Titanium dioxide composite photocatalyst, and preparation method and application thereof

Abstract

The application provides a titanium dioxide composite photocatalyst and a preparation method and application thereof, and belongs to the technical field of chemical materials. The preparation method provided by the application is prepared by using a specific raw material formula, and the titanium dioxide composite photocatalyst is prepared through the preparation method of mixing and calcining part of raw materials first, and then mixing and ball milling the remaining raw materials. The titanium dioxide composite photocatalyst provided by the application can utilize more wavelengths of light, achieve better photocatalytic effect, and achieve the effect of degrading organic wastewater under natural light without needing to specially provide an ultraviolet light environment, and the treatment efficiency is relatively high. For a small amount of wastewater, the COD content can reach the discharge standard only by treating the wastewater for 6 hours, and the development of the related wastewater treatment agent has important significance.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of chemical materials, in particular to a titanium dioxide composite photocatalyst and a preparation method and application thereof. BACKGROUND

[0002] Titanium dioxide (TiO2) is an oxide widely existing in nature and is widely used in various fields due to its unique physical and chemical properties. In the field of photocatalysis, titanium dioxide, as an important photocatalyst, can promote the progress of chemical reactions under light conditions. This property mainly originates from the semiconductor properties of titanium dioxide. Semiconductor materials have a special energy band structure, in which there is a forbidden band between the valence band and the conduction band. Under light conditions, when the photon energy is greater than the forbidden band width, the electrons in the valence band can be excited into the conduction band to form electron-hole pairs. These electron-hole pairs have high reactivity and can participate in redox reactions, thereby driving the progress of photocatalytic processes.

[0003] Due to the semiconductor properties of titanium dioxide and its excellent photocatalytic performance, it has broad application prospects in the field of semiconductors: 1. Environmental purification: titanium dioxide photocatalyst can be used to degrade organic pollutants, remove heavy metal ions, etc., to purify air and water, and has great potential in the field of environmental protection. 2. Energy conversion: titanium dioxide photocatalyst can be used in the fields of solar cells, water splitting to produce hydrogen, etc., to realize the conversion of solar energy to electrical or chemical energy. This is of great significance to solving the energy crisis and realizing sustainable development. 3. Antibacterial and mildew-proof: titanium dioxide photocatalyst can generate free radicals with strong oxidizing properties under light conditions, which can kill bacteria, mold and other microorganisms. Therefore, it can be used to manufacture antibacterial and mildew-proof coating, ceramic and other building materials products.

[0004] There are various schemes in the prior art to modify titanium dioxide to make it have better performance in the field of photocatalysts, for example:

[0005] Chinese patent CN112044423A discloses a graphite-titanium dioxide composite photocatalyst and a preparation method thereof, which belongs to the technical field of photocatalyst material preparation. The preparation method of the graphite-titanium dioxide composite photocatalyst and the preparation method thereof is carried out according to the following steps: a, mix graphite powder with solvent uniformly to obtain graphite powder dispersion liquid; b, mix titanium dioxide with graphite powder dispersion liquid uniformly to obtain graphite-titanium dioxide slurry; c, hydrothermally ultrasonically disperse the graphite-titanium dioxide slurry to obtain a composite photocatalyst precursor; d, vacuum calcine the composite photocatalyst precursor to obtain a composite photocatalyst calcined material; e, ball mill the composite photocatalyst calcined material for 8-24 hours to obtain the graphite-titanium dioxide composite photocatalyst. The process broadens the spectral response range of the photocatalyst, improves the photocatalytic activity, and has good application prospect in the field of wastewater treatment.

[0006] Chinese patent CN107952426A discloses a preparation method of a vanadium-titanium dioxide composite photocatalyst, comprising the following steps: (1) taking titanyl sulfate and sodium metavanadate and dissolving them in deionized water, magnetically stirring, adding urea, magnetically stirring, then heating the system to 50 DEG C and keeping the temperature for reaction; (2) ultrasonic reaction, natural cooling to room temperature, then microwave reaction for 10 min; (3) heating to 140-150 DEG C, then reaction for 10 h, natural cooling to room temperature, standing for 24 h; (4) suction filtration, washing the filter residue with deionized water, first drying at 60 DEG C for 12 h, then calcining in a muffle furnace, and the vanadium-titanium dioxide composite photocatalyst can be obtained. The vanadium-titanium dioxide composite photocatalyst is prepared by a hydrothermal method, the preparation method is simple, the absorption band of titanium dioxide is red-shifted to visible light, the utilization of visible light is improved, and the photocatalytic activity is improved.

[0007] Wastewater containing oil discharged in industrial production process. The oil contained in the oil-containing wastewater includes natural oil, oil products, tar and its fraction, and edible animal and plant oil and fat. From the pollution of water body, the main is oil and tar. The concentration of oil contained in wastewater discharged by different industrial departments is quite different. For example, the oil content in wastewater generated in oil refining process is about 150-1000 mg / L, the tar content in wastewater of coking plant is 500-800 mg / L, and the tar content in wastewater of coal gas station can reach 2000-3000 mg / L. The oil in wastewater usually exists in three states: ① the dispersed particles of oil in wastewater are large, the particle size is greater than 100 μm, and the oil is easy to separate from wastewater, and in oil sewage, the oil accounts for 60-80% of the total oil content in water; ② the dispersed particles of oil in wastewater are small, and the oil is in emulsified state and is not easy to separate from wastewater; ③ a small part of oil is in dissolved state, and the solubility is about 5-15 mg / L. The oil-containing wastewater is usually recovered by oil separation tank.

