CN1986409A - Preparing process of nano gamma-alumina powder with intraparticle mesoporous structure - Google Patents

Abstract

Translated fromChinese

本发明公开了一种具有粒子内介孔结构的γ－氧化铝纳米粉体的制备方法，其步骤是称取硫酸铝铵、氯化铝和碳酸氢铵，分别溶于二次水中，各加入表面活性剂并调节碳酸氢铵溶液的pH值。磁力搅拌下铝盐滴加到碳酸氢铵中，反应完毕继续搅拌至反应充分，经分离、洗涤、干燥、共沸蒸馏脱水后高温煅烧，即得到粒径分布较均匀，粒子内平均粒径在20－63nm，平均粒子内孔径在2.8－7.4nm，比表面积在95－212m²/g范围内局部可调的具有粒子内介孔结构的γ－Al₂O₃纳米粉末。本发明操作简便，生产条件温和、能耗和成本低，适合工业化生产。制备的氧化铝粉体同时具有纳米尺寸、γ纳米晶相与介孔特性，在吸附、分离、催化剂及其载体、色谱柱材料等方面具有广阔的应用前景。

The invention discloses a preparation method of γ-alumina nanopowder with inner mesoporous structure of particles. Surfactants and adjust the pH of the ammonium bicarbonate solution. Add the aluminum salt dropwise to the ammonium bicarbonate under magnetic stirring, and continue to stir until the reaction is complete. After separation, washing, drying, azeotropic distillation and dehydration, high-temperature calcination, the particle size distribution is relatively uniform, and the average particle size in the particle is γ-Al₂ O₃ nanometer powder with internal mesoporous structure of 20-63nm, average particle internal pore diameter of 2.8-7.4nm, and specific surface area locally adjustable within the range of 95-212m² /g. The invention has the advantages of simple and convenient operation, mild production conditions, low energy consumption and low cost, and is suitable for industrialized production. The prepared alumina powder has nanometer size, γ nanocrystalline phase and mesoporous characteristics at the same time, and has broad application prospects in adsorption, separation, catalyst and its carrier, and chromatographic column materials.

Description

A kind of preparation method with gama-alumina nano-powder of intraparticle mesoporous structure

Technical field

The present invention relates to a kind of gama-alumina nanometer particle process method, belong to the mesoporous inorganic field of nanometer material technology with intraparticle mesoporous structure.

Background technology

Nano aluminium oxide (Al₂O₃) be meant the alumina product of particle size less than 100nm, because its particle is little, specific surface area is big, thereby higher chemically reactive is arranged, and is widely used in hard mass, reagent and catalyzer and carrier, luminescent material, electronic ceramic substrate and aerospace field.At present, the industrial preparation alumina powder mainly adopts methods such as Bel's method and the thermolysis of aluminium ammonium alum, needs special heating installation, has increased synthetic difficulty.And traditional wet chemical method is difficult to control effectively the size and the microtexture of particle, thereby traditional wet chemical method is difficult to truly nano alumina powder jointed of preparation.

The inorganic mesoporous material of M41S series silicon oxide that the seventies in last century, Mobile company utilized tensio-active agent self-assembly principle at first to synthesize to have meso-hole structure (pore size distribution in the 2-50nm scope be referred to as mesoporous material).At present, tensio-active agent successfully prepares the mesoporous or porous gama-alumina aspect of material.Mesoporous or porous gama-alumina has been widely used in aspects such as industrial adsorbents, chromatographic separation column material, catalyzer and carrier thereof.Yet, with the porous Al of surfactant templates method preparation₂O₃Be generally the relatively poor amorphous structure of thermostability, in its crystallization is the process of γ-phase alumina, can cause subsiding of vesicular structure, greatly reduced the specific surface area of material, thereby had a strong impact on its application aspect catalyzer and sorbent material.This shows that the gama-alumina mesoporous material that preparation has high thermal stability and specific surface area has important practical significance.At present, do not see both at home and abroad the document of the preparation of relevant nanometer gama-alumina nano-powder and application and use and report as yet with intraparticle mesoporous structure.

Summary of the invention

The object of the invention is to provide a kind of preparation method with gama-alumina nano-powder of intraparticle mesoporous structure, this method is easy and simple to handle, cost is low, and the aluminum oxide of preparation with nano-scale, γ-mutually nanocrystalline and mesoporous feature set has higher thermostability and specific surface area.

