Preparation method and application of efficient adsorption composite flocculant

Abstract

The invention relates to a preparation method and application of an efficient adsorption composite flocculant, and belongs to the technical field of flocculants for water quality purification. The preparation method comprises the following steps: slowly adding ammonia water into a zirconium oxychloride aqueous solution, heating, stirring, standing at room temperature, adding a silane coupling agent solution in an inert gas environment, and continuously stirring to obtain a mixed solution A; preheating the mixed solution A, adding EPTAC, and stirring at a constant temperature to obtain a mixed solution B; and in an inert gas environment, adding a reaction monomer into the mixed solution B, mixing, adding an initiator, stirring, reacting, standing at room temperature, cutting a gel material into pieces, soaking, taking a precipitated solid, putting the precipitated solid into a drying oven, drying in vacuum, and grinding, thereby obtaining the product. The composite flocculant prepared by the invention has efficient adsorption capacity and cationic charge characteristics, can strongly capture negatively charged colloidal particles in water, has a good water purification effect, and has excellent turbidity purification performance.

Description

Technical Field

[0001] This invention belongs to the technical field of flocculants for water purification, and relates to a method for preparing and applying a highly efficient adsorption composite flocculant. Background Technology

[0002] Flocculation sedimentation is known for its simple process, easy operation, and high cost-effectiveness, making it an important operational unit in drinking water treatment. This method utilizes flocculants to settle and effectively remove impurities such as algae and sludge from source water.

[0003] Traditional flocculants are divided into inorganic and organic categories. While traditional aluminum salt flocculants are relatively inexpensive, they suffer from problems such as high dosage, low efficiency, high residue, and difficulty in sedimentation. Traditional iron salt flocculants can neutralize the negatively charged algal cells, disrupting their stability and forming denser flocs, but they easily cause water discoloration and equipment corrosion after use. Traditional organic flocculants, on the other hand, suffer from problems such as high dosage and high residual toxicity. Existing inorganic-organic flocculant blends can improve algae removal efficiency, reduce dosage, and produce larger, more easily sedimenting flocs, but they still suffer from high flocculant residue, weak interaction forces during blending, poor hydraulic shear stability, and complex dosing methods. Therefore, developing a convenient and structurally stable inorganic-organic composite flocculant is crucial for effectively reducing iron and aluminum residue. Summary of the Invention

[0004] The purpose of this invention is to provide a method for preparing and applying a highly efficient adsorption composite flocculant. The flocculant prepared by this invention has both high adsorption capacity and cationic charge characteristics, which can strongly capture negatively charged colloidal particles in water. After treating turbid water, the removal rate exceeds 98%, demonstrating excellent water purification performance.

[0005] The objective of this invention can be achieved through the following technical solutions:

[0006] A method for preparing a high-efficiency adsorption composite flocculant includes the following steps:

[0007] Step 1: Slowly add ammonia to the zirconium oxychloride aqueous solution, heat and stir, let stand at room temperature, add silane coupling agent solution under an inert gas environment and continue stirring to obtain mixture A;

[0008] Step 2: After preheating mixture A, add EPTAC and stir at a constant temperature to obtain mixture B;

[0009] Step 3: In an inert gas environment, add the reactant monomer to the mixture B and mix. Add the initiator and stir to react. Let it stand at room temperature. Cut the gel into small pieces and soak it. Take the precipitated solid and place it in an oven to dry under vacuum. Grind it to complete the preparation.

[0010] As a preferred embodiment of the present invention, the zirconium oxychloride aqueous solution in step one is composed of zirconium oxychloride and deionized water mixed at a mass ratio of 1.0-1.2:18-20, the amount of ammonia water used is to adjust the pH value to 4.0-4.5, the heating and stirring temperature is 60-70℃, the stirring time is 2-4h, and the standing time is 18-24h.

[0011] As a preferred embodiment of the present invention, the inert gas environment in step one is a nitrogen gas environment, and the temperature for continued stirring is 50-60℃ and the stirring time is 4-6h.

[0012] As a preferred embodiment of the present invention, the mass ratio of the zirconium oxychloride aqueous solution and the silane coupling agent solution in step one is 180-200:20-23.

[0013] As a preferred embodiment of the present invention, the silane coupling agent solution in step one is composed of silane coupling agent NQ-62 and anhydrous ethanol mixed in a mass ratio of 3.5-3.8:15-16, wherein the silane coupling agent NQ-62 is diethylenetriaminepropyltrimethoxysilane.

[0014] As a preferred embodiment of the present invention, the mass ratio of the mixture A and EPTAC in step two is 100-110:1.35-1.50.

