Composite water purifying agent, preparation method and application thereof

Abstract

The application provides a composite water purifying agent and a preparation method and application thereof, wherein the composite water purifying agent comprises the following components in mass fraction: polymeric aluminum ferric silicate 25-35 parts, graphene oxide loaded nanometer titanium dioxide 18-25 parts, chitosan quaternary ammonium salt 20-28 parts, activated carbon loaded iron and copper 12-18 parts, and magnetic carrier 5-15 parts. The composite water purifying agent has the synergistic effect of polymeric aluminum ferric silicate, graphene oxide loaded nanometer titanium dioxide and chitosan quaternary ammonium salt, and the adsorption, flocculation and degradation capacity of the water purifying agent are enhanced, so that the water purifying agent has excellent effect when treating complex wastewater.

Description

TECHNICAL FIELD

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

[0002] Arsenic has high toxicity and carcinogenic and mutagenic effects, and enters the human body or other organisms through the food chain, groundwater and surface water, seriously endangering human health and the ecological environment; hexavalent chromium is also a heavy metal with high toxicity, and a large amount of chromium-containing wastewater is generated in the electroplating, leather making, mining and steel making industries, seriously endangering human life and health, and chromium is one of the 129 key pollutants recognized by the US EPA. With the development of the economy, many heavy metal-containing wastewater also contains high content of organic matter, such as chelating agents, antibiotics, etc., and such wastewater has complex composition, high color, high biological toxicity, poor biodegradability and high chemical treatment cost. The treatment of such heavy metal organic wastewater and residues is a recognized technical problem at home and abroad.

[0003] At present, in the traditional water treatment method, the adsorption method is widely used in the purification treatment of heavy metal organic wastewater. Many natural adsorbents such as activated carbon and plant waste have high specific surface area and high microporous structure, and are the most common and widely used adsorbents in the current sewage treatment technology. Although they have been widely used, their adsorption performance is weak, and they have weak adsorption for some specific heavy metal pollutants.

[0004] Traditional flocculants, traditional flocculants (such as PAC) have low removal rate for dissolved organic matter. Patent application No. CN202010377948.4 discloses a method for preparing a microbial flocculant by using a mud-water mixture, but the purification effect is unstable and the effect is general. Patent application No. CN201810792565.6 discloses a preparation method of a magnetic composite flocculant, its product and application, and the removal rate of COD is 50-60%, which is not good. SUMMARY

[0005] The present application is made in view of the above problems, and aims to provide a composite water purifying agent and a preparation method and application thereof to improve the sewage treatment effect of the water purifying agent.

[0006] Specifically, the first aspect of the present application provides a composite water purifying agent, which comprises the following components in mass parts: 25-35 parts of polymeric aluminum ferric silicate, 18-25 parts of graphene oxide loaded nanometer 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.

[0007] The preparation method of the activated carbon loaded with iron and copper is as follows: the coconut shell activated carbon is pretreated with HNO3, immersed in a mixed solution of FeCl3 and CuSO4, and then subjected to calcination treatment.

[0008] The magnetic carrier is a magnetic Fe3O4 nanoparticle.

[0009] Further, the particle size of the polymeric aluminum ferric silicate is 50-70 nm.

[0010] Further, the preparation method of the graphene oxide loaded with nanometer titanium dioxide is as follows: tetrabutyl titanate and anhydrous ethanol are added to a graphene oxide dispersion liquid, subjected to hydrothermal reaction, and subjected to vacuum freeze drying.

[0011] The second aspect of the present application provides a preparation method of the composite water purifying agent, comprising the following steps:

[0012] S1: the activated carbon loaded with iron and copper is immersed in a polymeric aluminum ferric silicate solution, and a premix liquid is obtained by stirring;

[0013] S2: the graphene oxide loaded with nanometer titanium dioxide is added to the premix liquid, ultrasonic dispersion is performed, the chitosan quaternary ammonium salt solution is then added, uniformly mixed, and spray drying granulation is performed to obtain a composite material;

[0014] S3: the magnetic carrier is loaded on the surface of the composite material.