[0008] However, the titanium dioxide catalyst in the prior art has limited degradation performance on oil-containing wastewater. SUMMARY

[0009] The purpose of the present application is to provide a titanium dioxide composite photocatalyst and a preparation method and application thereof, which has excellent degradation performance on oil-containing wastewater.

[0010] In order to achieve the above-mentioned purpose of the application, the present application provides the following technical solutions:

[0011] The present application provides a preparation method of a titanium dioxide composite photocatalyst, comprising the following steps:

[0012] S1, titanium dioxide, silicon dioxide and quartz sand are mixed and calcined to obtain intermediate material 1;

[0013] S2, mixing intermediate material 1 with lignite ultrafine coal powder, kaolin, low-sulfur coke and auxiliary agent, and performing ball milling to obtain the titanium dioxide composite photocatalyst.

[0014] Preferably, in S1, the weight ratio of the mixed titanium dioxide, silicon dioxide and quartz sand is 80-120:10-30:20-40.

[0015] Preferably, the calcination temperature is 500-700℃.

[0016] The calcination time is 2-5h.

[0017] Preferably, before mixing intermediate material 1 with lignite ultrafine coal powder, kaolin, low-sulfur coke and auxiliary agent, grinding is further included, and the particle size of the ground material is 180-220 mesh.

[0018] Preferably, the weight ratio of the titanium dioxide, lignite ultrafine coal powder, kaolin and low-sulfur coke is 80-120:10-30:10-30:30-50.

[0019] Preferably, the rotation speed of the ball milling is 400-600rpm.

[0020] And / or, the ball-to-material ratio of the ball milling is 10-30:1.

[0021] And / or, the ball milling time is 6-18h.

[0022] And / or, the ball milling medium used is 0.05-0.2mm zirconium oxide microbeads.

[0023] Preferably, the auxiliary agent contains polyvinyl alcohol and ethylenediaminetetraacetic acid.

[0024] The volume ratio of polyvinyl alcohol and ethylenediaminetetraacetic acid in the auxiliary agent is 1:0.8-1.2.

[0025] The addition amount of the auxiliary agent is 0.5-2% of the weight of all materials for ball milling.

[0026] The application also provides a titanium dioxide composite photocatalyst prepared by the above preparation method.

[0027] The application also provides the use of the above titanium dioxide composite photocatalyst in wastewater treatment.

[0028] Preferably, the wastewater is oil-containing wastewater.

[0029] The technical effects and advantages of the application are as follows:

[0030] The preparation method provided by the application is prepared by using a specific raw material formula, and the preparation method is that part of the raw materials are mixed and calcined first, and then mixed with the remaining raw materials by ball milling to obtain the titanium dioxide composite photocatalyst. The titanium dioxide composite photocatalyst provided by the application can utilize more wavelength light, achieve better photocatalytic effect, and achieve the effect of degrading organic wastewater under natural light without special provision of ultraviolet light illumination environment, and the treatment efficiency is higher, and for a small amount of wastewater, only 6h is needed to treat the COD content to reach the discharge standard, and it has important significance for the development of related wastewater treatment agents. DETAILED DESCRIPTION

[0031] The application provides a preparation method of a titanium dioxide composite photocatalyst, which comprises the following steps:

[0032] S1, titanium dioxide, silicon dioxide and quartz sand are mixed and calcined to obtain intermediate material 1;

[0033] S2, the intermediate material 1 is mixed with lignite ultra-fine coal powder, kaolin, low-sulfur coke and an auxiliary agent, and is subjected to ball milling to obtain the titanium dioxide composite photocatalyst.

[0034] In the application, the titanium dioxide is preferably nano-titanium dioxide; preferably, in S1, the weight ratio of the mixed titanium dioxide, silicon dioxide and quartz sand is 80-120:10-30:20-40. Preferably, the calcination temperature is 500-700 DEG C; the calcination time is 2-5h. Preferably, before the intermediate material 1 is mixed with the lignite ultra-fine coal powder, kaolin, low-sulfur coke and auxiliary agent, grinding is further included, and the particle size of the ground material is 180-220 meshes. Preferably, the weight ratio of the titanium dioxide, lignite ultra-fine coal powder, kaolin and low-sulfur coke is 80-120:10-30:10-30:30-50. Preferably, the rotation speed of the ball milling is 400-600 rpm; and / or, the ball-to-material ratio of the ball milling is 10-30:1; and / or, the ball milling time is 6-18h; and / or, the ball milling medium used is 0.05-0.2mm zirconia microbeads. Preferably, the auxiliary agent contains polyvinyl alcohol and ethylenediaminetetraacetic acid; the volume ratio of polyvinyl alcohol and ethylenediaminetetraacetic acid in the auxiliary agent is 1:0.8-1.2; and the addition amount of the auxiliary agent is 0.5-2% of the weight of all the materials for ball milling.

