Metal-doped mesoporous titanium dioxide composite material, and preparation method and application thereof

Abstract

The application discloses a metal-doped mesoporous titanium dioxide composite material and a preparation method and application thereof. The material is prepared by the following steps: dropping a small amount of titanium chloride into ice to form a solution, stirring and adding a small amount of metal chloride (Cu, Fe), adding strontium chloride, dropping potassium hydroxide solution and stirring to obtain a slurry, placing the slurry into a high-temperature and high-pressure kettle, rapidly heating to 100-105 DEG C, heating for a period of time, washing the solution to neutral pH by centrifugation after cooling, and drying to obtain metal-doped strontium titanate. A small amount of metal-doped strontium titanate is taken into a high-pressure kettle, pure water and concentrated hydrochloric acid are added, the mixture is naturally cooled after high-temperature reaction for a period of time, the slurry after cooling is washed to neutral pH by a centrifugal machine, and the slurry is placed into a freeze dryer to be freeze-dried to obtain the mesoporous titanium dioxide composite material. The material can efficiently adsorb and remove pollutants (such as organic arsenic) in water, and realizes deep purification of water body organic pollutants.

Description

Technical Field

[0001] This invention relates to a novel metal-doped titanium dioxide composite material, its preparation method, and its application, specifically belonging to the fields of chemistry, environmental protection, and materials science and technology. Background Technology

[0002] As we all know, agriculture is a fundamental industry supporting national economic construction and development, providing other sectors of the national economy with food, non-staple foods, industrial raw materials, capital, and export goods. As a rapidly developing and populous country, China's rapid social development and continuous population growth have placed enormous pressure and challenges on its agriculture. Animal husbandry is a major component of agriculture and a crucial link in the exchange of resources between humanity and nature. As one of the most important components of agriculture, animal husbandry plays a vital role in improving my country's agricultural development level, promoting economic development, and improving people's lives.

[0003] Organic arsenic has the effects of promoting growth, inhibiting bacterial infection, and improving feed utilization, and is widely used in the animal husbandry industry. The widespread use of organic arsenic feed has promoted the development of the animal husbandry industry and brought significant economic benefits. However, only 10% of organic arsenic can be metabolized by the animal intestines, and most of the rest is excreted with excrement, slowly degraded in the environment, and gradually transformed into highly water-soluble and toxic inorganic arsenic, polluting the environment.

[0004] Globally, although many countries and regions have begun to reduce or even ban the use of organic arsenic preparations as animal additives, their use continues to grow in some developing countries. Most organic arsenic feed additives cannot be absorbed by livestock and poultry; this portion largely enters the natural environment directly or through fertilization without proper treatment, leading to the accumulation of arsenic in the environment. In the natural environment, organic arsenic undergoes physicochemical and microbial transformations into more toxic and easily diffused inorganic arsenic, thus harming the health of humans and other animals.

[0005] Although traditional titanium dioxide materials have a certain affinity for organic arsenic and the specific surface area can be increased by synthesizing mesoporous titanium dioxide materials, their overall adsorption activity is low and their adsorption and removal efficiency for organic arsenic in water is poor.

[0006] Therefore, it is necessary to provide a novel method for preparing a metal-doped mesoporous titanium dioxide composite material to improve the adsorption activity of titanium dioxide materials, so as to solve or at least alleviate the current pollution of organic arsenic in environmental water bodies. Summary of the Invention

[0007] In response to the current overuse of organic arsenic in animal feed, large amounts of organic arsenic accumulate in the natural environment through animals, posing a serious risk of environmental pollution. Traditional adsorption materials suffer from low adsorption activity and poor adsorption efficiency for organic arsenic. The primary objective of this invention is to provide a novel method for preparing a metal-doped mesoporous titanium dioxide composite material. This method generates mesoporous titanium dioxide material through a hydrothermal process and improves the adsorption activity of the mesoporous titanium dioxide composite material for organic arsenic by improving the reaction conditions and utilizing metal doping, thereby achieving efficient adsorption and removal of organic arsenic from water.

[0008] To achieve the above objectives, the present invention provides a novel method for preparing a metal-doped mesoporous titanium dioxide composite material, specifically comprising the following steps:

[0009] (1) Titanium chloride is added dropwise onto ice to form a titanium chloride solution. Doped metal chloride is added and heated and stirred. After cooling, strontium chloride is added. Potassium hydroxide solution is added dropwise and stirred to obtain a slurry.

[0010] (2) The slurry from step (1) is placed in a high-pressure reactor, heated rapidly, nitrogen gas is introduced to regulate the pressure of the reactor, sealed and heated for a period of time, and after it cools naturally, the solution is washed until the pH value is neutral and dried to obtain metal-doped strontium titanate.

[0011] (3) Take metal-doped strontium titanate, add pure water and concentrated hydrochloric acid, react in a high-temperature and high-pressure reactor and then cool naturally. Wash the cooled slurry until the pH value is neutral, and put it into a freeze dryer to dry to obtain mesoporous titanium dioxide composite material.

