Preparation process of inorganic microsphere particles with uniformly positioned titanium dioxide on surfaces

Preparation technology of inorganic microsphere particles with uniformly positioned titanium dioxide on the surfaceTechnical field

[0001] The present invention relates to the field of air purification materials, in particular to a preparation process of photocatalyst materials, in particular to a preparation process of inorganic microsphere particles with uniformly positioned titanium dioxide on the surface.

Background technique

[0002] As the earliest discovered photocatalytic material, TiO2 has the characteristics of non-toxicity, high catalytic activity (degradation and purification and hydrogen production by water decomposition), strong oxidation ability, good stability, low cost, and environmental friendliness. It is most likely to be practical. With the rapid development of nanotechnology, the preparation, modification and application of nano-sized titanium dioxide have become a research hotspot in the field of air purification. However, because nano-TiO2 is prone to agglomeration, on the other hand, the wide band gap (3.2 eV) of TiO2 determines that it can only exert its photocatalytic activity under ultraviolet light, and the utilization rate of sunlight is very low. Greatly restrict its application.

[0003] There are many preparation methods for titanium dioxide and modified titanium dioxide, such as alkoxide hydrolysis, hydrothermal preparation, sol-gel, chemical precipitation, and solid-phase methods. Among them, the sol-gel method is simple to prepare and easy to operate. The conditions are easy to control, etc., which is a common preparation method. In order to improve the photocatalytic performance of titanium dioxide, on the one hand, by controlling the reaction conditions, such as concentration, temperature, etc., to increase the dispersion of titanium dioxide, thereby increasing the contact surface to improve the catalytic performance; On the one hand, through modification methods such as ion doping, loading, etc., defects can be introduced on the surface or crystallinity can be changed by doping, thereby affecting the recombination of electrons and holes or expanding the light absorption band, thereby improving the photocatalytic activity of titanium dioxide . However, the current method still has many problems, such as the complicated preparation process; the titanium dioxide produced by the reaction cannot be stored, the agglomeration rate is greatly increased over time, and the catalytic effect is greatly reduced. How to improve and maintain the dispersion of titanium dioxide is in this field. Technical problems that need to be solved urgently.

Summary of the invention

[0004] In order to solve the existing technical problems of poor dispersion of titanium dioxide and low activity due to the inability to store it for a long time, the present invention provides a preparation process for inorganic microsphere particles with uniformly positioned titanium dioxide on the surface, by coating solized titanium dioxide on On the surface of the inorganic microspheres, the secondary dispersion and sintering positioning of the titanium dioxide dispersion on the surface of the inorganic microspheres are realized by the process of drying and sintering under dynamic disturbance, which ensures the dispersion of titanium dioxide and greatly improves the high dispersion of titanium dioxide. Time, thereby improving the catalytic performance of titanium dioxide.

[0005] The technical solution adopted by the present invention is: a preparation process of inorganic microsphere particles with titanium dioxide uniformly positioned on the surface, characterized in that the preparation process includes the following steps: (1) Dissolving a water-soluble titanium source in water and stirring Add a weak base solution, where the mass ratio of titanium source, water, and weak base is 1:10-100:1-50, let stand for 10-120 minutes, and add peroxide to obtain a solized titanium dioxide system; (2) The solized titanium dioxide system was sprayed uniformly on the surface of inorganic microspheres or impregnated with inorganic microspheres, dried at room temperature to 100C for 1-3 hours, and sintered below 600-800°C for 1-10 hours to obtain inorganic microsphere particles with uniformly positioned titanium dioxide on the surface.

[0006] Further, the solized titanium dioxide system of the step (1) is centrifuged or filtered, and the precipitate or filter cake is uniformly resuspended in water for further purification, and the mass ratio * of titanium dioxide to water is controlled to be 1:10^1000.

[0007] Further, in the step (2), when the solized titanium dioxide system is uniformly sprayed on the surface of the inorganic microspheres or when the inorganic microspheres are impregnated, the mass ratio relationship between the titanium dioxide and the inorganic microspheres is controlled to be πίτ/mg=AC, where mt is Titanium dioxide quality, dish is the quality of inorganic microspheres, C is the water absorption rate of inorganic microspheres.

[0008] Further, the peroxide includes, but is not limited to, one or more of hydrogen peroxide, sodium peroxide, potassium peroxide, calcium peroxide, sodium persulfate, and potassium persulfate.

[0009] Further, the water-soluble titanium source is one or two or more of titanium oxysulfate, titanium tetrachloride, titanium trichloride, titanium tetrafluoride or titanium alkoxide, and the weak base is ammonia.

[0010] Further, the inorganic microspheres include, but are not limited to, glass microspheres, silica gel beads, ceramsites, zeolite beads, alumina beads, silicon carbide particles, steel beads, aluminum beads or copper beads.

