Composite water purifying agent as well as preparation method and application thereof

Abstract

The invention provides a composite water purifying agent as well as a preparation method and application thereof. The composite water purifying agent is prepared from the following components in parts by mass: 25 to 35 parts of polyaluminum ferric silicate, 18 to 25 parts of graphene oxide loaded nano titanium dioxide, 20 to 28 parts of chitosan quaternary ammonium salt, 12 to 18 parts of activated carbon loaded iron copper and 5 to 15 parts of magnetic carrier. According to the composite water purifying agent disclosed by the invention, the adsorption, flocculation and degradation capacities of the water purifying agent are enhanced through the synergistic effect of the components such as the polysilicate aluminum ferric, the graphene oxide loaded nano titanium dioxide and the chitosan quaternary ammonium salt, so that the water purifying agent has an excellent effect when being used for treating complex wastewater.

Description

Technical Field

[0001] The present application relates to the technical field of sewage treatment agents, and in particular to a composite water purifier and a preparation method and application thereof. Background Art

[0002] Arsenic is highly toxic, carcinogenic, and mutagenic. It enters the human body and other organisms through the food chain, groundwater, and surface water, seriously endangering human health and the ecological environment. Hexavalent chromium is also a highly toxic heavy metal. Industries such as electroplating, leather making, mining, and steelmaking all generate large amounts of chromium-containing wastewater, which poses a serious threat to human health. Chromium is one of the 129 priority pollutants recognized by the US EPA. With economic development, many heavy metal-containing wastewaters also contain high levels of organic matter, such as chelating agents and antibiotics. This type of wastewater has complex composition, high color, high biotoxicity, poor biodegradability, and high chemical treatment costs. The treatment of this type of heavy metal-containing organic wastewater and residues is a recognized technical challenge both domestically and internationally.

[0003] Among traditional water treatment methods, adsorption is widely used to purify heavy metal-containing organic wastewater. Many natural adsorbent materials, such as activated carbon and plant waste, possess high surface areas and highly porous structures, making them the most common and widely used adsorbents in wastewater treatment. Despite their widespread application, these materials often exhibit weak adsorption properties, with limited ability to adsorb certain heavy metal pollutants.

[0004] Traditional flocculants, such as PAC, have low removal rates for dissolved organic matter. Patent application number CN202010377948.4 discloses a method for preparing a microbial flocculant from a mud-water mixture, but its purification results are unstable and mediocre. Patent application number CN201810792565.6 discloses a method for preparing a magnetic composite flocculant, its product, and its application. Its COD removal rate is only 50-60%, which is not very effective. Summary of the Invention

[0005] The present application is made in view of the above problems, and its purpose is to provide a composite water purifier and its preparation method and application, so as to improve the sewage treatment effect of the water purifier.

[0006] Specifically, the first aspect of the present application provides a composite water purifier comprising the following components, in parts by mass: 25-35 parts of polyaluminium ferrosilicate, 18-25 parts of graphene oxide-loaded nano-titanium dioxide, 20-28 parts of chitosan quaternary ammonium salt, 12-18 parts of activated carbon-loaded iron and copper, and 5-15 parts of a magnetic carrier; The preparation method of the activated carbon loaded with iron and copper is as follows: coconut shell activated carbon is pretreated with HNO3, immersed in a mixture of FeCl3 and CuSO4, and then calcined; The magnetic carrier is magnetic Fe3O4 nanoparticles.

[0007] Furthermore, the particle size of the polyaluminium ferrosilicate is 50-70 nm.

[0008] Furthermore, the preparation method of the graphene oxide loaded nano-titanium dioxide is: adding tetrabutyl titanate and anhydrous ethanol to the graphene oxide dispersion, performing a hydrothermal reaction, and vacuum freeze-drying.

