Nanometer short fiber catalyst prepared by taking water body micro-nano plastic as raw material as well as preparation method and application of nanometer short fiber catalyst

Abstract

The invention discloses a short nano-fiber catalyst prepared from water micro-nano plastic as a raw material and a preparation method and application of the short nano-fiber catalyst. The short nano-fiber catalyst is prepared by taking polylactic acid short fibers in a water body as a template, titanium dioxide coated ferroferric oxide as a carrier, cerium dioxide as an active component and cobaltosic oxide as a cocatalyst. The catalyst is prepared by adopting an external field enhanced microbial mineralization-sol-gel growth-ice crystal self-assembly-dipping roasting method. The catalyst disclosed by the invention is environment-friendly, not only can efficiently catalyze and reduce organic matters in the wastewater, but also can treat wastes with wastes, realizes high-value utilization of micro-nano plastics in the wastewater, and has relatively high economic value and scientific significance.

Description

Technical Field

[0001] The invention relates to a method for preparing a nanometer short fiber catalyst by taking water micro-nano plastic as raw material and application thereof, belonging to the field of water treatment. Background Art

[0002] Micro-nano plastics are now widely present in the global water environment, including inland waters, estuaries, coastal areas, and even the polar regions. Domestic micro-nano plastics are also widely present in sewage treatment plants, freshwater and marine environments, mainly from household and industrial wastewater discharge, atmospheric input, surface runoff, etc. In addition, plastic waste is decomposed by light, oxidation, weathering and other factors in the natural environment, which will also produce a large amount of micro-nano plastics. Micro-nano plastics are not only easily ingested by aquatic organisms, causing intestinal dysfunction and even death, but are also passed to higher trophic levels through the food chain, causing greater ecological harm. Although sewage treatment plants have a certain removal effect on micro-nano plastics, a large amount of micro-nano plastics are still discharged into the environment through sewage treatment plants. For example, a small sewage treatment plant can release about 1.83×10 10 Currently, wastewater treatment plants remove an average of approximately 80% of microplastics and nanoplastics, but the specific removal rate varies depending on the treatment process and the characteristics of the microplastics. Existing technologies, such as membrane filtration, while effective at removing larger microplastics, are less effective against smaller particles and have not yet enabled further resource utilization of microplastics in water. Therefore, developing technologies to recycle microplastics in water has become a major research focus.

[0003] On the other hand, p-nitrophenol is a significant organic pollutant, widely present in wastewater from industries such as pesticides, dyes, and pharmaceuticals. With the rapid development of industry, the use and discharge of p-nitrophenol have continued to increase, leading to increasingly serious water pollution problems. p-nitrophenol is highly toxic and difficult to biodegrade, posing a serious threat to the environment and human health. Currently, Fenton oxidation technology is one of the key methods for treating p-nitrophenol wastewater. This technology oxidizes and degrades p-nitrophenol by generating hydroxyl radicals, offering high efficiency and rapidity. However, the degradation rate of Fenton oxidation technology is only high under artificial ultraviolet light, while the degradation rate is relatively low under sunlight. Catalytic reduction methods, which utilize catalysts to reduce p-nitrophenol, also offer highly efficient degradation, with the development of catalytic materials being a key research focus. Therefore, developing highly efficient catalysts for p-nitrophenol is an important research direction. Summary of the Invention

[0004] The purpose of the present invention is to address the current situation and existing problems in the field of water pollution treatment, and to propose a nano-short fiber catalyst prepared by using water micro-nano plastic as raw material, as well as a preparation method and application thereof.

[0005] The present invention can be achieved through the following technical solutions: the catalyst uses activated polylactic acid short fibers as a template, forms short fibers by cutting commercial polylactic acid fibers and then wet-ball milling, and then uses plasma surface modification to increase the number of hydroxyl and carboxyl groups on the fiber surface, which can not only simulate the occurrence form of micro-nano plastics in actual wastewater, but also make the short fibers easier to adsorb ferroferric oxide in the subsequent mineralization process. At the same time, it can also ensure the uniformity of the morphology of micro-nano plastics in the research process, avoiding the difficulty in repeating the research results due to the different morphologies of micro-nano plastics in actual wastewater; because conventional methods make it difficult to evenly grow ferroferric oxide on the surface of short fibers, the present invention utilizes the advantage that magnetotactic bacteria can form nanomagnetic particles in the body, and utilizes micro The biomineralization technology deposits ferroferric oxide on the surface of short fibers, and at the same time enhances microbial metabolism through the ultrasonic cavitation effect of pulsed ultrasound, accelerating the heterogeneous nucleation of ferroferric oxide on the fiber surface; then the present invention utilizes the property of titanium salt that is easily hydrolyzed to form gel in an alkaline environment to wrap titanium dioxide on the surface of ferroferric oxide, and directionally assembles nanofibers through ice crystal growth to avoid structural collapse caused by high-temperature sintering. In addition, to avoid structural collapse, the polylactic acid fiber template is carbonized and ablated using an atmosphere furnace gradient heating calcination system to form a titanium dioxide-wrapped ferroferric oxide nano-short fiber carrier; finally, the cerium dioxide and cobalt oxide are loaded on the carrier surface by the impregnation calcination method to form a nano-short fiber catalyst.

