Nanoscale bismuth hydroxide as well as preparation method and application thereof

Abstract

The invention discloses nanoscale bismuth hydroxide as well as a preparation method and application thereof. The invention provides a preparation method of bismuth hydroxide. The preparation method comprises the following steps: reacting a mixture solution of a surfactant solution and a bismuth source solution at the temperature of 100-300 DEG C and the pressure of 0.5-5 MPa to obtain bismuth hydroxide, the pH value of the mixture liquid is 5-12; the bismuth source is bismuth nitrate; the surfactant is selected from polyvinylpyrrolidone or hexadecyl trimethyl ammonium bromide. According to the preparation method, bismuth hydroxide with the microscopic primary particle size of about 40-90 nm, uniform distribution, the secondary particle size D99 of 2-4 microns, the purity of 99.9% and the particle size of more than 99.9% can be obtained, and the adsorption rate of bismuth hydroxide to bromide ions and iodide ions reaches 80% or more.

Description

Technical Field

[0001] The invention relates to nano-scale bismuth hydroxide and a preparation method and application thereof. Background Art

[0002] Nano-bismuth hydroxide (Bi(OH)3) is a compound with unique properties. Due to its high specific surface area and ionic conductivity, it has shown potential application value in many fields of material science and chemical engineering, such as electronic device manufacturing, photocatalytic degradation, energy storage, drug carriers, biosensors, and adsorption of hetero-ions. In recent years, as a highly efficient halogen ion adsorbent, it has important application value in the fields of environmental protection and water resources management.

[0003] The traditional method for preparing bismuth hydroxide is to use concentrated acid to dissolve metallic bismuth or bismuth oxide, and then use strong alkali to adjust the pH value to a certain range to promote the precipitation of bismuth hydroxide, and then filter and dry the product to obtain bismuth hydroxide. The bismuth hydroxide prepared by this method is in block form, and irregular particles need to be obtained by means of crushing to obtain a powder with a relatively small particle size, and the application effect is poor.

[0004] Therefore, the preparation of nano-sized bismuth hydroxide has a positive effect on many fields. Summary of the invention

[0005] In view of the defects of the existing preparation technology, the present invention aims to provide a nano-scale bismuth hydroxide and a preparation method and application thereof, which can obtain a microscopic primary particle size of about 40-90nm, uniformly distributed, and a secondary particle size D 99 The bismuth hydroxide of the present invention has a particle size of 2-4 μm and a purity of 99.9% or more. The adsorption rate of the bismuth hydroxide to bromide ions is more than 80% and the adsorption rate to iodide ions is more than 70%.

[0006] The present invention solves the above technical problems through the following technical solutions.

[0007] The invention provides a method for preparing bismuth hydroxide, which comprises the following steps: a mixture of a surfactant solution and a bismuth source solution is reacted at 100-300 DEG C and 0.5MPa-5Mpa to obtain the bismuth hydroxide; the pH value of the mixture is 5-12; the bismuth source is bismuth nitrate; and the surfactant is selected from polyvinylpyrrolidone or hexadecyltrimethylammonium bromide.

[0008] In some embodiments, in the preparation method, certain components and contents have the following definitions, and definitions not mentioned are as described in any scheme of the present invention (hereinafter referred to as "in some embodiments").

[0009] In some embodiments, the concentration of the surfactant solution is 0.01-0.05 mol / L, for example 0.02 mol / L.

[0010] In some embodiments, the volume ratio of the surfactant solution to the bismuth source solution is 10-7.5, for example, 10.

[0011] In some embodiments, the mass ratio of the surfactant solution to the bismuth source solution is 10-7.6, such as 7.6.

[0012] In some embodiments, the solvent of the surfactant solution is a polyol, preferably ethanol, ethylene glycol, propylene glycol or glycerol, such as ethylene glycol.

[0013] In some embodiments, the solvent of the bismuth source solution is dilute nitric acid, for example, dilute nitric acid with a concentration of 0.5 mol / L.