[0035] The application further provides a titanium dioxide composite photocatalyst prepared by the above preparation method.

[0036] The application further provides the application of the above titanium dioxide composite photocatalyst in wastewater treatment. Preferably, the wastewater is oil-containing wastewater.

[0037] In the present application, the titanium dioxide composite photocatalyst can be preferably used for wastewater treatment in combination with other reagents, including: flocculants: used in primary sedimentation tank, secondary sedimentation tank, air floatation tank and coagulation advanced treatment process, etc., to strengthen the solid-liquid separation effect. Common flocculants include polyaluminum chloride, polymeric ferric sulfate, cationic polyamine, etc. Coagulant aids: auxiliary flocculants to strengthen the coagulation effect, commonly used to improve the flocculation effect and settling velocity. Demulsifiers: mainly used for pretreatment of oil-containing wastewater containing emulsified oil before air floatation, including some flocculants and coagulant aids. Defoamers: used to eliminate a large amount of foam generated during aeration or stirring process, to prevent foam from affecting the treatment effect. pH adjuster: used to adjust the pH value of acidic wastewater and alkaline wastewater to neutral, to ensure the normal operation of subsequent treatment processes. Oxidizing and reducing agents: used for the treatment of industrial wastewater containing oxidizing or reducing substances, color, etc., to remove pollutants through oxidation-reduction reaction. Disinfectants: used for disinfection treatment before discharge or reuse after wastewater treatment, to ensure water quality safety.

[0038] In the present application, the titanium dioxide composite photocatalyst can be preferably used for wastewater treatment in combination with other treatment methods, including: gravity separation method: using the density difference and insolubility of oil and water, oil droplets are separated by floating through gravity. Commonly used equipment includes oil separation tank, suitable for treating high-concentration oil-containing wastewater. Air floatation method: by injecting air into wastewater to generate micro-bubbles, making the micro oil droplets adhere to the bubbles and float to the water surface, achieving the separation purpose. Common air floatation methods include air floatation, dissolved air floatation and electrolytic floatation. Adsorption method: using porous adsorbents (such as activated carbon, oil-absorbing soil, fiber, etc.) to adsorb oil in wastewater. Adsorption method is suitable for advanced treatment, but the adsorption capacity is limited and the cost is relatively high. Membrane separation method: using porous membrane to intercept oil and surfactants in wastewater, allowing water molecules to pass through, suitable for treating small amount of high-quality wastewater. Biological treatment method: using the degradation ability of microorganisms to decompose organic matter and oil in wastewater. Biological treatment method includes aerobic treatment and anaerobic treatment, suitable for treating low-concentration oil-containing wastewater. Chemical demulsification method: by adding inorganic electrolytes (such as magnesium chloride, hydrochloric acid, sulfuric acid, etc.) to destroy the repulsive force of oil droplets, making the oil droplets aggregate and float. Electrolytic flocculation method: using metal ions generated by electrode plates for flocculation treatment, suitable for treating high-concentration oil-containing wastewater.

[0039] The above methods can be combined with the method provided by the present application to treat oil-containing wastewater. In actual application, appropriate method combination is selected according to the properties and treatment requirements of wastewater to achieve the best treatment effect.

[0040] The technical solutions provided by the present application will be described in detail below in combination with examples, but they should not be understood as limiting the scope of protection of the present application.

[0041] The oil-containing wastewater parameters of the embodiment of the present application are: COD: 718-725 mg / L, Cl - : 563-570 mg / L.

[0042] Example 1

[0043] Accurately take 100 g of nano-titanium dioxide, 20 g of silicon dioxide and 30 g of quartz sand, mix uniformly, and calcine at 600 DEG C for 3 h to obtain a mixture;

[0044] Preliminarily grind to 200 mesh particle size, then add 20 g of brown coal ultra-fine coal powder, 20 g of kaolin and 40 g of low-sulfur coke, add 1% of auxiliary agent (polyvinyl alcohol + ethylenediaminetetraacetic acid, 1:1 volume mixture) based on the weight of all materials, set the ball milling speed to 500 rpm, the ball-to-material ratio to 20:1, and the ball milling time to 12 h (the ball milling medium used is 0.1 mm zirconia microbeads), to obtain a titanium dioxide composite photocatalyst.

[0045] The photocatalyst prepared in this embodiment is added to the oil-containing wastewater at a dosage of 10 g / L (three parallel experiments are performed on the catalyst prepared in this embodiment), and after mixing uniformly, it is subjected to natural light (about 3000 lux). The COD content of the sample is detected at 3 h and 6 h after addition, respectively, according to the "Determination of Chemical Oxygen Demand (COD) in Water by Preparing Reagent Spectrophotometry" (T / ZJATA0001-2020), to obtain the COD content of the sample at different time points after treatment, and the results are shown in Table 1 below.

