Recyclable composite water purifying agent and preparation method thereof

Abstract

The invention relates to a recyclable composite water purifying agent and a preparation method thereof, and belongs to the technical field of high polymer materials. The recyclable composite water purifying agent comprises the following components in parts by weight: 12-18 parts of activated carbon, 20-25 parts of diatomite, 15-25 parts of polyaluminum chloride, 6-12 parts of a modified flocculant, 5-10 parts of polyethylene glycol, 1-3 parts of a modified photocatalyst and 250-370 parts of deionized water, the recyclable composite water purifying agent prepared by the invention not only has a good pollutant adsorption effect, but also has an excellent antibacterial effect.

Description

Technical Field

[0001] The present invention belongs to the technical field of polymer materials, and particularly relates to a recyclable composite water purifying agent and a preparation method thereof. Background Art

[0002] With the rapid advancement of China's industrialization process, environmental pollution, especially water pollution, has become increasingly serious, seriously affecting people's physical health and living environment. Using water purifying agents to coagulate industrial wastewater and urban sewage is one of the most commonly used methods in water treatment and an important means to eliminate pollution and protect the environment.

[0003] However, although traditional water purifying agents can purify sewage to a certain extent, most of these water purifying agents are chemical agents with complex compositions. They may not only cause secondary pollution and cannot be reused, but also the overall water purification effect is not very satisfactory. In addition, although water purifying agents have certain antibacterial properties, with the improvement of actual application requirements, their own antibacterial properties can no longer meet the needs. Therefore, researching and developing an excellent recyclable composite water purifying agent and its preparation method has important practical significance and application value. Summary of the Invention

[0004] In order to solve the above technical problems, the present invention provides a recyclable composite water purifying agent and a preparation method thereof.

[0005] The object of the present invention can be achieved by the following technical solutions:

[0006] A recyclable composite water purifying agent and a preparation method thereof, comprising the following raw materials in parts by weight: 12 - 18 parts of activated carbon, 20 - 25 parts of diatomite, 15 - 25 parts of polyaluminum chloride, 6 - 12 parts of modified flocculant, 5 - 10 parts of polyethylene glycol, 1 - 3 parts of modified photocatalyst, and 250 - 370 parts of deionized water.

[0007] The modified flocculant is prepared by the following method:

[0008] Step A1: Dissolve chitosan and 1 - hydroxy - benzotriazole in deionized water, stir evenly, then add N - acetyl - L - cysteine and 1 - ethyl - (3 - dimethylaminopropyl) carbodiimide hydrochloride, adjust the pH to 3 - 6, stir at room temperature for 3 h, filter and freeze - dry to obtain a compound;

[0009] Furthermore, the dosage ratio of chitosan, 1 - hydroxy - benzotriazole, deionized water, N - acetyl - L - cysteine, and 1 - ethyl - (3 - dimethylaminopropyl) carbodiimide hydrochloride is 2.03 - 3.04 g: 5 - 10 g: 200 - 360 mL: 3.15 - 4.73 g: 30 mL;

[0010] First, an amidation reaction occurs between the amino group of chitosan and the carboxyl group of N-acetyl-L-cysteine to obtain a compound;

[0011] Step A2: Mix the compound with an ethanol-water mixed solution, stir at 80 °C for 30 min, then add NaOH and 2,3-epoxypropyltrimethylammonium chloride and react at 80 °C for 2.5 h. Finally, add acetone, filter, wash, and dry in vacuo at 60 °C to obtain a pre-product;

[0012] Furthermore, the dosage ratio of the compound, ethanol-water mixed solution, NaOH, 2,3-epoxypropyltrimethylammonium chloride, and acetone is 0.01 - 0.02 mol : 50 - 70 mL : 0.7 g : 3 - 6 g : 20 - 40 mL, and the volume ratio of ethanol to deionized water in the ethanol-water mixed solution is 1∶1;

[0013] Secondly, the hydroxyl group of the compound reacts with the epoxy group of 2,3-epoxypropyltrimethylammonium chloride to obtain a pre-product;

[0014] Step A3: Stir acrylamide and deionized water evenly, adjust the pH to 6, raise the temperature to 40 °C, keep warm for 2 h, then add the pre-product and azobisisobutyronitrile and continue to react for 2 h, wash, and dry in vacuo at 40 °C for 12 h to obtain a modified flocculant;

