Bismuth oxychloride powder as well as preparation method and application thereof

Abstract

The invention provides bismuth oxychloride powder, the bismuth oxychloride powder is in a sheet shape, and the particle size D50 of the bismuth oxychloride powder is 1-3 microns. The provided small-particle bismuth oxychloride can be widely applied to photocatalysis and environmental pollution treatment, cosmetics, functional coatings, battery materials and biological medicines. The invention also provides a preparation method of the bismuth oxychloride powder. The preparation method comprises the following steps: preparing a bismuth salt solution from bismuth nitrate and hydrochloric acid; the preparation method comprises the following steps: by taking a hydrochloric acid solution as a base solution, adding a bismuth salt solution and a sodium hydroxide solution into the base solution while stirring, controlling the pH value and the feeding rate of the bismuth salt solution, carrying out a heating hydrolysis reaction, and after the reaction is finished, carrying out solid-liquid separation, washing and drying to obtain the flaky bismuth oxychloride powder with the particle size D50 of 1-3 microns. The preparation method can be used for directly synthesizing the flaky bismuth oxychloride powder with smaller particle size and uniform size and morphology, and is simple, simple and convenient to operate, free of a surfactant, high in conversion rate and easy for industrial production.

Description

Technical Field

[0001] The invention belongs to the technical field of inorganic synthesis, and in particular relates to small-sized bismuth oxychloride powder, a preparation method and application thereof. Background Art

[0002] Bismuth oxychloride is a basic bismuth salt with the molecular formula BiOCl. It is a tetragonal, silvery-white, flaky, shiny crystalline powder with a silvery-white pearlescent luster. It is a new, environmentally friendly, green pearlescent pigment. Traditional pearlescent pigments include mica titanium pearlescent pigments and basic lead carbonate. Mica titanium pearlescent pigments suffer from light scattering caused by the steps and edge thickness of their layers, which reduces their pearlescent effect. Furthermore, the removal cost of the colored impurity ions contained in the mica is high. Basic lead carbonate, on the other hand, contains the highly toxic substance lead, and long-term use poses a certain risk to human health. Bismuth oxychloride avoids the toxicity of lead carbonate, a traditional inorganic pearlescent pigment, and overcomes the drawbacks of mica titanium pearlescent pigments, such as their thick structure and complex pretreatment process. It offers excellent properties such as non-toxicity, good adhesion, corrosion resistance, and excellent color. It holds broad market prospects in cosmetics, automotive interior materials, and apparel accessories.

[0003] The preparation methods of bismuth oxychloride mainly include traditional hydrolysis, hydrothermal and high-temperature solid-phase methods. Among them, the hydrothermal method has high equipment cost and complex operation. The particle size of bismuth oxychloride prepared by the high-temperature solid-phase method is difficult to control, and the particle uniformity is poor. The traditional hydrolysis method can prepare bismuth oxychloride. By regulating the reaction conditions and adding surfactants, bismuth oxychloride crystals with controllable shape and particle size can be prepared. This method has low equipment cost and simple operation. For example, CN103303975B discloses a method for preparing bismuth oxychloride. It uses a certain concentration of bismuth hydrochloride as raw material, controls the temperature, time, stirring rate and other parameters during the reaction process, and controls the system pH below 2.5 by adding water. A bismuth oxychloride powder with good dispersibility and controllable morphology is prepared. However, the bismuth oxychloride crystals obtained by this method have a large diameter, between 5 and 15 microns. Compared to larger bismuth oxychloride crystals, small-particle BiOCl powders are easier to evenly disperse in cosmetic matrices (such as foundation, eye shadow, lipstick, and nail polish), providing a finer, more natural pearlescent effect and improving skin feel and product texture. Furthermore, small-particle bismuth oxychloride can act as a physical sunscreen, providing additional UV protection while imparting a pearlescent aesthetic to the product. Summary of the Invention

[0004] In view of the above technical problems, the purpose of the present invention is to provide small-sized bismuth oxychloride powder and its preparation method and application.

[0005] To achieve the above objectives, the present invention proposes the following solutions: The present invention adopts cheap bismuth salt as raw material and utilizes hydrolysis method to synthesize bismuth oxychloride powder with uniform and controllable morphology and small particle size of only 1 to 3 microns.