[0014] In some embodiments, in the bismuth source solution, the molar volume ratio of the bismuth source to dilute nitric acid is 20:1-40:1, for example 40:1.

[0015] In some embodiments, in the bismuth source solution, the mass ratio of the bismuth source to dilute nitric acid is 0.8:1-1:0.8, for example 1:1.

[0016] In some embodiments, the bismuth source may be bismuth nitrate pentahydrate.

[0017] In some embodiments, the molar ratio of the bismuth source to the surfactant is 70:1-90:1, for example 90:1.

[0018] In some embodiments, the mixing temperature of the mixture is 20-50°C.

[0019] In some embodiments, the reaction temperature is 150°C to 220°C, such as 150°C or 180°C.

[0020] In some embodiments, the reaction duration is preferably 2-6 hours, such as 3 hours or 5 hours.

[0021] In some embodiments, the reaction pressure is preferably 0.5 MPa.

[0022] In some embodiments, the reaction is carried out in a high-temperature reactor, and the inner lining material of the reactor is preferably polytetrafluoroethylene.

[0023] In some embodiments, the pH of the mixture is 7-9, such as 8.5.

[0024] In some embodiments, the pH of the mixture is controlled by adding an alkali source, and the alkali source is selected from one or more of sodium hydroxide, potassium hydroxide, ammonia water, urea, triethylamine, tert-butylamine and sodium carbonate, wherein ammonia water (3wt% ammonia water), urea or sodium hydroxide (2mol / L sodium hydroxide) is preferred.

[0025] In some embodiments, the raw materials of the preparation method consist of the surfactant solution, the bismuth source solution and the alkali source.

[0026] In some embodiments, the alkaline source is added by dropwise addition.

[0027] In some embodiments, the preparation method comprises:

[0028] (1) dissolving the bismuth source in dilute nitric acid to obtain the bismuth source solution;

[0029] (2) dissolving the surfactant in the solvent of the surfactant solution to obtain the surfactant solution;

[0030] (3) adding the alkali source to the mixed solution of the bismuth source solution and the surfactant solution;

[0031] (4) The solution obtained in step (3) is reacted to obtain the bismuth hydroxide.

[0032] In some embodiments, the bismuth source is dissolved in dilute nitric acid by ultrasound to obtain the bismuth source solution.

[0033] In some embodiments, the preparation method further comprises the following post-processing steps: after the reaction is completed, the product is cooled, centrifuged, washed and dried in sequence.

[0034] In some embodiments, the cooling is cooling the reactor to room temperature (20-35°C).

[0035] In some embodiments, the centrifugal rotation speed is 3000-12000r, preferably 5000-9000r; for example 9000r.

[0036] In some embodiments, the centrifugation time is 3-15 min, preferably 5-10 min, such as 8 min.

[0037] In some embodiments, in the post-treatment, the centrifugation and washing are repeated alternately (eg, repeated three times).

[0038] In some embodiments, the washing solvent is water, such as deionized water.

[0039] In some embodiments, the amount of the washing solvent used is 40-50 mL each time, for example 45 mL.

[0040] In some embodiments, the drying temperature is 40-100°C, preferably 60-80°C, such as 70°C.

[0041] In some embodiments, the drying time is 6-24 hours, preferably 8-12 hours, for example 10 hours.

[0042] In some embodiments, the microscopic primary particle size of the bismuth hydroxide is 40-90 nm, preferably 50 nm, 60 nm, 70 nm or 80 nm.

[0043] In some embodiments, the secondary particle size D of the bismuth hydroxide is 99 2-4 μm, for example, 2.5 μm, 3 μm, 2.7 μm, 3.5 μm or 3.8 μm.

[0044] In some embodiments, the specific surface area of ​​the bismuth hydroxide is preferably 50-100 m 2 / g, for example 60m 2 / g, 65m 2 / g, 68m 2 / g or 70m 2 / g.