Technical scheme provided by the invention is that a kind of preparation method with gama-alumina nano-powder of intraparticle mesoporous structure comprises following concrete steps:

(1), takes by weighing exsiccated ammonium alum, aluminum chloride and bicarbonate of ammonia as required, be dissolved in respectively in the secondary water, be made into the liquor alumini chloridi that the aluminum ion total concn is 0.3-0.5mol/L or the mixing solutions of exsiccated ammonium alum and aluminum chloride, the molar ratio range of exsiccated ammonium alum/aluminum chloride is 0-3 in the mixing solutions, and concentration is the ammonium bicarbonate soln of 0.3-0.6mol/L, with the impurity in the microporous membrane elimination solution;

(2), in the mixing solutions of liquor alumini chloridi or exsiccated ammonium alum and aluminum chloride, add poly(oxyethylene glycol) 400, be mixed with the Al that contains the 4-8wt% poly(oxyethylene glycol) 400³⁺Concentration is the aluminium salt A solution of 0.3-0.5mol/L, adds Macrogol 2000 in ammonium bicarbonate soln, is made into the bicarbonate of ammonia B solution of the 0.3-0.6mol/L that contains the 1-8wt% Macrogol 2000, and adding ammoniacal liquor is regulated its pH value to 9-10;

(3), under magnetic agitation, in bicarbonate of ammonia B solution, drip 1/2 volume to isopyknic aluminium salt A solution, after titration is finished, continue to be stirred to and react completely, the centrifugation precipitation is washed to detecting no SO with secondary water washing₄^2-, the dry then dry powder that obtains;

(4), the dry powder that obtains is joined in the propyl carbinol of capacity, after the ultrasonic dispersing, fully reflux, distillation removes the azeotrope of 93-95 ℃ n-butanol-water, when the cut temperature rises to 115-120 ℃ of propyl carbinol boiling point, stop distillation, continue to reflux, propyl carbinol is reclaimed in underpressure distillation then, obtains loose γ-Al₂O₃Nano-powder;

(5), with the γ-Al that obtains₂O₃Nano-powder is at 850-900 ℃ of calcining, the γ-Al that obtains having the intraparticle mesoporous structure₂O₃Nanometer powder.

And, in step (1), the impurity in each solution that is disposed with the microporous membrane elimination at last.Dripping with 250-350 under the magnetic agitation of 1000-1300r/min in the step (3)/minute speed in bicarbonate of ammonia B solution, drip 1/2 volume to isopyknic aluminium salt A solution, and the precipitation of centrifugation washed with secondary water washing, detect to there not being SO with the 1-2% nitrate of baryta₄^2-, and then back for several times with washing with alcohol in 70-90 ℃ of dry 3-4 hour acquisition dry powder.Calcination time is 2-3 hour in the step (5), the γ-Al with intraparticle mesoporous structure that is obtained₂O₃The size distribution of nanometer powder is even, and median size is at 20-63nm in the particle, and the averaged particles internal orifice dimension is that specific surface area is at 95-212m at 2.8-7.4nm²Local adjustable in the/g scope.

As shown from the above technical solution, the present invention by optimizing the precipitin reaction initiator kind, concentration and suitably add tensio-active agent and effectively regulated Al₂O₃Microtextures such as the particle size of product, aperture and specific surface area, thereby more stable γ-Al that acquisition has the intraparticle mesoporous structure₂O₃Nano-powder.Use the inventive method can prepare median size at 20-63nm, mean pore size is that specific surface area is at 95-212m at 2.8-7.4nm²Local adjustable in the/g scope, as to have the stable and specific surface area of higher thermal gama-alumina nano-powder.And this with nano-scale, γ-mutually nanocrystalline and mesoporous feature set meso-porous nano gama-alumina will adsorb, separate, aspects such as catalyzer and carrier thereof, automobile three-effect catalysis conversion system, chromatographic separation column material show wide application prospect.

The present invention compared with prior art has the following advantages and effect:

1. starting material sources is wide, working condition is gentle, energy consumption and cost are low, is fit to suitability for industrialized production.

2. utilize the template action of tensio-active agent, realize nanometer Al by the concentration and the kind of regulating polyglycol surfactants and aluminium salt₂O₃The particle diameter of powder, particle internal orifice dimension size and the partial controllable that distributes thereof.

3.850-900 a ℃ calcining time can keep meso-hole structure when making mesoporous wall crystallization, thereby obtains high surface-area.And the mesoporous of usual method preparation subsided when 900 ℃ of calcinings fully.