[0006] In a first aspect, a bismuth oxychloride powder is provided. The bismuth oxychloride powder has a flake-like morphology and a particle size D50 of 1 to 3 microns.

[0007] In a second aspect, a method for preparing bismuth oxychloride powder is provided, comprising: Prepare a bismuth salt solution with bismuth nitrate and hydrochloric acid; With hydrochloric acid solution as the base liquid, bismuth salt solution and sodium hydroxide solution were added to the base liquid under stirring conditions, the pH value was controlled to be 1-1.5, and the feeding rate of bismuth salt solution was 0.033-0.05V 底液 / min, and perform heating and hydrolysis reaction. After the reaction, solid-liquid separation, washing and drying are performed to obtain flaky bismuth oxychloride powder with a particle size D50 of 1-3 μm.

[0008] Furthermore, the temperature of the heating hydrolysis reaction is 60-70°C.

[0009] Furthermore, the stirring speed is 300-400 rpm.

[0010] Furthermore, the heating hydrolysis reaction lasts for 30 to 65 minutes.

[0011] Furthermore, the bismuth salt solution is prepared by using a bismuth nitrate solution with a bismuth content of 24-26% and hydrochloric acid with a concentration of 31-33% in a volume ratio of 1-1.5:1.

[0012] Furthermore, the pH value of the base liquid is 1.0-1.4; and the volume of the base liquid is 1 / 2-2 / 3 times the volume of the reaction container.

[0013] In a third aspect, the present invention provides applications of the aforementioned bismuth oxychloride powder or the bismuth oxychloride powder prepared by the aforementioned preparation method in photocatalysis and environmental pollution control, cosmetics, functional coatings, battery materials, and biomedicine.

[0014] Compared with the prior art, the present invention has the following beneficial effects: To address the problems of large bismuth oxychloride particles produced by existing hydrolysis reaction synthesis technology, poor uniformity in particle size and morphology, complex processes, and high costs, the preparation method provided by the present invention can directly synthesize flaky bismuth oxychloride powder with smaller particle size, uniform size and morphology, and a bismuth content of 79% or more. The method is simple and easy to operate, does not require surfactants, has a high conversion rate (>95%), and is easy to industrialize. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] 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 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.

[0016] Figure 1 This is the SEM image of bismuth oxychloride prepared in Example 1.

[0017] Figure 2 This is the SEM image of bismuth oxychloride prepared in Example 2.

[0018] Figure 3 This is the SEM image of bismuth oxychloride prepared in Example 3. DETAILED DESCRIPTION

[0019] Some embodiments of the present invention provide bismuth oxychloride powder, wherein the bismuth oxychloride has a flake-like morphology and a particle size D50 of 1 to 3 microns.

[0020] It is worth noting that the particle size D50 here is the maximum lateral dimension of the flake bismuth oxychloride powder on a two-dimensional plane.

[0021] Some embodiments of the present invention provide a method for preparing the above-mentioned bismuth oxychloride powder, comprising: Prepare a bismuth salt solution with bismuth nitrate and hydrochloric acid; With hydrochloric acid solution as the base liquid, bismuth salt solution and sodium hydroxide solution were added to the base liquid under stirring conditions, the pH value was controlled to be 1-1.5, and the feeding rate of bismuth salt solution was 0.033-0.05V 底液 / min, and perform heating and hydrolysis reaction. After the reaction, solid-liquid separation, washing and drying are performed to obtain flaky bismuth oxychloride powder with a particle size D50 of 1-3 μm.

[0022] After research, the applicant found that by using a dilute hydrochloric acid solution as the base liquid, feeding a bismuth salt solution mixed with bismuth nitrate and hydrochloric acid and a sodium hydroxide solution as raw materials into the base liquid in parallel to carry out a thermal hydrolysis reaction, and strictly controlling factors such as the feed rate and pH of the bismuth salt solution, on the one hand, it is possible to ensure the preparation of bismuth oxychloride powder with a flake morphology and good size and morphology uniformity with a particle size D50 of 1 to 3 microns, and on the other hand, it can also ensure a high conversion rate.