[0006] The present invention can be achieved through the following technical solutions:

[0007] A nanofiber catalyst is prepared using water-based micro-nano plastic as raw material. The catalyst uses polylactic acid short fibers dispersed in water as a template, titanium dioxide-coated ferroferric oxide as a carrier, cerium dioxide as an active component, and cobalt oxide as a co-catalyst. The catalyst is prepared using an external field-enhanced microbial mineralization-sol-gel growth-ice crystal self-assembly-impregnation and roasting method.

[0008] Based on the mass of the carrier, the mass percentage of the active component is 1-10%, the mass percentage of the co-catalyst is 1-3%, and the mass ratio of titanium dioxide to ferrosoferric oxide in the carrier is 1:(2-8).

[0009] In the technical solution of the present invention: the preparation method of the catalyst is as follows:

[0010] (1) External field enhanced microbial mineralization deposition of ferroferric oxide

[0011] Placing polylactic acid short fiber powder in a plasma surface modification instrument and introducing oxygen for surface modification and activation to obtain activated polylactic acid short fiber powder;

[0012] Mixed solution A was prepared by uniformly mixing magnetotactic bacteria (CGMCC 1.5154), activated polylactic acid staple fiber powder, succinic acid, sodium nitrate, and deionized water;

[0013] A mixture of carbon dioxide and nitrogen is introduced into a mixed solution A to remove oxygen from the reaction system; after the oxygen is removed, a ferric chloride solution is added under the same conditions and the pH value of the reaction system is adjusted to 6.0-6.9; the solution of the reaction system is then subjected to pulse ultrasound using a probe ultrasonic instrument and then allowed to stand for mineralization; after the standby incubation and mineralization is completed, a magnet is placed in the reaction system to adsorb ferroferric oxide-coated polylactic acid staple fibers; and finally, the particles adsorbed on the surface of the magnet are dried to obtain ferroferric oxide-coated polylactic acid staple fiber particles;

[0014] (2) Preparation of carriers by combined sol-gel growth and ice crystal self-assembly

[0015] The titanium salt, anhydrous ethanol, and the ferroferric oxide-coated polylactic acid short fiber particles obtained in step (1) are uniformly mixed to obtain a mixed solution B; under stirring, ammonia water is added to the mixed solution B until the pH value of the system is 8.5 to 9.5 for reaction; the titanium dioxide gel layer obtained by the reaction is placed in liquid nitrogen for direction freezing, then freeze-dried, and finally placed in an atmosphere furnace for calcination to obtain a titanium dioxide-coated ferroferric oxide nano short fiber carrier;

[0016] (3) Preparation of catalyst by impregnation and calcination

[0017] Cerium salt, cobalt salt and deionized water are weighed and mixed evenly to prepare a precursor solution, and then the titanium dioxide-coated ferroferric oxide nanofiber carrier prepared in step (2) is placed in the precursor solution, impregnated and then dried, and finally placed in a muffle furnace for calcination to obtain a catalyst.

[0018] Further: the polylactic acid fiber described in step (1) is purchased from Tai'an Anfeng New Material Technology Co., Ltd., and the length of the polylactic acid fiber after cutting is 20 to 30 mm;

[0019] During the surface modification and activation process, the mass volume ratio of the polylactic acid short fiber powder to the introduced oxygen is 1g: (20-30)mL, the power is 50-100W, and the time is 5-10min.

[0020] Furthermore: in step (1), the mass ratio of magnetotactic bacteria, activated polylactic acid staple fiber powder, succinic acid, sodium nitrate and deionized water is 1: (0.05-0.10): (0.05-0.10): (0.02-0.04): (500-1000).

