Composite water treatment agent and preparation method thereof

Abstract

This application belongs to the technical field of water treatment agents, specifically providing a composite water treatment agent and its preparation method, including the following steps: 1) Adding ferric chloride hexahydrate and polysaccharide to an L-aspartic acid solution and stirring evenly to obtain a base solution; 2) Mixing wood pulp, deionized water, and tetrabutylphosphine hydroxide evenly, then adding sepiolite and aluminum lactate, and grinding thoroughly to obtain a dispersion; 3) Slowly adding the base solution to the dispersion, then adding mixed monomers and an initiator, aging at a constant temperature of 50-65℃ overnight, washing, drying, and grinding to obtain the final product. The water treatment agent prepared by this application has the advantage of good adsorption effect.

Description

Technical Field

[0001] This application belongs to the field of water treatment agent technology, and in particular relates to a composite water treatment agent and its preparation method. Background Technology

[0002] With socio-economic growth and increased industrialization, large amounts of domestic and industrial wastewater are being discharged, putting greater pressure on wastewater treatment. However, traditional water treatment agents have drawbacks when treating pollutants in polluted water bodies, including high costs, impact on water color, and a tendency to cause secondary pollution.

[0003] Traditional water treatment agents typically use polyaluminum sulfate and polyferric chloride as flocculation and adsorption components. However, these flocculation and adsorption materials are increasingly unable to meet the requirements of advanced treatment and are prone to secondary ionic pollution. In recent years, some natural adsorbent materials such as diatomaceous earth, chitosan, starch, and lignin have received widespread attention. Technicians have rationally modified these materials to some extent, thereby compensating for the shortcomings of traditional inorganic flocculants, such as poor flocculation effect on small molecule pollutants and limited flocculation capabilities. For example, Zhang Tianzhong et al. prepared hydroxyl iron-pillared diatomaceous earth using natural diatomaceous earth as raw material, which showed good treatment effect on pollutants in slightly polluted water bodies. Another example is CN107649100A, which discloses a method for preparing water treatment materials using lignin. This method involves preparing lignin into an aqueous solution, freeze-drying it to obtain lignin aerogel, and then heat-treating the obtained lignin aerogel in a tube furnace under an argon atmosphere. After cooling, a porous lignin-based water treatment material is prepared, which has a good adsorption effect on pollutants.

[0004] The aforementioned adsorption materials have good treatment effects on slightly polluted water bodies, but their treatment effects on complex water bodies such as oilfield wastewater, industrial wastewater, and river pollution are still poor. Therefore, it is of practical technical significance to improve the water treatment agent's ability to cope with complex water environments and enhance its adsorption treatment effect on highly polluted water bodies. Summary of the Invention

[0005] To address the aforementioned issues and further improve the adsorption treatment effect of water treatment materials, this application provides a composite water treatment agent and its preparation method.

[0006] This application first provides a method for preparing a composite water treatment agent, comprising the following steps:

[0007] 1) Add ferric chloride hexahydrate and polysaccharide to L-aspartic acid solution and stir until homogeneous to obtain base solution;

[0008] 2) Take wood pulp, deionized water, and tetrabutylphosphine hydroxide and mix them evenly. Then add sepiolite and aluminum lactate, and grind them thoroughly to obtain a dispersion.

[0009] 3) Slowly add the base liquid to the dispersion, then add the mixed monomers and initiator, age at 50-65℃ overnight, wash, dry and grind to obtain the final product.

[0010] Furthermore, the polysaccharide is at least one of sodium alginate, carrageenan, and xanthan gum.

[0011] Furthermore, the polysaccharide is composed of carrageenan and xanthan gum in a mass ratio of 1:(0.1-0.15).

[0012] Furthermore, in the base liquid, the mass ratio of L-aspartic acid, ferric chloride hexahydrate, and polysaccharide is (0.2-0.25):(0.55-0.65):1.

[0013] Furthermore, the mass fraction of wood pulp in the dispersion is 1.5-3%.

[0014] Furthermore, the wood pulp undergoes pretreatment, which involves impregnating the raw wood pulp in an impregnation solution, then draining and drying it; the impregnation solution includes modified cyclodextrin and deionized water.