[0046] Table 1 Wastewater treatment effect of the composite photocatalyst of Example 1

[0047] 3h sample COD 6h sample COD Sample 1 342.37 37.06 Sample 2 350.31 34.97 Sample 3 356.20 42.99

[0048] Example 2

[0049] Accurately take 120 g of nano-titanium dioxide, 30 g of silicon dioxide and 40 g of quartz sand, mix uniformly, and calcine at 600 DEG C for 3 h to obtain a mixture;

[0050] Preliminarily grind to 200 mesh particle size, then add 20 g of brown coal ultra-fine coal powder, 20 g of kaolin and 40 g of low-sulfur coke, add 1% of auxiliary agent (polyvinyl alcohol + ethylenediaminetetraacetic acid, 1:1 volume mixture) based on the weight of all materials, set the ball milling speed to 500 rpm, the ball-to-material ratio to 20:1, and the ball milling time to 12 h (the ball milling medium used is 0.1 mm zirconia microbeads), to obtain a titanium dioxide composite photocatalyst.

[0051] The photocatalyst prepared in this example was added to the oil-containing wastewater at a dosage of 10 g / L (three parallel experiments were performed for the catalyst prepared in this example), mixed uniformly, and then exposed to natural light (about 3000 lux). The COD content of the sample was detected at 3 h and 6 h after addition, respectively, according to the "Determination of Chemical Oxygen Demand (COD) in Water - Prepackaged Reagent Spectrophotometric Method" (T / ZJATA0001-2020), to obtain the COD content of the sample at different time points after treatment. The results are shown in Table 1 below.

[0052] Table 2 Wastewater treatment effect of composite photocatalyst of Example 2

[0053] 3h sample COD 6h sample COD Sample 1 350.55 42.16 Sample 2 346.74 38.90 Sample 3 345.12 33.85

[0054] Example 3

[0055] Accurately weigh 100 g of nano-titanium dioxide, 20 g of silicon dioxide and 30 g of quartz sand, mix uniformly, and calcine at 700°C for 3 h to obtain a mixture;

[0056] Preliminary grinding to 200 mesh particle size, then add 25 g of brown coal ultrafine coal powder, 25 g of kaolin and 50 g of low-sulfur coke, add 1% of the weight of all materials of auxiliary agent (polyvinyl alcohol + ethylenediaminetetraacetic acid, 1:1 volume mixture), set the ball milling speed to 500 rpm, the ball-to-material ratio to 20:1, and the ball milling time to 12 h (the ball milling medium used is 0.1 mm zirconia microbeads), to obtain a titanium dioxide composite photocatalyst.

[0057] The photocatalyst prepared in this example was added to the oil-containing wastewater at a dosage of 10 g / L (three parallel experiments were performed for the catalyst prepared in this example), mixed uniformly, and then exposed to natural light (about 3000 lux). The COD content of the sample was detected at 3 h and 6 h after addition, respectively, according to the "Determination of Chemical Oxygen Demand (COD) in Water - Prepackaged Reagent Spectrophotometric Method" (T / ZJATA0001-2020), to obtain the COD content of the sample at different time points after treatment. The results are shown in Table 1 below.

[0058] Table 3 Wastewater treatment effect of composite photocatalyst of Example 3

[0059] 3h sample COD 6h sample COD Sample 1 347.79 35.04 Sample 2 355.12 34.20 Sample 3 340.77 31.08

[0060] Example 4

[0061] Accurately weigh 80 g of nano-titanium dioxide, 20 g of silicon dioxide and 25 g of quartz sand, mix uniformly, and calcine at 600°C for 3 h to obtain a mixture;

[0062] The primary grinding is to 200 mesh particle size, then 20 g of lignite ultrafine coal powder, 20 g of kaolin and 40 g of low-sulfur coke are added, 1.5% of auxiliary agent (polyvinyl alcohol + ethylenediamine tetraacetic acid, 1:1 volume mixing) of the weight of all materials is added, the ball milling speed is set to 500 rpm, the ball-to-material ratio is 20:1, and the ball milling time is 11 h (the ball milling medium used is 0.1 mm zirconia microbeads), to obtain the titanium dioxide composite photocatalyst.

[0063] The photocatalyst prepared in this example is added to the oil-containing wastewater at a dosage of 10 g / L (three groups of parallel experiments are performed on the catalyst prepared in this example), mixed uniformly, and then exposed to natural light (about 3000 lux). The COD content of the sample is detected at 3 h and 6 h after addition, respectively, according to the "Determination of Chemical Oxygen Demand (COD) in Water - Preparing Reagent Spectrophotometric Method" (T / ZJATA0001-2020), to obtain the COD content of the sample at different time points after treatment. The results are shown in Table 1 below.