[0012] Step (1) Add titanium chloride to ice to form a solution at a temperature of -25 to -5°C. Add the titanium chloride solution at a constant rate of 0.05 to 0.20 ml / min. Preferably, the ice cube is a geometrically regular cube or cuboid, and more preferably, the ice cube is a regular shape with a size of 5 to 20 mm.

[0013] In step (1), the ratio of the mass of ice to the mass of added titanium chloride liquid is 8 to 12, and the stirring speed is 50 to 150 rpm.

[0014] The doped metal chloride in step (1) includes at least one of ferric chloride and copper chloride; the mass ratio of the added doped metal chloride salt to titanium chloride is 0.05 to 1; the heating temperature is 35 to 60°C; the holding time is 5 to 30 min; the mass ratio of the added strontium chloride to the mass of titanium chloride in the solution is 0.75 to 0.95; and KOH solution is added to adjust the pH value to 14-14.5.

[0015] After adding potassium hydroxide solution in step (1), stir the reaction at a speed of 150-200 rpm for 10-40 minutes.

[0016] The rapid heating rate in step (2) is 8-15℃ / min, nitrogen gas is introduced to adjust the pressure of the reactor to 0.5-2.0 MPa; the sealing heating time is 22-28 hours; and the reaction temperature is 100-105℃.

[0017] In steps (2) and (3), centrifugal washing is used. The slurry temperature is 5-35℃, the centrifuge speed is 7000-10000rpm, the centrifugation time is 4-10min, and the pH of the supernatant after centrifugation is 6.6-7.0. The drying time of the slurry obtained after washing in step (2) is 3-6 hours, and the drying temperature is 65-80℃.

[0018] In step (3), the ratio of the solution to the dried sample in the reactor is 55-60; the concentrated hydrochloric acid is used to adjust the pH of the solution to 0-0.3; the temperature of the high-pressure reactor is 125-135℃; the reaction time is 2-3h; and the freeze-drying temperature is -40 to -50℃, and the time is 16-24h.

[0019] A second objective of this invention is to provide a metal-doped mesoporous titanium dioxide composite material prepared by the method described above.

[0020] A third objective of this invention is to provide the application of the aforementioned metal-doped mesoporous titanium dioxide composite material for the removal of contaminants in water, particularly organic arsenic.

[0021] Those skilled in the art should understand that organic arsenic, such as roxarsone and arsanilic acid, are important animal feed additives widely used in the livestock industry. Statistics show that the average annual consumption of roxarsone and arsanilic acid exceeds 20 million tons. Such a massive amount of organic arsenic enters the natural environment through animal excrement and other means. Once in the environment, organic arsenic undergoes physicochemical and biological reactions, producing various substances such as arsenates and their substates. These reactions and the resulting arsenic-containing substances are mobile and highly water-soluble, easily entering water bodies and causing water pollution, which expands the polluted area and increases the difficulty of pollution treatment. Therefore, adsorption methods are considered an important means of removing organic arsenic from water bodies due to their advantages such as simple operation, good removal efficiency, no need for additional chemical reagents, ability to recover arsenic from wastewater, and minimal environmental impact. How to achieve efficient adsorption and fixation of organic arsenic in organically polluted water bodies (especially those with low concentrations of organic pollution) is the biggest challenge facing water treatment and harmlessness.

[0022] Based on this, in order to effectively adsorb and remove organic arsenic pollutants in water, the present invention provides a method for preparing a novel metal-doped mesoporous titanium dioxide composite material, preferably comprising the following steps:

[0023] S1, provide several ice cubes with regular shapes, and add titanium chloride solution to the ice cubes dropwise at a uniform rate, while slowly stirring until a homogeneous titanium chloride solution is formed.

[0024] It should be noted that the ice cubes are at a temperature of -25℃ to -5℃, and are 5 to 20 mm in size with a regular shape, i.e., the ice cubes are geometrically regular cubes or cuboids. When adding the titanium chloride solution, the operation should be uniform, with the dripping speed controlled at 0.05 to 0.20 ml / min, the ratio of the mass of the ice cubes to the mass of the added titanium chloride solution being 8 to 12, and the stirring speed being 50 to 150 rpm.

[0025] S2, Place the above titanium chloride solution in a magnetic stirrer, add a certain mass of doped metal chloride salt, raise the temperature and turn on the stirrer for a period of time, then add a small amount of strontium chloride and a high-concentration potassium hydroxide solution (concentration 4mol / L), stir at a uniform speed for a period of time to form a slurry; then place the mixed solution in an autoclave, raise the temperature in the high-pressure reactor, and react for a period of time.

