g.

[0028] The test method provided in this application is particularly suitable for testing silica with high specific surface area. In a preferred embodiment, x ≥ 250m 2 / g. Compared to other ranges, using silica within the specific surface area range specified above in the BET method as the test silica significantly improves the accuracy of the specific surface area test results and reduces test errors.

[0029] In a preferred embodiment, x is taken as 250–420m. 2 Any value within / g. Compared to other ranges, using silica with a specific surface area within this range as the silica to be tested is beneficial to further improve the accuracy of the specific surface area test results and further reduce test errors.

[0030] In a preferred embodiment, in step S2, the volume of the hexadecyltrimethylammonium bromide (CTAB) solution is 30 mL, and the molar concentration is 0.0151 mol / L. The volume and molar concentration of the CTAB solution include, but are not limited to, the ranges described above. Limiting them to these ranges allows a portion of the CTAB molecules to be adsorbed by the silica to be tested, while the remaining unadsorbed CTAB molecules participate in the subsequent potentiometric titration step, thereby improving the accuracy of the specific surface area test results for the silica.

[0031] In a preferred embodiment, stirring is performed during the mixing process in step S2 for 35–50 minutes at a stirring speed of 400–600 r / min. Stirring during this process facilitates sufficient adsorption of CTAB molecules from the precipitated silica and the CTAB solution. Compared to other ranges, limiting the stirring time and speed to this range allows for more thorough contact and adsorption, reducing the amount of CTAB not adsorbed by the precipitated silica. This ensures the smooth execution of the subsequent potentiometric titration step with the OT solution, thereby improving the accuracy of the precipitated silica specific surface area test results.

[0032] To improve the separation effect of unadsorbed CTAB molecules and remove the analyte silica that adsorbs CTAB, thereby improving the accuracy of subsequent potentiometric titration steps, in a preferred embodiment, the solid-liquid separation process is centrifugation, preferably at a speed of 4000–9000 r / min for 20–60 min.

[0033] To improve the separation of unadsorbed CTAB molecules and remove the precipitated silica adsorbed with CTAB, thereby improving the accuracy of subsequent potentiometric titration, in a preferred embodiment, step S3 further includes filtration. Preferably, an aqueous filter membrane with a pore size of 0.1–0.45 μm is used for filtration.

[0034] In a preferred embodiment, step S4 includes: taking 5 mL of supernatant and diluting it with water to 25-70 mL to obtain the test solution; titrating the test solution with a portion of sodium dioctyl sulfosuccinate solution until the titration endpoint, and recording the volume consumption V in mL; taking 2.5 mL of cetyltrimethylammonium bromide solution and diluting it with water to 25-70 mL to obtain a blank control solution; titrating the blank control solution with the remaining portion of sodium dioctyl sulfosuccinate solution until the titration endpoint, and recording the volume consumption V0 in mL; and calculating the specific surface area of ​​the silica to be tested using formula (II): (II), where y is the sample weight in g, X is the percentage of mass lost by the tested silica after heating to constant weight at 105℃ in 1g, and S CTAB The unit is m 2 / g.

[0035] The above titration method allows the adsorption of CTAB molecules (positively charged) and OT molecules (negatively charged) that were not adsorbed by the silica to be tested in the supernatant, thereby achieving potential equilibrium. The specific surface area of ​​the silica to be tested can then be calculated according to equation (II). This titration method has high sensitivity, which helps reduce testing errors and improve the accuracy of the test results. It should be noted that equation (II) can be derived by referring to the formula derivation process in the appendix of GB / T 23656-2016.

[0036] In a preferred embodiment, the molar concentration of the sodium dioctyl sulfosuccinate solution is 0.00389 mol / L. Compared to other ranges, limiting the molar concentration of the sodium dioctyl sulfosuccinate solution to the above range is beneficial to improving the sensitivity and accuracy of potentiometric titration endpoint determination. It also helps optimize the time efficiency of the potentiometric titration process, avoiding excessively short or long titration times due to inappropriate molar concentration, thereby improving the accuracy of the test results.

[0037] In a preferred embodiment, the volume of the test solution obtained after dilution in step S4 is 60 mL; the volume of the blank control solution obtained after dilution is 60 mL. Compared to other ranges, limiting the volumes of the test solution and the blank control solution to the above ranges is beneficial to save reagents as much as possible while meeting the reagent requirements for titration, and to reduce waste.