[0064] Table 4 Wastewater treatment effect of the composite photocatalyst of Example 4

[0065] 3h sample COD 6h sample COD Sample 1 359.13 42.78 Sample 2 341.36 30.53 Sample 3 340.63 37.25

[0066] Example 5

[0067] Accurately take 100 g of nano-titanium dioxide, 20 g of silicon dioxide and 35 g of quartz sand, mix uniformly, and then calcine at 650°C for 3.5 h to obtain the mixed material;

[0068] The primary grinding is to 200 mesh particle size, then 20 g of lignite ultrafine coal powder, 20 g of kaolin and 40 g of low-sulfur coke are added, 1.5% of auxiliary agent (polyvinyl alcohol + ethylenediamine tetraacetic acid, 1:1 volume mixing) of the weight of all materials is added, the ball milling speed is set to 500 rpm, the ball-to-material ratio is 20:1, and the ball milling time is 11 h (the ball milling medium used is 0.1 mm zirconia microbeads), to obtain the titanium dioxide composite photocatalyst.

[0069] The photocatalyst prepared in this example is added to the oil-containing wastewater at a dosage of 10 g / L (three groups of parallel experiments are performed on the catalyst prepared in this example), mixed uniformly, and then exposed to natural light (about 3000 lux). The COD content of the sample is detected at 3 h and 6 h after addition, respectively, according to the "Determination of Chemical Oxygen Demand (COD) in Water - Preparing Reagent Spectrophotometric Method" (T / ZJATA0001-2020), to obtain the COD content of the sample at different time points after treatment. The results are shown in Table 1 below.

[0070] Table 5 Wastewater treatment effect of the composite photocatalyst of Example 5

[0071] 3h sample COD 6h sample COD Sample 1 352.57 44.90 Sample 2 349.97 30.84 Sample 3 359.14 42.83

[0072] Example 6

[0073] Accurately weigh 105 g of nano-titanium dioxide, 20 g of silicon dioxide and 30 g of quartz sand, mix uniformly, and calcine at 600°C for 3 h to obtain a mixture;

[0074] Preliminarily grind to 200 mesh particle size, then add 15 g of ultrafine coal powder, 15 g of kaolin and 50 g of low-sulfur coke, add 0.8% of auxiliary agent (polyvinyl alcohol + ethylenediaminetetraacetic acid, 1:1 volume mixture) based on the weight of all materials, set the ball milling speed to 500 rpm, the ball-to-material ratio to 20:1, and the ball milling time to 12 h (the ball milling medium used is 0.1 mm zirconia microbeads), to obtain a titanium dioxide composite photocatalyst.

[0075] The photocatalyst prepared in this example was added to the oil-containing wastewater at a dosage of 10 g / L (three parallel experiments were performed using the catalyst prepared in this example), mixed uniformly, and then exposed to natural light (about 3000 lux). The COD content of the samples was measured at 3 h and 6 h after addition, according to the "Determination of Chemical Oxygen Demand (COD) in Water by Preparing Reagent Spectrophotometry" (T / ZJATA0001-2020), to obtain the COD content of the samples at different time points after treatment. The results are shown in Table 1 below.

[0076] Table 6 Wastewater treatment effect of the composite photocatalyst of Example 6

[0077] 3h sample COD 6h sample COD Sample 1 353.83 31.79 Sample 2 351.63 34.25 Sample 3 340.94 32.47

[0078] Example 7

[0079] Accurately weigh 110 g of nano-titanium dioxide, 15 g of silicon dioxide and 35 g of quartz sand, mix uniformly, and calcine at 600°C for 3 h to obtain a mixture;

[0080] Preliminarily grind to 200 mesh particle size, then add 22 g of ultrafine coal powder, 18 g of kaolin and 40 g of low-sulfur coke, add 1% of auxiliary agent (polyvinyl alcohol + ethylenediaminetetraacetic acid, 1:1 volume mixture) based on the weight of all materials, set the ball milling speed to 500 rpm, the ball-to-material ratio to 20:1, and the ball milling time to 11 h (the ball milling medium used is 0.1 mm zirconia microbeads), to obtain a titanium dioxide composite photocatalyst.

[0081] The photocatalyst prepared in this example was added to the oil-containing wastewater at a dosage of 10 g / L (three parallel experiments were performed for the catalyst prepared in this example), mixed uniformly, and then exposed to natural light (about 3000 lux). The COD content of the sample was detected at 3 h and 6 h after addition, respectively, according to the method of "Determination of Chemical Oxygen Demand (COD) in Water - Prepackaged Reagent Spectrophotometric Method" (T / ZJATA0001-2020), to obtain the COD content of the sample at different time points after treatment. The results are shown in Table 1 below.

[0082] Table 7 Wastewater treatment effect of composite photocatalyst of Example 7

[0083] 3h sample COD 6h sample COD Sample 1 350.18 40.13 Sample 2 358.00 39.44 Sample 3 358.72 35.76

[0084] Example 8

[0085] Accurately weigh 95 g of nano-titanium dioxide, 30 g of silicon dioxide and 25 g of quartz sand, mix uniformly, and calcine at 600°C for 3 h to obtain a mixture;

[0086] Preliminary grinding to 200 mesh particle size, then adding 20 g of ultrafine coal powder, 20 g of kaolin and 40 g of low-sulfur coke, adding 1% of auxiliary agent (polyvinyl alcohol + ethylenediaminetetraacetic acid, 1:1.2 volume mixture) based on the weight of all materials, setting the ball milling speed to 500 rpm, the ball-to-material ratio to 20:1, and the ball milling time to 12 h (the ball milling medium used is 0.1 mm zirconia microbeads), to obtain a titanium dioxide composite photocatalyst.