[0009] The second aspect of the present application provides a method for preparing the composite water purifier, comprising the following steps: S1: Immersing activated carbon loaded with iron and copper in a polyaluminium-ferric silicate solution and stirring to obtain a premixed solution; S2: adding graphene oxide loaded nano-titanium dioxide to the premixed solution, ultrasonically dispersing, then adding chitosan quaternary ammonium salt solution, mixing evenly, and spray drying to granulate to obtain a composite material; S3: Loading the magnetic carrier on the surface of the composite material.

[0010] Furthermore, the activated carbon loaded with iron and copper is immersed in a polyaluminium-iron silicate solution, heated in a water bath at 55-65° C., and reacted for 2-3 hours.

[0011] Furthermore, the compressed air pressure of the spray drying is 0.3-0.5 MPa; and / or Flow rate of 45-55 L / h; and / or Inlet air temperature is 117-123°C; and / or Air outlet temperature ≤70℃.

[0012] Furthermore, in step S3, the magnetic carrier is loaded on the surface of the composite material by a fluidized bed coating process, and the fluidization gas velocity is 0.7-0.8 m / s; and / or Atomization pressure is 0.25-0.35MPa; and / or The magnetic carrier includes 8-12% Fe3O4 nanoparticles and 1-3% polyvinyl alcohol.

[0013] The third aspect of the present application provides an application of the composite water purifier in sewage treatment, wherein the addition amount of the composite water purifier in sewage treatment is 0.01-0.08 g / L.

[0014] The present invention has the following beneficial effects: (1) The composite water purifier of the present application enhances the adsorption, flocculation and degradation capabilities of the water purifier through the synergistic effect of components such as polyaluminium ferric silicate, graphene oxide loaded nano-titanium dioxide, and chitosan quaternary ammonium salt, making the water purifier perform well in treating complex wastewater. Among them, graphene oxide loaded nano-titanium dioxide combines the high specific surface area of graphene oxide and the photocatalytic performance of nano-titanium dioxide, enhancing the water purifier's ability to degrade organic pollutants; chitosan quaternary ammonium salt, as a cationic polymer, has good adsorption and antibacterial properties, which can further remove organic pollutants and bacteria in water. Its synergistic effect with polyaluminium ferric silicate enhances the flocculation and adsorption effect of the water purifier; the activated carbon in the activated carbon loaded with iron and copper adsorbs suspended matter and dissolved organic matter in water, while the iron and copper ions further remove tiny particles and colloidal substances in water through flocculation; the use of magnetic carriers facilitates the recycling and reuse of the water purifier, improving its stability and dispersibility in the water treatment process. Magnetic Fe3O4 nanoparticles, as magnetic carriers, have good magnetic responsiveness and biocompatibility. They are loaded on the surface of the composite material through a fluidized bed coating process, realizing the magnetic separation and recovery of the water purifier.

[0015] (2) The composite water purifier of this application enhances the adsorption, flocculation, and degradation capabilities of the water purifier through the synergistic effect of its components, thereby improving the sewage treatment effect. At the same time, its preparation method is simple, easy to operate, and easy to industrialize. The resulting water purifier has stable performance and is suitable for various sewage treatment scenarios. DETAILED DESCRIPTION

[0016] In order to make the purpose, technical solutions and advantages of this application more clearly understood, the present application is described and illustrated below in conjunction with the embodiments. It should be understood that the specific embodiments described herein are merely used to explain this application and are not intended to limit this application. Based on the embodiments provided in this application, all other embodiments obtained by those of ordinary skill in the art without making any creative work are within the scope of protection of this application.

[0017] Obviously, the following descriptions are merely some examples or embodiments of the present application. Those skilled in the art can apply the present application to other similar scenarios without inventive effort. Furthermore, it is also understood that, although the effort involved in such a development process may be complex and lengthy, for those skilled in the art related to the content disclosed in the present application, changes in design, manufacturing, or production based on the technical content disclosed in the present application are merely conventional technical means and should not be construed as an insufficiency of the content disclosed in the present application.

[0018] Unless otherwise specified, the terms "include" and "comprising" used in this application may be open-ended or closed-ended. For example, "include" and "comprising" may mean that other components not listed may also be included or that only the listed components are included.

