A bismuth hydroxide material and preparation method thereof
By using the PEG-PLA micelle system to control the preparation process of bismuth hydroxide, the problems of uneven bismuth hydroxide particle size and agglomeration in the prior art are solved, and a high-purity, nanoscale, and excellently dispersed bismuth hydroxide material is achieved.
Patent Information
- Application Number
- CN202510959569.9
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2025-07-11
- Publication Date
- 2025-09-19
- Estimated Expiration
- 2045-07-11
AI Technical Summary
Existing methods for preparing bismuth hydroxide result in uneven particle size and agglomeration, which affects the dispersibility and stability of the material.
By using a PEG-PLA micelle system as the reaction medium and controlling the reaction conditions of bismuth salt and ammonia water, a nanoscale, spherical, and well-dispersed bismuth hydroxide material was prepared.
The uniformity and dispersion of bismuth hydroxide particles are achieved, and the material purity is as high as 99.8%, effectively solving the problems of uneven particle size and agglomeration.
Smart Images
Figure CN120440952B_ABST
Abstract
Description
Technical Field
[0001] The present invention belongs to the technical field of inorganic material preparation, and in particular relates to a bismuth hydroxide material and a preparation method thereof. Background Art
[0002] As an important bismuth-based compound, bismuth hydroxide exhibits promising application prospects in a variety of fields due to its unique physical and chemical properties. In photocatalysis, bismuth hydroxide has the ability to degrade a variety of organic pollutants. In sensing, it can be used to construct highly sensitive gas or ion sensors. In the biomedical field, its low toxicity and unique chemical activity have also attracted considerable research attention.
[0003] However, there are still many problems with the current preparation methods of bismuth hydroxide materials. The traditional precipitation method for preparing bismuth hydroxide, for example, using a simple alkali solution and a bismuth salt solution to directly mix and precipitate, is simple to operate and low in cost. However, in the actual preparation process, due to the local concentration differences and rapid precipitation kinetics in the reaction system, the size distribution of the generated bismuth hydroxide particles is extremely uneven, with particles ranging from tens of nanometers to several microns mixed together. At the same time, the strong surface energy and van der Waals forces between nanoscale particles make it very easy for them to agglomerate and form dense agglomerates. This agglomeration phenomenon not only leads to a significant reduction in the specific surface area of the material, a large number of active sites are wrapped in the agglomerates and cannot be effectively exposed, but also seriously affects the dispersibility and stability of the material. Therefore, the development of a new and efficient method for preparing bismuth hydroxide to solve the problems of uneven particle size and agglomeration is of great significance to promoting its industrial application. Summary of the Invention
[0004] The present invention aims to overcome the shortcomings of the prior art and provide a bismuth hydroxide material and a preparation method thereof. The method aims to develop a new and efficient method for preparing bismuth hydroxide and solve the problems of uneven particle size and agglomeration.
[0005] To achieve the above object, the present invention provides the following technical solutions:
[0006] A bismuth hydroxide material is provided. The bismuth hydroxide material is in the form of nano-scale particles with a particle size distribution between 85 and 175 nm. The particles have a spherical structure, excellent dispersibility, and a material purity of over 99.8%.
[0007] A method for preparing a bismuth hydroxide material, the steps of the preparation method are as follows:
[0008] S1. Preparation of micelle solution: dissolving polyethylene glycol-polylactic acid (PEG-PLA) block copolymer in dichloromethane and stirring evenly. Separately, stirring evenly with concentrated ammonia water and anhydrous ethanol at a mass fraction of 25-28%, slowly dropwise adding the above-mentioned PEG-PLA dichloromethane solution to the above-mentioned ammonia-ethanol mixed solution while continuously stirring. After the addition is complete, stirring is continued for 30-60 minutes to remove the dichloromethane by volatilization to form a stable PEG-PLA micelle system, thereby obtaining a micelle solution;
[0009] S2. Synthesis of bismuth hydroxide: adding a bismuth salt to the micellar solution of step S1 at room temperature. After the addition is complete, continue stirring and reacting for 1 to 2 hours;
[0010] S3. Product separation and purification: After the reaction is completed, the reaction mixture is centrifuged at a speed of 8000-12000 r / min for 8-10 minutes, and the precipitate is collected and washed multiple times with deionized water. After each wash, the precipitate is centrifuged and the washing-centrifugation operation is repeated three times. The washed bismuth hydroxide precipitate is then dried in a vacuum drying oven to obtain a bismuth hydroxide material.
[0011] The PEG-PLA micelle system can precisely control the growth environment of bismuth hydroxide particles. Its unique amphiphilic structure makes the bismuth ions more evenly distributed in the micelle system, thereby making the reaction rate more consistent and effectively improving the uniformity of the particles.