[0045] The invention provides a nano-scale bismuth hydroxide, which is obtained by preparing the bismuth hydroxide described above.

[0046] The present invention provides a use of the above-mentioned bismuth hydroxide as a halogen ion adsorbent. The halogen ions are bromide ions and / or iodide ions.

[0047] In some embodiments, the experimental temperature not separately specified in the present invention is room temperature, generally 20-35°C.

[0048] Without violating the common sense in the art, the above-mentioned preferred conditions can be arbitrarily combined to obtain the preferred embodiments of the present invention.

[0049] The reagents and raw materials used in the present invention are commercially available.

[0050] The positive improvement effect of the present invention is that the preparation method of the present invention can obtain microscopic primary particle size of about 40-90nm, uniform distribution, and secondary particle size D 99 The bismuth hydroxide of the present invention has a particle size of 2-4 μm and a purity of 99.9% or more. The adsorption rate of the bismuth hydroxide to bromide ions is more than 80% and the adsorption rate to iodide ions is more than 70%. DETAILED DESCRIPTION

[0051] The present invention is further described below by way of examples, but the present invention is not limited to the scope of the examples. The experimental methods in the following examples without specifying specific conditions are carried out according to conventional methods and conditions, or selected according to the product specifications.

[0052] Example 1

[0053] (1) Dissolve 9.7 g of bismuth nitrate pentahydrate in dilute nitric acid (10 g of dilute nitric acid with a concentration of 0.5 mol / L) and stir ultrasonically until dissolved to obtain A. Dissolve the surfactant polyvinylpyrrolidone (PVP) in an aqueous solution of ethylene glycol to obtain B (150 g) (the concentration of B solution is 0.02 mol / L). Mix solutions A and B to obtain C.

[0054] (2) Take ammonia water as the alkaline source. The concentration of ammonia water is 3 wt %. Add it dropwise into solution C so that the end point pH is within the range of 8.5. Stir ultrasonically.

[0055] (3) Transfer the above solution to a high-pressure reactor with a polytetrafluoroethylene liner and react at 150°C and 0.5 MPa for 5 h. When the oven temperature drops to room temperature, take out the reactor and put it in a fume hood. When the reactor cools to 30°C, slowly open the reactor and transfer the precipitated solution to a clean beaker.

[0056] (4) The precipitate is washed three times by centrifugation with deionized water, each time with 45 mL of deionized water, and the centrifugation parameter is 9000 r / 8 min. The sample obtained by centrifugation is placed in a vacuum oven and dried at 70° C. for 10 h. The product bismuth hydroxide powder can be obtained by coarse crushing with a pulverizer.

[0057] The powder obtained in Example 1 was ground in a mortar for about 10 minutes until no obvious particles were seen, and then tablets were pressed using the positive pressure method, and the tablets were put into the instrument and the program was set to perform XRD testing. The model of the XRD testing instrument used in this experiment was: Bruker D8 advance, with a scanning range of 5-80°, a step length of 0.02°, a scanning speed of 10° / min, and Cu as the test target. The XRD powder data values ​​are shown in Table 1 below.

[0058] Table 1. X-ray powder diffraction data values ​​of the product of Example 1

[0059]

[0060]

[0061] Example 2

[0062] The alkaline source in step (2) of Example 1 is replaced with sodium hydroxide, and the concentration of sodium hydroxide can be 2 mol / L. The other experimental conditions are the same as those of Example 1.

[0063] Example 3

[0064] The surfactant in solution B of step (1) of Example 1 was replaced with cetyltrimethylammonium bromide (CTAB), and the other experimental conditions were the same as those of Example 1.

[0065] Embodiment 4:

[0066] The reaction temperature in step (3) of Example 1 was changed to 180° C., and the other experimental conditions were the same as those in Example 1.

[0067] Embodiment 5:

[0068] The reaction time in step (3) of Example 1 was changed to 3 h, and the other experimental conditions were the same as those in Example 1.