[0019] Unless otherwise specified, the term "or" is used in this application to be inclusive. For example, the phrase "A or B" means "A, B, or both A and B." More specifically, the condition "A or B" is satisfied if any of the following conditions are met: A is true (or exists) and B is false (or does not exist); A is false (or does not exist) and B is true (or exists); or both A and B are true (or exist).

[0020] An embodiment of the first aspect of the present application provides a composite water purifier, which includes the following components in parts by mass: 25-35 parts of polyaluminum ferrosilicate, 18-25 parts of graphene oxide-loaded nano-titanium dioxide, 20-28 parts of chitosan quaternary ammonium salt, 12-18 parts of activated carbon-loaded iron and copper, and 5-15 parts of magnetic carrier.

[0021] The mass fraction of the polyaluminum ferric silicate is any value or any combination range among 25 parts, 28 parts, 30 parts, 33 parts, and 35 parts. When the amount of polyaluminum ferric silicate is higher than 35 parts, the adsorption and flocculation effects of the composite water purifier are not significantly improved, and the cost will increase; when the amount of polyaluminum ferric silicate is lower than 25 parts, the adsorption and flocculation capacity of the composite water purifier is insufficient, and the water purification effect is not ideal.

[0022] The mass fraction of the graphene oxide-loaded nano-titanium dioxide is any numerical value or any combination range selected from 18 parts, 20 parts, 22 parts, and 25 parts. Graphene oxide-loaded nano-titanium dioxide combines the high specific surface area of graphene oxide with the photocatalytic properties of nano-titanium dioxide, thereby enhancing the water purifier's ability to degrade organic pollutants. When the amount of graphene oxide-loaded nano-titanium dioxide used is higher than 25 parts, although the degradation ability of organic pollutants can be further improved, the cost will be increased and the stability of the composite water purifier may be affected. When the amount of graphene oxide-loaded nano-titanium dioxide used is lower than 18 parts, the degradation ability of organic pollutants is insufficient.

[0023] The mass fraction of described chitosan quaternary ammonium salt is any numerical value or arbitrary combination range among 20 parts, 22 parts, 25 parts, 28 parts.Chitosan quaternary ammonium salt, as a kind of cationic polymer, has good adsorption performance and antibacterial property, can further remove organic pollutants and bacteria in water.When the consumption of chitosan quaternary ammonium salt is higher than 28 parts, although can further improve adsorption and antibacterial property, cost can be increased equally, and may affect the solubility and stability of composite water purifier; When the consumption of chitosan quaternary ammonium salt is lower than 20 parts, adsorption and antibacterial property are insufficient.

[0024] The activated carbon loading of iron and copper is any number or combination of 12, 14, 16, or 18 parts by weight. The porous structure of the activated carbon not only increases the loading area but also promotes the uniform distribution of the iron and copper ions, thereby enhancing the flocculation effect. The iron and copper ions chemically react with tiny particles and colloidal substances in the water to form flocs, accelerating their sedimentation and further purifying the water.

[0025] The composite water purifier of the present application enhances the adsorption, flocculation and degradation capabilities of the water purifier through the synergistic effect of components such as polysilicate aluminum iron, graphene oxide loaded nano titanium dioxide, and chitosan quaternary ammonium salt, so that the water purifier performs well in treating complex wastewater. Among them, graphene oxide loaded nano titanium dioxide combines the high specific surface area of graphene oxide and the photocatalytic performance of nano titanium dioxide, enhancing the degradation ability of the water purifier to organic pollutants; chitosan quaternary ammonium salt, as a cationic polymer, has good adsorption properties and antibacterial properties, can further remove organic pollutants and bacteria in water, and its synergistic effect with polysilicate aluminum iron enhances the flocculation and adsorption effect of the water purifier; activated carbon in activated carbon loaded iron and copper adsorbs suspended matter and dissolved organic matter in water, while iron and copper ions further remove tiny particles and colloidal substances in water through flocculation; the use of magnetic carriers facilitates the recycling of the water purifier, improving its stability and dispersibility in the water treatment process. Magnetic Fe3O4 nanoparticles, as magnetic carriers, have good magnetic responsiveness and biocompatibility. They are loaded on the surface of the composite material through a fluidized bed coating process, realizing the magnetic separation and recovery of the water purifier.