[0015] As a preferred technical solution of the present invention, the temperature of the constant temperature stirring in step two is 60-70℃ and the stirring time is 6-8h.

[0016] As a preferred embodiment of the present invention, the EPTAC mentioned in step two is 2,3-epoxypropyltrimethylammonium chloride.

[0017] As a preferred embodiment of the present invention, in step three, the mass ratio of the reaction monomer, mixture B and initiator is 10-12:110-120:0.06-0.08, the reaction monomer is one or a combination of acrylamide and N,N-dimethylacrylamide, and the initiator is composed of ammonium persulfate and sodium bisulfite in a mass ratio of 1:1.

[0018] As a preferred embodiment of the present invention, the stirring reaction temperature in step three is 40-50℃ and the reaction time is 8-10h, the standing time is 2-3h, the soaking treatment is soaking in acetone and anhydrous ethanol for 24h respectively, the vacuum drying is vacuum drying at 60℃ to constant weight, and the grinding is to a particle size of 5μm.

[0019] As a preferred technical solution of the present invention, an application of a high-efficiency adsorption composite flocculant prepared by the above preparation method in water purification.

[0020] The beneficial effects of this invention are:

[0021] This invention utilizes zirconium hydroxide to provide a basic porous adsorption carrier and active hydroxyl sites. The silane coupling agent NQ-62 modifies zirconium hydroxide and introduces amino functional groups through an "inorganic-organic bridging" process. EPTAC grafts quaternary ammonium salt cationic groups through a ring-opening reaction with amino groups. The synergistic effect of these three components enables the flocculant to possess both high-efficiency adsorption capacity and cationic charge characteristics, effectively capturing negatively charged colloidal particles in turbid water. The removal rate of turbid water after treatment exceeds 98%, demonstrating excellent water turbidity purification performance. Detailed Implementation

[0022] To further illustrate the technical means and effects of the present invention in achieving its intended purpose, the following detailed description of the specific implementation methods, structures, features, and effects of the present invention, in conjunction with embodiments, is provided below.

[0023] Example 1

[0024] A method for preparing a high-efficiency adsorption composite flocculant includes the following steps:

[0025] Step 1: Slowly add ammonia to the zirconium oxychloride aqueous solution to adjust the pH to 4.0, heat and stir at 60°C for 2 hours, let stand at room temperature for 18 hours, add silane coupling agent solution under nitrogen atmosphere and continue stirring at 50°C for 4 hours to obtain mixture A;

[0026] The zirconium oxychloride aqueous solution is composed of zirconium oxychloride and deionized water at a mass ratio of 1.0:18. The mass ratio of the zirconium oxychloride aqueous solution to the silane coupling agent solution is 180:20. The silane coupling agent solution is composed of silane coupling agent NQ-62 and anhydrous ethanol at a mass ratio of 3.5:15. The silane coupling agent NQ-62 is diethylenetriaminepropyltrimethoxysilane.

[0027] Step 2: After preheating mixture A, add EPTAC and stir at 60℃ for 6 hours to obtain mixture B;

[0028] The mass ratio of the mixture A to EPTAC is 100:1.35, and the EPTAC is 2,3-epoxypropyltrimethylammonium chloride;

[0029] Step 3: Under an inert gas environment, add the reactant monomer to the mixture B and mix. Add the initiator and stir at 40°C for 8 hours. Let stand at room temperature for 2 hours. Cut the gel into small pieces and soak it in acetone and anhydrous ethanol for 24 hours respectively. Take the precipitated solid and place it in an oven to dry under vacuum at 60°C until constant weight. Grind it to a particle size of 5μm to complete the preparation.

[0030] The mass ratio of the reaction monomer, mixture B and initiator is 10:110:0.06. The reaction monomer is composed of acrylamide and N,N-dimethylacrylamide mixed in a mass ratio of 4:1. The initiator is composed of ammonium persulfate and sodium bisulfite in a mass ratio of 1:1.

[0031] Example 2

[0032] A method for preparing a high-efficiency adsorption composite flocculant includes the following steps:

[0033] Step 1: Slowly add ammonia to the zirconium oxychloride aqueous solution to adjust the pH to 4.2, heat and stir at 65°C for 3 hours, let stand at room temperature for 21 hours, add silane coupling agent solution under nitrogen atmosphere and continue stirring at 55°C for 5 hours to obtain mixture A;

[0034] The zirconium oxychloride aqueous solution is composed of zirconium oxychloride and deionized water at a mass ratio of 1.1:19. The mass ratio of the zirconium oxychloride aqueous solution to the silane coupling agent solution is 190:22. The silane coupling agent solution is composed of silane coupling agent NQ-62 and anhydrous ethanol at a mass ratio of 3.6:15.5. The silane coupling agent NQ-62 is diethylenetriaminepropyltrimethoxysilane.