[0012] During the reaction, the hydrophilic PEG chains of the PEG-PLA micelles extend onto the particle surface, creating a steric hindrance that effectively inhibits the aggregation of the bismuth hydroxide particles. Furthermore, after the reaction is complete and centrifugation is complete, the PEG-PLA micelles wrap around the bismuth hydroxide particles, further preventing them from agglomerating. The wrapped PEG-PLA micelles can then be washed away with deionized water.
[0013] PEG-PLA micelles can also slow down the collision between bismuth ions and hydroxide ions, making the reaction milder, thereby ensuring more uniform particle formation. At the same time, high concentration of ammonia water can form higher purity bismuth hydroxide particles.
[0014] It is further preferred as a preparation method of bismuth hydroxide material.
[0015] Preferably, the molecular weight of the polyethylene glycol-polylactic acid (PEG-PLA) block copolymer described in step S1 is 2000-10000.
[0016] Preferably, the amounts of the polyethylene glycol-polylactic acid (PEG-PLA) block copolymer, dichloromethane, concentrated ammonia water and anhydrous ethanol added in step S1 are: 1-3 g, 10-30 mL, 6-10 mL and 60-100 mL, respectively.
[0017] Preferably, the added amounts of the bismuth salt and the micelle solution are 0.25-0.5 g and 60-80 mL, respectively.
[0018] Preferably, the bismuth salt is added to the micelles in step S2 by dividing the bismuth salt into 5 equal parts and adding the bismuth salt once every 10 to 20 minutes.
[0019] Preferably, the drying temperature of the vacuum drying oven in step S4 is 40-60° C., and the drying time is 8-12 hours.
[0020] The beneficial effects of the present invention compared to the prior art are:
[0021] (1) The PEG-PLA micelle system can precisely control the growth environment of bismuth hydroxide particles. Its unique amphiphilic structure makes the bismuth ions more evenly distributed in the micelle system, thereby making the reaction rate more consistent and effectively improving the particle uniformity. The particle size distribution is between 85 and 175 nm.
[0022] (2) During the reaction, the hydrophilic PEG chain segments of the PEG-PLA micelles extend onto the particle surface, forming a steric hindrance that effectively inhibits the agglomeration of the bismuth hydroxide particles. In addition, after the reaction is completed and centrifuged, the PEG-PLA micelles will wrap around the outside of the bismuth hydroxide particles, further preventing the agglomeration of the bismuth hydroxide particles. The wrapped PEG-PLA micelles can then be washed away with deionized water to obtain bismuth hydroxide particles with good dispersion.
[0023] (3) PEG-PLA micelles can also slow down the collision between bismuth ions and hydroxide ions, significantly slowing down the reaction rate between bismuth salt and ammonia, making the reaction milder and more controllable, thereby ensuring more uniform particle formation. At the same time, high concentrations of ammonia can form higher purity bismuth hydroxide particles. The material purity is as high as over 99.8%. BRIEF DESCRIPTION OF THE DRAWINGS
[0024] Figure 1 is a scanning electron microscope photograph (SEM) of the bismuth hydroxide material prepared in Example 1;
[0025] Figure 2 It is a statistical diagram of the particle size of the sample in Example 1;
[0026] Figure 3 is a scanning electron microscope photograph (SEM) of the bismuth hydroxide material prepared in the comparative example;
[0027] Figure 4 is a photograph of the bismuth hydroxide powder prepared in Example 1;
[0028] Figure 5 This is the thermogravimetric analysis curve (TG) of the bismuth hydroxide material prepared in Example 1. DETAILED DESCRIPTION
[0029] To make the above-mentioned objects, features, and advantages of the present invention more clearly understood, the following detailed description of the specific embodiments of the present invention is given in conjunction with the following examples. The following is merely an example and illustration of the concept of the present invention. Any modification, supplement, or replacement of the specific embodiments described by those skilled in the art shall fall within the scope of protection of the present invention.
[0030] The above preparation method of the present invention is described below through specific examples and comparative examples.
[0031] Example 1
[0032] A method for preparing bismuth hydroxide material, the specific steps are as follows:
[0033] S1. Preparation of micellar solution: 1 g of polyethylene glycol-polylactic acid (PEG-PLA) block copolymer with a molecular weight of 2000 was dissolved in 10 mL of dichloromethane and stirred evenly. Separately, 6 mL of concentrated ammonia and 60 mL of anhydrous ethanol were stirred evenly. The dichloromethane solution of PEG-PLA was slowly added dropwise to the ammonia-ethanol mixed solution. Stirring was continued during the addition. After the addition was completed, stirring was continued for 30 minutes. The dichloromethane was removed by volatilization to form a stable PEG-PLA micelle system to obtain a micellar solution.