[0069] Comparative Example 1:

[0070] The bismuth source in step (1) of Example 1 was replaced with bismuth chloride, and the other experimental conditions were the same as those of Example 1.

[0071] Comparative Example 2:

[0072] The surfactant in step (1) of Example 1 was replaced with polyethylene glycol, and the other experimental conditions were the same as those of Example 1.

[0073] Comparative Example 3:

[0074] The concentration of the surfactant polyvinylpyrrolidone (PVP) in step (1) of Example 1 was changed to 2 mol / L, and the other experimental conditions were the same as those of Example 1.

[0075] The samples prepared in the examples and comparative examples were tested for microscopic particle size using SEM, and single particles were measured using high-magnification SEM (10000X). Three different points were randomly selected, and five particles were measured at each point to take the average value.

[0076] The secondary particle size D99 was tested using a laser particle size tester. The powder was directly placed in the test cell and ultrasonicated for 3 minutes. The test was performed 4 times in total to obtain the average value and record the data.

[0077] The specific surface area is measured by a fully automatic specific surface area and pore size test instrument of model ASAP2460. The main test content is the specific surface area test item, and nitrogen is used as the adsorption and desorption atmosphere.

[0078] The test method for adsorption efficiency is: take 0.5g powder and add it to 100mL of 0.05mol / L hydrobromic acid and hydroiodic acid solution respectively, stir at room temperature for 8h, take the supernatant to test the bromide ion and iodide ion content in the solution, compare the amount reduced before and after, and the difference compared to the total amount is the adsorption efficiency.

[0079] The particle size of the samples and the adsorption test results of bromide ions and iodide ions are shown in Table 2

[0080] Table 2 .

Claims

1. A method for preparing bismuth hydroxide, characterized in that: It includes the following steps: The mixture of the surfactant solution and the bismuth source solution is reacted at 100-300° C. and 0.5 MPa-5 MPa to obtain the bismuth hydroxide; the pH of the mixture is 5-12; the bismuth source is bismuth nitrate; and the surfactant is selected from polyvinylpyrrolidone or hexadecyltrimethylammonium bromide.

2. The method for preparing bismuth hydroxide according to claim 1, wherein The preparation method meets one or more of the following conditions: (1) The concentration of the surfactant solution is 0.01-0.05 mol / L; (2) The volume ratio of the surfactant solution to the bismuth source solution is 10-7.5; (3) The mass ratio of the surfactant solution to the bismuth source solution is 10-7.6; (4) The solvent of the surfactant solution is a polyol; (5) The solvent of the bismuth source solution is dilute nitric acid; (6) The bismuth source is bismuth nitrate pentahydrate; (7) The molar ratio of the bismuth source to the surfactant is 70:1-90:1; (8) The reaction temperature is 150°C to 220°C; (9) The reaction time is 2-6 hours; (10) The reaction pressure is 0.5 MPa; (11) The reaction is carried out in a high-temperature reactor, and the inner lining material of the reactor is preferably polytetrafluoroethylene; (12) The pH of the mixture is 7-9; (13) The pH of the mixture is controlled by adding an alkali source, wherein the alkali source is selected from one or more of sodium hydroxide, potassium hydroxide, ammonia water, urea, triethylamine, tert-butylamine and sodium carbonate; (14) The microscopic primary particle size of the bismuth hydroxide is 40-90 nm; (15) The secondary particle size D of the bismuth hydroxide 99 2-4μm; and (16) the specific surface area of ​​the bismuth hydroxide is 50-100m 2 / g.