[0035] Step 2: After preheating mixture A, add EPTAC and stir at 65℃ for 7 hours to obtain mixture B;

[0036] The mass ratio of the mixture A to EPTAC is 105:1.42, and the EPTAC is 2,3-epoxypropyltrimethylammonium chloride;

[0037] Step 3: Under an inert gas environment, add the reactant monomer to the mixture B and mix. Add the initiator and stir at 45°C for 9 hours. Let stand at room temperature for 2.5 hours. Cut the gel into small pieces and soak it in acetone and anhydrous ethanol for 24 hours respectively. Take the precipitated solid and place it in an oven to dry under vacuum at 60°C until constant weight. Grind it to a particle size of 5 μm to complete the preparation.

[0038] The mass ratio of the reactant monomer, mixture B, and initiator is 11:115:0.07. The reactant monomer is composed of acrylamide and N,N-dimethylacrylamide mixed in a mass ratio of 4:1. The initiator is composed of ammonium persulfate and sodium bisulfite in a mass ratio of 1:1.

[0039] Example 3

[0040] A method for preparing a high-efficiency adsorption composite flocculant includes the following steps:

[0041] Step 1: Slowly add ammonia to the zirconium oxychloride aqueous solution to adjust the pH to 4.5, heat and stir at 70°C for 4 hours, let stand at room temperature for 24 hours, add silane coupling agent solution under nitrogen atmosphere and continue stirring at 60°C for 6 hours to obtain mixture A;

[0042] The zirconium oxychloride aqueous solution is composed of zirconium oxychloride and deionized water at a mass ratio of 1.2:20. The mass ratio of the zirconium oxychloride aqueous solution to the silane coupling agent solution is 200:23. The silane coupling agent solution is composed of silane coupling agent NQ-62 and anhydrous ethanol at a mass ratio of 3.8:16. The silane coupling agent NQ-62 is diethylenetriaminepropyltrimethoxysilane.

[0043] Step 2: After preheating mixture A, add EPTAC and stir at 70℃ for 8 hours to obtain mixture B;

[0044] The mass ratio of the mixture A to EPTAC is 110:1.50, and the EPTAC is 2,3-epoxypropyltrimethylammonium chloride;

[0045] Step 3: Under an inert gas environment, add the reactant monomer to the mixture B and mix. Add the initiator and stir at 50°C for 10 hours. Let stand at room temperature for 3 hours. Cut the gel into small pieces and soak it in acetone and anhydrous ethanol for 24 hours respectively. Take the precipitated solid and place it in an oven to dry under vacuum at 60°C until constant weight. Grind it to a particle size of 5μm to complete the preparation.

[0046] The mass ratio of the reactant monomer, mixture B, and initiator is 12:120:0.08. The reactant monomer is composed of acrylamide and N,N-dimethylacrylamide mixed in a mass ratio of 4:1. The initiator is composed of ammonium persulfate and sodium bisulfite in a mass ratio of 1:1.

[0047] Comparative Example 1

[0048] Compared with Example 3, Comparative Example 1 used silane coupling agent APTES instead of silane coupling agent NQ-62, and all other aspects were the same.

[0049] Comparative Example 2

[0050] Compared to Example 3, Comparative Example 2 did not use EPTAC, but all other aspects were the same.

[0051] Turbidity purification test: Diatomaceous earth was mixed with tap water to prepare turbid water with a turbidity of 120 NTU. The mixture was placed at room temperature (25°C) and the water temperature was adjusted to obtain the turbid water required for the experiment. Then, 3L of this turbid water was taken and divided into 6 portions. The composite flocculants prepared in Examples 1-3 and Comparative Examples 1-2 (dosage of 12 mg / L) were added to each portion, while the blank control group was not added with flocculant. The mixture was stirred at 400 r / min for 3 min and allowed to settle for 15 min. The supernatant was then collected for further treatment and turbidity testing.

[0052] Turbidity was measured according to the spectrophotometric method in GB13200-1991, and the test results are shown in Table 1.

[0053] Table 1

[0054]

[0055] As can be seen from the test results in Table 1, compared with Comparative Examples 1-2, the composite flocculant prepared by the present invention has a significant effect on the removal of diatomaceous earth in Examples 1-3.

[0056] Fluoride removal water purification test:

[0057] Prepare simulated fluoride-containing water with an initial fluoride ion concentration of 5 mg / L by mixing sodium fluoride (NaF) with deionized water, and equilibrate at room temperature (25°C) for 1 hour before use.