[0015] Further, the activated carbon loaded with iron and copper is immersed in a polymeric aluminum ferric silicate solution, and heated in a water bath at 55-65°C for 2-3h.

[0016] Further, the compressed air pressure of the spray drying is 0.3-0.5 MPa; and / or

[0017] the flow rate is 45-55 L / h; and / or

[0018] the inlet air temperature is 117-123°C; and / or

[0019] the outlet air temperature is ≤70°C.

[0020] Further, 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 speed is 0.7-0.8 m / s; and / or

[0021] the atomization pressure is 0.25-0.35 MPa; and / or

[0022] The magnetic carrier comprises 8-12% Fe3O4 nanoparticles and 1-3% polyvinyl alcohol.

[0023] The third aspect of the present application provides an application of the composite water purifying agent in sewage treatment, and the addition amount of the composite water purifying agent in the sewage treatment is 0.01-0.08 g / L.

[0024] The present application has the following beneficial effects:

[0025] (1) The composite water purifying agent of the present application enhances the adsorption, flocculation and degradation capacity of the water purifying agent through the synergistic effect of polymeric aluminum ferric silicate, graphene oxide loaded nanometer titanium dioxide, chitosan quaternary ammonium salt and other components, so that the water purifying agent performs well in treating complex wastewater. The graphene oxide loaded nanometer titanium dioxide combines the high specific surface area of graphene oxide and the photocatalytic performance of nanometer titanium dioxide, enhancing the degradation capacity of the water purifying agent for organic pollutants; chitosan quaternary ammonium salt, as a cationic polymer, has good adsorption performance and antibacterial performance, and can further remove organic pollutants and bacteria in water, and the synergistic effect of chitosan quaternary ammonium salt and polymeric aluminum ferric silicate enhances the flocculation and adsorption effect of the water purifying agent; the activated carbon loaded iron and copper removes suspended solids and dissolved organic matter in water through adsorption, and the iron and copper ions further remove small particles and colloidal substances in water through flocculation; the use of magnetic carriers facilitates the recycling of the water purifying agent, improving its stability and dispersibility in the water treatment process. The magnetic Fe3O4 nanoparticles, as magnetic carriers, have good magnetic responsiveness and biocompatibility, and are loaded on the surface of the composite material through fluidized bed coating process, realizing the magnetic separation and recycling of the water purifying agent.

[0026] (2) The composite water purifying agent of the present application enhances the adsorption, flocculation and degradation capacity of the water purifying agent through the synergistic effect of the components, improving the wastewater treatment effect. At the same time, the preparation method is simple in process, easy to operate and suitable for industrial production, and the prepared water purifying agent has stable performance and is suitable for various wastewater treatment scenarios. DETAILED DESCRIPTION

[0027] In order to make the purpose, technical scheme and advantages of the present application clearer, the present application is described and explained below in combination with embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and not to limit the present application. Based on the embodiments provided by the present application, all other embodiments obtained by those of ordinary skill in the art without creative labor fall within the scope of the present application.

[0028] Obviously, the following description is only some examples or embodiments of the present application, and for those of ordinary skill in the art, the present application can also be applied to other similar scenarios without creative labor. In addition, it can be understood that although the efforts made in this development process may be complex and lengthy, for those of ordinary skill in the art related to the content disclosed in the present application, some design, manufacture or production changes based on the technical content disclosed in the present application are only routine technical means and should not be understood as insufficient disclosure of the present application.

[0029] If not specifically stated, the terms "including" and "comprising" as used in the present application are open-ended and also include the case where only listed components are present. For example, the terms "including" and "comprising" can mean the inclusion of other components, or exclusion of listed components, as well as only the inclusion of listed components.

[0030] If not specifically stated, the term "or" in the present application is inclusive. For example, the phrase "A or B" means "A, B, or both A and B." More specifically, any one of the following conditions satisfies the condition "A or B": A is true (or present) and B is false (or not present); A is false (or not present) and B is true (or present); or both A and B are true (or present).