[0026] The doped metal chloride is copper chloride or ferric chloride, and the mass ratio of the added metal chloride to titanium chloride is 0.05–1. The heating temperature is 35–60°C, the holding time is 5–30 min, and the mass ratio of added strontium chloride to titanium chloride in the solution is 0.75–0.95. KOH solution is added to adjust the pH to 14–14.5, and the stirring rate is 150–200 rpm. Subsequently, it is placed in a high-temperature and high-pressure reactor, with a rapid heating rate of 8–15°C / min and the pressure adjusted to 0.5–2.0 MPa. The slurry is sealed and heated for 22–28 hours. The reaction temperature in the high-pressure reactor is 100–105°C.

[0027] S3. After the above reaction, put the slurry into a centrifuge tube, add a small amount of pure water, centrifuge the slurry at high speed, pour off the supernatant and measure the pH value. Repeat the above operation until the pH value is neutral, and dry the solid substance obtained by centrifugation.

[0028] The temperature of the slurry before centrifugation should be 5-35℃, the centrifuge speed should be 7000-10000 rpm, the centrifugation time should be 4-10 min, the pH of the supernatant after centrifugation should be 6.6-7.0, the drying temperature should be 65-80℃, and the drying time should be 3-6 h.

[0029] S4. Take out a small amount of dried sample, add a small amount of pure water, mix well, add concentrated hydrochloric acid to adjust the pH, then put the mixed solution into a high-pressure reactor, and then place the reactor in a high-temperature and high-pressure reactor to react for a period of time.

[0030] The pH value is adjusted to 0-0.3 with concentrated hydrochloric acid, the ratio of solution to dried sample is 55-60, the liner of the autoclave is Teflon, the temperature of the high-temperature and high-pressure reactor is 125-135℃, and the reaction time is 2-3 hours.

[0031] S5, remove the above high-temperature reaction object, let it cool naturally to room temperature, place it in a centrifuge tube, add a small amount of pure water, centrifuge, take out the supernatant and measure the pH value, repeat the centrifugation and washing operation until the pH is neutral 6.5-7.0; put it in a freeze dryer to freeze dry to obtain a novel metal-doped mesoporous titanium dioxide composite material.

[0032] The cooling to ambient temperature is 20-30℃, the centrifuge speed is 7000-10000 rpm, the centrifugation time is 4-10 min, and the freeze-drying time is 16-24 h; the freeze-drying temperature is -40 to -50℃.

[0033] It is important to understand that this invention addresses the current overuse of organic arsenic in animal feed, leading to the accumulation of large amounts of organic arsenic in the natural environment and posing a serious environmental pollution risk. Traditional adsorption materials suffer from low adsorption activity and poor adsorption efficiency for organic arsenic. This invention provides a novel method for preparing a metal-doped mesoporous titanium dioxide composite material. This method generates mesoporous titanium dioxide material via a hydrothermal process and enhances the adsorption activity of the mesoporous titanium dioxide composite material for organic arsenic by utilizing metal doping and improved reaction conditions, achieving highly efficient adsorption and removal of organic arsenic from water. The method of this invention is simple, easy to operate, and has good treatment effects, effectively removing organic arsenic (especially low concentrations) from water.

[0034] Compared with the prior art, the technical solution of the present invention has at least the following advantages:

[0035] 1. This invention develops a novel method for preparing a metal-doped mesoporous titanium dioxide composite material, which can adsorb and fix organic arsenic pollutants in situ in polluted water bodies, with low treatment cost and high removal efficiency.

[0036] 2. Compared with existing photodegradation methods or traditional adsorption-degradation methods, the adsorption and removal of organic arsenic from water by the metal-doped mesoporous titanium dioxide composite material of this invention significantly improves the removal efficiency of organic arsenic and avoids the environmental risk of inorganic arsenic re-release. Attached Figure Description

[0037] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the content shown in these drawings without creative effort.

[0038] Figure 1 The images show SEM images of the synthesized metal-doped mesoporous titanium dioxide in the examples and comparative examples.

[0039] Figure 2 The images show the XRD patterns of the synthesized metal-doped mesoporous titanium dioxide in the examples and comparative examples.

[0040] Figure 3 The image shows the zeta potential diagrams of the synthesized metal-doped mesoporous titanium dioxide in the examples and comparative examples.

[0041] Figure 4 Infrared images of the synthesized metal-doped mesoporous titanium dioxide in the examples and comparative examples.

[0042] Figure 1 Scanning electron microscopy images revealed doped metals ( Figure 1 TiO2 materials with bcd) compared to undoped ( Figure 1 a) Metal doping leads to larger TiO2 grains, reduced agglomeration, and the appearance of mesopores inside.

[0043] Figure 2 XRD also indicates that the crystal structure of metal-doped TiO2 changes. Compared with undoped TiO2, the intensity of its crystal diffraction peaks is weaker, the defects on the material surface are more numerous, and the adsorption and reaction activity is greater.