[0023] In the above preparation method, the pH value is controlled to be 1-1.5 during the heating hydrolysis reaction, for example, 1, 1.1, 1.2, 1.3, 1.4, 1.5, etc.

[0024] In the above preparation method, the feeding rate of the bismuth salt solution is 0.033~0.05V底液 / min, for example 0.033V 底液 / min, 0.035V 底液 / min, 0.038V 底液 / min, 0.04V 底液 / min, 0.042V 底液 / min, 0.045V 底液 / min, 0.048V 底液 / min, 0.05V 底液 / min, etc., where V 底液 is the volume of the base liquid.

[0025] In some preferred embodiments, the temperature of the heating hydrolysis reaction is 60-70° C. The applicant has found through research that controlling the heating hydrolysis reaction temperature within this temperature range can improve the conversion rate while ensuring the size of the bismuth oxychloride particles.

[0026] In some preferred embodiments, the stirring speed is 300-400 rpm. The applicant has discovered that optimizing the stirring speed can not only prevent crystal aggregation and growth but also avoid defects in crystal shape, thereby producing flaky bismuth oxychloride powder with smaller particle size and more uniform size and morphology.

[0027] In some preferred embodiments, the heating hydrolysis reaction lasts for 30 to 65 minutes, for example, 30 minutes, 35 minutes, 40 minutes, 45 minutes, 50 minutes, 55 minutes, 60 minutes, 65 minutes, etc.

[0028] In some preferred embodiments, the bismuth salt solution is prepared by using a bismuth nitrate solution with a bismuth content of 24-26% and hydrochloric acid with a concentration of 31-33% in a volume ratio of 1-1.5:1. The volume ratio can be 1:1, 1.1:1, 1.2:1, 1.3:1, 1.4:1, 1.5:1, etc.

[0029] In some preferred embodiments, the pH value of the base solution is 1-1.4, for example, 1, 1.1, 1.2, 1.3, 1.4, etc.

[0030] In some embodiments, the volume of the base liquid is 1 / 2 to 2 / 3 times the volume of the reaction container.

[0031] The aforementioned bismuth oxychloride powder or the bismuth oxychloride powder prepared by the aforementioned preparation method can be applied in the fields of photocatalysis and environmental pollution control, cosmetics, functional coatings, battery materials, biomedicine, etc. In photocatalysis and environmental pollution control, it can be used to degrade organic pollutants and reduce heavy metal ions. In cosmetics, it can provide a soft and bright pearly luster and have strong scattering and certain absorption capabilities for ultraviolet rays. In functional coatings, its high hardness and pearlescent effect can be used to enhance the wear resistance of the coating and impart an aesthetic pearly luster, such as in automotive coatings, furniture paints, and industrial decorative paints. In battery materials, it can improve the interfacial stability or ionic / electronic conductivity of positive electrode materials (such as lithium-rich manganese-based and lithium cobalt oxide). In biomedicine, it can be used as a drug delivery carrier, bioimaging, and tumor treatment.

[0032] To facilitate understanding of the present invention, the present invention will be described in more comprehensive and detailed form below in conjunction with the accompanying drawings and preferred embodiments. However, the protection scope of the present invention is not limited to the following specific embodiments.

[0033] Unless otherwise defined, all technical terms used hereinafter have the same meanings as those generally understood by those skilled in the art. The technical terms used herein are only for the purpose of describing specific embodiments and are not intended to limit the scope of protection of the present invention.

[0034] Unless otherwise specified, various raw materials, reagents, instruments and equipment used in the present invention can be purchased from the market or prepared by existing methods.

[0035] Example 1 Prepare 3L of hydrochloric acid base solution (add 25mL of hydrochloric acid to pure water), the pH value of the base solution is 1.17, and heat to 60°C; use 25.17% mass concentration of bismuth nitrate solution and 32.44% mass concentration of hydrochloric acid as raw materials, and prepare 144mL of a mixed solution according to a volume ratio of bismuth nitrate to hydrochloric acid of 1.2; add the mixed solution to the base solution at a liquid feeding rate of 120mL / min, the reaction temperature is 60°C, the stirring rate is 300rpm, the pH value is 1.0-1.2 during the liquid feeding and reaction process, and the reaction is carried out for 30min to obtain bismuth oxychloride crystals with a particle size D50 of 1-3μm, such as Figure 1 As shown by Figure 1 It can be seen that the obtained bismuth oxychloride has a flake-like morphology, a small particle size, and uniform size and morphology.