[0015] Furthermore, the modified cyclodextrin is prepared by reacting β-cyclodextrin with allyl glycidyl ether.

[0016] Furthermore, the mass fraction of modified cyclodextrin in the impregnation solution is 2-5%.

[0017] Furthermore, the mixed monomers include acrylic acid and N,N'-methylenebisacrylamide.

[0018] This application also provides a composite water treatment agent, which is prepared by the above-described preparation method.

[0019] Compared with the prior art, this application has the following beneficial effects:

[0020] This application uses a base liquid and a dispersion liquid as a mixed phase, which, after polymerization, forms a homogeneous foam porous adsorbent material. In the base liquid, polysaccharides, L-aspartic acid solution, and iron salts form a composite system. The polysaccharide molecular chains can form coordination structures with iron ions, allowing for partial ion exchange during subsequent adsorption. This release of iron ions through hydrolysis results in excellent flocculation and adsorption. In the dispersion liquid, wood pulp fibers undergo surface micro-dissolution under the action of tetrabutylphosphine hydroxide, forming an adhesion layer that adheres to components such as sepiolite. After solidification, a uniform porous foam adsorbent structure is formed, which enhances the mass transfer driving force of small molecule impurities in complex polluted water bodies within the adsorbent material, weakens concentration polarization, and thus strongly enhances the adsorption effect on small molecules. Furthermore, aluminum lactate can stabilize the mixed phase through coordination bonds and electrostatic interactions, optimizing the spatial conformation of the porous adsorbent material and further improving its deep adsorption performance and adsorption stability. Attached Figure Description

[0021] Figure 1 This is a schematic diagram showing the performance data of the water treatment agent in simulated water samples from Examples 1-2 and Control Groups 1-2 of this application.

[0022] Figure 2 This is a schematic diagram showing the adsorption performance data of the water treatment agents in Examples 1-2 and Control Groups 1-2 of this application.

[0023] Figure 3 This is a schematic diagram of the TEM and elemental distribution of the water treatment agent in Embodiment 2 of this application. Detailed Implementation

[0024] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this application.

[0025] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0026] When using “including,” “having,” and “contains” as described herein, the intention is to cover non-exclusive inclusion, unless an explicit qualifying term such as “only,” “consisting of,” etc., is used, in which case another component may be added.

[0027] The terms "preferred," "more preferably," "better," and "even better" used in this application refer to embodiments of this application that provide certain beneficial effects under certain circumstances. However, other embodiments may also be preferred under the same or other circumstances. Furthermore, the description of one or more preferred embodiments does not imply that other embodiments are unavailable, nor is it intended to exclude other embodiments from the scope of this application. That is, in this application, "preferred," "more preferably," "better," and "even better" are merely descriptions of implementations or embodiments with better effects, but do not constitute a limitation on the scope of protection of this application.

[0028] In this application, terms such as "further," "even more," and "particularly" are used for descriptive purposes and indicate differences in content, but should not be construed as limiting the scope of protection of this application.

[0029] In this application, "at least one" means one or more, such as one, two, or more. "Multiple" or "several" means at least two, such as two, three, etc., and "multi-layered" means at least two layers, such as two layers, three layers, etc., unless otherwise explicitly specified. In the description of this application, "several" means at least one, such as one, two, etc., unless otherwise explicitly specified.

[0030] When a numerical range is disclosed herein, the range is considered continuous and includes the minimum and maximum values ​​of the range, as well as every value between the minimum and maximum values. Furthermore, when the range refers to integers, it includes every integer between the minimum and maximum values ​​of the range. Additionally, when multiple ranges are provided to describe a feature or characteristic, the ranges may be combined. In other words, unless otherwise specified, all ranges disclosed herein should be understood to include any and all subranges to which they are incorporated.

[0031] Unless otherwise specified, all steps in this application may be performed sequentially or randomly. For example, the method comprising steps (a) and (b) indicates that the method may include steps (a) and (b) performed sequentially, or it may include steps (b) and (a) performed sequentially. For example, the mention that the method may also include step (c) indicates that step (c) may be added to the method in any order; for example, the method may include steps (a), (b), and (c), or it may include steps (a), (c), and (b), or it may include steps (c), (a), and (b), etc. Unless otherwise stated, singular terms may include plural forms and should not be construed as having a quantity of one.