[0011] The present invention also provides the application of the above-mentioned inorganic microsphere particles with uniformly positioned titanium dioxide on the surface in a fluidized bed device.

[0012] In the above technical solution, a preparation process of monodisperse titanium dioxide positioned on the surface of inorganic microspheres is provided, which specifically includes the following steps: dissolving a water-soluble titanium source in water, and adding a weak base solution under stirring, wherein the titanium source, water The mass ratio of the weak base is 1:10-100:1-50, let stand for 10-120min, and use peroxide for surface treatment to obtain a solized titanium dioxide system. At this time, the nanoparticles in the system are not sufficiently long. Large, low crystallinity, mostly amorphous. In order to ensure the dispersion, the concentration of the solized titanium dioxide system is generally controlled below 10%; the solized titanium dioxide system is uniformly coated or immersed on the surface of the inorganic microspheres at room temperature to 100°C Drying for 1-3 h, because the dispersion of titanium oxide in the aqueous solution is very uniform, and its specific surface area is very large. When the solized titanium dioxide system is uniformly sprayed on the surface of the inorganic microspheres or immersed in the inorganic microspheres, it will be absorbed by water. , While forming a uniform water film, the solized titanium dioxide is uniformly loaded on the surface of the inorganic microspheres, connected by van der Waals force, and dried at room temperature to 100°C for 1-3 hours to slowly remove water to prevent rapid heating from causing water vapor to damage the surface of the titanium dioxide. Shock. Moreover, the unadsorbed excess titanium dioxide can be washed off with water after drying at room temperature, which greatly reduces the agglomeration of titanium oxide. After lightly rinsing with deionized water to remove the unadsorbed titanium dioxide, sinter it at 400-800°C for 0.1-10 h. The rutile titanium dioxide that can be obtained at low temperature has high crystallinity, high activity, and low temperature will lead to too long sintering time, reduced activity, high energy consumption, and too high temperature will easily cause crystal transformation. During the sintering process, the surface of titanium dioxide The grafted peroxide groups undergo a cross-linking reaction between particles and form a bridging chemical bond with the surface of the microspheres, thereby obtaining inorganic microsphere particles with uniform and firm support of monodisperse titanium dioxide on the surface.

[0013] The beneficial effects of the present invention are: (1) the preparation process provided by the present invention is simple, the dispersion of titanium dioxide on the surface of the inorganic microspheres is high, it does not agglomerate for a long time, and the positioning is firm and not easy to fall off, which greatly improves the catalytic efficiency; (2) The preparation method does not involve organic solvents, saves energy, and is more environmentally friendly; (3) In the further improved technical scheme, by controlling all the water in the system to be exactly equal to the saturated water absorption of the inorganic microspheres, the surface of the inorganic microspheres The water film adsorbs stably without the presence of free water, which can ensure that the titanium dioxide on the surface of the inorganic microspheres is a single layer of monodispersed nanoparticles; by controlling the concentration of the titanium dioxide system and the ratio of titanium dioxide to the inorganic microspheres, the surface of the inorganic microspheres can be positioned on the monolayer The amount of dispersed titanium dioxide is large, the degree of dispersion is high, the distribution is uniform, and the catalytic efficiency is greatly improved.

Description of the drawings

[0014] FIGS. 1 and 2 are scanning electron micrographs of different magnifications of glass beads with monodisperse titanium dioxide nanoparticles positioned on the surface obtained in Example 1 of the present invention.

[0015] FIG. 3 is a data diagram of the degradation effect of acetaldehyde products obtained in Examples 1-4.

Detailed ways

[0016] The present invention provides a preparation process of monodisperse titanium dioxide positioned on the surface of inorganic microspheres. The following specific examples illustrate the present invention for ease of understanding, but do not limit the present invention in any form. The reagents involved in the examples are not limited.

Special instructions, can be purchased through commercial channels, the methods used, unless otherwise specified, are conventional methods.

[0017] Example 1: Dissolve 10g of titanyl sulfate in 500ml of water, add 110mL of 2.5% ammonia water under stirring, let the precipitation reaction stand for 30min, centrifuge at 8000-10000r/min, then remove the supernatant and centrifuge the result The solid precipitate was resuspended in 90ml of water, and the resuspended system was made uniform by stirring and ultrasound, and 60g of hydrogen peroxide (mass concentration of 30%) was added to obtain a solized titanium dioxide system; (2) A glass microparticle with an average particle size of 20 wn was selected. After washing with water and alcohol, degreasing and drying, spray solized titanium dioxide on the surface of glass beads, dry at 45°C for 3 hours, and sinter at 800°C for 1 hour to obtain glass microsphere particles with uniformly positioned titanium dioxide on the surface (S1 ), the scanning electron microscopy images are shown in Figure 1 and Figure 2. It can be seen that the surface of the glass microspheres is loaded with a layer of titanium dioxide nanoparticles, the particle dispersion is uniform, and the monodispersion performance is good. The particle size of the titanium dioxide nanoparticles is 50-100nm. The size is uniform. Further through the comparison of the quality before and after, it is found that the loading amount of the titanium dioxide nanoparticles is 1% of the mass of the glass microspheres.