[0031] Embodiments of the first aspect of the present application provide a composite water purifying agent, comprising the following components in mass fraction: 25-35 parts of polyaluminum ferric silicate, 18-25 parts of graphene oxide loaded nanometer 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.

[0032] The mass fraction of the polyaluminum ferric silicate is any value or any combination range selected from 25 parts, 28 parts, 30 parts, 33 parts, and 35 parts. When the amount of polyaluminum ferric silicate is greater than 35 parts, the adsorption and flocculation effects of the composite water purifying agent do not improve significantly, and the cost is increased. When the amount of polyaluminum ferric silicate is less than 25 parts, the adsorption and flocculation capacity of the composite water purifying agent is insufficient, and the water purification effect is not ideal.

[0033] The mass fraction of the graphene oxide loaded nanometer titanium dioxide is any value or any combination range selected from 18 parts, 20 parts, 22 parts, and 25 parts. The graphene oxide loaded nanometer titanium dioxide combines the high specific surface area of graphene oxide and the photocatalytic performance of nanometer titanium dioxide, thereby enhancing the degradation capacity of the water purifying agent for organic pollutants. When the amount of graphene oxide loaded nanometer titanium dioxide is greater than 25 parts, the degradation capacity for organic pollutants can be further improved, but the cost is increased, and the stability of the composite water purifying agent can be affected. When the amount of graphene oxide loaded nanometer titanium dioxide is less than 18 parts, the degradation capacity for organic pollutants is insufficient.

[0034] The mass fraction of the chitosan quaternary ammonium salt is any value or any combination range in 20 parts, 22 parts, 25 parts, 28 parts. As a cationic polymer, the chitosan quaternary ammonium salt has good adsorption performance and antibacterial performance, and can further remove organic pollutants and bacteria in water. When the amount of chitosan quaternary ammonium salt is higher than 28 parts, although the adsorption and antibacterial performance can be further improved, the cost will also increase, and the solubility and stability of the composite water purifying agent may be affected; when the amount of chitosan quaternary ammonium salt is lower than 20 parts, the adsorption and antibacterial performance is insufficient.

[0035] The mass fraction of the activated carbon loaded with iron and copper is any value or any combination range in 12 parts, 14 parts, 16 parts, 18 parts. The porous structure of activated carbon not only increases the loading area, but also promotes the uniform distribution of iron and copper ions, thereby improving the flocculation effect. Iron and copper ions form flocculation bodies by chemical reaction with small particles and colloidal substances in water, accelerate their sedimentation, and further purify the water quality.

[0036] The composite water purifying agent of the present application enhances the adsorption, flocculation and degradation capacity of the water purifying agent through the synergistic effect of polymeric aluminum ferric silicate, graphene oxide loaded nanometer titanium dioxide, chitosan quaternary ammonium salt and other components, so that the water purifying agent performs well in treating complex wastewater. Graphene oxide loaded nanometer titanium dioxide combines the high specific surface area of graphene oxide and the photocatalytic performance of nanometer titanium dioxide, thereby enhancing the degradation capacity of the water purifying agent for organic pollutants; chitosan quaternary ammonium salt, as a cationic polymer, has good adsorption performance and antibacterial performance, and can further remove organic pollutants and bacteria in water, and its synergistic effect with polymeric aluminum ferric silicate enhances the flocculation and adsorption effect of the water purifying agent; activated carbon in activated carbon loaded with iron and copper adsorbs suspended solids and dissolved organic matter in water, while iron and copper ions further remove small particles and colloidal substances in water through flocculation; the use of magnetic carrier facilitates the recycling of the water purifying agent, and improves its stability and dispersibility in the water treatment process. As a magnetic carrier, magnetic Fe3O4 nanoparticles have good magnetic responsiveness and biocompatibility, and are loaded on the surface of the composite material through fluidized bed coating process, so as to realize the magnetic separation and recycling of the water purifying agent.