[0087] The photocatalyst prepared in this example was added to the oil-containing wastewater at a dosage of 10 g / L (three parallel experiments were performed for the catalyst prepared in this example), mixed uniformly, and then exposed to natural light (about 3000 lux). The COD content of the sample was detected at 3 h and 6 h after addition, respectively, according to the method of "Determination of Chemical Oxygen Demand (COD) in Water - Prepackaged Reagent Spectrophotometric Method" (T / ZJATA0001-2020), to obtain the COD content of the sample at different time points after treatment. The results are shown in Table 1 below.

[0088] Table 8 Wastewater treatment effect of composite photocatalyst of Example 8

[0089] 3h sample COD 6h sample COD Sample 1 349.98 42.09 Sample 2 340.72 42.21 Sample 3 356.62 31.77

[0090] Example 9

[0091] Accurately weigh 100 g of nano-titanium dioxide, 20 g of silicon dioxide and 30 g of quartz sand, mix uniformly, and calcine at 650°C for 3 h to obtain a mixture;

[0092] The primary grinding is to 200 mesh particle size, then 30 g of lignite ultrafine coal powder, 30 g of kaolin and 20 g of low-sulfur coke are added, 1% of auxiliary agent (polyvinyl alcohol + ethylenediamine tetraacetic acid, 1:1 volume mixing) is added to all materials, the ball milling speed is set to 500 rpm, the ball material ratio is 20:1, and the ball milling time is 12 h (the ball milling medium used is 0.1 mm zirconium oxide microbeads), to obtain the titanium dioxide composite photocatalyst.

[0093] The photocatalyst prepared in this example is added to the oil-containing wastewater at a dosage of 10 g / L (three groups of parallel experiments are performed on the catalyst prepared in this example), mixed uniformly, and then exposed to natural light (about 3000 lux). The COD content of the sample is detected at 3 h and 6 h after adding, respectively, according to the "Determination of Chemical Oxygen Demand (COD) in Water - Preparing Reagent Spectrophotometric Method" (T / ZJATA0001-2020), to obtain the COD content of the sample at different time points after treatment. The results are shown in Table 1 below.

[0094] Table 9 Wastewater treatment effect of the composite photocatalyst of Example 9

[0095] 3h sample COD 6h sample COD Sample 1 351.30 35.85 Sample 2 346.54 31.31 Sample 3 356.55 43.49

[0096] Example 10

[0097] Accurately weigh 110 g of nano-titanium dioxide, 20 g of silicon dioxide and 30 g of quartz sand, mix uniformly, and then calcine at 600°C for 3 h to obtain the mixed material;

[0098] The primary grinding is to 200 mesh particle size, then 30 g of lignite ultrafine coal powder, 30 g of kaolin and 20 g of low-sulfur coke are added, 1% of auxiliary agent (polyvinyl alcohol + ethylenediamine tetraacetic acid, 1:1 volume mixing) is added to all materials, the ball milling speed is set to 500 rpm, the ball material ratio is 20:1, and the ball milling time is 12 h (the ball milling medium used is 0.1 mm zirconium oxide microbeads), to obtain the titanium dioxide composite photocatalyst.

[0099] The photocatalyst prepared in this example is added to the oil-containing wastewater at a dosage of 10 g / L (three groups of parallel experiments are performed on the catalyst prepared in this example), mixed uniformly, and then exposed to natural light (about 3000 lux). The COD content of the sample is detected at 3 h and 6 h after adding, respectively, according to the "Determination of Chemical Oxygen Demand (COD) in Water - Preparing Reagent Spectrophotometric Method" (T / ZJATA0001-2020), to obtain the COD content of the sample at different time points after treatment. The results are shown in Table 10 below.

[0100] Table 10 Wastewater treatment effect of the composite photocatalyst of Example 10

[0101] 3h sample COD 6h sample COD Sample 1 358.94 37.78 Sample 2 345.36 34.24 Sample 3 351.94 37.83

[0102] Comparative Example 1

[0103] Accurately weigh 100 g of nano-titanium dioxide, 20 g of silicon dioxide and 30 g of quartz sand, mix uniformly, calcine at 600°C for 3 h, and then preliminarily grind to 200 mesh particle size. Then, set the ball milling speed to 500 rpm, the ball-to-material ratio to 20:1, and the ball milling time to 12 h (the ball milling medium used is 0.1 mm zirconia microbeads), to obtain a titanium dioxide composite photocatalyst.

[0104] The photocatalyst prepared in this comparative example was added to the oily wastewater (three groups of parallel experiments were performed using the catalyst prepared in this example) at a dosage of 10 g / L, mixed uniformly, and then subjected to natural light (about 3000 lux). The COD content of the sample was detected at 3 h and 6 h after addition, respectively, according to the “Determination of Chemical Oxygen Demand (COD) in Water by Spectrophotometry with Pre-prepared Reagent” (T / ZJATA0001-2020), to obtain the COD content of the sample at different time points after treatment. The results are shown in Table 11 below.

