Low-temperature preparation method of high-crystallinity bismuth vanadate nano-powder
By preparing bismuth vanadate nanopowder at low temperature, the combination of precipitation reaction and crystallization reaction is used to solve the complex problems of high-temperature roasting and hydrothermal processes, and the efficient and environmentally friendly preparation of bismuth vanadate nanopowder is achieved, satisfying the market Demand for high crystallinity and size requirements.
Patent Information
- Application Number
- CN202411184482.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-08-27
- Publication Date
- 2024-12-10
AI Technical Summary
The existing bismuth vanadate powder preparation process requires high temperature calcination and long-term hydrothermal reaction, resulting in complex processes, high energy consumption and large particle size, which cannot meet the requirements of efficient preparation and environmental protection.
By dissolving the vanadium and bismuth sources in the corresponding solution, adjusting the pH value for precipitation reaction, forming an amorphous gel, and performing crystallization reaction in a low-temperature environment to avoid high-temperature calcination and hydrothermal processes, and directly obtaining high crystallinity bismuth vanadate nanopowder.
The preparation of bismuth vanadate nanopowders is achieved at low temperature, simplifying the process and reducing costs, and obtaining nanopowders with high crystallinity, uniform particle morphology and small size. They are suitable for industrial production, and have bright colors and meet market demand.
Smart Images
Figure CN119100451A_ABST
Abstract
Description
Technical Field
[0001] The invention relates to the technical field of inorganic pigment nanopowders, and in particular to a low-temperature preparation method of high-crystallinity bismuth vanadate nanopowders. Background Art
[0002] Bismuth vanadate is a high-performance, green and environmentally friendly yellow inorganic pigment that is widely used in fields with high requirements for pigment performance and environmental protection, such as high-end coatings, plastics, paints, etc.
[0003] The preparation methods of bismuth vanadate pigment nanopowders mainly include high-temperature hydrothermal method, chemical precipitation-roasting method, reflux-roasting method, solid phase calcination method, etc. Patent CN106747437A discloses a preparation method of bismuth molybdate vanadate pigment. First, ammonium metavanadate and bismuth oxide are evenly mixed to obtain a mixture, and then four steps of roasting are performed. The first step is to keep warm at 180℃-240℃ for 80-120min, the second step is to keep warm at 550-600℃ for 8-11h, the third step is to keep warm at 1050℃-1200℃ for 3-6h, and the fourth step is to keep warm at 900℃-1000℃ for 4-8h, and finally obtain a high-quality and high-temperature resistant bismuth molybdate vanadate pigment. U.S. Patent US8004332 discloses a preparation process of an inorganic pigment. First, a bismuth vanadate precursor is obtained by a chemical precipitation method. After drying, the bismuth vanadate pigment powder is obtained by keeping warm in a muffle furnace at 550℃ for 1h. CN114920293A discloses a method for preparing a monoclinic scheelite-type spherical bismuth vanadate, in which the prepared amorphous bismuth vanadate colloid is transferred into a microwave digestion instrument and redispersed in water, and then kept warm for 6 hours in a hydrothermal environment at 170°C, and after solid-liquid separation, dried at 90°C to obtain nano-scale monoclinic scheelite-type bismuth vanadate crystals. Patent CN103449518 A discloses a lanthanum, yttrium and cerium co-doped bismuth vanadate inorganic pigment and a preparation method thereof. The method utilizes microwave radiation heating to heat the reaction mixture to 160°C-220°C, and after a hydrothermal reaction for 1-3 hours, a bismuth vanadate pigment with excellent coloring properties is obtained.