[0044] Figure 3 The zeta potential indicates that the surface charge variation range of doped TiO2 is larger, and its reactivity is increased;

[0045] Infrared images are displayed at 3400-3500cm. -1 The peak intensity of the hydroxyl stretching vibration is between the copper and iron peaks. The addition of metals increases the intensity of the hydroxyl peak, indicating that the increased surface defects in the copper and iron materials lead to an increased content of adsorbed hydroxyl groups on their surface. Furthermore, compared to copper and iron in equal proportions, the iron-containing mesoporous TiO2 composite material has more surface defects. Detailed Implementation

[0046] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0047] Furthermore, the technical solutions of the various embodiments of the present invention can be combined with each other, but only if they are based on the ability of those skilled in the art to implement them. When the combination of technical solutions is contradictory or cannot be implemented, it should be considered that such combination of technical solutions does not exist and is not within the scope of protection claimed by the present invention.

[0048] When numerical ranges are given in the embodiments, it should be understood that, unless otherwise stated in the present invention, both endpoints of each numerical range and any value between the two endpoints may be selected. Unless otherwise defined, all technical and scientific terms used in this invention, as well as the prior art known to those skilled in the art and the description of this invention, may be implemented using any prior art methods, devices, and materials similar to or equivalent to those described, used, or made of materials in the embodiments of this invention.

[0049] The technical solutions provided by the present invention will be described in detail below with reference to specific examples, but they should not be construed as limiting the scope of protection of the present invention.

[0050] Example 1

[0051] A novel method for preparing a metal-doped mesoporous titanium dioxide composite material includes the following steps:

[0052] 1. Take a small amount of regularly shaped ice cubes and add titanium chloride liquid dropwise to the ice cubes at a uniform rate, stirring slowly until a homogeneous titanium chloride solution is formed.

[0053] It should be noted that the ice cube is at a temperature of -15℃, is a rectangular ice cube with a size of 8-15mm, and has a mass of 10g; titanium chloride is added to the ice cube at a drip rate of 0.10ml / min, with a mass of 1.00g of titanium chloride added, and the stirring speed is 120rpm.

[0054] 2. Place the above titanium chloride solution in a magnetic stirrer, add 1.00g of ferric chloride, raise the temperature and start stirring for a period of time, then add a small amount of strontium chloride and potassium hydroxide solution, stir at a constant speed for a period of time to form a slurry; then place the mixed solution in an autoclave, raise the temperature in the high-pressure reactor, and react for a period of time.

[0055] The heating temperature was 40℃, the holding time was 5 min, and 0.80 g of strontium chloride was added. The pH was adjusted to 14.5 by adding 4 mol / L KOH solution, and the stirring rate was 200 rpm. The mixture was placed in a high-pressure reactor, the heating rate was 8℃ / min, the pressure inside the reactor was adjusted to 0.5 MPa, the reaction temperature was 100℃, and the reaction time was 24 h.

[0056] 3. Place the slurry after the above reaction into a centrifuge tube, add a small amount of pure water, centrifuge the slurry at high speed, pour off the supernatant and measure the pH value. Repeat the above operation until the pH value is neutral, and dry the solid substance obtained by centrifugation.

[0057] The slurry temperature before centrifugation should be 25℃, the centrifuge speed should be 8000rpm, the centrifugation time should be 10min, the pH of the supernatant after washing and centrifugation should be 6.8, the drying temperature should be 75℃, and the drying time should be 5h.

[0058] 4. Take out 0.50g of dried sample, add 25ml of pure water, mix well, then add concentrated hydrochloric acid (to adjust pH to 0.1), and then put the mixed solution into a high-pressure reactor. Then place the reactor in a high-temperature and high-pressure reactor for a period of time.

[0059] The temperature of the high-temperature and high-pressure reactor is 130℃, and the reaction time is 2.5h.

[0060] 5. Remove the above-mentioned high-temperature reaction object, allow it to cool naturally to room temperature, place it in a centrifuge tube, add a small amount of pure water, centrifuge, take out the supernatant and measure the pH value, repeat the centrifugation and washing operation until the pH is neutral; place it in a freeze dryer to freeze dry and obtain iron-doped mesoporous titanium dioxide composite material.

[0061] The cooling to ambient temperature was 30°C, the centrifuge speed was 8000 rpm, the centrifugation time was 10 min, the washing pH was neutral 6.7; the freeze-drying time was 20 h, and the freezing temperature was -40°C; after drying the powder sample, an iron-doped titanium dioxide composite material was obtained.

[0062] 6. Using organic arsenic-contaminated water (No. 1 organic arsenic-contaminated water body) as the treatment target, the main information of the solution is as follows: organic arsenic (roxarsone) 5 mg / L, pH = 4.2, chloride ion concentration 0.001 mol / L, sulfate ion concentration 0.005 mol / L, phosphate ion concentration 0.00003 mol / L. 0.005 g of iron-doped titanium dioxide composite material was added to 30 ml of wastewater, and the mixture was placed in a shaker and reacted for 12 h at 200 rpm. After the reaction, the solution was filtered through a 0.22 μm glass fiber membrane, and the supernatant was collected. The residual total As concentration was measured, and the adsorption capacity was calculated.

