Nano barium sulfate and preparation method thereof

Abstract

The invention belongs to the technical field of material chemistry, and relates to nano barium sulfate and a preparation method thereof. The invention provides a preparation method of nano barium sulfate, which comprises the following steps: adding a barium acetate solution, sulfhydrylated chitosan and sodium stearate into a sodium sulfate solution for mixing reaction, collecting the obtained product after the reaction is ended, filtering, drying and grinding to obtain the nano barium sulfate, the concentration of the sodium sulfate solution is 1.4 to 2.6 mol / L, and the concentration of the barium acetate solution is 1.4 to 2.6 mol / L; 0.05 to 0.15 g of thiolated chitosan and 0.05 to 0.15 g of sodium stearate are correspondingly added into each 100 mL of the sodium sulfate solution. The invention solves the technical problems of high particle size and non-uniform particle size distribution of nano barium sulfate particles when the nano barium sulfate particles are prepared by adopting a direct precipitation method.

Description

Technical Field

[0001] The invention belongs to the technical field of material chemistry and relates to nano barium sulfate and a preparation method thereof. Background Art

[0002] Barium sulfate is widely used in various fields due to its chemical stability and unique physical properties. As a common, non-toxic barium salt, barium sulfate plays a vital role in modern industry and technology. Applications of nanobarium sulfate include as a high-quality filler in the coatings and inks industry, as a functional enhancer in the rubber and plastics industry, as an X-ray contrast agent and whitening component in the pharmaceutical and cosmetics fields, as an electronic ceramic raw material in specialty ceramics manufacturing, and as an electrolyte additive in battery production. Nanobarium sulfate's excellent brightness, acid and alkali resistance, light resistance, and good dispersibility make it a valuable additive for enhancing product performance. The main methods for preparing nanobarium sulfate include pulverization, direct precipitation, complexation, ultrasonic precipitation, and microreactor methods. The direct precipitation method involves directly mixing the reaction raw materials, filtering, drying, and grinding the resulting product to obtain barium sulfate powder. While the direct precipitation method offers a simple process and high product purity, it also presents challenges such as a wide particle size distribution and difficulty in size control. Summary of the Invention

[0003] The present invention aims to solve the technical problem of high particle size and uneven particle size distribution of nano-barium sulfate particles when preparing nano-barium sulfate particles by direct precipitation. To this end, the present invention provides a nano-barium sulfate and a preparation method thereof to address this need in the art.

[0004] In one aspect, the present invention relates to a method for preparing nano-barium sulfate, comprising: adding a barium acetate solution, thiolated chitosan, and sodium stearate to a sodium sulfate solution for a mixing reaction; collecting the resulting product after the reaction, filtering, drying, and grinding to obtain nano-barium sulfate;

[0005] The concentration of the sodium sulfate solution is 1.4 to 2.6 mol / L, and the concentration of the barium acetate solution is 1.4 to 2.6 mol / L;

[0006] For every 100 mL of the sodium sulfate solution, add 0.05-0.15 g of thiolated chitosan and 0.05-0.15 g of sodium stearate;

[0007] The particle size and polydispersity index of the product were reduced by adding thiolated chitosan and sodium stearate.

[0008] Furthermore, in the method for preparing nano-barium sulfate provided by the present invention, in the mixing reaction, the reaction temperature is 15 to 45°C.

[0009] Furthermore, in the preparation method of nano-barium sulfate provided by the present invention, in the mixing reaction, the reaction temperature is 55°C.

[0010] Furthermore, in the method for preparing nano-barium sulfate provided by the present invention, in the mixing reaction, before the mixing reaction is carried out, the pH of the reaction system is adjusted to 6-9.

[0011] Furthermore, in the preparation method of nano-barium sulfate provided by the present invention, in the mixing reaction, before the mixing reaction is carried out, the pH of the reaction system is adjusted to 8.