This law preparation alumina powder jointed with nano-scale and mesoporous feature set, have broad application prospects at aspects such as catalyzer and carrier thereof, automobile three-effect catalysis conversion system, chromatographic separation column materials.

Description of drawings

Fig. 1 is the transmission electron microscope photo of embodiment 1 products obtained therefrom.

Fig. 2 is the transmission electron microscope photo of embodiment 2 products obtained therefroms.

Fig. 3 is the transmission electron microscope photo of embodiment 3 products obtained therefroms.

Fig. 4 is the transmission electron microscope photo of embodiment 4 products obtained therefroms.

Fig. 5 is the transmission electron microscope photo of embodiment 5 products obtained therefroms.

Embodiment

Take by weighing exsiccated ammonium alum, aluminum chloride and bicarbonate of ammonia at first as required, be dissolved in respectively in the secondary water, be made into the liquor alumini chloridi that the aluminum ion total concn is 0.3-0.5mol/L or the mixing solutions of exsiccated ammonium alum and aluminum chloride, the molar ratio range of exsiccated ammonium alum/aluminum chloride is 0-1 in the mixing solutions, and concentration is the ammonium bicarbonate soln of 0.3-0.6mol/L, with the impurity in the microporous membrane elimination solution.

In the mixing solutions of liquor alumini chloridi or exsiccated ammonium alum and aluminum chloride, add poly(oxyethylene glycol) 400 then, be mixed with the Al that contains the 4-8wt% poly(oxyethylene glycol) 400³⁺Concentration is 0.3-0.4mol/L's, adds Macrogol 2000 in ammonium bicarbonate soln, is made into the bicarbonate of ammonia B solution of the 0.3-0.6mol/L that contains the 1-8wt% Macrogol 2000, and adding ammoniacal liquor is regulated its pH value to 9-10.

Above-mentioned two steps are preparation storing solutions, all can repeat in the following embodiments, and are succinct for making embodiment, and this two step is listed separately, just no longer repeat among each embodiment.

The concentration that respectively contains 4.5wt% polyoxyethylene glycol (PEG) 400 under the magnetic agitation of embodiment 1:1300r/min is 0.3mol/LAlCl₃Solution be in the bicarbonate of ammonia B solution (pH is 9.3) of 0.6mol/L as aluminium salt A solution with the concentration that 300 droplets/minute speed adds the isopyknic 4.6wt% of containing polyoxyethylene glycol (PEG) 2000, after titration is finished, continue to stir 0.5h; Centrifugation is washed 3 times, washing with alcohol 3 times with secondary water washing, and 80 ℃ of dry 4h remove surface water, obtains dry powder.The dry powder that obtains is joined in the propyl carbinol of 80ml, after the ultrasonic dispersing, backflow 2h, distillation removes 93 ℃ the azeotrope of n-butanol-water, when the cut temperature rises to 117 ℃ of propyl carbinol boiling points, stops distillation, after continuing backflow 2h, propyl carbinol is reclaimed in underpressure distillation, obtains loose powder.

900 ℃ of calcinings obtained γ-Al in 2 hours₂O₃Product, its particle morphology is seen Fig. 1.Particle distribution is more even, and particle size range is 18-68nm, and median size is 38nm; Particle internal orifice dimension scope is 2-12nm, and mean pore size is 3.8nm in the particle.Specific surface area is 121m²/ g, the crystallization degree of hole wall is higher.

The Al that will contain 4.5wt%PEG400 under the magnetic agitation of embodiment 2:1000r/min³⁺Concentration is 0.30mol/L (AlCl₃: NH₄Al (SO₄)₂=1: 1 mol ratio) solution is in the bicarbonate of ammonia B solution (pH is 9.3) of 0.60mol/L as aluminium salt A solution with the concentration that 250 droplets/minute speed adds isopyknic 4.6wt%PEG2000 of containing, and after titration is finished, continues to stir 0.5h; Centrifugation is washed 3 times, washing with alcohol 3 times with secondary water washing, and 80 ℃ of dry 4h remove surface water, obtains dry powder.The dry powder that obtains is joined in the propyl carbinol of 80ml, after the ultrasonic dispersing, backflow 2h, distillation removes 93 ℃ the azeotrope of n-butanol-water, when the cut temperature rises to 117 ℃ of propyl carbinol boiling points, stops distillation, after continuing backflow 2h, propyl carbinol is reclaimed in underpressure distillation, obtains loose powder.