[0038] The present application will be further described in detail below with reference to specific embodiments, which should not be construed as limiting the scope of protection claimed in the present application.

[0039] Example 1

[0040] A method for testing the specific surface area of ​​silica includes:

[0041] (1) A portion of the silica to be tested was taken as a silica sample, and its specific surface area was tested by nitrogen adsorption method. The measured value of x was 282.0 m. 2 / g, Substitute into equation (I): In (I), the sample weight y was calculated to be 0.1859 g; a portion of the silica to be tested was taken as a silica sample, and after being heated to constant weight at 105℃, the mass loss percentage X was calculated to be 6.02.

[0042] (2) Weigh 0.1859 g of the silica to be tested, mix it with 30 mL of 0.0151 mol / L CTAB solution, stir for 35 min at a stirring speed of 450 r / min to obtain a suspension;

[0043] (3) Centrifuge the suspension obtained in step (2) to obtain the supernatant; wherein the rotation speed is 4000 r / min and the time is 50 min;

[0044] (4) Take 5 mL of supernatant, add deionized water to dilute to 60 mL to obtain the test solution; use 0.00389 mol / L OT solution for titration until the titration endpoint, and record the volume consumption V as 10.3663 mL;

[0045] (5) Take 2.5 mL of blank CTAB solution, dilute it to 60 mL to obtain a blank control solution; titrate with 0.00389 mol / L OT solution until the titration endpoint, and record the volume consumption V0 as 10.0125 mL;

[0046] (6) Substitute V and V0 obtained in steps (4) and (5), and y and X obtained in step (1) into equation (II), (II) The specific surface area (S) of the silica to be tested was calculated. CTAB The value is 263.6m. 2 / g.

[0047] Example 2

[0048] The difference from Example 1 is that in step (1), the specific surface area x of the silica sample was measured to be 162.0 m² using the BET method. 2 / g, Substitute into equation (I): (I) The calculated sample weight y is 0.3332 g; the remaining steps are the same as in Example 1. CTAB The test results are shown in Table 1.

[0049] The sample weight was verified using standard carbon black IRM100. When the sample weight was 0.3098 g, the test result was 161.8 m. 2 / g, which meets the requirement of an integer value for standard substances. This indicates that the test results of Example 1 are highly accurate.

[0050] Example 3

[0051] The difference from Example 1 is that in step (1), the specific surface area x of the silica sample was measured to be 374.4 m² using the BET method. 2 / g, Substitute into equation (I): (I) The calculated sample weight y is 0.1379 g; the remaining steps are the same as in Example 1. CTAB The test results are shown in Table 1.

[0052] Example 4

[0053] The difference from Example 1 is that in step (1), the specific surface area x of the silica sample was measured to be 390.4 m² using the BET method. 2 / g, Substitute into equation (I): (I) The calculated sample weight y is 0.1320 g; the remaining steps are the same as in Example 1. CTAB The test results are shown in Table 1.

[0054] Example 5

[0055] The difference from Example 1 is that in step (1), the specific surface area x of the silica sample was measured to be 244.6 m² using the BET method. 2 / g, Substitute into equation (I): (I) The calculated sample weight y is 0.2159 g; the remaining steps are the same as in Example 1. CTAB The test results are shown in Table 1.

[0056] Example 6

[0057] The difference from Example 1 is that in step (1), the specific surface area x of the silica sample was measured to be 276.7 m² using the BET method. 2 / g, Substitute into equation (I): (I) The calculated sample weight y is 0.1897 g; the remaining steps are the same as in Example 1. CTAB The test results are shown in Table 1.

[0058] Example 7

[0059] The difference from Example 1 is that in step (1), the specific surface area x of the silica sample was measured to be 285.0 m² using the BET method. 2 / g, Substitute into equation (I): (I) The calculated sample weight y is 0.1838 g; the remaining steps are the same as in Example 1. CTAB The test results are shown in Table 1.

[0060] Example 8

[0061] The difference from Example 1 is that in step (1), the specific surface area x of the silica sample was measured to be 210.0 m² using the BET method. 2 / g, Substitute into equation (I): (I) The calculated sample weight y is 0.2536 g; the remaining steps are the same as in Example 1. CTAB The test results are shown in Table 1.