[0012] Furthermore, in the method for preparing nano-barium sulfate provided by the present invention, the reaction time of the mixing reaction is 10 to 30 minutes.

[0013] Furthermore, in the preparation method of nano-barium sulfate provided by the present invention, the reaction time of the mixing reaction is 20 minutes.

[0014] Furthermore, in the preparation method of nano-barium sulfate provided by the present invention, during the mixing reaction, the stirring rate is 270 to 360 r / min.

[0015] Furthermore, in the preparation method of nano-barium sulfate provided by the present invention, during the mixing reaction, the stirring rate is 360 r / min.

[0016] On the other hand, the present invention relates to nano-barium sulfate, which is prepared by the preparation method of nano-barium sulfate.

[0017] Compared with the prior art, the technical solution provided by the present invention has at least the following beneficial effects or advantages:

[0018] The present invention effectively reduces the particle size of nano-barium sulfate by adding a dispersant when preparing nano-barium sulfate particles by direct precipitation, and prepares barium sulfate powder with a particle size of nanometer level, which is spherical in shape and relatively uniform in particle distribution, but still has agglomeration. The present invention further reduces the particle size and polydispersity index of the product by adding thiolated chitosan and sodium stearate. The thiol groups in thiolated chitosan have a strong coordination ability for barium ions. This allows the thiolated chitosan to be more firmly anchored on the surface of the barium sulfate particles (especially the crystal plane rich in barium ions), adsorbing more firmly and more persistently than ordinary chitosan, and not easily desorbed during reaction or subsequent treatment, which greatly enhances its steric stability. The strong anchoring and thick steric hindrance layer of thiolated chitosan provide basic stability, which can effectively block particle contact even when the ionic strength is high. The additional electrostatic repulsion provided by sodium stearate (even if partially weakened) is superimposed on the steric hindrance, providing a second line of defense, further inhibiting agglomeration. The combined effect of the two can more effectively stabilize the newly formed nano-barium sulfate nuclei and nanoparticles in the high supersaturation and high ionic strength environment where the reaction occurs, avoiding the problem of large particle size and high dispersion caused by the rapid generation of nano-barium sulfate.

[0019] When sodium stearate is used in combination with unmodified chitosan, it is unable to synergistically reduce the particle size and polydispersity index of the product. The reason is that in a high ionic strength environment (i.e., the reaction environment of sodium sulfate and barium acetate), the electrostatic effect of ordinary chitosan is severely shielded, the adsorption strength is greatly reduced, and the hydrogen bond is easily weakened by interference from water molecules and ions. The adsorption of ordinary chitosan on the particle surface is weak, reversible, and easy to desorb. It cannot "firmly grasp" the particle surface like thiolated chitosan, especially under intense precipitation reactions and stirring conditions. When sodium stearate is used in combination with unmodified chitosan, the particle surface may eventually be mainly covered by sodium stearate, and ordinary chitosan is repelled into the solution body or only loosely attached, and ultimately there is no obvious improvement effect compared to using only sodium stearate.

[0020] In addition, when thiolated chitosan is used in combination with other dispersants (sodium dodecylbenzene sulfonate), when sodium dodecylbenzene sulfonate is adsorbed on the particle surface, its large hydrophobic groups with rigid benzene rings will occupy a large amount of particle surface space like a "shield" and extend outward to form a physical barrier. This will seriously hinder the long molecular chains of thiolated chitosan from approaching and effectively adsorbing to areas on the particle surface not covered by SDBS, or penetrating the SDBS adsorption layer. This results in the adsorption of thiolated chitosan being weakened by the steric hindrance effect, and its strong anchoring ability (dependent on the thiol group) and the steric hindrance effect provided by the long chain cannot be fully utilized. The thiol group cannot fully approach the surface for coordination anchoring, and ultimately cannot reduce the particle size and polydispersity index of the product. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0022] Figure 1 This is a line graph showing the effect of concentration on barium sulfate particle size.