[0004] The above-mentioned bismuth vanadate powder preparation process usually requires high temperature and long-term roasting and hydrothermal reaction, which is complex and energy-intensive, greatly increasing the preparation cost of bismuth vanadate powder. In addition, due to high-temperature roasting and long-term aqueous phase reaction, the size of bismuth vanadate powder is usually hundreds of nanometers or even micrometers. The hiding power and coloring power are difficult to meet the requirements. Summary of the invention
[0005] In order to solve the problem of bismuth vanadate powder, the purpose of the present invention is to provide a low-temperature preparation method of high-crystallinity bismuth vanadate nanopowder to solve the problems of high-temperature roasting, complex process, high energy consumption and large particle size in the preparation process of the prior art.
[0006] To achieve the above object, the present invention is implemented through the following technical solutions:
[0007] The present invention provides a low-temperature preparation method of high-crystallinity bismuth vanadate nanopowder, the method comprising the following steps:
[0008] (1) dissolving a vanadium source in a sodium hydroxide solution to obtain a solution A, and dissolving a bismuth source in a nitric acid solution to obtain a solution B;
[0009] (2) mixing solution A and solution B, adjusting the pH of the solution system to 3.0-5.0, performing a precipitation reaction, separating the mixed solution into a solid-liquid state and washing it with deionized water to obtain an amorphous Bi(III)-V(V)-oxide-hydroxide gel;
[0010] (3) subjecting the Bi(III)-V(V)-oxide-hydroxide gel obtained in step (2) to crystallization reaction for 2-10 hours in an environment with a temperature of 80-140° C. and a relative humidity of 40%-100%, and grinding to obtain bismuth vanadate nanopowder.
[0011] In the above technical solution, further, the vanadium source is one of vanadium pentoxide, sodium metavanadate, and ammonium metavanadate; the bismuth source is one of bismuth nitrate pentahydrate and bismuth oxide.
[0012] In the above technical solution, further, the concentrations of the sodium hydroxide solution and the nitric acid solution are both 1-3 mol / L.
[0013] In the above technical solution, further, the concentration of vanadium in solution A and the concentration of bismuth in solution B are both 0.4-1 mol / L.
[0014] In the above technical solution, further, the molar ratio of vanadium in solution A to bismuth in solution B is 1:1.
[0015] In the above technical solution, further, solution A and solution B are mixed under stirring by a high-speed shearing machine, the temperature of the precipitation reaction is 35-60° C., and the reaction time is 0.5-1.5 h.
[0016] The beneficial effects of the present invention are:
[0017] (1) The present invention mixes an alkaline solution of vanadium and an acidic solution of bismuth under stirring in a high-speed shearing machine, and after chemical precipitation reaction, obtains an amorphous Bi(III)-V(V)-oxide-hydroxide solid phase gel; the prepared gel is placed in an environment with a certain temperature and relative humidity for solid phase crystallization reaction to obtain a bismuth vanadate nanopowder with high crystallinity. The present invention avoids high-temperature calcination or high-temperature and high-pressure hydrothermal reaction, and directly crystallizes and dries the solid phase amorphous gel at low temperature at the same time, thereby obtaining a bismuth vanadate nanopowder with high crystallinity, uniform particle morphology, and a size between 90-150nm, and the color tone is bright green-yellow.
[0018] (2) The present invention eliminates the need for powder drying and high-temperature calcination or hydrothermal processes, simplifies the preparation process, is more suitable for industrial preparation, and significantly reduces the preparation cost of bismuth vanadate nanopowder. BRIEF DESCRIPTION OF THE DRAWINGS
[0019] Figure 1 XRD patterns of the samples in Comparative Examples 1-2 and Examples 1-4;
[0020] Figure 2 These are scanning electron microscope images of samples of Examples 1-4, a is Example 1, b is Example 2, c is Example 3, and d is Example 4. DETAILED DESCRIPTION
[0021] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the specific embodiments required to be used in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the specific embodiments described below are some implementation methods of the present invention. For ordinary technicians in this field, other specific embodiments can be obtained based on these specific embodiments without paying creative work.
[0022] The components of the embodiments of the present invention generally described and shown in the specific embodiments herein can be arranged and designed in countless different configurations. Therefore, the following detailed description of the embodiments of the present invention provided in the specific embodiments is not intended to limit the scope of the invention claimed, but merely represents selected embodiments of the present invention.