[0037] In the present embodiment, the particle size of the polymeric aluminum ferric silicate is 50-70 nm. The preparation method of the polymeric aluminum ferric silicate is to mix sodium silicate, aluminum chloride and ferric chloride in a molar ratio of 1:0.8:0.2, add hydrochloric acid to maintain the pH value at 3.5-4.0 under water bath at 60-62℃, and stir at a speed of 80 rpm, and the polymeric aluminum ferric silicate is generated after 2h of polymerization reaction.

[0038] In this embodiment, the preparation method of graphene oxide loaded nanometer titanium dioxide is as follows: 10 kg of tetrabutyl titanate and 40 L of anhydrous ethanol are added to 20 L of graphene oxide dispersion solution with a concentration of 5 mg / mL, and then the mixture is subjected to hydrothermal reaction at 170-185°C for 5-6 h to form graphene oxide loaded nanometer titanium dioxide, which is then subjected to vacuum freeze drying.

[0039] In this embodiment, the preparation method of activated carbon loaded iron and copper is as follows: coconut shell activated carbon is pretreated with 10% HNO3, and then immersed in a mixed solution of 0.5 M FeCl3 and CuSO4 (wherein the molar ratio of Fe to Cu is 4:1), and after solid-liquid separation, the product is calcined at 600-610°C for 2-2.5 h.

[0040] In this embodiment, the magnetic carrier is magnetic Fe3O4 nanoparticles. The magnetic Fe3O4 nanoparticles facilitate the recycling and reuse of the water purifying agent, and improve the stability and dispersibility of the water purifying agent in the water treatment process. The magnetic Fe3O4 nanoparticles have good magnetic responsiveness, and can be easily separated by an external magnetic field, thereby simplifying the process of recycling the water purifying agent and reducing the processing cost. At the same time, the biocompatibility of the magnetic Fe3O4 nanoparticles also ensures the safety and reliability of the water purifying agent in the water treatment process.

[0041] The second aspect of the present application provides a preparation method of the composite water purifying agent, comprising the following steps:

[0042] S1: The activated carbon loaded iron and copper is immersed in a polymeric aluminum ferric silicate solution, and the mixture is stirred to obtain a premix;

[0043] S2: The graphene oxide loaded nanometer titanium dioxide is added to the premix, and ultrasonic dispersion is performed, and then the chitosan quaternary ammonium salt solution is added, and the mixture is uniformly mixed and spray dried to obtain a composite material;

[0044] S3: The magnetic carrier is loaded on the surface of the composite material.

[0045] The activated carbon loaded iron and copper is immersed in a polymeric aluminum ferric silicate solution, and the mixture is heated in a water bath at 55-65°C for 2-3 h to obtain a premix.

[0046] The graphene oxide loaded nanometer titanium dioxide is dispersed in deionized water, and ultrasonic dispersion treatment is performed using an ultrasonic processor to obtain a uniform graphene oxide loaded nanometer titanium dioxide suspension.

[0047] The chitosan quaternary ammonium salt is dissolved in deionized water, and heated until completely dissolved to obtain a chitosan quaternary ammonium salt solution.

[0048] The graphene oxide loaded nano titanium dioxide suspension is added to the premixed solution, and then the chitosan quaternary ammonium salt solution is added, and the mixture is uniformly mixed. The mixture is spray dried to obtain a composite material. In this embodiment, the compressed air pressure of the spray drying is 0.3-0.5 MPa; the feeding flow rate is 45-55 L / h; the inlet air temperature is 117-123 ℃; and the outlet air temperature is ≤70 ℃.

[0049] In this embodiment, the magnetic carrier is loaded on the surface of the composite material by a fluidized bed coating process in step S3. The inlet air temperature of the fluidized bed is 45 ℃; the air volume is 25 m 3 / min, the fluidization gas velocity is 0.7-0.8 m / s; the atomization pressure is 0.25-0.35 MPa, and the liquid spray rate is 200-220 mL / min; the magnetic carrier includes 8-12% Fe3O4 nanoparticles and 1-3% polyvinyl alcohol.