[0063] The organic arsenic removal rate was 95.07%; its material SEM image is as follows. Figure 1 As shown in Figure a, the XRD image is as follows: Figure 2 As shown, the Zeta potential image is as follows Figure 3 As shown, the infrared image is as follows Figure 4 As shown.

[0064] Comparative Example 1

[0065] The only difference between this comparative example and Example 1 is that it provides different organic arsenic wastewater (2# organic arsenic polluted water body), mainly to increase the concentration of phosphate ions in the water body.

[0066] The target wastewater was organic arsenic-contaminated water (No. 2 organic arsenic-contaminated water body). The main information of the solution was as follows: organic arsenic (roxarsone) 5 mg / L, pH = 4.2, chloride ion concentration 0.001 mol / L, sulfate ion concentration 0.005 mol / L, phosphate ion concentration 0.005 mol / L. 0.005 g of iron-doped titanium dioxide composite material was added to 30 ml of wastewater, and the mixture was reacted in a shaker for 12 h at 200 rpm. After the reaction, the solution was filtered through a 0.22 μm glass fiber membrane, and the supernatant was collected. The residual total As concentration was measured, and the adsorption capacity was calculated.

[0067] The organic arsenic removal rate was 45.07%.

[0068] Comparative Example 2

[0069] The only difference between this comparative example and Example 1 is that the adsorption time of the material is reduced.

[0070] The target wastewater was organic arsenic-contaminated water (No. 1 organic arsenic-contaminated water body). The main information of the solution was as follows: organic arsenic (roxarsone) 5 mg / L, pH = 4.2, chloride ion concentration 0.001 mol / L, sulfate ion concentration 0.005 mol / L, phosphate ion concentration 0.00003 mol / L. 0.005 g of iron-doped titanium dioxide composite material was added to 30 ml of wastewater, and the mixture was reacted in a shaker for 6 h at 200 rpm. After the reaction, the solution was filtered through a 0.22 μm glass fiber membrane, and the supernatant was collected. The residual total As concentration was measured, and the adsorption capacity was calculated.

[0071] The organic arsenic removal rate was 52.11%.

[0072] Comparative Example 3

[0073] The only difference between this comparative example and Example 1 is that it provides different organic arsenic wastewater (3# organic arsenic polluted water body), mainly to increase the concentration of sulfate ions in the water body.

[0074] The target treatment was wastewater contaminated with organic arsenic (No. 3 organic arsenic contaminated wastewater). The main information of the solution was as follows: organic arsenic (roxarsone) 5 mg / L, pH = 4.2, chloride ion concentration 0.001 mol / L, sulfate ion concentration 0.025 mol / L, phosphate ion concentration 0.00003 mol / L. 0.005 g of iron-doped titanium dioxide composite material was added to 30 ml of wastewater, and the mixture was reacted in a shaker for 12 h at 200 rpm. After the reaction, the solution was filtered through a 0.22 μm glass fiber membrane, and the supernatant was collected. The residual total As concentration was measured, and the adsorption capacity was calculated.

[0075] The organic arsenic removal rate was 83.26%.

[0076] Comparative Example 4

[0077] The only difference between this comparative example and Example 1 is that different organic arsenic wastewater (4# organic arsenic polluted water body) is provided, mainly to change the pH value of the polluted water body.

[0078] The target wastewater was organic arsenic-contaminated water (No. 4 organic arsenic-contaminated water body). The main information of the solution was as follows: organic arsenic (roxarsone) 5 mg / L, pH = 8.4, chloride ion concentration 0.001 mol / L, sulfate ion concentration 0.005 mol / L, phosphate ion concentration 0.00003 mol / L. 0.005 g of iron-doped titanium dioxide composite material was added to 30 ml of wastewater, and the mixture was reacted in a shaker for 12 h at 200 rpm. After the reaction, the solution was filtered through a 0.22 μm glass fiber membrane, and the supernatant was collected. The residual total As concentration was measured, and the adsorption capacity was calculated.

[0079] The organic arsenic removal rate was 34.95%.

[0080] Comparative Example 5

[0081] The only difference between this comparative example and Example 1 is that it provides different organic arsenic wastewater (5# organic arsenic polluted water body), mainly to reduce the concentration of organic arsenic (roxax arsenic) in the water body.

[0082] The target wastewater was organic arsenic-contaminated water (No. 5 organic arsenic-contaminated water body). The main information of the solution was: organic arsenic (roxarsone) 2 mg / L, pH = 4.2, chloride ion concentration 0.001 mol / L, sulfate ion concentration 0.005 mol / L, and phosphate ion concentration 0.00003 mol / L. 0.005 g of iron-doped titanium dioxide composite material was added to 30 ml of wastewater, and the mixture was reacted in a shaker for 12 h at 200 rpm. After the reaction, the solution was filtered through a 0.22 μm glass fiber membrane, and the supernatant was collected. The residual total As concentration was measured, and the adsorption capacity was calculated.