[0062] Example 9

[0063] The difference from Example 1 is that in step (1), the specific surface area x of the silica sample was measured to be 246.8 m² using the BET method. 2 / g, Substitute into equation (I): (I) The calculated sample weight y is 0.2139 g; the remaining steps are the same as in Example 1. CTAB The test results are shown in Table 1.

[0064] As shown in Table 1, the specific surface area x of the silica sample obtained by BET method, the sample weight y calculated by formula (I), and the measured S in the above embodiments of this application are obtained. CTAB The test results are shown in Table 1.

[0065] Table 1

[0066]

[0067] Comparative Example 1

[0068] Using 280 MPa silica as the sample to be tested, its specific surface area S was measured by the BET method. NSA It is 282.0m 2 / g, based on the specific surface area and combined with GB / T 23656-2016, the possible range of sample weight was estimated. The actual sample weight in Table 2 was used for weighing. The CTAB solution adsorption step and OT solution titration step were performed using the same methods as steps (4) to (6) of Example 1. The test results are shown in Table 2.

[0069] Table 2

[0070]

[0071] In Comparative Example 1, when the actual sample weight was 0.2506 g, S could not be measured. CTAB (Represented by " / "). This indicates that the sample weight was too large, and the 280 MPa of silica completely adsorbed all the CTAB molecules in the CTAB solution, making it impossible to perform the titration experiment with the OT solution. However, the sample weight calculated using formula (I) in Example 1, when weighed and tested, allows for the determination of S. CTAB .

[0072] Comparative Example 2

[0073] Using 1165 MPa silica as the sample to be tested, its specific surface area S was measured by the BET method. NSA 162m 2 / g, based on the specific surface area, the possible sample amount range is inferred, and the actual sample amount in Table 3 is used for weighing. The CTAB solution adsorption step and OT solution titration step are performed using the same methods as steps (4) to (6) of Example 1. The test results are shown in Table 3.

[0074] Table 3

[0075]

[0076] Therefore, in Comparative Example 2, when the actual sample weight is 0.5999g, S cannot be measured. CTAB (Represented by " / "). This indicates that the sample weight was too large, and the 1165MP silica completely adsorbed all the CTAB molecules in the CTAB solution, making it impossible to perform the titration experiment with the OT solution. However, the sample weight calculated using formula (I) in Example 2, when weighed and tested, allows for the determination of S. CTAB .

[0077] Comparative Example 3

[0078] The specific surface area S was measured using the BET method. NSA 374.4m 2 / g of silica was used as the sample to be tested. Based on the specific surface area, the possible sample amount range was inferred. The two actual sample amounts in Table 4 were weighed. The CTAB solution adsorption step and OT solution titration step were performed using the same method as steps (4) to (6) of Example 1. The test results are shown in Table 4.

[0079] Table 4

[0080]

[0081] Therefore, it can be concluded that in Comparative Example 3, when the actual sample weights were 0.3065g and 0.2710g respectively, S could not be measured. CTAB (Represented by " / "). This indicates that the sample weight was too large, and the silica completely adsorbed all the CTAB molecules in the CTAB solution, making it impossible to perform the titration experiment with the OT solution. However, the sample weight calculated using formula (I) in Example 3, when weighed and tested, allows for the determination of S. CTAB .

[0082] Comparative Example 4

[0083] The specific surface area S was measured using the BET method. NSA 390.4m 2 / g of silica was used as the sample to be tested. Based on the specific surface area, the possible sample amount range was inferred. The two actual sample amounts in Table 5 were used for weighing. The CTAB solution adsorption step and OT solution titration step were performed using the same method as steps (4) to (6) of Example 1. The test results are shown in Table 5.

[0084] Table 5

[0085]

[0086] Therefore, it can be concluded that in Comparative Example 4, when the actual sample weights were 0.3012 g and 0.2705 g, respectively, S could not be measured. CTAB (Represented by " / "). This indicates that the sample weight was too large, and the silica completely adsorbed all the CTAB molecules in the CTAB solution, making it impossible to perform the titration experiment with the OT solution. However, the sample weight calculated using formula (I) in Example 4, when weighed and tested, allows for the determination of S. CTAB .