[0015] Furthermore, the dosage ratio of acrylamide, deionized water, pre-product, and azobisisobutyronitrile is 0.71 - 1.42 g : 40 - 80 mL : 0.01 - 0.02 mol : 0.2 g;

[0016] Finally, the mercapto group of the pre-product reacts with the carbon-carbon double bond of acrylamide to form a modified flocculant;

[0017] The modified photocatalyst is prepared by the following method:

[0018] Step B1: Mix γ-aminopropyltriethoxysilane with an ethanol-water mixed solution evenly at 35 °C, then add titanium dioxide and mix at a speed of 800 rpm for 10 min, centrifuge and filter, and dry at 45 °C to obtain an intermediate;

[0019] Furthermore, the dosage ratio of γ-aminopropyltriethoxysilane, ethanol-water mixed solution, and titanium dioxide is 2.21 - 4.43 g : 50 - 100 mL : 0.80 - 1.6 g, and the volume ratio of ethanol to deionized water in the ethanol-water mixed solution is 4∶1;

[0020] First, the siloxy group of the silane coupling agent γ-aminopropyltriethoxysilane hydrolyzes into silanol groups, which react with the hydroxyl groups on the surface of titanium dioxide to form an intermediate;

[0021] Step B2: the intermediate and deionized water were mixed evenly, stirred in a constant temperature water bath at 80° C. for 15 min, the pH was adjusted to 5, and graphene oxide powder was added, mixed in an ultrasonic stirrer for 60 min, centrifuged, washed, and dried at 60° C. to obtain a modified photocatalyst;

[0022] Further, the usage ratio of the intermediate, deionized water, and graphene oxide powder is 0.01-0.02 mol: 100-150 mL: 1.52-3.04 g;

[0023] Finally, the amino groups on the surface of the intermediate react with the carboxyl groups of graphene oxide to form amide bonds to obtain a modified photocatalyst.

[0024] A method for preparing a recyclable composite water purifier comprises the following steps:

[0025] S1. Fully mix diatomaceous earth and activated carbon, add 150-200 parts of deionized water at a water temperature of 45-50° C., mix and stir evenly to obtain a mixture;

[0026] S2, mixing and stirring the modified flocculant, polyethylene glycol and modified photocatalyst at 50-55° C., adding the mixture, stirring at high speed, to obtain a mixed material;

[0027] S3. Mix polyaluminium chloride and 100-170 parts of deionized water, then slowly add the mixture into the mixed material, stir at 50-55°C for 20-30 minutes, and dry at 60°C for 12 hours to obtain a recyclable composite water purifier.

[0028] Beneficial effects of the present invention:

[0029] The recyclable composite water purifier of the present invention has a good pollutant adsorption effect and also has an excellent antibacterial effect, thereby extending the service life of the material.

[0030] The modified flocculant prepared by the present invention utilizes the long chain characteristics of chitosan to play a bridging role in the flocculation process, aggregating tiny particles in water into large floccules for easy sedimentation or filtration. The modified flocculant contains amide groups, quaternary ammonium salts and hydroxyl groups, which work together with chitosan as cationic polyelectrolytes to chelate metal ions and effectively adsorb or capture heavy metal ions in the solution, such as Hg 2+ , Ca 2+ 、Zn 2+etc., and can effectively flocculate negatively charged particles. Its unique adsorption and flocculation effects can precipitate suspended solids and turbidity, reduce the particles and harmful substances in water, and improve water quality. At the same time, as a biobased material, chitosan is biodegradable, environmentally friendly and sustainable. In addition, chitosan synergizes with quaternary ammonium salts to inhibit the reproduction of microorganisms and exhibit antibacterial effects. Moreover, acrylamide has good water solubility, which helps to improve the flocculation performance, adsorb suspended particles and colloidal substances in water, reduce the electrostatic repulsion, promote aggregation, further remove pollutants such as suspended solids, chromaticity and organic matter, and improve water quality.