[0023] Figure 2 This is a line graph showing the effect of temperature on barium sulfate particle size.

[0024] Figure 3 This is a line graph showing the effect of pH on barium sulfate particle size.

[0025] Figure 4 This is a line graph showing the effect of reaction time on barium sulfate particle size.

[0026] Figure 5 This is a line graph showing the effect of rotation speed on barium sulfate particle size.

[0027] Figure 6 This is the XRD comparison diagram of barium sulfate under the optimal conditions.

[0028] Figure 7 This is the infrared spectrum of barium sulfate under optimal conditions.

[0029] Figure 8 This is the scanning electron micrograph of barium sulfate under optimal conditions. DETAILED DESCRIPTION

[0030] The technical solutions of the present invention are described below with reference to the following examples. However, the present invention is not limited to the following examples. The experimental and detection methods described in each example are conventional methods unless otherwise specified. The reagents and materials described are commercially available unless otherwise specified. The percentages in the following examples are percentages by mass unless otherwise specified. The ratios in the following examples are ratios by mass unless otherwise specified.

[0031] Example 1

[0032] This example provides the preparation and particle size testing of nano-barium sulfate.

[0033] Experimental principle:

[0034] (CH3COO)2Ba+Na2SO4=2CH3COONa+BaSO4↓

[0035] First, a certain amount of barium acetate solution and sodium sulfate were weighed and dissolved in distilled water to prepare a barium acetate solution and a sodium sulfate solution, respectively. The two were mixed under certain conditions and stirred for a period of time. The resulting product was filtered, dried, and ground to obtain white powdered barium sulfate. Weigh 0.1g of barium sulfate powder and 0.1g of sodium hexametaphosphate, add 100mL of distilled water, and sonicate for 30 minutes (stirring with a glass rod for 60 seconds before sonication). The particle size was then measured using a laser particle size analyzer.

[0036] (1) Effect of concentration on barium sulfate particle size:

[0037] Prepare 100mL of each solution with a concentration of 0.5mol·L -1 , 0.8 mol·L -1 , 1.1 mol·L -1 , 1.4 mol·L -1 , 1.7 mol·L -1 , 2.0 mol·L -1 , 2.3 mol·L -1 , 2.6 mol·L -1 100mL of barium acetate solution with a concentration of 0.5mol·L -1 , 0.8 mol·L -1 , 1.1 mol·L -1 , 1.4 mol·L -1 , 1.7 mol·L -1 , 2.0 mol·L -1 , 2.3 mol·L -1 , 2.6 mol·L -1 Sodium sulfate solution. At 25℃, 360r·min -1 The reaction was carried out at a stirring rate of 10 minutes, and the barium sulfate sample was obtained after filtration, drying and grinding. 0.1g of barium sulfate powder and 0.1g of sodium hexametaphosphate were weighed and dispersed in 100mL of distilled water. After ultrasonication for 30 minutes, the particle size was measured to systematically investigate the effect of the reactant concentration on the particle size of barium sulfate. The experimental data are shown in Table 1 and Figure 1 shown.

[0038] Table 1 Concentration experimental data

[0039] sodium sulfate Barium acetate temperature Reaction time Speed Particle size <![CDATA[(mol·L -1 )]]> <![CDATA[(mol·L -1 )]]> (℃) (min) <![CDATA[(r·min -1 )]]> (nm) 0.5 0.5 25 10 360 148 0.8 0.8 25 10 360 132 1.1 1.1 25 10 360 115 1.4 1.4 25 10 360 108 1.7 1.7 25 10 360 78 2.0 2.0 25 10 360 51 2.3 2.3 25 10 360 72 2.6 2.6 25 10 360 104

[0040] Depend on Figure 1 It can be seen that the particle size of the product barium sulfate first decreases and then increases with the increase of concentration. -1 The reaction was carried out for 10 min at a stirring speed of 2.0 mol·L -1 The particle size is relatively small.