[0032] In this application, "above" or "below" includes the number itself. For example, "below 1" includes 1.

[0033] In this application, room temperature refers to 0~40℃, including but not limited to 10~40℃, or further to 20~30℃.

[0034] This application, based on extensive experimental research, provides a method for preparing a composite water treatment agent, comprising the following steps:

[0035] 1) Add ferric chloride hexahydrate and polysaccharide to L-aspartic acid solution and stir until homogeneous to obtain base solution;

[0036] 2) Take wood pulp, deionized water, and tetrabutylphosphine hydroxide and mix them evenly. Then add sepiolite and aluminum lactate, and grind them thoroughly to obtain a dispersion.

[0037] 3) Slowly add the base liquid to the dispersion, then add the mixed monomers and initiator, age at 50-65℃ overnight, wash, dry and grind to obtain the final product.

[0038] Furthermore, the polysaccharide is at least one of sodium alginate, carrageenan, and xanthan gum.

[0039] Furthermore, the polysaccharide is composed of carrageenan and xanthan gum in a mass ratio of 1:(0.1-0.15).

[0040] In some specific embodiments, the polysaccharide can be composed of carrageenan and xanthan gum in a mass ratio of 1:0.1, 1:0.105, 1:0.11, 1:0.115, 1:0.12, 1:0.125, 1:0.13, 1:0.135, 1:0.14, 1:0.145, or 1:0.15. Generally, a mass ratio of 1:0.12 for the polysaccharide yields better technical results.

[0041] Furthermore, in the base liquid, the mass ratio of L-aspartic acid, ferric chloride hexahydrate, and polysaccharide is (0.2-0.25):(0.55-0.65):1.

[0042] In some specific embodiments, the mass ratio of L-aspartic acid, ferric chloride hexahydrate, and polysaccharide in the base solution can be 0.2:0.55:1, 0.21:0.55:1, 0.22:0.55:1, 0.23:0.55:1, 0.24:0.55:1, 0.25:0.55:1, 0.2:0.56:1, 0.21:0.57:1, 0.22:0.58:1, 0.23:0.59:1, 0.24:0.6:1, 0.25:0.61:1, 0.2:0.62:1, 0.21:0.63:1, 0.22:0.64:1, or 0.23:0.65:1. Under normal circumstances, when the mass ratio of L-aspartic acid, ferric chloride hexahydrate, and polysaccharide in the base solution is 0.25:0.6:1, better experimental results can be obtained.

[0043] Furthermore, the mass fraction of wood pulp in the dispersion is 1.5-3%.

[0044] In some specific embodiments, the mass fraction of wood pulp in the dispersion can be 1.5%, 1.55%, 1.6%, 1.65%, 1.7%, 1.75%, 1.8%, 1.85%, 1.9%, 1.95%, 2%, 2.05%, 2.1%, 2.15%, 2.2%, 2.25%, 2.3%, 2.35%, 2.4%, 2.45%, 2.5%, 2.55%, 2.6%, 2.65%, 2.7%, 2.75%, 2.8%, 2.85%, 2.9%, 2.95%, or 3%. Generally, better experimental results can be obtained when the mass fraction of wood pulp in the dispersion is 2%, 2.05%, 2.1%, and 2.15%.

[0045] Furthermore, the wood pulp undergoes pretreatment, which involves impregnating the raw wood pulp in an impregnation solution, then draining and drying it; the impregnation solution includes modified cyclodextrin and deionized water.

[0046] Furthermore, the modified cyclodextrin is prepared by reacting β-cyclodextrin with allyl glycidyl ether.

[0047] Furthermore, the mass fraction of modified cyclodextrin in the impregnation solution is 2-5%.

[0048] In some specific embodiments, the mass fraction of modified cyclodextrin in the impregnation solution can be 2%, 2.5%, 3%, 3.5%, 4%, 4.5%, or 5%. Generally, a mass fraction of 2.5% of modified cyclodextrin in the impregnation solution yields the best results.