[0021] Further: the volume ratio of carbon dioxide to nitrogen in step (1) is 1:(49-99);

[0022] The mass fraction of the ferric chloride solution in step (1) is 10-15%;

[0023] The intensity of pulsed ultrasound is 50-70W / cm2 The working cycle of pulse ultrasound is 3 to 8 seconds on and 10 to 20 seconds off, and the duration of pulse ultrasound is 1 to 3 hours;

[0024] The static culture mineralization time is 24 to 48 hours; the drying temperature is 60 to 80° C., and the drying time is 12 to 24 hours.

[0025] Furthermore: the titanium salt described in step (2) is tetrabutyl titanate or tetraethyl titanate, the mass ratio of titanium salt and anhydrous ethanol is 1: (30-50); the reaction temperature is 50-70°C, the reaction time is 2-4h, and the mass fraction of ammonia water is 5-10%.

[0026] Furthermore: the freezing time in step (2) is 20 to 40 minutes; the freeze-drying temperature is -40 to -50°C, and the freeze-drying time is 24 to 48 hours;

[0027] The calcination adopts a programmed temperature rising method, firstly heating to 300-350°C at a rate of 5-10°C / min and introducing nitrogen at a rate of 20-30 mL / min, then heating to 500-600°C at a rate of 1-2°C / min and introducing oxygen at a rate of 20-30 mL / min.

[0028] Furthermore, the cerium salt described in step (3) is cerium nitrate hexahydrate or cerium chloride, the cobalt salt is cobalt nitrate or cobalt chloride, the impregnation time is 30 to 60 minutes, the drying temperature is 80 to 100° C., and the drying time is 4 to 8 hours; the calcination temperature is 500 to 700° C., and the calcination time is 3 to 6 hours.

[0029] In the technical solution of the present invention, the catalyst is used in the catalytic reduction of organic pollutants in water.

[0030] In some more preferred technical solutions, the organic pollutant is p-nitrophenol.

[0031] Beneficial effects

[0032] (1) The catalyst uses size-homogenized polylactic acid short fibers as a template. Through external field-enhanced microbial mineralization, it can not only realize the resource utilization of microplastics in water bodies, but also achieve size homogenization of the catalyst at the microscopic scale.

[0033] (2) The catalyst uses ferroferric oxide as the core of the carrier and titanium dioxide as the carrier coating. It can not only utilize the magnetism of ferroferric oxide to make the catalyst easily recyclable after catalytic reduction of p-nitrophenol in water, but also utilize the synergistic catalytic effect of ferroferric oxide and titanium dioxide to enhance the catalytic reduction effect of cerium dioxide and cobalt oxide.

[0034] (3) The catalyst component is environmentally friendly and can efficiently catalyze the reduction of p-nitrophenol in wastewater, and has strong application and promotion value. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 FE-SEM image of the nanofiber catalyst prepared in Example 1. DETAILED DESCRIPTION

[0036] The present invention will be further described below with reference to the embodiments, but the scope of protection of the present invention is not limited thereto:

[0037] The magnetotactic bacteria strain (CGMCC 1.5154) used in the examples was purchased from the China General Microbiological Culture Collection Center.

[0038] The polylactic acid fiber was purchased from Tai'an Anfeng New Material Technology Co., Ltd.

[0039] Example 1

[0040] (1) External field enhanced microbial mineralization deposition of ferroferric oxide

[0041] Weigh 10 g of polylactic acid fiber and cut it into short fibers with a length of 20 mm. Then add 100 g of grinding balls and 200 g of deionized water, mix, and place in a planetary ball mill at a speed of 100 rpm for 30 min to obtain polylactic acid short fiber powder. Then weigh 2 g of polylactic acid short fiber powder and place it in a plasma surface modification instrument. 40 mL of oxygen is introduced and the surface is modified and activated at a power of 50 W for 10 min to obtain activated polylactic acid short fiber powder (the surface modification activation process is repeated until the polylactic acid short fiber powder is used up);