[0083] The organic arsenic removal rate was 97.04%.

[0084] Comparative Example 6

[0085] The only difference between this comparative example and Example 1 is that it provides different organic arsenic wastewater (6# organic arsenic polluted water body), mainly to increase the chloride ion concentration in the water body.

[0086] The target treatment was wastewater contaminated with organic arsenic (No. 6 organic arsenic contaminated wastewater). The main information of the solution was as follows: organic arsenic (roxarsone) 5 mg / L, pH = 4.2, chloride ion concentration 0.015 mol / L, sulfate ion concentration 0.005 mol / L, phosphate ion concentration 0.00003 mol / L. 0.005 g of iron-doped titanium dioxide composite material was added to 30 ml of wastewater, and the mixture was reacted in a shaker for 12 h at 200 rpm. After the reaction, the solution was filtered through a 0.22 μm glass fiber membrane, and the supernatant was collected. The residual total As concentration was measured, and the adsorption capacity was calculated.

[0087] The removal rate of organic arsenic was 93.76%.

[0088] Comparative Example 7

[0089] The only difference between this comparative example and Example 1 is that no metal salt ions were doped during the synthesis process.

[0090] The target wastewater was organic arsenic-contaminated water (No. 1 organic arsenic-contaminated water body). The main information of the solution was: organic arsenic (roxarsone) 5 mg / L, pH = 4.2, chloride ion concentration 0.001 mol / L, sulfate ion concentration 0.005 mol / L, and phosphate ion concentration 0.00003 mol / L. 0.005 g of titanium dioxide was added to 30 ml of wastewater, and the mixture was reacted in a shaker for 12 h at 200 rpm. After the reaction, the solution was filtered through a 0.22 μm glass fiber membrane, and the supernatant was collected. The residual total As concentration was measured, and the adsorption capacity was calculated.

[0091] The organic arsenic removal rate was 68.65%; its material SEM image is as follows: Figure 1 As shown in b, the XRD image is as follows Figure 2 As shown, the Zeta potential image is as follows Figure 3 As shown, the infrared image is as follows Figure 4 As shown.

[0092] Comparative Example 8

[0093] The only difference between this comparative example and Example 1 is the slow heating reaction.

[0094] Step (2) is placed in a high-pressure reactor and slowly heated to 100°C at a rate of 3°C / min. The pressure inside the reactor is controlled at 0.5 MPa, the reaction temperature is 100°C, and the reaction time is 24 h.

[0095] The target wastewater was organic arsenic-contaminated water (No. 1 organic arsenic-contaminated water body). The main information of the solution was as follows: organic arsenic (roxarsone) 5 mg / L, pH = 4.2, chloride ion concentration 0.001 mol / L, sulfate ion concentration 0.005 mol / L, phosphate ion concentration 0.00003 mol / L. 0.005 g of iron-doped titanium dioxide composite material was added to 30 ml of wastewater, and the mixture was reacted in a shaker for 12 h at 200 rpm. After the reaction, the solution was filtered through a 0.22 μm glass fiber membrane, and the supernatant was collected. The residual total As concentration was measured, and the adsorption capacity was calculated.

[0096] The organic arsenic removal rate was 77.07%.

[0097] Example 2

[0098] A novel method for preparing a metal-doped mesoporous titanium dioxide composite material includes the following steps:

[0099] 1. Take a small amount of regularly shaped ice cubes and add titanium chloride solution to the ice cubes at a uniform rate, stirring slowly until a homogeneous titanium chloride solution is formed.

[0100] It should be noted that the ice cube is at a temperature of -10℃, is a rectangular ice cube with a size of 5-8mm, and has a mass of 10g; titanium chloride is added to the ice cube at a drip rate of 0.15ml / min, with a mass of 0.90g of titanium chloride added, and the stirring rate is 150rpm.

[0101] 2. Place the above titanium chloride solution in a magnetic stirrer, add 0.10g of ferric chloride, raise the temperature and start stirring for a period of time, then add a small amount of strontium chloride and potassium hydroxide solution, stir at a constant speed for a period of time to form a slurry; then place the mixed solution in an autoclave, raise the temperature in the high-pressure reactor, and react for a period of time.

[0102] The heating temperature was 45℃, the holding time was 10 min, and 0.70 g of strontium chloride was added. The pH was adjusted to 14.3 by adding 4 mol / L KOH solution, and the stirring rate was 200 rpm. The mixture was placed in a high-pressure reactor, the heating rate was 9℃ / min, the pressure inside the reactor was adjusted to 0.8 MPa, the reaction temperature was 102℃, and the reaction time was 23 h.

[0103] 3. Place the slurry after the above reaction into a centrifuge tube, add a small amount of pure water, centrifuge the slurry at high speed, pour off the supernatant and measure the pH value. Repeat the above operation until the pH value is neutral, and dry the solid substance obtained by centrifugation.