850 ℃ of calcinings obtained γ-Al in 3 hours₂O₃Product, its particle morphology is seen Fig. 2.Particle distribution is more even, and particle size range is 56-87nm, and median size is 63nm; Particle internal orifice dimension scope is 2-9nm, and mean pore size is 4.7nm in the particle, and specific surface area is 153m²/ g, the crystallization degree of hole wall is higher.

The Al that will contain 8wt%PEG400 under the magnetic agitation of embodiment 3:1300r/min³⁺Concentration is 0.4mol/L (AlCl₃: NH₄Al (SO₄)₂=1: solution 1) is in the bicarbonate of ammonia B solution (pH is 9.3) of 0.40mol/L as aluminium salt A solution with the concentration that contains 8wt%PEG2000 that 350 droplets/minute speed adds 2 times of volumes, after titration is finished, continues to stir 0.5h; Centrifugation, wash 3 times with secondary water washing, the precipitation that obtains is joined in the propyl carbinol of 80ml, after the ultrasonic dispersing, backflow 2h, distillation removes the azeotrope of 93 ℃ n-butanol-water, when the cut temperature rises to 117 ℃ of propyl carbinol boiling points, stop distillation, continue backflow 2h after, propyl carbinol is reclaimed in underpressure distillation, obtains loose powder.

880 ℃ of calcinings obtained γ-Al in 2.5 hours₂O₃Product, its particle morphology is seen Fig. 3.Particle surface is more coarse, is connected to form filamentary structure between medium hole nano particles, and particle size range is 25-75nm, and median size is 51nm; Particle internal orifice dimension scope is 2.2-9nm, and mean pore size is 5.2nm, and specific surface area is 212m²/ g, the crystallization degree of hole wall is higher.

The Al that will contain 8wt%PEG400 under the magnetic agitation of embodiment 4:1300r/min³⁺Concentration is 0.3mol/L (AlCl₃: NH₄Al (SO₄)₂=1: solution 1) is in the bicarbonate of ammonia B solution (pH is 9.3) of 0.30mol/L as aluminium salt A solution with the concentration that contains 1.4wt%PEG2000 that 300 droplets/minute speed adds 2 times of volumes, after titration is finished, continues to stir 0.5h; Centrifugation is washed 3 times, washing with alcohol 3 times with secondary water washing, and 80 ℃ of dry 4h remove surface water, obtains dry powder.The dry powder that obtains is joined in the propyl carbinol of 80ml, after the ultrasonic dispersing, backflow 2h, distillation removes 93 ℃ the azeotrope of n-butanol-water, when the cut temperature rises to 117 ℃ of propyl carbinol boiling points, stops distillation, after continuing backflow 2h, propyl carbinol is reclaimed in underpressure distillation, obtains loose powder.

900 ℃ of calcinings obtained γ-Al in 2 hours₂O₃Product, its particle morphology is seen Fig. 4, and particle distribution is more even, and particle size range is 10-50nm, and median size is 20nm; Particle internal orifice dimension scope is 2-7nm, and mean pore size is 2.8nm, and specific surface area is 132m²/ g, the crystallization degree of hole wall is higher.。

The Al that will contain 7wt%PEG400 under the magnetic agitation of embodiment 5:1300r/min³⁺Concentration is 0.4mol/L (AlCl₃: NH₄Al (SO₄)₂=1: 3) solution is in the bicarbonate of ammonia B solution (pH is 9.3) of 0.30mol/L as aluminium salt A solution with the concentration that 300 droplets/minute speed adds isopyknic 5.2wt%PEG2000 of containing, and after titration is finished, continues to stir 0.5h; Centrifugation, wash 3 times with secondary water washing, the precipitation that obtains is joined in the propyl carbinol of 80ml, after the ultrasonic dispersing, backflow 2h, distillation removes the azeotrope of 93 ℃ n-butanol-water, when the cut temperature rises to 117 ℃ of propyl carbinol boiling points, stop distillation, continue backflow 2h after, propyl carbinol is reclaimed in underpressure distillation, obtains loose powder.

900 ℃ of calcinings obtained γ-Al in 2 hours₂O₃Product, its particle morphology is seen Fig. 5.Particle surface is more coarse, and particle size range is 10-75nm, and median size is 25nm; Particle internal orifice dimension scope is 2-18nm, and mean pore size is 7.4nm, and specific surface area is 96m²/ g, the crystallization degree of hole wall is higher.