[0023] Example 1
[0024] (1) Weighing 194 g of bismuth nitrate pentahydrate, adding it to 1 L of nitric acid solution (1 mol / L), and stirring it magnetically until it is completely dissolved, to obtain solution A; adding 48.8 g of sodium metavanadate to 1 L of sodium hydroxide solution (1 mol / L), and stirring it magnetically until it is completely dissolved, to obtain solution B;
[0025] (2) adding solution B to solution A at a speed of 3000 rpm on a high-speed shearing machine, raising the temperature of the mixed solution to 50° C., adjusting the pH to 4.5, reacting for 0.5 h under the shear force generated by the continuous high-speed shearing machine, and subjecting the mixed solution to solid-liquid separation to obtain an amorphous Bi(III)-V(V)-oxide-hydroxide solid phase gel;
[0026] (3) After washing three times with deionized water, the amorphous solid phase gel was placed in an environment with a temperature of 100° C. and a humidity of 40% for 3 hours to undergo a crystallization reaction, and then dried and ground to obtain bismuth vanadate nanopowder.
[0027] As shown in Table 1, the chromaticity values Lab of the bismuth vanadate nanopowder prepared in Example 1 are L=87.27, a*=-1.22, and b*=67.56, respectively. Compared with the comparative example, it has higher brightness L value and yellowness b value, and the powder is greenish yellow, which meets market demand.
[0028] Figure 1 The characteristic diffraction peaks at 18.9°, 28.8°, 28.9° and 30.5° in the XRD spectrum of Example 1 match the monoclinic scheelite phase BiVO4 (JCPDS card No.14-0688), proving that the prepared sample is monoclinic scheelite phase BiVO4. Figure 2 The scanning electron microscope image of Example 1 proves that the prepared sample has uniform morphology and a size between 90nm and 150nm.
[0029] Example 2
[0030] (1) Weighing 139.8 g of bismuth oxide, adding it to 1 L of nitric acid solution (1.5 mol / L), stirring it magnetically until it is completely dissolved, obtaining solution A; adding 70.2 g of ammonium metavanadate to 1 L of sodium hydroxide solution (1.5 mol / L), stirring it magnetically until it is completely dissolved, obtaining solution B;
[0031] (2) adding solution B to solution A at a speed of 3000 rpm on a high-speed shearing machine, raising the temperature of the mixed solution to 60° C., adjusting the pH to 5, reacting for 0.5 h under the shear force generated by the continuous high-speed shearing machine, and performing solid-liquid separation on the mixed solution to obtain an amorphous Bi(III)-V(V)-oxide-hydroxide solid phase gel;
[0032] (3) After washing three times with deionized water, the amorphous solid phase gel was placed in an environment with a temperature of 80° C. and a humidity of 60% for 8 hours to undergo a crystallization reaction, and then dried and ground to obtain bismuth vanadate nanopowder.
[0033] As shown in Table 1, the chromaticity values Lab of the bismuth vanadate nanopowder prepared in Example 2 are L=86.43, a*=-1.03, and b*=65.76, respectively. Compared with the comparative example, it has higher brightness L value and yellowness b value, and the powder is greenish yellow, which meets market demand.
[0034] Figure 1 The XRD spectrum of Example 2 matches that of monoclinic scheelite phase BiVO4 (JCPDS card No. 14-0688), proving that the prepared sample is monoclinic scheelite phase BiVO4. Figure 2 The scanning electron microscope image of Example 2 proves that the prepared samples have uniform morphology and sizes are all below 120 nm.