[0031] In the modified photocatalyst prepared by the present invention, under ultraviolet light irradiation, the valence electrons of titanium dioxide jump to the conduction band, forming photogenerated electrons and holes, which then migrate to the surface to initiate redox reactions, generating strongly oxidizing free radicals, effectively oxidizing and decomposing organic and inorganic pollutants, and achieving water purification. Titanium dioxide can also mineralize organic pollutants into inorganic small molecules, carbon dioxide and water, and inhibit the growth of microorganisms such as bacteria and viruses in water, exhibiting bactericidal effects. Due to its excellent hydrophilicity and high specific surface area, graphene oxide can effectively adsorb and decompose organic matter and heavy metal ions in water. As a carbon nanomaterial prepared from natural graphite, graphene oxide has a two-dimensional single-atom layer structure, and its surface is rich in oxygen-containing groups such as epoxy groups, carboxyl groups and hydroxyl groups, enabling it to be stably dispersed in aqueous solution and efficiently adsorb heavy metal ions such as lead and mercury and organic pollutants. In addition, graphene oxide is compounded with titanium dioxide to form a synergistic effect, which not only enhances the efficiency of photocatalytic degradation of organic matter, but also quickly decomposes organic matter into carbon dioxide and water under visible light, effectively removing toxic and harmful substances in water and restoring the self-purification ability of water bodies. Detailed implementation manners

[0032] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without making creative efforts shall fall within the protection scope of the present invention.

[0033] Example 1: A preparation method of a recyclable composite water purifier specifically includes the following steps:

[0034] S1. Weigh the raw materials by weight: 12 parts of activated carbon, 20 parts of diatomite, 15 parts of polyaluminum chloride, 6 parts of modified flocculant (prepared in this example), 5 parts of polyethylene glycol, 1 part of modified photocatalyst (prepared in this example), and 250 parts of deionized water; fully mix the diatomite and activated carbon, and then add 150 parts of deionized water with the water temperature of 45°C, and mix and stir evenly to obtain a mixture;

[0035] S2. Mix the modified flocculant, polyethylene glycol, and modified photocatalyst evenly at 50°C, then add the mixture and stir at high speed to obtain a mixed material;

[0036] S3. Mix polyaluminum chloride and 100 parts of deionized water, then slowly add it to the mixed material, stir at 50°C for 20 min, and dry at 60°C for 12 h to obtain a recyclable composite water purifying agent;

[0037] The modified flocculant is prepared by the following method:

[0038] Step A1: Disperse 2.03 g of chitosan and 5 g of 1-hydroxybenzotriazole in 200 mL of deionized water, stir evenly, then add 3.15 g of N-acetyl-L-cysteine and 30 mL of 1-ethyl-(3-dimethylaminopropyl)carbodiimide hydrochloride, adjust the pH to 3, stir at room temperature for 3 h, filter, and freeze-dry to obtain a compound;

[0039] Step A2: Mix 0.01 mol of the compound and 50 mL of an ethanol-water mixed solution, stir at 80°C for 30 min, then add 0.7 g of NaOH and 3 g of 2,3-epoxypropyltrimethylammonium chloride and mix, react at 80°C for 2.5 h, finally add 20 mL of acetone, filter, wash, and dry in vacuo at 60°C to obtain a pre-product. The volume ratio of ethanol to deionized water in the ethanol-water mixed solution is 1:1;

[0040] Step A3: Stir 0.71 g of acrylamide and 40 mL of deionized water evenly, adjust the pH to 6, raise the temperature to 40°C, keep warm for 2 h, then add 0.01 mol of the pre-product and 0.2 g of azobisisobutyronitrile and mix, continue to react for 2 h, wash, and dry in vacuo at 40°C for 12 h to obtain the modified flocculant;

[0041] The modified photocatalyst is prepared by the following method:

[0042] Step B1: Mix 2.21 g of γ-aminopropyltriethoxysilane and 50 mL of an ethanol-water mixed solution evenly at 35°C, then add 0.80 g of titanium dioxide, mix at a speed of 800 rpm for 10 min, centrifuge, filter, and dry at 45°C to obtain an intermediate. The volume ratio of ethanol to deionized water in the ethanol-water mixed solution is 4:1;

[0043] Step B2: Mix 0.01 mol of the intermediate and 100 mL of deionized water evenly, stir in a constant temperature water bath at 80°C for 15 min, then adjust the pH to 5, add 1.52 g of graphene oxide powder, mix in an ultrasonic stirrer for 60 min, centrifuge, wash, and dry at 60°C to obtain the modified photocatalyst.