[0049] Furthermore, the mixed monomers include acrylic acid and N,N'-methylenebisacrylamide.

[0050] This application also provides a composite water treatment agent, which is prepared by the above-described preparation method.

[0051] The present application will be further illustrated by the following examples, but these examples do not limit the scope of the present application.

[0052] When numerical ranges are given in the embodiments, it should be understood that, unless otherwise stated in this application, both endpoints of each numerical range and any value between the two endpoints may be selected. Unless otherwise defined, all technical and scientific terms used in this application have the same meaning as commonly understood by one of ordinary skill in the art. Where specific conditions are not specified in the embodiments, conventional conditions or conditions recommended by the manufacturer shall apply. All reagents or instruments whose manufacturers are not specified are conventional products that can be purchased commercially. In addition to the specific methods, equipment, and materials used in the embodiments, based on the knowledge of the prior art possessed by one of ordinary skill in the art and the description in this application, any prior art methods, equipment, and materials similar to or equivalent to those described, used, or made by the methods, equipment, and materials in the embodiments of this application may be used to implement this application.

[0053] Example 1

[0054] The preparation method of the composite water treatment agent in this embodiment includes the following steps:

[0055] 1) Weigh 25g of L-aspartic acid and 2kg of deionized water and mix them evenly to prepare an L-aspartic acid solution. Then add 60g of ferric chloride hexahydrate and 100g of polysaccharide to the L-aspartic acid solution and stir evenly to obtain the base solution. The polysaccharide is composed of carrageenan and xanthan gum in a mass ratio of 1:0.12.

[0056] 2) Take 122g of eucalyptus pulp and 5g of 35% tetrabutylphosphine hydroxide solution and premix for 20min. Then add 5kg of deionized water and mix evenly. Then add 1kg of sepiolite and 50g of aluminum lactate. After grinding thoroughly in a disc mill, a dispersion is obtained.

[0057] 3) Slowly add 1 kg of base liquid to 3 kg of dispersion, then add 150 g of acrylic acid and 37.5 g of N,N'-methylenebisacrylamide, stir at 3500 rpm for 5 min, then add 3.5 g of ammonium persulfate and 3 g of sodium bisulfate, stir evenly, and age at 60°C overnight. Wash the obtained product with water, dry at 100°C, pulverize and grind to obtain the final product.

[0058] Example 2

[0059] The preparation method of the composite water treatment agent in this embodiment includes the following steps:

[0060] 1) Weigh 25g of L-aspartic acid and 2kg of deionized water and mix them evenly to prepare an L-aspartic acid solution. Then add 60g of ferric chloride hexahydrate and 100g of polysaccharide to the L-aspartic acid solution and stir evenly to obtain the base solution. The polysaccharide is composed of carrageenan and xanthan gum in a mass ratio of 1:0.12.

[0061] 2) Mix 9.75kg of deionized water, 250g of modified cyclodextrin, 15g of DMSO and 10g of urea evenly to prepare an impregnation solution. Then add 500g of ash pulp to the impregnation solution, impregnate for 30 minutes, filter out, drain and let dry naturally.

[0062] The preparation method of modified cyclodextrin includes the following steps: dissolving β-cyclodextrin and sodium hydroxide in water, then adding allyl glycidyl ether dropwise to the solution, controlling the molar ratio of β-cyclodextrin to allyl glycidyl ether to be 1:2, stirring the reaction at room temperature until the mixed solution becomes clear again, then neutralizing the solution with hydrochloric acid, filtering, adding ethanol to wash the solution, filtering, and distilling under reduced pressure to obtain the modified cyclodextrin.

[0063] Take 122g of pretreated eucalyptus pulp and 5g of 35% tetrabutylphosphine hydroxide solution and premix for 20min. Then add 5kg of deionized water and mix evenly. Then add 1kg of sepiolite and 50g of aluminum lactate and grind thoroughly in a disc mill to obtain a dispersion.