[0050] The addition of polyvinyl alcohol in the magnetic carrier can improve the stability and dispersibility of the magnetic carrier, which is beneficial to the recycling and reuse of the water purifying agent. The particle size of the magnetic Fe3O4 nanoparticles is 10-30 nm, which is loaded on the surface of the composite material by a fluidized bed coating process.

[0051] The composite water purifying agent of the present application performs well in wastewater treatment. In practical application, the amount of the composite water purifying agent can be adjusted according to the specific composition and concentration of the wastewater. Generally, when the amount of the composite water purifying agent is 0.01-0.08 g / L, good wastewater treatment effect can be achieved.

[0052] The composite water purifying agent of the present application enhances the adsorption, flocculation and degradation capacity of the water purifying agent through the synergistic effect of the components, thereby improving the wastewater treatment effect. At the same time, the preparation method is simple in process, easy to operate and suitable for industrial production, and the prepared water purifying agent is stable in performance and suitable for various wastewater treatment scenarios. Therefore, the composite water purifying agent of the present application has wide application prospect in the field of wastewater treatment.

[0053] The third aspect of the present application provides a use of the composite water purifying agent in wastewater treatment. The amount of the composite water purifying agent added in wastewater treatment is 0.01-0.08 g / L.

[0054] Example 1

[0055] A composite water purifying agent includes the following components in mass parts: polymeric aluminum ferric silicate 30 parts, graphene oxide loaded nano titanium dioxide 20 parts, chitosan quaternary ammonium salt 25 parts, activated carbon loaded iron and copper 15 parts, and magnetic carrier 10 parts.

[0056] The chitosan quaternary ammonium salt is purchased from Wuhan Lalanbai Pharmaceutical Chemical Co., Ltd. with the item number inb-1036.

[0057] The preparation method of the composite water purifying agent comprises the following steps:

[0058] S1: the activated carbon loaded with iron and copper is immersed in a polymeric aluminum ferric silicate solution, and a premix is obtained by stirring;

[0059] S2: graphene oxide loaded with nano titanium dioxide is added to the premix, ultrasonic dispersion is performed, then a chitosan quaternary ammonium salt solution is added, uniform mixing is performed, and spray drying granulation is performed 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 inlet air temperature is 120 DEG C; and the outlet air temperature is less than or equal to 70 DEG C;

[0060] S3: a magnetic carrier is loaded on the surface of the composite material; the magnetic carrier comprises 10% Fe3O4 nanoparticles and 2% polyvinyl alcohol; the magnetic carrier is loaded on the surface of the composite material by a fluidized bed coating process, the inlet air temperature of the fluidized bed is 45 DEG C; the air volume is 25 m 3 / min, the fluidization gas velocity is 0.8 m / s; the atomization pressure is 0.3 MPa, and the liquid injection rate is 200 mL / min.

[0061] Example 2

[0062] This example is basically the same as example 1, except that the polymeric aluminum ferric silicate is 26 parts.

[0063] Example 3

[0064] This example is basically the same as example 1, except that the graphene oxide loaded with nano titanium dioxide is 22 parts.

[0065] Example 4

[0066] This example is basically the same as example 1, except that the activated carbon loaded with iron and copper is 13 parts.

[0067] Example 5

[0068] This example is basically the same as example 1, except that the compressed air pressure of the spray drying is 0.3-0.5 MPa; the flow rate of the feed is 45-55 L / h; and the inlet air temperature is 117-123 DEG C.

[0069] Example 6

[0070] This example is basically the same as example 1, except that the fluidization gas velocity of the fluidized bed is 0.7 m / s; the atomization pressure is 0.28 MPa, and the liquid injection rate is 210 mL / min.

[0071] Comparative Example 1

[0072] The comparative example is basically the same as example 1, except that the raw material does not contain graphene oxide loaded nanometer titanium dioxide.