[0026] In this embodiment, the particle size of the polyaluminium ferric silicate is 50-70 nm. The polyaluminium ferric silicate is prepared by mixing sodium silicate, aluminium chloride and ferric chloride in a molar ratio of 1:0.8:0.2, adding hydrochloric acid to maintain the pH at 3.5-4.0 in a water bath at 60-62°C, stirring at 80 rpm, and performing a polymerization reaction for 2 hours to produce nano-polyaluminium ferric silicate.

[0027] In this embodiment, the preparation method of the graphene oxide-loaded nano-titanium dioxide is as follows: 10 kg of tetrabutyl titanate and 40 L of anhydrous ethanol are added to 20 L of a graphene oxide dispersion having a concentration of 5 mg / mL, and the mixture is hydrothermally reacted at 170-185° C. for 5-6 hours to form graphene oxide-loaded nano-titanium dioxide, which is then freeze-dried in vacuum.

[0028] In this embodiment, the preparation method of the activated carbon loaded with iron and copper is as follows: the coconut shell activated carbon is pretreated with 10% HNO3, then immersed in a mixture of 0.5M FeCl3 and CuSO4 (wherein the molar ratio of Fe:Cu is 4:1), and after solid-liquid separation, the product is calcined at 600-610°C for 2-2.5h.

[0029] In this embodiment, the magnetic carrier is magnetic Fe3O4 nanoparticles. Magnetic Fe3O4 nanoparticles facilitate the recycling and reuse of the water purifier, improving its stability and dispersibility during the water treatment process. Magnetic Fe3O4 nanoparticles have excellent magnetic responsiveness and can easily achieve magnetic separation of the water purifier using an external magnetic field, thereby simplifying the water purifier recovery process and reducing processing costs. Furthermore, the biocompatibility of magnetic Fe3O4 nanoparticles also ensures their safety and reliability during water purification.

[0030] The second aspect of the present application provides a method for preparing the composite water purifier, comprising the following steps: S1: Immersing activated carbon loaded with iron and copper in a polyaluminium-ferric silicate solution and stirring to obtain a premixed solution; S2: adding graphene oxide loaded nano-titanium dioxide to the premixed solution, ultrasonically dispersing, then adding chitosan quaternary ammonium salt solution, mixing evenly, and spray drying to granulate to obtain a composite material; S3: Loading the magnetic carrier on the surface of the composite material.

[0031] The activated carbon loaded with iron and copper is immersed in a polyaluminium ferric silicate solution, heated in a water bath at 55-65° C., and reacted for 2-3 hours to obtain a premixed solution.

[0032] The graphene oxide-loaded nano-titanium dioxide is dispersed in deionized water and ultrasonically dispersed using an ultrasonic processor to obtain a uniform graphene oxide-loaded nano-titanium dioxide suspension.

[0033] Dissolve chitosan quaternary ammonium salt in deionized water and heat until completely dissolved to obtain a chitosan quaternary ammonium salt solution.

[0034] A graphene oxide-loaded nano-titanium dioxide suspension is added to the premixed solution, followed by a chitosan quaternary ammonium salt solution, and the mixture is mixed uniformly. The mixture is spray-dried and granulated to obtain a composite material. In this embodiment, the spray drying process comprises a compressed air pressure of 0.3-0.5 MPa, a feed flow rate of 45-55 L / h, an inlet air temperature of 117-123°C, and an outlet air temperature of ≤70°C.

[0035] In this embodiment, in step S3, the magnetic carrier is loaded on the surface of the composite material by a fluidized bed coating process, and the inlet air temperature of the fluidized bed is 45°C; the air volume is 25m 3 / min, the fluidizing gas velocity is 0.7-0.8m / s; the atomizing pressure is 0.25-0.35MPa, the spraying rate is 200-220mL / min; the magnetic carrier includes 8-12% Fe3O4 nanoparticles and 1-3% polyvinyl alcohol.