[0104] The slurry temperature before centrifugation should be 25℃, the centrifuge speed should be 8000rpm, the centrifugation time should be 10min, the pH of the supernatant after washing and centrifugation should be 7.0, the drying temperature should be 80℃, and the drying time should be 4h.

[0105] 4. Take out 0.50g of dried sample, add 25ml of pure water, mix well, add concentrated hydrochloric acid to adjust the pH to 0.3, then put the mixed solution into a high-pressure reactor, and then place the reactor in a high-temperature and high-pressure reactor for a period of time.

[0106] The autoclave is lined with Teflon, the temperature of the high-temperature and high-pressure reactor is 135℃, and the reaction time is 2.5h.

[0107] 5. Remove the above-mentioned high-temperature reaction object, allow it to cool naturally to room temperature, place it in a centrifuge tube, add a small amount of pure water, centrifuge, take out the supernatant and measure the pH value, repeat the centrifugation and washing operation until the pH is neutral; place it in a freeze dryer to freeze dry and obtain iron-doped mesoporous titanium dioxide composite material.

[0108] The cooling process was carried out at 25°C, the centrifuge speed was 8000 rpm, the centrifugation time was 10 min, and the washing operation was performed until the pH was neutral at 6.7. The freeze-drying time was 16 h, and the powder sample was dried at -40°C to obtain an iron-doped titanium dioxide composite material.

[0109] 6. Using organic arsenic-contaminated water (No. 1 organic arsenic-contaminated water body) as the treatment target, the main information of the solution is as follows: organic arsenic (roxarsone) 5 mg / L, pH = 4.0, chloride ion concentration 0.001 mol / L, sulfate ion concentration 0.005 mol / L, phosphate ion concentration 0.00003 mol / L. 0.005 g of iron-doped titanium dioxide composite material was added to 30 ml of wastewater, and the mixture was placed in a shaker and reacted for 12 h at 200 rpm. After the reaction, the solution was filtered through a 0.22 μm glass fiber membrane, and the supernatant was collected. The residual total As concentration was measured, and the adsorption capacity was calculated.

[0110] The organic arsenic removal rate was 91.22%; its material SEM image is as follows. Figure 1 As shown in c, the XRD image is as follows Figure 2 As shown.

[0111] Example 3

[0112] A novel method for preparing a metal-doped mesoporous titanium dioxide composite material includes the following steps:

[0113] 1. Take a small amount of regularly shaped ice cubes and add titanium chloride solution to the ice cubes at a uniform rate, stirring slowly until a homogeneous titanium chloride solution is formed.

[0114] It should be noted that the ice cube is at a temperature of -15℃ and is a rectangular ice cube with a size of 8-15mm; titanium chloride is added to the ice cube at a drip rate of 0.10ml / min, the mass of titanium chloride added is 1.00g, and the stirring rate is 120rpm.

[0115] 2. Place the above titanium chloride solution in a magnetic stirrer, add 1.00g of copper chloride, raise the temperature and turn on the stirrer for a period of time, then add a small amount of strontium chloride and a high-concentration potassium hydroxide solution, stir at a constant speed for a period of time to form a slurry; then place the mixed solution in an autoclave, raise the temperature in the high-pressure reactor, and react for a period of time.

[0116] The heating temperature was 40℃, the holding time was 5 min, and 0.80 g of strontium chloride was added. The pH was adjusted to 14.5 by adding 4 mol / L KOH solution, and the stirring rate was 200 rpm. The mixture was placed in a high-pressure reactor, the heating rate was 8℃ / min, the pressure inside the reactor was adjusted to 0.6 MPa, the reaction temperature was 100℃, and the reaction time was 24 h.

[0117] 3. Place the slurry after the above reaction into a centrifuge tube, add a small amount of pure water, centrifuge the slurry at high speed, pour off the supernatant and measure the pH value. Repeat the above operation until the pH value is neutral, and dry the solid substance obtained by centrifugation.

[0118] The slurry temperature before centrifugation should be 25℃, the centrifuge speed should be 8000rpm, the centrifugation time should be 10min, the pH of the supernatant after washing and centrifugation should be 6.8, the drying temperature should be 75℃, and the drying time should be 5h.

[0119] 4. Take out 0.50g of dried sample, add 25ml of pure water, mix well, add concentrated hydrochloric acid to adjust the pH to 0.2, then put the mixed solution into a high-pressure reactor, and then place the reactor in a high-temperature and high-pressure reactor for a period of time.

[0120] The autoclave is lined with Teflon, the temperature of the high-temperature and high-pressure reactor is 130℃, and the reaction time is 2.5h.

[0121] 5. Remove the above-mentioned high-temperature reaction object, allow it to cool naturally to room temperature, place it in a centrifuge tube, add a small amount of pure water, centrifuge, take out the supernatant and measure the pH value, repeat the centrifugation and washing operation until the pH is neutral; place it in a freeze dryer to freeze dry and obtain copper-doped mesoporous titanium dioxide composite material.