[0041] In the initial stage of the reaction, when the solution concentration is relatively low, the supersaturation of the system increases with the increase in the concentration of the reactants. Crystal growth is restricted by supersaturation, and the nucleation rate and crystal growth rate are affected by supersaturation. In the initial stage, the supersaturation is low, the nucleation process is more sensitive to changes in supersaturation, and the increase in the nucleation rate significantly exceeds the crystal growth rate. When the concentration is low, the number of crystal nuclei formed per unit time dominates, causing the particle size of the final product to gradually decrease with increasing supersaturation. When the reaction concentration is further increased and the supersaturation increases to a critical value, a large number of crystal nuclei will quickly form in the solution and precipitate rapidly. At this time, the crystal growth process will dominate, the nucleation rate will be lower than the growth rate, and the average particle size of the product will begin to increase significantly.

[0042] (2) Effect of temperature on barium sulfate particle size:

[0043] Based on the above conditions, the concentration is 2.0 mol·L -1 Barium acetate solution and sodium sulfate solution were heated at 15℃, 25℃, 35℃, 45℃, 55℃, 65℃, 75℃, and 85℃, 360r·min -1 After 10 minutes of reaction at stirring rate, the barium sulfate sample was obtained after filtration, drying and grinding. 0.1g of barium sulfate powder and 0.1g of sodium hexametaphosphate were weighed and dispersed in 100mL of distilled water. After ultrasonication for 30 minutes, the particle size was measured. The effect of reaction temperature on the particle size of barium sulfate was systematically investigated, as shown in Table 2 and Figure 2 shown.

[0044] Table 2 Temperature experimental data

[0045] sodium sulfate Barium acetate temperature Reaction time Speed Particle size <![CDATA[(mol·L -1 )]]> <![CDATA[(mol·L -1 )]]> (℃) (min) <![CDATA[(r·min -1 )]]> (nm) 2.0 2.0 15 10 360 60 2.0 2.0 25 10 360 51 2.0 2.0 35 10 360 59 2.0 2.0 45 10 360 63 2.0 2.0 55 10 360 67 2.0 2.0 65 10 360 75 2.0 2.0 75 10 360 78 2.0 2.0 85 10 360 86

[0046] Depend on Figure 2 It can be seen that the particle size of the product barium sulfate first decreases and then increases with the increase of temperature. -1 、360r·min -1 Under the premise of stirring speed and reaction time of 10 min and temperature of 25 °C, the particle size is relatively small.

[0047] On the one hand, at lower temperatures, molecular kinetic energy is lower, making it easier for particles to attach to the surfaces of already nucleated molecules and grow, resulting in larger product particle size. At higher temperatures, the molecular kinetic energy increases, but the surface energy of the crystals decreases, favoring molecular agglomeration. On the other hand, at lower temperatures, the nucleation rate is higher and the growth rate is lower; at higher temperatures, the nucleation rate is lower and the growth rate is higher. Therefore, the product particle size first decreases and then increases with increasing temperature.

[0048] (3) Effect of pH on barium sulfate particle size:

[0049] Based on the above conditions, the concentration is 2.0 mol·L -1 The barium acetate solution and sodium sulfate solution were controlled at 25 °C and stirred at a speed of 360 r·min -1 The pH of the reaction solution was adjusted to 6, 7, 8, 9, and 10 using sodium hydroxide solution and hydrogen chloride solution, respectively. After 10 minutes of reaction, the solution was filtered, dried, and ground. 0.1 g of the obtained barium sulfate powder was weighed and placed in 100 mL of distilled water, and 0.1 g of sodium hexametaphosphate was added. After ultrasonication for 30 minutes, the particle size was measured to study the effect of pH on the particle size of barium sulfate. The experimental data are shown in Table 3 and Figure 3 shown.