[0042] 20 groups were weighed in parallel (each group underwent the following operation). Each mixed solution A was prepared by uniformly mixing 1 g of magnetotactic bacteria (CGMCC1.5154), 0.05 g of activated polylactic acid staple fiber powder, 0.05 g of succinic acid, 0.02 g of sodium nitrate, and 500 g of deionized water. A mixture of carbon dioxide and nitrogen was introduced into the mixed solution A at a rate of 20 mL / min for 10 min (the volume ratio of carbon dioxide to nitrogen was 1:49), and then magnetically stirred at a constant temperature of 25°C for 1 h to remove oxygen from the reaction system. After removing oxygen and under this condition, 25 g of 10% ferric chloride solution was added to each mixed solution A, and the pH of the reaction system was adjusted to 6.4 using a 10% sodium hydroxide solution. The mixture was stirred at 50 W / cm using a probe ultrasonicator. 2The reaction system was subjected to pulse ultrasound at a high intensity for 3 hours and then allowed to stand for mineralization for 24 hours (the working cycle of the pulse ultrasound was 5 seconds on and 15 seconds off). After the static incubation and mineralization, a magnet was placed in the reaction system to adsorb the polylactic acid short fibers wrapped with ferroferric oxide. Finally, the particles adsorbed on the surface of the magnet were placed in an oven at 60° C. and dried for 24 hours to obtain polylactic acid short fiber particles wrapped with ferroferric oxide.

[0043] (2) Preparation of carriers by combined sol-gel growth and ice crystal self-assembly

[0044] 5.07 g of tetrabutyl titanate, 152.10 g of anhydrous ethanol, and 2.48 g of the ferroferric oxide-coated polylactic acid short fiber particles obtained in step (1) (ferroferric oxide content of 2.38 g) were weighed and mixed uniformly to obtain a mixed solution B. The mixed solution B was placed in a constant temperature magnetic stirrer at 50° C. and rapidly stirred at a rate of 200 r / min for 4 h. During the stirring process, 5% by mass ammonia water was slowly added dropwise until the pH of the mixed solution B reached 9;

[0045] Weigh 20 g of titanium dioxide gel layer and place it in a 50 mL polytetrafluoroethylene can. Then, place the polytetrafluoroethylene can in 800 g of liquid nitrogen for directional freezing for 40 min. The frozen gel is placed in a freeze dryer at -40 ° C and freeze-dried for 48 h. Finally, it is placed in an atmosphere furnace and calcined by gradient temperature to obtain titanium dioxide-coated ferrosoferric oxide nanofiber carrier (the gradient temperature calcination process is to heat the temperature to 300 ° C at a rate of 5 ° C / min and pass nitrogen at a rate of 20 mL / min, then heat the temperature to 500 ° C at a rate of 1 ° C / min and pass oxygen at a rate of 20 mL / min);

[0046] (3) Preparation of catalyst by impregnation and calcination

[0047] 75.7 mg of cerium nitrate hexahydrate, 68.4 mg of cobalt nitrate, and 15.14 g of deionized water were weighed and mixed uniformly to prepare a precursor solution, and then 3.00 g of the titanium dioxide-coated ferroferric oxide nanofiber carrier prepared in step (2) was weighed and placed in the precursor solution. After impregnation for 30 min, the carrier was dried at 80 ° C for 8 h, and finally placed in a muffle furnace and calcined at 500 ° C for 6 h to obtain a catalyst (based on the mass of the carrier, the mass percentage of the active component is 1%, the mass percentage of the co-catalyst is 1%, and the mass ratio of titanium dioxide to ferroferric oxide in the carrier is 1:2);

[0048] (4) Performance evaluation

[0049] 1 mL of catalyst was loaded into a catalyst performance evaluation device, and a reaction solution was introduced for performance evaluation. The concentration of the reaction solution was: 40 mL of p-nitrophenol (100 mg / L) and 40 mL of sodium borohydride (1.89 g / L). The removal efficiency of p-nitrophenol at room temperature reached 100%, and the removal rate was 7 mL / min.

[0050] Example 2

[0051] (1) External field enhanced microbial mineralization deposition of ferroferric oxide

[0052] Weigh 10 g of polylactic acid fiber and cut it into short fibers with a length of 30 mm. Then add 200 g of grinding balls and 300 g of deionized water, mix them, and place them in a planetary ball mill at a speed of 200 rpm for 10 min to obtain polylactic acid short fiber powder. Then weigh 2 g of polylactic acid short fiber powder and place it in a plasma surface modification instrument. 60 mL of oxygen is introduced and the surface is modified and activated at a power of 100 W for 5 min to obtain activated polylactic acid short fiber powder (the surface modification activation process is repeated until the polylactic acid short fiber powder is used up);