[0018] Example 2: Dissolve 10g of titanium tetrachloride in 300ml of water, add 100ml of 2.5% ammonia water under stirring, let the precipitation reaction stand for 30min, centrifuge at 8000-10000r/min, then remove the supernatant and centrifuge the result The solid precipitate was resuspended in 100ml of water, and the resuspended system was made uniform by stirring and ultrasound. 50g of hydrogen peroxide was added to obtain the sol-state titanium dioxide system; (2) The solized titanium dioxide was sprayed on the surface of 100wn silica gel microspheres, 35° After drying at C for 3 h and sintering at 600°C for 3 h, silica gel microsphere particles (S2) with monodisperse titanium dioxide positioned on the surface were obtained. The comparison of the quality before and after showed that the loading of titanium dioxide nanoparticles was 0.89% of the mass of silica gel microspheres.

[0019] Example 3: 10g of titanium trichloride was dissolved in 300ml of water, 200ml of 2.5% ammonia water was added with stirring, the precipitation reaction was allowed to stand for 30min, and then suction filtered, the resulting filter cake was resuspended in 100ml of water, with the aid of stirring and ultrasound Make the resuspended system uniform and add 70g of hydrogen peroxide to obtain a sol-state titanium dioxide system; (2) Spray the solized titanium dioxide on the surface of 100wn ceramic beads, dry at 50°C for 2 hours, and sinter at 700°C for 3 hours. The ceramic microbeads (S3) with monodisperse titanium dioxide positioned on the surface are sintered, and the quality before and after comparison shows that the loading of titanium dioxide nanoparticles is 0.94% of the mass of the ceramic microbeads._O

[0020] Example 4: Dissolve 10g of a mixture of titanium trichloride and titanium alkoxide in 300ml of water and stir evenly, add 150ml of 2.5% ammonia water under stirring, stand for reaction for 50min, and filter with suction. The resulting filter cake is 100ml Resuspend in water, stir and ultrasound to make the resuspended system uniform, add 70g hydrogen peroxide to obtain a sol-state titanium dioxide system; (2) Spray the sol-solized titanium dioxide on the surface of 3wn copper beads, and dry at 65°C for 1 h After sintering at 600°C for 3 h, copper bead microspheres with monodisperse titanium dioxide positioned on the surface were obtained. Comparison of the mass before and after showed that the loading of titanium dioxide nanoparticles was 0.91% of the mass of ceramic microbeads.

[0021] Experimental performance test The acetaldehyde degradation performance test was performed on each product in the above-mentioned embodiments according to the following test methods.

[0022] The setting of the test chamber: prepare an experimental chamber with a volume of 1.5η? corresponding to each sample, and prepare a blank control chamber with a 1.5η? in each experimental chamber, respectively put 200g of the above-mentioned surface-positioned monodisperse titanium dioxide Inorganic microspheres, put 2g of dry titanium dioxide powder in the blank control chamber (the sol-state titanium dioxide system obtained in step 1 is spray-dried>600°C and sintered for 3 hours and then ground) and 198g of the glass microspheres in Example 1 are placed in the experimental chamber. And the blank control chamber were filled with the same concentration (5mg/m³) Acetaldehyde, turn off the test chamber; then turn on the fan of the test chamber at the same time to make the pollutants in the chamber circulate evenly, 24h

Then, sample the concentration of pollutants in the test chamber at the same time, analyze and test, and calculate the acetaldehyde residual rate. The calculation method refers to the following formula: acetaldehyde residual rate = acetaldehyde concentration value in sample experiment chamber ten blank control chamber acetaldehyde concentration value X100 The results of %o are shown in Figure 3. The data shows that the titanium dioxide nanoparticles in the particles obtained by the preparation method of the present invention with uniformly positioned titanium dioxide inorganic microsphere particles maintain a good high degree of dispersibility, which greatly improves the ease of titanium dioxide obtained by the current preparation method. The defect of agglomeration increases the contact area of the titanium dioxide with the outside air during use, ensures its high-efficiency catalytic efficiency, and also greatly avoids the problems of PM2.5 dust pollution caused by the titanium dioxide micro-nano particles themselves.

[0023] In summary, the inorganic microspheres with uniformly positioned titanium dioxide on the surface provided by the present invention have simple manufacturing process steps, simple and easy to operate, improve the monodispersed state of the resulting titanium dioxide, facilitate long-term storage, and improve its activity and catalysis Performance; as a catalytic filter material used in a fluidized bed device, it greatly improves the catalytic efficiency of the fluidized bed and the service life of the filter material. It can also be filled in air purifiers and other devices to improve indoor air quality.