[0087] As can be seen from the above description, the embodiments of the present invention achieve the following technical effects:

[0088] An appropriate sample weight can prevent the complete adsorption of CTAB molecules in the CTAB solution due to excessive weight, thus hindering subsequent potentiometric titration. Conversely, an insufficient sample weight can lead to unadsorbed CTAB molecules, excessive consumption of OT solution, and prolonged titration time, resulting in inaccurate test results. Compared to directly weighing a certain weight of silica for the CTAB adsorption step and the OT solution potentiometric titration step, the test method described in this application establishes a relationship between the specific surface area of ​​the silica sample measured by the nitrogen adsorption method (BET method) and the sample weight. This allows for the calculation of an appropriate sample weight of silica, ensuring the smooth execution of subsequent CTAB adsorption and OT solution potentiometric titration steps. Consequently, the accuracy of the specific surface area test results for silica is improved, which is of significant value for silica quality control and performance optimization.

[0089] It should be noted that the terms "first," "second," etc., used in the specification and claims of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such terms can be used interchangeably where appropriate so that the embodiments of this application described herein can be implemented, for example, in a sequence other than those described herein.

[0090] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for testing the specific surface area of ​​silica, characterized in that, The testing method includes: Step S1: Take a portion of the silica to be tested as a silica sample, test its specific surface area using nitrogen adsorption method, and calculate the sample weight according to formula (I): (I); where x is the specific surface area of ​​the silica sample measured by the nitrogen adsorption method, in m². 2 / g; y is the sample weight, in grams; Step S2: Weigh another portion of the silica to be tested according to the stated sample amount, and mix it with a hexadecyltrimethylammonium bromide solution to obtain a suspension; Step S3: Perform solid-liquid separation on the suspension to obtain supernatant; Step S4: Dilute the supernatant and perform potentiometric titration using sodium dioctyl sulfosuccinate solution. Upon reaching the titration endpoint, record the volume of sodium dioctyl sulfosuccinate solution consumed. Calculate the specific surface area of ​​the silica to be tested, denoted as S. CTAB .

2. The method for testing the specific surface area of ​​silica according to claim 1, characterized in that, The x≥60m 2 / g.

3. The method for testing the specific surface area of ​​silica according to claim 1, characterized in that, The x≥250m 2 / g; Preferably, x is between 250 and 420m. 2 Any value in / g.

4. The method for testing the specific surface area of ​​silica according to any one of claims 1 to 3, characterized in that, In step S2, the volume of the hexadecyltrimethylammonium bromide solution is 30 mL, and the molar concentration is 0.0151 mol / L.

5. The method for testing the specific surface area of ​​silica according to claim 4, characterized in that, In step S2, the mixing process is carried out by stirring for 35 to 50 minutes at a speed of 400 to 600 r / min.

6. The method for testing the specific surface area of ​​silica according to claim 5, characterized in that, The solid-liquid separation process is centrifugation, preferably with a rotation speed of 4000–9000 r / min and a time of 20–60 min.

7. The method for testing the specific surface area of ​​silica according to claim 4 or 5, characterized in that, Step S3 also includes a filtering process.

8. The method for testing the specific surface area of ​​silica according to any one of claims 1 to 7, characterized in that, Step S4 includes: Take 5 mL of the supernatant and dilute it with water to 25–70 mL to obtain the test solution; titrate the test solution with a portion of the sodium dioctyl sulfosuccinate solution until the titration endpoint, and record the volume V consumed, in mL. Take 2.5 mL of the hexadecyltrimethylammonium bromide solution and dilute it with water to 25–70 mL to obtain a blank control solution; titrate the blank control solution with the remaining portion of the sodium dioctyl sulfosuccinate solution until the titration endpoint, and record the volume consumption V0 in mL; The specific surface area of ​​the silica to be tested was calculated using formula (II): (II), where y is the sample weight in g, X is the percentage of mass lost by the tested silica after heating to constant weight at 105°C in 1g, and S CTAB The unit is m 2 / g.

9. The method for testing the specific surface area of ​​silica according to claim 8, characterized in that, The molar concentration of the sodium dioctyl sulfosuccinate solution is 0.00389 mol / L.

10. The method for testing the specific surface area of ​​silica according to claim 8, characterized in that, In step S4, the volume of the test solution obtained after dilution is 60 mL; and / or, the volume of the blank control solution obtained after dilution is 60 mL.

Images