[0036] Example 2 Prepare 3L of hydrochloric acid base solution (add 25mL of hydrochloric acid to pure water), the pH value of the base solution is 1.15, and heat to 65°C; use 25.6% mass concentration of bismuth nitrate solution and 31.6% mass concentration of hydrochloric acid as raw materials, and prepare 144mL of mixed solution according to the volume ratio of bismuth nitrate to hydrochloric acid of 1.2; add the mixed solution to the base solution at a liquid feeding rate of 120mL / min, the reaction temperature is 65°C, the stirring rate is 400rpm, the pH value during the liquid feeding and reaction process is 1.1-1.3, and the small-sized bismuth oxychloride crystals obtained after 60min of reaction are as follows: Figure 2 As shown by Figure 2 It can be seen that the obtained bismuth oxychloride has a flake-like morphology, a small particle size, and uniform size and morphology.

[0037] Example 3 Prepare 3L of hydrochloric acid base solution (add 25mL of hydrochloric acid to pure water), the pH value of the base solution is 1.22, and heat to 60°C; use 25.82% mass concentration of bismuth nitrate solution and 32.1% mass concentration of hydrochloric acid as raw materials, and prepare 144mL of mixed solution according to the volume ratio of bismuth nitrate to hydrochloric acid of 1.5; add the mixed solution to the base solution at a liquid feeding rate of 144mL / min, the reaction temperature is 60°C, the stirring rate is 300rpm, the pH value during the liquid feeding and reaction process is 1.2~1.5, and the bismuth oxychloride crystals obtained after 60min of reaction are as follows Figure 3 As shown by Figure 3 It can be seen that the obtained bismuth oxychloride has a flake-like morphology, a small particle size, and uniform size and morphology.

[0038] Table 1 The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be regarded as within the scope of protection of the present invention.

Claims

1. Bismuth oxychloride powder, characterized in that The bismuth oxychloride has a flake-like morphology and a particle size D50 of 1 to 3 microns.

2. A method for preparing bismuth oxychloride powder, characterized in that: include: Prepare a bismuth salt solution with bismuth nitrate and hydrochloric acid; With hydrochloric acid solution as the base liquid, bismuth salt solution and sodium hydroxide solution were added to the base liquid under stirring conditions, the pH value was controlled to be 1-1.5, and the feeding rate of bismuth salt solution was 0.033-0.05V 底液 / min, and perform heating and hydrolysis reaction. After the reaction, solid-liquid separation, washing and drying are performed to obtain flaky bismuth oxychloride powder with a particle size D50 of 1-3 μm.

3. The method for preparing bismuth oxychloride powder according to claim 2, wherein The temperature of the heating hydrolysis reaction is 60-70°C.

4. The method for preparing bismuth oxychloride powder according to claim 2, wherein The stirring speed is 300-400 rpm.

5. The method for preparing bismuth oxychloride powder according to claim 2, wherein: The heating and hydrolysis reaction lasts for 30 to 65 minutes.

6. The method for preparing bismuth oxychloride powder according to claim 2, wherein: The bismuth salt solution is prepared by mixing a bismuth nitrate solution having a bismuth content of 24-26% and hydrochloric acid having a concentration of 31-33% in a volume ratio of 1-1.5:

1.

7. The method for preparing bismuth oxychloride powder according to claim 2, wherein: The pH value of the base liquid is 1.0-1.4; the volume of the base liquid is 1 / 2-2 / 3 times the volume of the reaction container.

8. Use of the bismuth oxychloride powder according to claim 1 or the bismuth oxychloride powder prepared by the preparation method according to any one of claims 2 to 7 in photocatalysis and environmental pollution control, cosmetics, functional coatings, battery materials, and biomedicine.

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