[0036] The addition of polyvinyl alcohol to the magnetic carrier can improve the stability and dispersibility of the magnetic carrier, which is beneficial for the recycling and reuse of the water purifier. The magnetic Fe3O4 nanoparticles have a particle size of 10-30nm and are loaded onto the surface of the composite material through a fluidized bed coating process.

[0037] The composite water purifier described in this application has demonstrated excellent performance in wastewater treatment. In practical applications, the dosage of the composite water purifier can be adjusted based on the specific composition and concentration of the wastewater. Generally speaking, a dosage of 0.01-0.08 g / L of the composite water purifier achieves excellent wastewater treatment results.

[0038] The composite water purifier of this application enhances its adsorption, flocculation, and degradation capabilities through the synergistic effects of its components, improving wastewater treatment effectiveness. Furthermore, its preparation method is simple, easy to operate, and amenable to industrial production. The resulting water purifier has stable performance and is suitable for a variety of wastewater treatment scenarios. Therefore, the composite water purifier of this application has broad application prospects in the field of wastewater treatment.

[0039] The third aspect of the present application provides an application of the composite water purifier in sewage treatment, wherein the addition amount of the composite water purifier in sewage treatment is 0.01-0.08 g / L.

[0040] Example 1 A composite water purifier comprises the following components in parts by mass: 30 parts of polyaluminium ferrosilicate, 20 parts of graphene oxide-loaded nano-titanium dioxide, 25 parts of chitosan quaternary ammonium salt, 15 parts of activated carbon-loaded iron and copper, and 10 parts of a magnetic carrier; Chitosan quaternary ammonium salt was purchased from Wuhan Lanabai Pharmaceutical Chemical Co., Ltd., product number lnb-1036; The preparation method of the composite water purifier comprises the following steps: S1: Activated carbon loaded with iron and copper is immersed in a polyaluminium-iron silicate solution and stirred to obtain a premixed solution; S2: Add graphene oxide-loaded nano-titanium dioxide to the premixed solution, disperse it ultrasonically, then add chitosan quaternary ammonium salt solution, mix well, and spray-dry and granulate to obtain a composite material; the compressed air pressure of the spray drying is 0.4 MPa; the flow rate of the mixed solution is 50 L / h; the air inlet temperature is 120°C; and the air outlet temperature is ≤70°C; S3: The magnetic carrier is loaded onto the surface of the composite material; the magnetic carrier includes 10% Fe3O4 nanoparticles and 2% polyvinyl alcohol; the magnetic carrier is loaded onto the surface of the composite material by a fluidized bed coating process, and the inlet air temperature of the fluidized bed is 45°C; the air volume is 25m 3 / min, the fluidizing gas velocity is 0.8m / s; the atomizing pressure is 0.3MPa, and the spraying rate is 200mL / min.

[0041] Example 2 This embodiment is basically the same as embodiment 1, except that 26 parts of polyaluminium ferrosilicate are used.

[0042] Example 3 This embodiment is basically the same as embodiment 1, except that the graphene oxide is loaded with 22 parts of nano-titanium dioxide.

[0043] Example 4 This embodiment is basically the same as embodiment 1, except that the activated carbon is loaded with 13 parts of iron and copper.

[0044] Example 5 This embodiment is basically the same as embodiment 1, except that the compressed air pressure of the spray drying is 0.3-0.5 MPa; the feed flow rate is 45-55 L / h; and the inlet air temperature is 117-123°C.

[0045] Example 6 This embodiment is basically the same as embodiment 1, except that the fluidizing gas velocity of the fluidized bed is 0.7 m / s; the atomizing pressure is 0.28 MPa, and the liquid spraying rate is 210 mL / min.

[0046] Comparative Example 1 This comparative example is basically the same as Example 1, except that the raw material does not contain graphene oxide-loaded nano-titanium dioxide.