[0044] Example 2: A preparation method of a recyclable composite water purifying agent, specifically including the following steps:

[0045] S1. Weigh the raw materials by weight parts: 15 parts of activated carbon, 22.5 parts of diatomite, 20 parts of polyaluminum chloride, 9 parts of modified flocculant (prepared by this example), 7.5 parts of polyethylene glycol, 2 parts of modified photocatalyst (prepared by this example), and 310 parts of deionized water; fully mix the diatomite and activated carbon, then add 175 parts of deionized water, the water temperature is 47 °C, mix and stir evenly to obtain a mixture;

[0046] S2. Mix and stir the modified flocculant, polyethylene glycol and modified photocatalyst evenly at 52 °C, then add the mixture and stir at high speed to obtain a mixed material;

[0047] S3. Mix polyaluminum chloride and 135 parts of deionized water, then slowly add it to the mixed material, stir at 50 - 55 °C for 20 - 30 min, and dry at 60 °C for 12 h to obtain a recyclable composite water purifying agent;

[0048] The modified flocculant is prepared by the following method:

[0049] Step A1: Disperse 2.535 g of chitosan and 7.5 g of 1-hydroxy-benzotriazole in 280 mL of deionized water, stir evenly, then add 3.94 g of N-acetyl-L-cysteine and 30 mL of 1-ethyl-(3-dimethylaminopropyl) carbodiimide hydrochloride, adjust the pH to 4.5, stir at room temperature for 3 h, filter and freeze-dry to obtain a compound;

[0050] Step A2: Mix 0.015 mol of the compound and 60 mL of ethanol-water mixed solution, stir at 80 °C for 30 min, then add 0.7 g of NaOH and 4.5 g of 2,3-epoxypropyltrimethylammonium chloride and mix, react at 80 °C for 2.5 h, finally add 30 mL of acetone, filter, wash, and vacuum dry at 60 °C to obtain a pre-product, the volume ratio of ethanol to deionized water in the ethanol-water mixed solution is 1:1;

[0051] Step A3: Stir 1.065 g of acrylamide and 60 mL of deionized water evenly, adjust the pH to 6, raise the temperature to 40 °C, keep warm for 2 h, then add 0.015 mol of the pre-product and 0.2 g of azobisisobutyronitrile and mix, continue to react for 2 h, wash, and vacuum dry at 40 °C for 12 h to obtain the modified flocculant;

[0052] The modified photocatalyst is prepared by the following method:

[0053] Step B1: 3.32 g of γ-aminopropyltriethoxysilane and 75 mL of an ethanol-water mixed solution were mixed at 35° C., 1.2 g of titanium dioxide was added, the mixture was mixed at 800 rpm for 10 min, centrifuged, filtered, and dried at 45° C. to obtain an intermediate, wherein the volume ratio of ethanol to deionized water in the ethanol-water mixed solution was 4:1;

[0054] Step B2: 0.015 mol of the intermediate and 125 mL of deionized water were mixed evenly, stirred in a constant temperature water bath at 80°C for 15 min, the pH was adjusted to 5, 2.28 g of graphene oxide powder was added, mixed in an ultrasonic stirrer for 60 min, centrifuged, washed, and dried at 60°C to obtain a modified photocatalyst.

[0055] Embodiment 3: A method for preparing a recyclable composite water purifier, comprising the following steps:

[0056] S1. Weigh the raw materials by weight: 18 parts of activated carbon, 25 parts of diatomaceous earth, 25 parts of polyaluminium chloride, 12 parts of modified flocculant (prepared in this embodiment), 10 parts of polyethylene glycol, 3 parts of modified photocatalyst (prepared in this embodiment), and 370 parts of deionized water; fully mix the diatomaceous earth and activated carbon, add 200 parts of deionized water, the water temperature is 50° C., mix and stir evenly to obtain a mixture;

[0057] S2, mixing and stirring the modified flocculant, polyethylene glycol and the modified photocatalyst at 55° C., adding the mixture, stirring at high speed, to obtain a mixed material;

[0058] S3, mixing polyaluminium chloride and 170 parts of deionized water, then slowly adding the mixture to the mixed material, stirring at 55°C for 20-30min, and drying at 60°C for 12h to obtain a recyclable composite water purifier;

[0059] The modified flocculant is prepared by the following method:

[0060] Step A1: 3.04 g of chitosan and 10 g of 1-hydroxy-benzotriazole were dispersed in 360 mL of deionized water, stirred evenly, and then 4.73 g of N-acetyl-L-cysteine ​​and 30 mL of 1-ethyl-(3-dimethylaminopropyl)carbodiimide hydrochloride were added, the pH was adjusted to 6, stirred at room temperature for 3 h, filtered, and freeze-dried to obtain a compound;