[0053] 20 groups were weighed in parallel (each group underwent the following operation). Each mixed solution A was prepared by mixing 1 g of magnetotactic bacteria (CGMCC1.5154), 0.10 g of activated polylactic acid staple fiber powder, 0.10 g of succinic acid, 0.04 g of sodium nitrate, and 1000 g of deionized water. A mixture of carbon dioxide and nitrogen was introduced into the mixed solution A at a rate of 30 mL / min for 5 min (the volume ratio of carbon dioxide to nitrogen was 1:99), and then magnetically stirred at a constant temperature of 30°C for 2 h to remove oxygen. After deoxygenation, 100 g of 15% ferric chloride solution was weighed and added to each mixed solution A under this condition. The pH of the reaction system was adjusted to 6.8 using a 20% sodium hydroxide solution. The mixture was stirred at 70 W / cm using a probe ultrasonicator. 2 The reaction system was subjected to pulse ultrasound with a certain intensity for 1 hour and then allowed to stand for mineralization for 48 hours (the working cycle of the pulse ultrasound was 5 seconds on and 15 seconds off). After the static culture and mineralization, a magnet was placed in the reaction system to adsorb the polylactic acid staple fibers wrapped with ferroferric oxide. Finally, the particles adsorbed on the surface of the magnet were placed in an oven and dried at 80°C for 12 hours to obtain polylactic acid staple fiber particles wrapped with ferroferric oxide.

[0054] (2) Preparation of carriers by combined sol-gel growth and ice crystal self-assembly

[0055] Weigh 2.55g of tetraethyl titanate, 127.50g of anhydrous ethanol, and 7.24g of the ferroferric oxide-coated polylactic acid short fiber particles obtained in step (1) (the ferroferric oxide content is 7.14g) and mix them evenly to obtain a mixed solution B. The mixed solution B is placed in a constant temperature magnetic stirrer and rapidly stirred at a rate of 250r / min for 2h at 70°C. During the stirring process, 10% ammonia water is slowly added dropwise until the pH of the mixed solution B reaches 9. Weigh 20g of the titanium dioxide gel layer and place it in 100mL of polytetrafluoroethylene. The polytetrafluoroethylene tank was placed in 1000g liquid nitrogen for directional freezing for 20min, the frozen gel was placed in a freeze dryer at -50℃ for freeze drying for 24h, and finally placed in an atmosphere furnace for gradient temperature calcination to obtain titanium dioxide-coated ferrosoferric oxide nanofiber carrier (the gradient temperature calcination process was to heat the temperature to 350℃ at a rate of 10℃ / min and pass nitrogen at a rate of 30mL / min, then heat the temperature to 600℃ at a rate of 2℃ / min and pass oxygen at a rate of 30mL / min);

[0056] (3) Preparation of catalyst by impregnation and calcination

[0057] 429.6 mg of cerium chloride, 145.6 mg of cobalt chloride, and 42.96 g of deionized water were weighed and mixed evenly to prepare a precursor solution. Then, 3.00 g of the titanium dioxide-coated ferroferric oxide nanofiber carrier prepared in step (2) was weighed and placed in the precursor solution. After immersion for 60 min, the carrier was dried at 100 ° C for 4 h, and finally placed in a muffle furnace and calcined at 700 ° C for 3 h to obtain a catalyst (based on the mass of the carrier, the mass percentage of the active component is 10%, the mass percentage of the co-catalyst is 3%, and the mass ratio of titanium dioxide and ferroferric oxide in the carrier is 1:8).

[0058] (4) Performance evaluation

[0059] 1 mL of catalyst was loaded into a catalyst performance evaluation device, and a reaction solution was introduced for performance evaluation. The concentration of the reaction solution was: 40 mL of p-nitrophenol (100 mg / L) and 40 mL of sodium borohydride (1.89 g / L). The removal efficiency of p-nitrophenol reached 100% at room temperature, and the removal rate was 10 mL / min.

Claims

1. A nanofiber catalyst prepared from water micro-nano plastics as raw materials, characterized by: The catalyst uses polylactic acid short fibers dispersed in water as a template, titanium dioxide-coated ferroferric oxide as a carrier, cerium dioxide as an active component, and cobalt oxide as a cocatalyst. It is prepared by an external field-enhanced microbial mineralization-sol-gel growth-ice crystal self-assembly-impregnation and calcination method. Based on the mass of the carrier, the mass percentage of the active component is 1-10%, the mass percentage of the co-catalyst is 1-3%, and the mass ratio of titanium dioxide to ferrosoferric oxide in the carrier is 1:(2-8).