[0073] Comparative example 2

[0074] The comparative example is basically the same as example 1, except that the raw material does not contain activated carbon loaded iron copper.

[0075] Comparative example 3

[0076] The comparative example is basically the same as example 1, except that the raw material does not contain a magnetic carrier.

[0077] Comparative example 4

[0078] The commercially available PAC polyaluminum chloride flocculant is purchased from Zhengzhou Aomei Environmental Protection Technology Co., Ltd., and the CAS number is 1327-41-9.

[0079] Experimental cases

[0080] The electroplating wastewater of a certain enterprise in Hengyang City is used for testing, and the water purifying agents in examples 1-6 and comparative examples 1-4 are tested respectively, and the specific results are shown in Table 1.

[0081]

[0082] As can be seen from the above table, the water purifying agents in examples 1-6 have higher organic pollutant degradation rate, heavy metal ion removal rate and turbidity removal rate than the water purifying agents in comparative examples 1-4 and the commercially available PAC polyaluminum chloride flocculant when treating electroplating wastewater.

[0083] As can be seen from comparative example 1, when the raw material does not contain graphene oxide loaded nanometer titanium dioxide, the organic pollutant degradation rate of the water purifying agent is significantly reduced. The reason may be that graphene oxide loaded nanometer titanium dioxide, as an important photocatalyst, plays a key role in degrading organic pollutants due to its high specific surface area and excellent photocatalytic performance. When this component is lacking, the photocatalytic degradation ability of the water purifying agent is weakened, resulting in a significant decrease in the degradation rate of organic pollutants.

[0084] As can be seen from comparative example 2, when the raw material does not contain activated carbon loaded iron copper, the heavy metal ion removal rate of the water purifying agent decreases. The activated carbon and iron copper ions in activated carbon loaded iron copper work synergistically to efficiently remove heavy metal ions from water. The porous structure of activated carbon provides a large adsorption area, while iron copper ions combine with heavy metal ions through chemical reactions to form precipitates, thereby removing them from water. Therefore, when this component is lacking, the heavy metal ion removal ability of the water purifying agent is affected, and the removal rate decreases accordingly.

[0085] 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.

[0086] 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.

[0087] 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.

[0088] Magnetic recovery effect test

[0089] 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:

[0090]

[0091] 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.

[0092] 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.

[0093] 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.

[0094] 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 method for preparing a composite water purifier, characterized in that: The following steps are involved: S1: Coconut shell activated carbon was pretreated with HNO3, impregnated in a mixture of FeCl3 and CuSO4, and then calcined to obtain activated carbon loaded with iron and copper; S2: impregnating activated carbon loaded with iron and copper into a polyaluminium ferric silicate solution and stirring to obtain a premixed solution; S3: 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; S4: The magnetic carrier is loaded onto the surface of the composite material through a fluidized bed coating process with a fluidizing gas velocity of 0.7-0.8 m / s and an atomization pressure of 0.25-0.35 MPa; the magnetic carrier includes 8-12% Fe3O4 nanoparticles and 1-3% polyvinyl alcohol.

2. The method for preparing the composite water purifier according to claim 1, wherein: The preparation method of graphene oxide loaded nano-titanium dioxide in step S3 is: adding tetrabutyl titanate and anhydrous ethanol to the graphene oxide dispersion, performing a hydrothermal reaction, and vacuum freeze-drying.

3. The method for preparing the composite water purifier according to claim 1, wherein: In step S2, 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.

4. The method for preparing the composite water purifier according to claim 1, wherein: The compressed air pressure of the spray drying in step S3 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℃.

5. A composite water purifier, characterized in that: The composite water purifier is prepared by the preparation method of any one of claims 1 to 4, wherein the composite water purifier 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 magnetic carrier is magnetic Fe3O4 nanoparticles; The particle size of the polyaluminium ferrosilicate is 50-70 nm.

6. Use of the composite water purifier according to claim 5 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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