Find by embodiment and a large amount of experiment, particle size and pore size and distribution thereof and surfactant concentrations and the polymerization degree and relevant with the composition and the concentration of inorganic salt can be selected polyglycol surfactants and aluminium salt or its mixture of the different ratios and the polymerization degree as required for use.In certain scope (as: poly(oxyethylene glycol) 400 concentration 4-8wt%, the concentration 1-8wt% of Macrogol 2000), the concentration of PEG is big more, and particle size is more little, aperture and specific surface area are big more.900 ℃ of calcinings obtain γ-Al₂O₃The main diffraction peak of X-ray powder diffraction pattern of nano-powder is: 46.0 ° (100), 67.1 ° (90), 37.0 ° 60), 49.0 ° (58), 39.7 ° (53) are γ-Al₂O₃Characteristic peak, and do not find the characteristic diffraction peak of any other type body, specific surface area is along with aluminium salt and PEG concentration, the kind 95-212m that do not coexist²Change in/g the scope.Specific surface area, crystallization degree, particle size are relevant with the setting of warm area, along with the rising of calcining temperature, can obtain specific surface area and reduce gradually, the nano-powder that crystallization degree, crystal grain and particle size increase gradually.1000 ℃ of calcinings are after 2 hours, and principal crystalline phase still is γ-Al₂O₃

Claims (4)

1, a kind of preparation method with gama-alumina nano-powder of intraparticle mesoporous structure is characterized in that comprising following concrete steps:

(1), takes by weighing exsiccated ammonium alum, aluminum chloride and bicarbonate of ammonia as required, be dissolved in respectively in the secondary water, be made into the liquor alumini chloridi that the aluminum ion total concn is 0.3-0.5mol/L or the mixing solutions of exsiccated ammonium alum and aluminum chloride, the molar ratio range of exsiccated ammonium alum/aluminum chloride is 0-3 in the mixing solutions, and concentration is the ammonium bicarbonate soln of 0.3-0.6mol/L, with the impurity in the microporous membrane elimination solution;

(2), in the mixing solutions of liquor alumini chloridi or exsiccated ammonium alum and aluminum chloride, add poly(oxyethylene glycol) 400, be mixed with the Al that contains the 4-8wt% poly(oxyethylene glycol) 400³⁺Concentration is the aluminium salt A solution of 0.3-0.5mol/L, adds Macrogol 2000 in ammonium bicarbonate soln, is made into the bicarbonate of ammonia B solution of the 0.3-0.6mol/L that contains the 1-8wt% Macrogol 2000, and adding ammoniacal liquor is regulated its pH value to 9-10;

(3), under magnetic agitation, in bicarbonate of ammonia B solution, drip 1/2 volume to isopyknic aluminium salt A solution, after titration is finished, continue to be stirred to and react completely, the centrifugation precipitation is washed to detecting no SO with secondary water washing₄^2-, the dry then dry powder that obtains;

(4), the dry powder that obtains is joined in the propyl carbinol of capacity, after the ultrasonic dispersing, fully reflux, distillation removes the azeotrope of 93-95 ℃ n-butanol-water, when the cut temperature rises to 115-120 ℃ of propyl carbinol boiling point, stop distillation, continue to reflux, propyl carbinol is reclaimed in underpressure distillation then, obtains loose γ-Al₂O₃Nano-powder;

(5), with the γ-Al that obtains₂O₃Nano-powder is at 850-900 ℃ of calcining, the γ-Al that obtains having the intraparticle mesoporous structure₂O₃Nanometer powder.

2, the preparation method with gama-alumina nano-powder of intraparticle mesoporous structure according to claim 1 is characterized in that: in step (1), and the impurity in each solution that is disposed with the microporous membrane elimination at last.

3, the preparation method with gama-alumina nano-powder of intraparticle mesoporous structure according to claim 1, it is characterized in that: dripping with 250-350 under the magnetic agitation of 1000-1300r/min in the step (3)/minute speed in bicarbonate of ammonia B solution, drip 1/2 volume to isopyknic aluminium salt A solution, and the precipitation of centrifugation washed with secondary water washing, detect to there not being SO with the 1-2% nitrate of baryta₄^2-, and then back for several times with washing with alcohol in 70-90 ℃ of dry 3-4 hour acquisition dry powder.

4, the preparation method with gama-alumina nano-powder of intraparticle mesoporous structure according to claim 1 is characterized in that: calcination time is 2-3 hour in the step (5), the γ-Al with intraparticle mesoporous structure that is obtained₂O₃The size distribution of nanometer powder is even, and median size is at 20-63nm in the particle, and the averaged particles internal orifice dimension is that specific surface area is at 95-212m at 2.8-7.4nm²Local adjustable in the/g scope.