[0047] Comparative Example 2 This comparative example is basically the same as Example 1, except that the raw materials do not contain activated carbon loaded with iron and copper.

[0048] Comparative Example 3 This comparative example is basically the same as Example 1, except that the raw materials do not contain a magnetic carrier.

[0049] Comparative Example 4 Commercially available PAC polyaluminium chloride flocculant was purchased from Zhengzhou Aomei Environmental Protection Technology Co., Ltd., CAS No. 1327-41-9.

[0050] Experimental Case Electroplating wastewater from an enterprise in Hengyang City was used for the test. The water purifiers in Examples 1-6 and Comparative Examples 1-4 were tested respectively. The specific results are shown in Table 1.

[0051]

[0052] As can be seen from the above table, when treating electroplating wastewater, the water purifiers in Examples 1-6 of the present invention showed higher organic pollutant degradation rate, heavy metal ion removal rate and turbidity removal rate compared with the water purifiers in Comparative Examples 1-4 and the commercially available PAC polyaluminum chloride flocculant.

[0053] Comparative Example 1 shows that when the raw materials do not contain graphene oxide-loaded nano-titanium dioxide, the organic pollutant degradation rate of the water purifier is significantly reduced. This may be because the graphene oxide-loaded nano-titanium dioxide acts as an important photocatalyst, and its high specific surface area and excellent photocatalytic performance play a key role in degrading organic pollutants. When this component is missing, the water purifier's photocatalytic degradation ability is weakened, resulting in a significant decrease in the degradation rate of organic pollutants.

[0054] As can be seen from Comparative Example 2, when the raw material does not contain activated carbon-loaded iron and copper, the heavy metal ion removal rate of the water purifier decreases. The activated carbon and iron and copper ions in the activated carbon-loaded iron and copper work synergistically to efficiently remove heavy metal ions in water. The porous structure of the activated carbon provides a large adsorption area, while the iron and copper ions combine with the heavy metal ions through chemical reactions to form a precipitate, thereby removing them from the water. Therefore, when the activated carbon-loaded iron and copper component is missing, the heavy metal ion removal ability of the water purifier is affected, and the removal rate is correspondingly reduced.

[0055] Comparative Example 3 shows that when the raw materials do not contain a magnetic carrier, while the adsorption and flocculation capabilities of the water purifier remain essentially unchanged, its recycling becomes difficult. The introduction of a magnetic carrier is primarily to facilitate magnetic separation and recovery of the water purifier, thereby improving its stability and dispersibility during the water treatment process. Therefore, while the absence of a magnetic carrier does not directly affect the water purification effect, it does increase processing costs and operational complexity.

[0056] In addition, although the commercially available PAC polyaluminum chloride flocculant also has a certain sewage treatment effect, compared with the composite water purifier of the present invention, there is still a large gap in terms of organic pollutant degradation rate, heavy metal ion removal rate and turbidity removal rate.

[0057] In summary, the composite water purifier produced by this invention, through scientific component design and optimized preparation methods, demonstrates excellent performance in treating electroplating wastewater. The synergistic effect of the components significantly enhances the adsorption, flocculation, and degradation capabilities of the water purifier, achieving efficient and environmentally friendly wastewater treatment.

[0058] Magnetic recovery effect test The water purifiers in Examples 1-6 and Comparative Examples 1-4 were ultrasonically cleaned with 0.1 mol / L NaOH for 15 min, and then calcined at 800°C for 2 h under nitrogen protection. The water purifiers were recycled. After each cycle, the following measurement was performed: magnetic recovery rate = (mass of recovered magnetic cores / initial added mass) × 100%. The results are shown in Table 2:

[0059] As can be seen from the table above, the water purifiers in Examples 1-6 maintained a high magnetic recovery rate after multiple cycles of use. This is primarily due to the introduction of magnetic Fe3O4 nanoparticles, which impart excellent magnetic responsiveness to the water purifiers, facilitating magnetic separation and recovery using an external magnetic field. Furthermore, the addition of polyvinyl alcohol further enhances the stability and dispersibility of the magnetic carrier, thereby ensuring the stable performance of the water purifiers during repeated use.