[0050] Table 3 pH experimental data

[0051] sodium sulfate Barium acetate temperature pH Reaction time Speed Particle size <![CDATA[(mol·L -1 )]]> <![CDATA[(mol·L -1 )]]> (℃) / (min) <![CDATA[(r·min -1 )]]> (nm) 2.0 2.0 25 6 10 360 78 2.0 2.0 25 7 10 360 74 2.0 2.0 25 8 10 360 59 2.0 2.0 25 9 10 360 73 2.0 2.0 25 10 10 360 86

[0052] Depend on Figure 3 It can be seen that the particle size of barium sulfate decreases first and then increases with the increase of pH value. -1 , temperature 25℃, reaction 10min, 360r·min -1 Under the premise of stirring speed, the particle size is relatively small when the pH value is 8.

[0053] (4) Effect of time on barium sulfate particle size:

[0054] Based on the above conditions, 2.0 mol·L -1 The barium acetate solution and sodium sulfate solution were stirred at 360 r·min at 25℃ and pH 8. -1 The stirring rate was 5min, 10min, 20min, 30min, 40min, 50min, and 60min respectively. The obtained product was filtered, dried, and ground. 0.1g of barium sulfate powder and 0.1g of sodium hexametaphosphate were weighed and dispersed in 100mL of distilled water. After ultrasonication for 30min, the particle size was measured. The effect of reaction time on the particle size of barium sulfate was systematically investigated. The results are shown in Table 4 and Figure 4 .

[0055] Table 4 Time experimental data

[0056] sodium sulfate Barium acetate temperature pH Reaction time Speed Particle size <![CDATA[(mol·L -1 )]]> <![CDATA[(mol·L -1 )]]> (℃) / (min) <![CDATA[(r·min -1 )]]> (nm) 2.0 2.0 25 8 5 360 65 2.0 2.0 25 8 10 360 59 2.0 2.0 25 8 20 360 51 2.0 2.0 25 8 30 360 55 2.0 2.0 25 8 40 360 61 2.0 2.0 25 8 50 360 63 2.0 2.0 25 8 60 360 64

[0057] Depend on Figure 4 It can be seen that the particle size of the barium sulfate product decreases first and then increases with the reaction time. When the concentration of the reaction system is 2.0 mol·L -1 , temperature 25℃, pH 8, stirring rate 360r·min -1 When the reaction proceeds for 20 minutes, the particle size is relatively small.

[0058] (5) Effect of stirring speed on barium sulfate particle size:

[0059] Based on the above conditions, the concentration is 2.0 mol·L -1 The barium acetate solution and sodium sulfate solution were at 25℃, pH 8, and were heated at 90 r·min -1 , 180r·min -1 , 270r·min -1 , 360r·min -1 , 450r·min -1 , 540r·min -1 The reaction was carried out at a stirring speed for 20 minutes, and then the obtained product was filtered, dried and ground. 0.1g of barium sulfate powder was weighed and placed in 100mL of distilled water, and 0.1g of sodium hexametaphosphate was added. After ultrasonication for 30 minutes, the particle size was measured. The experimental data are shown in Table 5 and Figure 5 shown.

[0060] Table 5 Stirring speed experimental data

[0061] sodium sulfate Barium acetate temperature pH Reaction time Speed Particle size <![CDATA[(mol·L -1 )]]> <![CDATA[(mol·L -1 )]]> (℃) / (min) <![CDATA[(r·min -1 )]]> (nm) 2.0 2.0 25 8 20 90 56 2.0 2.0 25 8 20 180 55 2.0 2.0 25 8 20 270 53 2.0 2.0 25 8 20 360 51 2.0 2.0 25 8 20 450 55 2.0 2.0 25 8 20 540 56

[0062] Depend on Figure 5 It can be seen that the particle size of the product barium sulfate first decreases and then increases with the increase of stirring speed. -1 , temperature 25℃, pH value 8, reaction time 20min, stirring speed 360r·min -1 The particle size is relatively small.