[0035] Example 3
[0036] (1) 776 g of bismuth nitrate pentahydrate was weighed and added to 2 L of nitric acid solution (2 mol / L), and magnetically stirred until completely dissolved to obtain solution A; 145.5 g of vanadium pentoxide was added to 2 L of sodium hydroxide solution (2 mol / L), and magnetically stirred until completely dissolved to obtain solution B;
[0037] (2) adding solution B to solution A at a high-speed shearing machine at a speed of 3000 rpm, raising the temperature of the mixed solution to 40° C., adjusting the pH to 4, reacting for 1 hour under the shear force generated by the high-speed shearing machine, and performing solid-liquid separation on the mixed solution to obtain an amorphous Bi(III)-V(V)-oxide-hydroxide solid phase gel;
[0038] (3) After washing three times with deionized water, the amorphous solid phase gel was placed in an environment with a temperature of 140° C. and a humidity of 80% for 2 hours to undergo a crystallization reaction, and then dried and ground to obtain bismuth vanadate nanopowder.
[0039] As shown in Table 1, the chromaticity values Lab of the bismuth vanadate nanopowder prepared in Example 3 are L=85.66, a*=-1.33, and b*=65.45, respectively. Compared with the comparative example, it has a higher brightness L value and yellowness b value, and the powder is greenish yellow, which meets market demand.
[0040] Figure 1 The XRD spectrum of Example 3 matches that of monoclinic scheelite phase BiVO4 (JCPDS card No. 14-0688), proving that the prepared sample is monoclinic scheelite phase BiVO4. Figure 2 The scanning electron microscope image of Example 3 proves that the prepared sample has uniform morphology and a size between 90nm and 110nm.
[0041] Example 4
[0042] (1) 1940 g of bismuth nitrate pentahydrate was weighed and added to 4 L of nitric acid solution (3 mol / L), and magnetically stirred until completely dissolved to obtain solution A; 363.8 g of vanadium pentoxide was added to 4 L of sodium hydroxide solution (3 mol / L), and magnetically stirred until completely dissolved to obtain solution B;
[0043] (2) adding solution B to solution A at a speed of 3000 rpm on a high-speed shearing machine, raising the temperature of the mixed solution to 35° C., adjusting the pH to 3.0, reacting for 1.5 h under the shear force generated by the continuous high-speed shearing machine, and performing solid-liquid separation on the mixed solution to obtain an amorphous Bi(III)-V(V)-oxide-hydroxide solid phase gel;
[0044] (3) After washing three times with deionized water, the amorphous solid phase gel was placed in an environment with a temperature of 120° C. and a humidity of 100% for 3 hours to undergo a crystallization reaction, and then dried and ground to obtain bismuth vanadate nanopowder.
[0045] As shown in Table 1, the chromaticity values Lab of the bismuth vanadate nanopowder prepared in Example 4 are L=86.39, a*=-1.49, and b*=66.07, respectively. Compared with the comparative example, it has a higher brightness L value and yellowness b value, and the powder is greenish yellow, which meets market demand.
[0046] Figure 1 The XRD spectrum of Example 4 matches that of monoclinic scheelite phase BiVO4 (JCPDS card No. 14-0688), proving that the prepared sample is monoclinic scheelite phase BiVO4. Figure 2 The scanning electron microscope image of Example 4 proves that the prepared sample has uniform morphology and a size below 110 nm.
[0047] Comparative Example 1
[0048] (1) Weighing 194 g of bismuth nitrate pentahydrate, adding it to 1 L of nitric acid solution (1 mol / L), stirring it magnetically until it is completely dissolved, to obtain solution A; adding 48.8 g of sodium metavanadate to 1 L of sodium hydroxide solution (1 mol / L), stirring it magnetically until it is completely dissolved, to obtain solution B;
[0049] (2) adding solution B to solution A at a speed of 3000 rpm on a high-speed shearing machine, raising the temperature of the mixed solution to 50° C., adjusting the pH to 4.5, reacting for 1 hour under the shear force generated by the continuous high-speed shearing machine, and performing solid-liquid separation on the mixed solution to obtain an amorphous Bi(III)-V(V)-oxide-hydroxide solid phase gel;
[0050] (3) After washing three times with deionized water, the amorphous solid phase gel was placed in an environment with a temperature of 100° C. and a humidity of 10% for 5 h, and then dried and ground to obtain a sample.