[0060] As can be seen from the data in the table, the magnetic recovery rates of Examples 1-6 are all higher than those of Comparative Examples 1-4, further demonstrating the importance of the magnetic carrier in the present invention. It is particularly noteworthy that even in Comparative Example 3, where the raw materials do not contain a magnetic carrier, the water purifier still exhibits certain adsorption and flocculation capabilities, but the magnetic recovery rate is significantly reduced, which directly leads to difficulties in recycling and reusing the water purifier.

[0061] In addition, it can be seen from the table that, although the magnetic recovery rate of Examples 1-6 has decreased after repeated recycling, the overall reduction is not large, which illustrates that the composite water purifier of the present invention has good recycling performance. In practical applications, this means that the replacement frequency of the water purifier can be reduced, further reducing processing costs, while also being beneficial to environmental protection.

[0062] It should be noted that the present application is not limited to the above-mentioned embodiments. The above-mentioned embodiments are merely examples, and any embodiments having substantially the same structure and effect as the technical concept within the scope of the present application are all included in the technical scope of the present application. In addition, without departing from the scope of the present application, any other embodiments that can be conceived by those skilled in the art and that combine some of the constituent elements in the embodiments are also included in the scope of the present application.

Claims

1. A composite water purifier, characterized in that: The composition comprises the following components in parts by mass: 25-35 parts of polyaluminium ferrosilicate, 18-25 parts of graphene oxide-supported nano-titanium dioxide, 20-28 parts of chitosan quaternary ammonium salt, 12-18 parts of activated carbon-supported iron and copper, and 5-15 parts of a magnetic carrier; The preparation method of the activated carbon loaded with iron and copper is as follows: coconut shell activated carbon is pretreated with HNO3, immersed in a mixture of FeCl3 and CuSO4, and then calcined; The magnetic carrier is magnetic Fe3O4 nanoparticles.

2. The composite water purifier according to claim 1, characterized in that The particle size of the polyaluminium ferrosilicate is 50-70 nm.

3. The composite water purifier according to claim 1, characterized in that The preparation method of the graphene oxide loaded nano-titanium dioxide comprises the following steps: adding tetrabutyl titanate and anhydrous ethanol to a graphene oxide dispersion, performing a hydrothermal reaction, and performing vacuum freeze drying.

4. A method for preparing the composite water purifier according to any one of claims 1 to 3, characterized in that: The following steps are involved: S1: Immersing activated carbon loaded with iron and copper in a polyaluminium-ferric silicate solution and stirring to obtain a premixed solution; S2: adding graphene oxide loaded nano-titanium dioxide to the premixed solution, ultrasonically dispersing, then adding chitosan quaternary ammonium salt solution, mixing evenly, and spray drying to granulate to obtain a composite material; S3: Loading the magnetic carrier on the surface of the composite material.

5. The method for preparing the composite water purifier according to claim 4, characterized in that: The activated carbon loaded with iron and copper is immersed in a polyaluminium-iron silicate solution, heated in a water bath at 55-65° C., and reacted for 2-3 hours.

6. The method for preparing the composite water purifier according to claim 5, characterized in that: The compressed air pressure of the spray drying is 0.3-0.5 MPa; and / or Flow rate of 45-55 L / h; and / or Inlet air temperature is 117-123°C; and / or Air outlet temperature ≤70℃.

7. The method for preparing the composite water purifier according to claim 4, characterized in that: In step S3, the magnetic carrier is loaded on the surface of the composite material by a fluidized bed coating process, and the fluidization gas velocity is 0.7-0.8 m / s; and / or Atomization pressure is 0.25-0.35MPa; and / or The magnetic carrier includes 8-12% Fe3O4 nanoparticles and 1-3% polyvinyl alcohol.

8. Use of the composite water purifier according to any one of claims 1 to 3 in sewage treatment, characterized in that: The addition amount of the composite water purifier in sewage treatment is 0.01-0.08 g / L.

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