[0122] The cooling to room temperature was 30°C, the centrifuge speed was 8000 rpm, the centrifugation time was 10 min, and the washing operation was carried out until the pH was neutral 6.7; the freeze drying time was 20 h, and the temperature was -40°C; after drying the powder sample, copper-doped titanium dioxide composite material was obtained.

[0123] 6. Using organic arsenic-contaminated water (No. 1 organic arsenic-contaminated water body) as the treatment target, the main information of the solution is as follows: organic arsenic (roxarsone) 5 mg / L, pH = 4.2, chloride ion concentration 0.001 mol / L, sulfate ion concentration 0.005 mol / L, phosphate ion concentration 0.00003 mol / L. 0.005 g of copper-doped titanium dioxide composite material was added to 30 ml of wastewater, and the mixture was placed in a shaker and reacted for 12 h at 200 rpm. After the reaction, the solution was filtered through a 0.22 μm glass fiber membrane, and the supernatant was collected. The residual total As concentration was measured, and the adsorption capacity was calculated.

[0124] The organic arsenic removal rate was 88.29%; its material SEM image is as follows: Figure 1 As shown in d, the XRD image is as follows Figure 2 As shown, the Zeta potential image is as follows Figure 3 As shown, the infrared image is as follows Figure 4 As shown.

[0125] The above technical solutions of the present invention are merely preferred embodiments of the present invention and do not limit the patent scope of the present invention. All equivalent structural transformations made under the technical concept of the present invention using the contents of the present invention specification and drawings, or direct / indirect applications in other related technical fields, are included in the patent protection scope of the present invention.

Claims

1. A method for preparing a metal-doped mesoporous titanium dioxide composite material, characterized by, Specifically comprising the following steps: (1) titanium chloride is added dropwise to ice to form a titanium chloride solution, a doped metal chloride is added and stirred while warming, strontium chloride is added after cooling, potassium hydroxide solution is added dropwise and stirred to obtain a slurry; (2) the slurry of step (1) is placed in an autoclave, rapidly heated, nitrogen is injected to control the pressure of the reaction kettle, sealed and heated for a period of time, and after natural cooling, the solution is washed to neutral pH, and dried to obtain metal-doped strontium titanate; (3) the metal-doped strontium titanate is taken, pure water and concentrated hydrochloric acid are added, and after reaction in a high-temperature and high-pressure reaction kettle, it is naturally cooled, the cooled slurry is washed to neutral pH, and is placed in a freeze dryer to dry to obtain mesoporous titanium dioxide composite material; In step (1), the doped metal chloride includes at least one of iron chloride and copper chloride; the mass ratio of the added amount of the doped metal chloride to titanium chloride is 0.05-1; the warming temperature is 35-60℃, and the holding time is 5-30 min; the mass ratio of the added strontium chloride to titanium chloride in the solution is 0.75-0.95, and the pH value of the solution is adjusted to 14-14.5 by adding KOH solution; In step (2), the rapid heating rate is 8-15℃ / min, nitrogen is injected to control the pressure of the reaction kettle to 0.5-2.0 Mpa; the sealing and heating time is 22-28 hours; and the heating to the reaction temperature is 100-105℃; In step (3), the ratio of the solution in the reaction kettle to the dried sample is 55-60; the pH value of the solution is adjusted to 0-0.3 by the concentrated hydrochloric acid; the temperature of the high-pressure reaction kettle is 125-135℃; the reaction time is 2-3h; and the freeze drying temperature is -40--50℃, and the time is 16-24h.

2. The method of claim 1, wherein: In step (1), titanium chloride is added to ice to form a solution, the temperature is -25--5℃, and the uniform speed of adding titanium chloride solution is 0.05-0.20ml / min.

3. The method of claim 1, wherein: The shape of the ice block is a geometrically regular cube or cuboid.

4. The method of claim 3, wherein: The ice block with a regular shape has a size of 5-20 mm.

5. The method of any one of claims 1-4, wherein: In step (1), the mass ratio of the ice block to the added titanium chloride solution is 8-12, and the stirring rate is 50-150 rpm.

6. The method of claim 1, wherein: In step (1), after adding potassium hydroxide solution, the stirring is performed at a rotation speed of 150-200 rpm for 10-40 min.

7. The method of claim 1, wherein: In steps (2) and (3), centrifugal washing is used, the slurry temperature is 5-35℃, the centrifuge rotation speed is 7000-10000 rpm, the centrifugation time is 4-10 min, and the pH value of the supernatant after centrifugation is 6.6-7.0; the drying time of the slurry obtained after step (2) is 3-6 hours; and the drying temperature is 65-80℃.

8. A metal-doped mesoporous titania composite material, characterized by, The mesoporous titanium dioxide composite material is prepared by the method of any one of claims 1-7.

9. Use of the metal-doped mesoporous titanium dioxide composite material according to claim 8, characterized in that Removal of organic arsenic in water.

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