[0105] Table 11 Wastewater treatment effect of the composite photocatalyst of Comparative Example 1

[0106] 3h sample COD 6h sample COD Sample 1 544.18 230.66 Sample 2 595.47 214.49 Sample 3 586.76 228.54

[0107] Comparative Example 2

[0108] Accurately weigh 100 g of nano-titanium dioxide, 20 g of silicon dioxide, 30 g of quartz sand, 20 g of ultra-fine coal powder, 20 g of kaolin and 40 g of low-sulfur coke, add 1% of the auxiliary agent (polyvinyl alcohol + ethylenediaminetetraacetic acid, 1:1 by volume) based on the total weight of the materials, set the ball milling speed to 500 rpm, the ball-to-material ratio to 20:1, and the ball milling time to 12 h (the ball milling medium used is 0.1 mm zirconia microbeads), to obtain a titanium dioxide composite photocatalyst.

[0109] The photocatalyst prepared in this comparative example was added to the oily wastewater (three groups of parallel experiments were performed using the catalyst prepared in this example) at a dosage of 10 g / L, mixed uniformly, and then subjected to natural light (about 3000 lux). The COD content of the sample was detected at 3 h and 6 h after addition, respectively, according to the “Determination of Chemical Oxygen Demand (COD) in Water by Spectrophotometry with Pre-prepared Reagent” (T / ZJATA0001-2020), to obtain the COD content of the sample at different time points after treatment. The results are shown in Table 12 below.

[0110] Table 12 Wastewater treatment effect of the composite photocatalyst of Comparative Example 2

[0111] 3h sample COD 6h sample COD Sample 1 587.18 266.08 Sample 2 541.00 217.82 Sample 3 544.29 254.93

[0112] Comparative Example 3

[0113] Accurately take 100 g of nano-titanium dioxide and 20 g of silicon dioxide, mix uniformly, and calcine at 600°C for 3 h to obtain a mixture;

[0114] Preliminary grinding to 200 mesh particle size, then adding 20 g of kaolin and 40 g of low-sulfur coke, adding 1% of the total weight of the auxiliary agent (polyvinyl alcohol + ethylenediaminetetraacetic acid, 1:1 volume mixing), setting the ball milling speed to 500 rpm, the ball-to-material ratio to 20:1, and the ball milling time to 12 h (the ball milling medium used is 0.1 mm zirconia microbeads), to obtain a titanium dioxide composite photocatalyst.

[0115] The photocatalyst prepared in this comparative example was added to the oil-containing wastewater at a dosage of 10 g / L (three sets of parallel experiments were performed using the catalyst prepared in this example), mixed uniformly, and then exposed to natural light (about 3000 lux). The COD content of the sample was detected at 3 h and 6 h after addition, respectively, according to the “Determination of Chemical Oxygen Demand (COD) in Water by Spectrophotometry with Pre-prepared Reagent” (T / ZJATA0001-2020), to obtain the COD content of the sample at different time points after treatment. The results are shown in Table 13 below.

[0116] Table 13 Wastewater treatment effect of the composite photocatalyst of Comparative Example 3

[0117] 3h sample COD 6h sample COD Sample 1 596.58 254.53 Sample 2 550.26 204.99 Sample 3 595.63 262.39

[0118] Comparative Example 4

[0119] Accurately take 100 g of nano-titanium dioxide, 20 g of silicon dioxide, and 30 g of quartz sand, mix uniformly, and calcine at 600°C for 3 h to obtain a mixture; preliminary grinding to 200 mesh particle size, then adding 40 g of low-sulfur coke, adding 1% of the total weight of the auxiliary agent (polyvinyl alcohol + ethylenediaminetetraacetic acid, 1:1 volume mixing), setting the ball milling speed to 500 rpm, the ball-to-material ratio to 20:1, and the ball milling time to 12 h (the ball milling medium used is 0.1 mm zirconia microbeads), to obtain a titanium dioxide composite photocatalyst.

[0120] The photocatalyst prepared in this comparative example was added to the oil-containing wastewater at a dosage of 10 g / L (three sets of parallel experiments were performed using the catalyst prepared in this example), mixed uniformly, and then exposed to natural light (about 3000 lux). The COD content of the sample was detected at 3 h and 6 h after addition, respectively, according to the “Determination of Chemical Oxygen Demand (COD) in Water by Spectrophotometry with Pre-prepared Reagent” (T / ZJATA0001-2020), to obtain the COD content of the sample at different time points after treatment. The results are shown in Table 14 below.