[0034] S2. Synthesis of bismuth hydroxide: At room temperature, 0.25 g of anhydrous bismuth nitrate was divided into 5 equal portions, and one portion was added to 60 mL of the micellar solution described in step S1 every 10 minutes, and the reaction was continued with stirring for 1 hour;
[0035] S3. Product separation and purification: After the reaction is completed, the reaction mixture is centrifuged at a speed of 8000 r / min for 8 minutes, the precipitate is collected, and the precipitate is washed multiple times with deionized water. After each wash, the precipitate is centrifuged, and the washing-centrifugation operation is repeated three times. The washed bismuth hydroxide precipitate is then placed in a vacuum drying oven to obtain a bismuth hydroxide material.
[0036] The bismuth hydroxide material is nano-scale particles with a particle size distribution between 85 and 175 nm. The particles have a spherical structure and excellent dispersion. The material purity is 98.75%.
[0037] Example 2
[0038] A method for preparing bismuth hydroxide material, the specific steps are as follows:
[0039] S1. Preparation of micellar solution: 2 g of polyethylene glycol-polylactic acid (PEG-PLA) block copolymer with a molecular weight of 5000 was dissolved in 20 mL of dichloromethane and stirred evenly. Separately, 80 mL of concentrated ammonia and 80 mL of anhydrous ethanol were stirred evenly. The dichloromethane solution of PEG-PLA was slowly added dropwise to the ammonia-ethanol mixed solution. Stirring was continued during the addition. After the addition was completed, stirring was continued for 40 minutes to remove the dichloromethane by volatilization to form a stable PEG-PLA micelle system to obtain a micellar solution.
[0040] S2. Synthesis of bismuth hydroxide: At room temperature, 0.35 g of anhydrous bismuth nitrate was divided into 5 equal portions, and one portion was added to 70 mL of the micellar solution described in step S1 every 15 minutes. The reaction was continued with stirring for 1.5 hours.
[0041] S3. Product separation and purification: After the reaction is completed, the reaction mixture is centrifuged at a speed of 10,000 r / min for 9 minutes, and the precipitate is collected. The precipitate is washed multiple times with deionized water, and centrifuged after each wash. The washing-centrifugation operation is repeated three times. The washed bismuth hydroxide precipitate is then placed in a vacuum drying oven at 50° C. and dried for 10 hours to obtain a bismuth hydroxide material.
[0042] The bismuth hydroxide material is nano-scale particles with a particle size distribution between 85 and 175 nm. The particles have a spherical structure and excellent dispersion. The material purity is 99.24%.
[0043] Example 3
[0044] A method for preparing bismuth hydroxide material, the specific steps are as follows:
[0045] S1. Preparation of micellar solution: 3 g of polyethylene glycol-polylactic acid (PEG-PLA) block copolymer with a molecular weight of 10,000 was dissolved in 30 mL of dichloromethane and stirred evenly. Separately, 10 mL of concentrated ammonia and 100 mL of anhydrous ethanol were stirred evenly, and then the dichloromethane solution of PEG-PLA was slowly added dropwise to the ammonia-ethanol mixed solution. Stirring was continued during the addition. After the addition was completed, stirring was continued for 30-60 minutes to remove the dichloromethane by volatilization to form a stable PEG-PLA micelle system to obtain a micellar solution.
[0046] S2. Synthesis of bismuth hydroxide: At room temperature, 0.5 g of anhydrous bismuth nitrate was divided into 5 equal portions, and one portion was added to 80 mL of the micellar solution described in step S1 every 20 minutes, and the reaction was continued with stirring for 2 hours;
[0047] S3. Product separation and purification: After the reaction is completed, the reaction mixture is centrifuged at a speed of 12000 r / min for 10 min, and the precipitate is collected. The precipitate is washed multiple times with deionized water, and centrifuged after each wash. The washing-centrifugation operation is repeated three times. The washed bismuth hydroxide precipitate is then placed in a vacuum drying oven at 60° C. and dried for 8 h to obtain a bismuth hydroxide material.
[0048] The bismuth hydroxide material is nano-scale particles with a particle size distribution between 85 and 175 nm. The particles have a spherical structure and excellent dispersion. The material purity is 99.32%.
[0049] Comparative Example
[0050] A method for preparing bismuth hydroxide material, the specific steps are as follows:
[0051] S1. Prepare alkaline solution: stir 6 mL of concentrated ammonia and 60 mL of anhydrous ethanol to obtain an alkaline solution;
[0052] S2. Synthesis of bismuth hydroxide: At room temperature, 0.25 g of anhydrous bismuth nitrate was divided into 5 portions, and one portion was added to 60 mL of the micellar solution described in step S1 every 10 minutes. After the addition of all the materials was completed, the reaction was continued with stirring for 1 hour;
[0053] S3. Product separation and purification: After the reaction is completed, the reaction mixture is centrifuged at a speed of 10,000 r / min for 9 minutes, and the precipitate is collected. The precipitate is washed multiple times with deionized water, and centrifuged after each wash. The washing-centrifugation operation is repeated three times. The washed bismuth hydroxide precipitate is then placed in a vacuum drying oven at 50° C. and dried for 10 hours to obtain a bismuth hydroxide material.