2. A method for preparing the catalyst according to claim 1, characterized in that: The preparation method of the catalyst is as follows: (1) External field enhanced microbial mineralization deposition of ferroferric oxide Placing polylactic acid short fiber powder in a plasma surface modification instrument and introducing oxygen for surface modification and activation to obtain activated polylactic acid short fiber powder; Mixed solution A was prepared by uniformly mixing magnetotactic bacteria (CGMCC 1.5154), activated polylactic acid staple fiber powder, succinic acid, sodium nitrate, and deionized water; A mixture of carbon dioxide and nitrogen is introduced into a mixed solution A to remove oxygen from the reaction system; after the oxygen is removed, a ferric chloride solution is added under the same conditions and the pH value of the reaction system is adjusted to 6.0-6.9; the solution of the reaction system is then subjected to pulse ultrasound using a probe ultrasonic instrument and then allowed to stand for mineralization; after the standby incubation and mineralization is completed, a magnet is placed in the reaction system to adsorb ferroferric oxide-coated polylactic acid staple fibers; and finally, the particles adsorbed on the surface of the magnet are dried to obtain ferroferric oxide-coated polylactic acid staple fiber particles; (2) Preparation of carriers by combined sol-gel growth and ice crystal self-assembly The titanium salt, anhydrous ethanol, and the ferroferric oxide-coated polylactic acid short fiber particles obtained in step (1) are uniformly mixed to obtain a mixed solution B; under stirring, ammonia water is added to the mixed solution B until the pH value of the system is 8.5 to 9.5 for reaction; the titanium dioxide gel layer obtained by the reaction is placed in liquid nitrogen for direction freezing, then freeze-dried, and finally placed in an atmosphere furnace for calcination to obtain a titanium dioxide-coated ferroferric oxide nano short fiber carrier; (3) Preparation of catalyst by impregnation and calcination Cerium salt, cobalt salt and deionized water are weighed and mixed evenly to prepare a precursor solution, and then the titanium dioxide-coated ferroferric oxide nanofiber carrier prepared in step (2) is placed in the precursor solution, impregnated and then dried, and finally placed in a muffle furnace for calcination to obtain a catalyst.

3. The preparation method according to claim 2, wherein: The polylactic acid fiber described in step (1) was purchased from Tai'an Anfeng New Material Technology Co., Ltd., and the length of the polylactic acid fiber after cutting was 20 to 30 mm; During the surface modification and activation process, the mass volume ratio of the polylactic acid short fiber powder to the introduced oxygen is 1g: (20-30)mL, the power is 50-100W, and the time is 5-10min.

4. The preparation method according to claim 2, wherein: In step (1), the mass ratio of magnetotactic bacteria, activated polylactic acid staple fiber powder, succinic acid, sodium nitrate and deionized water is 1: (0.05-0.10): (0.05-0.10): (0.02-0.04): (500-1000).

5. The preparation method according to claim 2, wherein: The volume ratio of carbon dioxide to nitrogen in step (1) is 1:(49-99); The mass fraction of the ferric chloride solution in step (1) is 10-15%; The intensity of pulsed ultrasound is 50-70W / cm 2 The working cycle of pulse ultrasound is 3 to 8 seconds on and 10 to 20 seconds off, and the duration of pulse ultrasound is 1 to 3 hours; The static culture mineralization time is 24 to 48 hours; the drying temperature is 60 to 80° C., and the drying time is 12 to 24 hours.

6. The preparation method according to claim 2, wherein: The titanium salt described in step (2) is tetrabutyl titanate or tetraethyl titanate, and the mass ratio of the titanium salt to anhydrous ethanol is 1:(30-50); the reaction temperature is 50-70°C, the reaction time is 2-4h, and the mass fraction of ammonia water is 5-10%.

7. The preparation method according to claim 2, characterized in that: The freezing time in step (2) is 20 to 40 minutes; the freeze-drying temperature is -40 to -50°C, and the freeze-drying time is 24 to 48 hours; The calcination adopts a programmed temperature rising method, firstly heating to 300-350°C at a rate of 5-10°C / min and introducing nitrogen at a rate of 20-30 mL / min, then heating to 500-600°C at a rate of 1-2°C / min and introducing oxygen at a rate of 20-30 mL / min.

8. The preparation method according to claim 2, wherein: The cerium salt described in step (3) is cerium nitrate hexahydrate or cerium chloride, the cobalt salt is cobalt nitrate or cobalt chloride, the impregnation time is 30 to 60 minutes; the drying temperature is 80 to 100° C., and the drying time is 4 to 8 hours; the roasting temperature is 500 to 700° C., and the roasting time is 3 to 6 hours.

9. Use of the catalyst according to claim 1 in catalytic reduction of organic pollutants in water.

10. The use according to claim 10, characterized in that The organic pollutant is p-nitrophenol.

Images