[0063] (6) Effect of dispersant type on barium sulfate particle size:

[0064] Based on the above conditions, the concentration is 2.0 mol·L -1 barium acetate solution and sodium sulfate solution at 25°C, pH 8, 360 r·min -1 0.1g of different dispersants were added at a stirring speed of 1000 rpm. After a 20-minute reaction, the resulting product was filtered, dried, and ground. 0.1g of barium sulfate powder was then weighed and placed in 100mL of distilled water. 0.1g of sodium hexametaphosphate was also added. After ultrasonication for 30 minutes, the particle size was measured. The experimental data are shown in Table 6.

[0065] Table 6 Experimental data of different dispersants

[0066]

[0067]

[0068] It can be seen from Table 6 that under the above experimental conditions, the particle size of barium sulfate is relatively small when 0.1 g of sodium stearate is added.

[0069] Based on the above experiments, the optimal conditions for the preparation of nano-barium sulfate were obtained, which were to prepare 100 mL of 2.0 mol·L -1 of barium acetate solution and 100 mL of 2.0 mol·L -1 Sodium sulfate solution, at 25 ° C, pH 8, 360 r·min -1 0.1 g of sodium stearate was added under stirring conditions, and after reacting for 20 minutes, the obtained product was filtered, dried and ground to obtain nano-barium sulfate.

[0070] Under the optimal conditions, the barium sulfate particles were analyzed by X-ray diffraction and compared with the standard barium sulfate card (PDF#24-1035). Figure 6 As shown, the results show that the measured barium sulfate peak is highly close to the theoretical value, and the produced barium sulfate has high purity and crystallinity.

[0071] Figure 7 The infrared spectrum analysis showed that the experimental product had a -1 The characteristic peaks appearing at are attributed to the vibration mode of Ba-O bond, SO4 2- The typical vibration absorption peak appears at 605cm -1 , 983cm -1 、1067cm -1 、1181cm -1 Multiple bands can confirm that the product is barium sulfate crystals.

[0072] Figure 8 The scanning electron microscope image of barium sulfate under the best conditions is shown in Figure 2. Figure 8 It can be observed that this experiment successfully prepared barium sulfate powder with a particle size of nanometer level. Its morphology is spherical and the particle distribution is relatively uniform, but agglomeration still exists.

[0073] Based on the above experimental results, this embodiment optimizes the reaction conditions for preparing nano-barium sulfate particles by direct precipitation using barium acetate solution and sodium sulfate solution as raw materials, and obtains the optimal preparation conditions; on the other hand, by adding a dispersant when preparing nano-barium sulfate particles by direct precipitation, nano-barium sulfate particles with more uniform particle distribution and smaller particle size are obtained.

[0074] Example 2

[0075] This example provides a verification experiment of reducing the particle size and polydispersity index of the product by adding thiolated chitosan and sodium stearate.

[0076] In this embodiment, the thiolated chitosan is chitosan that has been thiolated and obtained in the laboratory.1 HNMR detected the changes in the characteristic peaks, and the peak area ratio of -SH and H2 was 10.32%, that is, the substitution degree was 10.32%.

[0077] Experimental basic settings: Prepare 100mL of 2.0mol·L -1 of barium acetate solution and 100 mL of 2.0 mol·L -1 Sodium sulfate solution, at 25 ° C, pH 8, 360 r·min -1 Under stirring conditions, 0.05-0.15g of dispersant and 0.05-0.15g of additive were added. After reacting for 20 minutes, the resulting product was filtered, dried, and ground to produce nano-barium sulfate. 0.1g of barium sulfate powder was weighed and placed in 100mL of distilled water. 0.1g of sodium hexametaphosphate was added. After ultrasonication for 30 minutes, the average particle size and standard deviation were measured. The experimental groups are shown in Table 7.