[0054] Figure 1 This is a scanning electron microscope (SEM) photograph of the bismuth hydroxide material prepared in Example 1. From the SEM picture, it can be seen that the bismuth hydroxide material is nano-scale particles with a spherical structure.
[0055] Figure 2 This is a statistical diagram of the particle size of the sample in Example 1. The statistical distribution of the bismuth hydroxide particle size is between 85 and 175 nm, mainly distributed between 100 and 120 nm. The distribution of the particle size is narrow, which indicates that the synthesized particles have good uniformity.
[0056] Figure 3 is a scanning electron microscope photograph (SEM) of the bismuth hydroxide material prepared in the comparative example, Figure 1 By comparison, it can be seen that the bismuth hydroxide particles synthesized by conventional methods are severely agglomerated and have poor size uniformity.
[0057] Figure 4 This is a photo of the bismuth hydroxide powder prepared in Example 1; it can be seen that the bismuth hydroxide material is a white powder, which is fine and loose, without obvious agglomeration of powder.
[0058] Figure 5 It is the thermogravimetric analysis curve (TG) of the bismuth hydroxide material prepared in Example 1. It can be seen that it begins to decompose when the temperature reaches about 200°C, and the decomposition process is relatively concentrated, indicating that the impurity content in the bismuth hydroxide material is very low, which also shows that its purity is very high. By continuing to heat and decompose until stable, the decomposition rate reaches 10.25%, which is that Bi(OH)3 is completely converted into Bi2O3, which is very close to the theoretical loss rate of 10.38%. The purity is calculated according to the actual loss rate. Let the sample purity be x, then: theoretical weight loss rate × x = actual loss rate. It can be calculated that the purity of the bismuth hydroxide material in Example 1 of the present invention is 98.75%.
Claims
1. A method for preparing a bismuth hydroxide material, characterized in that: The preparation method steps are as follows: S1. Preparation of micelle solution: dissolving polyethylene glycol-polylactic acid block copolymer in dichloromethane and stirring evenly; separately, stirring evenly with concentrated ammonia water and anhydrous ethanol at a mass fraction of 25-28%, and then slowly dropping the dichloromethane solution of the polyethylene glycol-polylactic acid block copolymer into the ammonia-ethanol mixed solution; stirring continuously during the dropping process; stirring continuously for 30-60 minutes after the dropping is completed; removing dichloromethane by volatilization to form a stable polyethylene glycol-polylactic acid block copolymer micelle system, thereby obtaining a micelle solution; S2. Synthesis of bismuth hydroxide: adding a bismuth salt to the micellar solution of step S1 at room temperature. After the addition is complete, continue stirring and reacting for 1 to 2 hours; S3. Product separation and purification: After the reaction is completed, the reaction mixture is centrifuged at a speed of 8000-12000 r / min for 8-10 minutes, and the precipitate is collected and washed multiple times with deionized water. After each wash, the precipitate is centrifuged and the washing-centrifugation operation is repeated three times. The washed bismuth hydroxide precipitate is then dried in a vacuum drying oven to obtain a bismuth hydroxide material.
2. The method for preparing bismuth hydroxide material according to claim 1, wherein The molecular weight of the polyethylene glycol-polylactic acid block copolymer described in step S1 is 2000~10000.
3. The method for preparing bismuth hydroxide material according to claim 1, wherein The amounts of the polyethylene glycol-polylactic acid block copolymer, dichloromethane, concentrated aqueous ammonia, and anhydrous ethanol added in step S1 are 1-3 g, 10-30 mL, 6-10 mL, and 60-100 mL, respectively.
4. The method for preparing the bismuth hydroxide material according to claim 1, wherein In step S2, the bismuth salt is bismuth nitrate pentahydrate, and the added amounts of the bismuth salt and the micelle solution are 0.25-0.5 g and 60-80 mL, respectively. The dropping speed is controlled to 1 mL / min.
5. The method for preparing the bismuth hydroxide material according to claim 1, wherein The bismuth salt is added to the micelles in step S2 by dividing the bismuth salt into 5 equal parts and adding the bismuth salt once every 10 to 20 minutes.
6. The method for preparing bismuth hydroxide material according to claim 1, wherein The drying temperature of the vacuum drying oven in step S4 is 40-60° C., and the drying time is 8-12 hours.