[0061] Step A2: 0.02 mol of the compound was mixed with 70 mL of an ethanol-water mixed solution, stirred at 80° C. for 30 min, then 0.7 g of NaOH and 6 g of 2,3-epoxypropyltrimethylammonium chloride were added and mixed, reacted at 80° C. for 2.5 h, and finally 40 mL of acetone was added, filtered, washed, and vacuum dried at 60° C. to obtain a pre-product, wherein the volume ratio of ethanol to deionized water in the ethanol-water mixed solution was 1:1;

[0062] Step A3: Stir 1.42 g of acrylamide and 80 mL of deionized water evenly, adjust the pH to 6, heat up to 40 °C, keep warm for 2 h, then add 0.02 mol of pre-product and 0.2 g of azobisisobutyronitrile and mix, continue to react for 2 h, wash, and dry in vacuum at 40 °C for 12 h to obtain the modified flocculant;

[0063] The modified photocatalyst is prepared by the following method:

[0064] Step B1: Mix 4.43 g of γ-aminopropyltriethoxysilane and 100 mL of ethanol-water mixed solution evenly at 35 °C, then add 1.6 g of titanium dioxide, mix at a speed of 800 rpm for 10 min, centrifuge and filter, and dry at 45 °C to obtain the intermediate. The volume ratio of ethanol to deionized water in the ethanol-water mixed solution is 4:1;

[0065] Step B2: Mix 0.02 mol of the intermediate and 150 mL of deionized water evenly, after stirring in a constant temperature water bath at 80 °C for 15 min, adjust the pH to 5, then add 3.04 g of graphene oxide powder, mix in an ultrasonic stirrer for 60 min, centrifuge, wash, and dry at 60 °C to obtain the modified photocatalyst.

[0066] Comparative Example 1: This comparative example is a recyclable composite water purifier. The difference from Example 3 is that an equal amount of alum is used to replace the modified flocculant prepared in Example 3, and the rest are the same.

[0067] Comparative Example 2: This comparative example is a recyclable composite water purifier. The difference from Example 3 is that an equal amount of zinc oxide is used to replace the modified photocatalyst prepared in Example 3, and the rest are the same.

[0068] Performance test: For the recyclable composite water purifiers prepared in Examples 1 - 3 and Comparative Examples 1 - 2, add 0.5 g of kaolin and 2 mg of the recyclable composite water purifier to a beaker, then add distilled water to 100 mL, stir at 400 rpm for 30 s and 100 rpm for 5 min, let stand for 10 min, take the supernatant, and use a 722-type spectrophotometer to measure the absorbance of the supernatant at a wavelength of 550 nm. Calculate the flocculation rate according to the following formula: FR(=(B - A) / B×100; in the formula, FR is the flocculation rate, A is the absorbance of the supernatant in the example, and B is the absorbance of the supernatant in the comparative example; Collect 100 mL of water samples and 100 mL of water samples treated with the recyclable composite water purifier for bacteriostatic rate detection; The test results are shown in Table 1 below:

[0069] Table 1

[0070]

[0071] As can be seen from the data tested in Table 1, the recyclable composite water purifying agent prepared by the present invention has a good effect of adsorbing pollutants. It can also be seen from the above table that the recyclable composite water purifying agent prepared by the present invention has antibacterial effect and can extend the service life of the material.

[0072] Take 100 mL of the sewage from a paper mill, adjust the pH = 7, add 0.1 mg of flocculant, stir at 400 rpm for 30 s, stir at 100 rpm for 5 min, let it stand for 10 min, take the supernatant, and measure the COD and turbidity of the sewage and the supernatant obtained after treatment with the flocculant respectively. The COD is determined by the method of standard solution calibration of potassium dichromate-ferrous ammonium sulfate; the turbidity is measured by using a Hach 2100 turbidity meter; the test results are shown in Table 2 below:

[0073] Table 2

[0074]

[0075] As can be seen from the data tested in Table 2, the recyclable composite water purifying agent prepared by the present invention has a good effect of adsorbing pollutants.

[0076] The above content is only an example and illustration of the concept of the present invention. Those skilled in the art of this technology can make various modifications or supplements to the specific embodiments described or use similar methods to replace them. As long as they do not deviate from the concept of the invention or exceed the scope defined by this claim book, they should all fall within the protection scope of the present invention.