[0121] Table 14 Wastewater treatment effect of the composite photocatalyst of Comparative Example 4

[0122] 3h sample COD 6h sample COD Sample 1 580.02 289.53 Sample 2 536.51 225.98 Sample 3 577.35 261.18

[0123] Comparative Example 5

[0124] 100 g of nano-titanium dioxide, 10 g of silicon dioxide and 10 g of quartz sand were accurately weighed, mixed uniformly and calcined at 600 DEG C for 1 h to obtain a mixture;

[0125] Preliminary grinding to 200 mesh particle size, then adding 10 g of lignite ultra-fine coal, 20 g of kaolin and 20 g of low-sulfur coke, setting the ball milling speed to 500 rpm, the ball-to-material ratio to 20:1, and the ball milling time to 6 h (the ball milling medium used was 0.1 mm zirconia microbeads), to obtain a titanium dioxide composite photocatalyst.

[0126] The photocatalyst prepared in this comparative example was added to the oil-containing wastewater at a dosage of 10 g / L (three parallel experiments were performed using the catalyst prepared in this example), mixed uniformly and then subjected to natural light (about 3000 lux), and the COD content of the sample was detected at 3 h and 6 h after addition, respectively, according to the "Determination of Chemical Oxygen Demand (COD) in Water - Preparative Reagent Spectrophotometric Method" (T / ZJATA0001-2020), to obtain the COD content of the sample at different time points after treatment, and the results are shown in Table 15 below.

[0127] Table 15 Wastewater treatment effect of the composite photocatalyst of Comparative Example 5

[0128] 3h sample COD 6h sample COD Sample 1 576.02 209.48 Sample 2 591.20 204.72 Sample 3 3h sample COD 6h sample COD Sample 1 Sample 2 Sample 3 3h sample COD 6h sample COD Sample 1 Sample 2 Sample 3 3h sample COD 6h sample COD Sample 1 Sample 2 Sample 3 3h sample COD 6h sample COD Sample 1 Sample 2 Sample 3 3h sample COD 6h sample COD Sample 1 Sample 2 Sample 3 3h sample COD 6h sample COD Sample 1 Sample 2 Sample 3 3h sample COD 6h sample COD Sample 1 Sample 2 Sample 3 3h sample COD 6h sample COD Sample 1 Sample 2 Sample 3 3h sample COD 6h sample COD Sample 1 Sample 2 Sample 3 3h sample COD 6h sample COD Sample 1 Sample 2 Sample 3 3h sample COD 6h sample COD Sample 1 Sample 2 Sample 3 3h sample COD 6h sample COD Sample 1 Sample 2 Sample 3 3h sample COD 6h sample COD Sample 1 Sample 2 Sample 3 3h sample COD 6h sample COD Sample 1 Sample 2 Sample 3 3h sample COD 6h sample COD Sample 1 Sample 2 Sample 3 3h sample COD 6h sample COD Sample 1 Sample 2 Sample 3 3h sample COD 6h sample COD Sample 1 Sample 2 Sample 3 3h sample COD 6h sample COD Sample 1 Sample 2 592.49 272.52

[0129] The above only describes the preferred embodiments of the present application, and it should be noted that for ordinary skilled persons in the art, several improvements and refinements can be made without departing from the principles of the present application, and these improvements and refinements should also be considered within the protection scope of the present application.

Claims

1. A method for preparing a titanium dioxide composite photocatalyst, characterized in that, Includes the following steps: S1. Titanium dioxide, silicon dioxide and quartz sand are mixed and calcined to obtain intermediate material 1; S2. Mix intermediate material 1 with lignite ultrafine coal powder, kaolin, low-sulfur coke and auxiliary agent, and ball mill to obtain the titanium dioxide composite photocatalyst. In S1, the weight ratio of the mixture of titanium dioxide, silicon dioxide and quartz sand is 80-120:10-30:20-40; The calcination temperature is 500–700℃; the calcination time is 2–5 hours. The weight ratio of titanium dioxide to lignite ultrafine coal powder, kaolin, and low-sulfur coke is 80–120:10–30:10–30:30–50.

2. The preparation method of the titanium dioxide composite photocatalyst according to claim 1, characterized in that, Before the intermediate material 1 is mixed with lignite ultrafine coal powder, kaolin, low-sulfur coke and auxiliary agents, it is further ground, and the particle size of the ground material is 180-220 mesh.

3. The preparation method of the titanium dioxide composite photocatalyst according to claim 1, characterized in that, The ball mill rotates at a speed of 400–600 rpm; And / or, the ball-to-material ratio of the ball mill is 10 to 30:1; And / or, the ball milling time is 6 to 18 hours; And / or, the ball milling media used is 0.05-0.2 mm zirconia microspheres.

4. The method for preparing the titanium dioxide composite photocatalyst according to claim 1, characterized in that, The auxiliary agent contains polyvinyl alcohol and ethylenediaminetetraacetic acid; The volume ratio of polyvinyl alcohol to ethylenediaminetetraacetic acid in the auxiliary agent is 1:0.8-1.2; The amount of the auxiliary agent added is 0.5% to 2% of the total weight of all materials in the ball mill.

5. A titanium dioxide composite photocatalyst prepared by the preparation method according to any one of claims 1 to 4.

6. The application of the titanium dioxide composite photocatalyst according to claim 5 in wastewater treatment.

7. The application according to claim 6, characterized in that, The wastewater is oily wastewater.