[0051] As shown in Table 1, the chromaticity values Lab of the sample of Comparative Example 1 are L=76.75, a*=16.44, b*=43.64. The powder is reddish yellow.
[0052] Figure 1 There is no obvious characteristic peak in the XRD spectrum of Comparative Example 1, which proves that the sample still has an amorphous structure.
[0053] Comparative Example 2
[0054] (1) Weighing 194 g of bismuth nitrate pentahydrate, adding it to 1 L of nitric acid solution (1 mol / L), stirring it magnetically until it is completely dissolved, to obtain solution A, and adding 48.8 g of sodium metavanadate to 1 L of sodium hydroxide solution (1 mol / L), to obtain solution B;
[0055] (2) adding solution B to solution A at a speed of 3000 rpm on a high-speed shearing machine, raising the temperature of the mixed solution to 50° C., adjusting the pH to 4.5, reacting for 1 hour under the shear force generated by the continuous high-speed shearing machine, and performing solid-liquid separation on the mixed solution to obtain an amorphous Bi(III)-V(V)-oxide-hydroxide solid phase gel;
[0056] (3) After washing three times with deionized water, the amorphous solid phase gel was placed in an environment with a temperature of 80° C. and a humidity of 20% for 6 h, and then dried and ground to obtain a sample.
[0057] As shown in Table 1, the chromaticity values Lab of the sample prepared in Comparative Example 2 are L=75.10, a*=16.65, b*=40.78, respectively. The powder is reddish yellow. Figure 1 There is no obvious characteristic peak in the XRD spectrum of Comparative Example 2, proving that the sample still has an amorphous structure.
[0058] Table 1 Chroma values Lab of samples in Comparative Examples 1-2 and Examples 1-4
[0059]
[0060] It should be understood that the application of the present invention is not limited to the above examples. For ordinary technicians in this field, they can make improvements or changes based on the above description. All these improvements and changes should fall within the scope of protection of the claims attached to the present invention.
Claims
1. A low-temperature preparation method for high-crystallinity bismuth vanadate nanopowder, characterized in that: The method comprises the following steps: (1) dissolving a vanadium source in a sodium hydroxide solution to obtain a solution A, and dissolving a bismuth source in a nitric acid solution to obtain a solution B; (2) mixing solution A and solution B, adjusting the pH of the solution system to 3.0-5.0, performing a precipitation reaction, separating the mixed solution into a solid-liquid state and washing it with deionized water to obtain an amorphous Bi(III)-V(V)-oxide-hydroxide gel; (3) subjecting the Bi(III)-V(V)-oxide-hydroxide gel obtained in step (2) to crystallization reaction for 2-10 hours in an environment with a temperature of 80-140° C. and a relative humidity of 40%-100%, and grinding to obtain bismuth vanadate nanopowder.
2. The low temperature preparation method according to claim 1, characterized in that: The vanadium source is one of vanadium pentoxide, sodium metavanadate, and ammonium metavanadate; the bismuth source is one of bismuth nitrate pentahydrate and bismuth oxide.
3. The low temperature preparation method according to claim 1, characterized in that: The concentrations of the sodium hydroxide solution and the nitric acid solution are both 1-3 mol / L.
4. The low temperature preparation method according to claim 1, characterized in that: The concentrations of vanadium in solution A and bismuth in solution B are both 0.4-1 mol / L.
5. The low temperature preparation method according to claim 1, characterized in that: The molar ratio of vanadium in solution A to bismuth in solution B is 1:
1.
6. The low temperature preparation method according to claim 1, characterized in that: Solution A and solution B are mixed under stirring by a high-speed shearing machine, the precipitation reaction temperature is 35-60° C., and the reaction time is 0.5-1.5 h.