3. The method for preparing bismuth hydroxide according to claim 2, wherein: The preparation method meets one or more of the following conditions: (1) The concentration of the surfactant solution is 0.02 mol / L; (2) The volume ratio of the surfactant solution to the bismuth source solution is 10; (3) The mass ratio of the surfactant solution to the bismuth source solution is 7.6; (4) The solvent of the surfactant solution is ethanol, ethylene glycol, propylene glycol or glycerol; (5) The solvent of the bismuth source solution is 0.5 mol / L dilute nitric acid; (6) The molar ratio of the bismuth source to the surfactant is 90:1; (7) The reaction temperature is 150°C or 180°C; (8) The reaction time is 3 h or 5 h; (9) The reaction is carried out in a high-temperature reactor, the inner lining of which is made of polytetrafluoroethylene; (10) The pH of the mixture is 8.5; (11) The alkaline source is aqueous ammonia, urea or sodium hydroxide; (12) In the bismuth source solution, the molar volume ratio of the bismuth source to dilute nitric acid is 20:1-40:1; (13) In the bismuth source solution, the mass ratio of the bismuth source to dilute nitric acid is 0.8:1-1:0.8; (14) the alkali source is added dropwise; (15) The microscopic primary particle size of the bismuth hydroxide is 50 nm, 60 nm, 70 nm or 80 nm; (16) The secondary particle size D of the bismuth hydroxide 99 .5μm, 3μm, 2.7μm, 3.5μm or 3.8μm; and (17) the specific surface area of ​​the bismuth hydroxide is 60 m 2 / g, 65m 2 / g, 68m 2 / g or 70m 2 / g.

4. The method for preparing bismuth hydroxide according to claim 3, characterized in that: The preparation method meets one or more of the following conditions: (1) The solvent of the surfactant solution is ethylene glycol; (2) In the bismuth source solution, the mass ratio of the bismuth source to dilute nitric acid is 1:1; (3) The alkaline source is 3wt% ammonia water, urea or 2mol / L sodium hydroxide; and (4) the preparation method comprises: (1) dissolving the bismuth source in dilute nitric acid to obtain the bismuth source solution; (2) the surfactant is dissolved in the solvent of the surfactant solution to obtain the surfactant solution; (3) the alkali source is added to the mixed solution of the bismuth source solution and the surfactant solution; (4) the solution obtained in step (3) reacts to obtain the bismuth hydroxide.

5. The method for preparing bismuth hydroxide according to any one of claims 2 to 4, characterized in that: The raw materials of the preparation method are composed of the surfactant solution, the bismuth source solution and the alkali source; And / or, the preparation method further comprises the following post-processing steps: cooling the product after the reaction is completed, centrifuging, washing and drying in sequence.

6. The method for preparing bismuth hydroxide according to claim 5, characterized in that: The preparation method meets one or more of the following conditions: (1) the bismuth source is dissolved in dilute nitric acid by ultrasonication to obtain the bismuth source solution; (2) The cooling is cooling the reactor to room temperature; (3) The centrifugal speed is 3000-12000r; (4) The centrifugation time is 3-15 min; (5) In the post-treatment, the centrifugation and washing are repeated alternately; (6) The washing solvent is water; (7) The amount of the washing solvent used is 40-50 mL each time; (8) The drying temperature is 40-100°C; The drying time in (9) is 6-24 hours.

7. The method for preparing bismuth hydroxide according to claim 6, characterized in that: The preparation method meets one or more of the following conditions: (1) The cooling is to cool the reactor to 20-35°C; (2) The centrifugal speed is 5000-9000r, for example 9000r; (3) The centrifugation time is 5-10 minutes, for example 8 minutes; (4) In the post-treatment, the centrifugation and washing are repeated alternately three times; (5) The washing solvent is deionized water; (6) The amount of the washing solvent is 45 mL; (7) The drying temperature is 60-80°C, for example 70°C; The drying time in (8) is 8-12 hours, for example 10 hours.

8. A nano-scale bismuth hydroxide, characterized in that: The bismuth hydroxide is prepared by the method for preparing bismuth hydroxide according to any one of claims 1 to 7.

9. Use of the bismuth hydroxide as claimed in claim 8 as a halogen ion adsorbent.

10. The use according to claim 9, characterized in that: The halogen ion is a bromide ion and / or an iodide ion.

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