[0058] Take 3L of the simulated fluoride-containing water and divide it into 6 portions (corresponding to Examples 1-3, Comparative Examples 1-2, and blank control group). Add 12mg / L of the corresponding composite flocculant to each portion, stir at 400r / min for 3min, and then let it stand for 30min to settle. Take the supernatant and filter it through a 0.45μm microporous membrane. The concentration of fluoride ions in the supernatant is determined by ion-selective electrode method. The results are shown in Table 2.

[0059] Table 2

[0060]

[0061] As can be seen from the test results in Table 1, compared with Comparative Examples 1-2, the composite flocculant prepared by the present invention has a significant effect on fluoride removal in Examples 1-3.

[0062] This invention utilizes zirconium hydroxide colloid, generated by the reaction of zirconium oxychloride and ammonia, as a basic adsorption carrier. Its abundant hydroxyl groups and porous structure allow it to capture colloidal particles and pollutants in water through physical adsorption. The numerous exposed hydroxyl groups on the colloid surface provide active sites for subsequent grafting of the silane coupling agent NQ-62. A condensation reaction introduces amino functional groups, enhancing the compatibility between the zirconium hydroxide carrier and the organic acrylamide component, and providing reaction sites for EPTAC grafting. Finally, EPTAC undergoes a ring-opening reaction with the amino group of the silane coupling agent through its epoxy group, grafting quaternary ammonium salt cationic groups onto the modified zirconium hydroxide surface. This gives the carrier both inorganic adsorption properties and cationic charge characteristics, enabling efficient binding of negatively charged colloidal particles and impurities in water through electrostatic attraction. Ultimately, this synergistically enhances the adsorption capacity and flocculation sedimentation efficiency of the composite flocculant.

[0063] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some modifications or alterations to the above-disclosed technical content to create equivalent embodiments without departing from the scope of the present invention. Any indirect modifications, equivalent changes, and alterations made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the scope of the present invention.

Claims

1. A method for preparing a high-efficiency adsorption composite flocculant, characterized in that, The preparation method includes the following steps: Step 1: Slowly add ammonia to the zirconium oxychloride aqueous solution, heat and stir, let stand at room temperature, add silane coupling agent solution under an inert gas environment and continue stirring to obtain mixture A; the silane coupling agent solution includes silane coupling agent NQ-62; Step 2: After preheating mixture A, add EPTAC and stir at a constant temperature to obtain mixture B; Step 3: In an inert gas environment, add the reactant monomer to the mixture B and mix. Add the initiator and stir to react. Let it stand at room temperature. Cut the gel into small pieces and soak it. Take the precipitated solid and place it in an oven to dry under vacuum. Grind it to complete the preparation.

2. The preparation method of a high-efficiency adsorption composite flocculant according to claim 1, characterized in that: The zirconium oxychloride aqueous solution mentioned in step one is composed of zirconium oxychloride and deionized water in a mass ratio of 1.0-1.2:18-20.

3. The method for preparing a high-efficiency adsorption composite flocculant according to claim 1, characterized in that: In step one, the amount of ammonia used is to adjust the pH value to 4.0-4.5, and the heating and stirring temperature is 60-70℃, with a stirring time of 2-4 hours.

4. The preparation method of a high-efficiency adsorption composite flocculant according to claim 1, characterized in that: The temperature for continued stirring in step one is 50-60℃, and the stirring time is 4-6 hours.

5. The method for preparing a high-efficiency adsorption composite flocculant according to claim 1, characterized in that: In step one, the mass ratio of the zirconium oxychloride aqueous solution to the silane coupling agent solution is 180-200:20-23. The silane coupling agent solution is composed of silane coupling agent NQ-62 and anhydrous ethanol mixed in a mass ratio of 3.5-3.8:15-16.

6. The method for preparing a high-efficiency adsorption composite flocculant according to claim 1, characterized in that: In step two, the mass ratio of mixture A to EPTAC is 100-110:1.35-1.

50.

7. The method for preparing a high-efficiency adsorption composite flocculant according to claim 1, characterized in that: The temperature for constant temperature stirring in step two is 60-70℃, and the stirring time is 6-8 hours.

8. The method for preparing a high-efficiency adsorption composite flocculant according to claim 1, characterized in that: In step three, the mass ratio of the reaction monomer, mixture B, and initiator is 10-12:110-120:0.06-0.08, and the reaction monomer is one or a combination of acrylamide and N,N-dimethylacrylamide.

9. The method for preparing a high-efficiency adsorption composite flocculant according to claim 1, characterized in that: The stirring reaction in step three is carried out at a temperature of 40-50℃ for 8-10 hours.

10. The application of a highly efficient adsorption composite flocculant prepared by the preparation method according to any one of claims 1 to 8 in water purification.

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