Claims

1. A method for preparing a recyclable composite water purifier, characterized in that: The specific steps include: S1. Weigh the raw materials by weight, mix 20-25 parts of diatomaceous earth and 12-18 parts of activated carbon, add 150-200 parts of deionized water at a water temperature of 45-50° C., mix and stir evenly to obtain a mixture; S2, mixing 6-12 parts of modified flocculant, 5-10 parts of polyethylene glycol and 1-3 parts of modified photocatalyst at 50-55° C. and stirring evenly, then adding the mixture and stirring at high speed to obtain a mixed material; S3, mix 15-25 parts of polyaluminium chloride and 100-170 parts of deionized water, then slowly add it to the mixed material, stir at 50-55°C for 20-30 minutes, and dry at 60°C for 12 hours to obtain a recyclable composite water purifier; The modified flocculant is prepared by the following method: Step A1: Disperse chitosan and 1-hydroxy-benzotriazole in deionized water, stir evenly, then add N-acetyl-L-cysteine ​​and 1-ethyl-(3-dimethylaminopropyl)carbodiimide hydrochloride, adjust the pH to 3-6, stir at room temperature for 3 hours, filter, and freeze-dry to obtain a compound; Step A2: the compound and an ethanol-water mixed solution were mixed, stirred at 80° C. for 30 min, then NaOH and 2,3-epoxypropyltrimethylammonium chloride were added and mixed, reacted at 80° C. for 2.5 h, and finally acetone was added, filtered, washed, and vacuum dried at 60° C. to obtain a pre-product; Step A3: Stir acrylamide and deionized water evenly, adjust the pH to 6, heat to 40°C, keep warm for 2 hours, then add the pre-product and azobisisobutyronitrile and mix, continue to react for 2 hours, wash, and vacuum dry at 40°C for 12 hours to obtain a modified flocculant.

2. The method for preparing a recyclable composite water purifier according to claim 1, characterized in that: In step A1, the amount ratio of chitosan, 1-hydroxy-benzotriazole, deionized water, N-acetyl-L-cysteine, and 1-ethyl-(3-dimethylaminopropyl)carbodiimide hydrochloride is 2.03-3.04 g: 5-10 g: 200-360 mL: 3.15-4.73 g: 30 mL.

3. The method for preparing a recyclable composite water purifier according to claim 1, characterized in that: In step A2, the amount ratio of the compound, ethanol-water mixed solution, NaOH, 2,3-epoxypropyltrimethylammonium chloride and acetone is 0.01-0.02 mol: 50-70 mL: 0.7 g: 3-6 g: 20-40 mL, and the volume ratio of ethanol and deionized water in the ethanol-water mixed solution is 1:

1.

4. The method for preparing a recyclable composite water purifier according to claim 1, characterized in that: In step A3, the usage ratio of acrylamide, deionized water, pre-product and azobisisobutyronitrile is 0.71-1.42 g: 40-80 mL: 0.01-0.02 mol: 0.2 g.

5. The method for preparing a recyclable composite water purifier according to claim 1, characterized in that: The modified photocatalyst is prepared by the following method: Step B1: Y-aminopropyltriethoxysilane and ethanol-water mixed solution were mixed uniformly at 35° C., titanium dioxide was added, mixed at 800 rpm for 10 min, centrifuged, filtered, and dried at 45° C. to obtain an intermediate; Step B2: The intermediate and deionized water were mixed evenly, stirred in a constant temperature water bath at 80°C for 15 minutes, the pH was adjusted to 5, and graphene oxide powder was added, mixed in an ultrasonic stirrer for 60 minutes, centrifuged, washed, and dried at 60°C to obtain a modified photocatalyst.

6. The method for preparing a recyclable composite water purifier according to claim 5, characterized in that: In step B1, the usage ratio of Y-aminopropyltriethoxysilane, ethanol-water mixed solution, and titanium dioxide is 2.21-4.43 g: 50-100 mL: 0.80-1.6 g, and the volume ratio of ethanol to deionized water in the ethanol-water mixed solution is 4:

1.

7. The method for preparing a recyclable composite water purifier according to claim 5, characterized in that: The usage ratio of the intermediate, deionized water and graphene oxide powder in step B2 is 0.01-0.02 mol: 100-150 mL: 1.52-3.04 g.

8. A recyclable composite water purifier, characterized in that: Prepared according to the preparation method according to any one of claims 1 to 7.

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