[0078] Table 7 Experimental settings of different dispersants and morphology control agents

[0079] dispersants Dispersant dosage (g) additive Additive dosage (g) Group 1 Sodium stearate 0.05 Thiol chitosan 0.05 Group 2 Sodium stearate 0.1 Thiol chitosan 0.1 Group 3 Sodium stearate 0.15 Thiol chitosan 0.15 Group 4 Sodium stearate 0.1 Chitosan 0.1 Group 5 Sodium lauryl sulfate 0.1 Thiol chitosan 0.1 Group 6 Sodium stearate 0.1 Thiol chitosan 0 Group 7 Sodium lauryl sulfate 0.1 Thiol chitosan 0

[0080] The experimental results are shown in Table 8.

[0081] Table 8 Experimental results of different dispersants and morphology control agents

[0082] Average particle size (nm) Standard Deviation PDI Group 1 34 4.3 0.0157 Group 2 32 3.2 0.0099 Group 3 37 4.6 0.0152 Group 4 48 8.5 0.0304 Group 5 58 9.1 0.0240 Group 6 49 8.3 0.0279 Group 7 61 8.9 0.0208

[0083] Table 8 shows that when preparing nanobarium sulfate particles using the direct precipitation method, the addition of thiolated chitosan and sodium stearate reduces the particle size and polydispersity index of the product. Group 4 shows that the use of chitosan has little effect on the particle size and polydispersity index of the product. Group 5 shows that the combination of other dispersants (such as sodium lauryl sulfate) with thiolated chitosan has little effect on the particle size and polydispersity index of the product.

[0084] As described above, the basic principles, main features and advantages of the present invention are well described. The above embodiments and descriptions are merely descriptions of preferred embodiments of the present invention, and the present invention is not limited to the above embodiments. Various changes and improvements made to the technical solutions of the present invention by those skilled in the art without departing from the spirit and scope of the present invention should fall within the scope of protection determined by the present invention.

Claims

1. A method for preparing nano-barium sulfate, characterized in that: include: Adding barium acetate solution, thiolated chitosan and sodium stearate to a sodium sulfate solution for mixing and reacting, collecting the resulting product after the reaction is completed, filtering, drying and grinding to obtain nano-barium sulfate; The concentration of the sodium sulfate solution is 1.4 to 2.6 mol / L, and the concentration of the barium acetate solution is 1.4 to 2.6 mol / L; For every 100 mL of the sodium sulfate solution, add 0.05-0.15 g of thiolated chitosan and 0.05-0.15 g of sodium stearate; The particle size and polydispersity index of the product were reduced by adding thiolated chitosan and sodium stearate.

2. The preparation method of nano barium sulfate according to claim 1, wherein In the mixing reaction, the reaction temperature is 15-45°C.

3. The preparation method of nano barium sulfate according to claim 2, wherein During the mixing reaction, the reaction temperature was 55°C.

4. The preparation method of nano barium sulfate according to claim 1, wherein In the mixing reaction, the pH of the reaction system is adjusted to 6-9 before the mixing reaction is carried out.

5. The preparation method of nano barium sulfate according to claim 4, wherein In the mixing reaction, the pH of the reaction system is adjusted to 8 before the mixing reaction is carried out.

6. The method for preparing nano-barium sulfate according to claim 1, wherein The reaction time of the mixing reaction is 10 to 30 minutes.

7. The method for preparing nano-barium sulfate according to claim 6, wherein The reaction time of the mixing reaction is 20 min.

8. The method for preparing nano-barium sulfate according to claim 1, wherein During the mixing reaction, the stirring rate is 270-360 r / min.

9. The method for preparing nano-barium sulfate according to claim 8, wherein During the mixing reaction, the stirring rate was 360 r / min.

10. A nano-barium sulfate, characterized in that: The nano-barium sulfate is prepared by the preparation method of any one of claims 1 to 9.

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