[0064] 3) Slowly add 1 kg of base liquid to 3 kg of dispersion, then add 150 g of acrylic acid and 37.5 g of N,N'-methylenebisacrylamide, stir at 3500 rpm for 5 min, then add 3.5 g of ammonium persulfate and 3 g of sodium bisulfate, stir evenly, and age at 60°C overnight. Wash the obtained product with water, dry at 100°C, pulverize and grind to obtain the final product.

[0065] Control group 1

[0066] The preparation method of the water treatment agent in this control group includes the following steps:

[0067] 1) Add 100g of lignin to a sodium hydroxide solution with a pH of 10.5, stir for 30 minutes, add 15g of sodium sulfate, stir at 90℃ for 5 hours, dialyze and dry to obtain sulfonated lignin;

[0068] 2) Dissolve 30g of sulfonated lignin in 500mL of deionized water, then add an ethanol solution containing 40g of tetrabutyl titanate, mix well, and then perform a hydrothermal reaction at 130℃. The resulting product is obtained after drying.

[0069] Control group 2

[0070] The preparation method of the composite water treatment agent in this control group includes the following steps:

[0071] 1) Take 122g of eucalyptus pulp and 5kg of deionized water and mix them evenly. Then add 1kg of sepiolite and 50g of aluminum lactate. Grind them thoroughly in a disc mill to obtain a dispersion.

[0072] 2) Add 150g of acrylic acid and 37.5g of N,N'-methylenebisacrylamide to 3kg of dispersion, stir at 3500rpm for 5min, then add 3.5g of ammonium persulfate and 3g of sodium bisulfate, stir evenly, and age at 60℃ overnight. Wash the obtained product with water, dry at 100℃, and then crush and grind to obtain the final product.

[0073] Performance testing

[0074] Weigh 85.02g of dried potassium hydrogen phthalate into a beaker, add deionized water to the beaker, stir to dissolve, transfer to a 1000mL volumetric flask, dilute to the mark, and shake well to obtain a solution with a COD concentration of 100g / L. Then take 40mL of this solution and add it dropwise to a 1000mL volumetric flask, dilute to the mark, and shake well to prepare a COD simulated water sample with a COD concentration of 4g / L.

[0075] Weigh 2.197 g of dried potassium dihydrogen phosphate and place it in a beaker. Add deionized water to the beaker, stir to dissolve, and then transfer to a 1000 mL volumetric flask. Dilute to the mark and shake well to obtain a TP concentration of 500 mg / L. Then, take 20 mL of this solution and add it dropwise to a 1000 mL volumetric flask. Dilute to the mark and shake well to obtain a TP simulated water sample with a TP concentration of 10 mg / L.

[0076] Weigh 3.819 g of dried ammonium chloride into a beaker, add deionized water, stir to dissolve, transfer to a 1000 mL volumetric flask, dilute to the mark, and shake well to obtain a solution with an NH3-N concentration of 1000 mg / L. Then, take 20 mL of this solution and add it dropwise to a 1000 mL volumetric flask, dilute to the mark, and shake well to prepare a simulated NH3-N water sample with an NH3-N concentration of 20 mg / L.

[0077] Take 2g of the water treatment agent from Examples 1-2 and Control Groups 1-2 and put it into a beaker. Add 1000mL of the simulated water sample mentioned above and adjust the pH to 6. Place the beaker in a constant temperature shaking incubator at 200r / min. Centrifuge the supernatant according to different adsorption times and determine the removal rate. Removal rate = (concentration of pollutants before reaction - concentration of pollutants after reaction) / concentration of pollutants before reaction × 100%. Specific test results are as follows: Figure 1 As shown.

[0078] Take 20 mg of the water treatment agent from Examples 1-2 and Control Groups 1-2 and add it to a beaker. Add 20 mL of a 300 mg / L methylene blue solution. Shake at 25 °C and 180 r / min, and measure the adsorption amount at different times. The concentration of residual dye in the solution after adsorption is measured using a UV spectrophotometer (UV1900). The UV measurement wavelength of methylene blue is 664 nm. Adsorption amount = (C0-C1)V / m, where C0 is the initial concentration of methylene blue solution (mg / L), C1 is the equilibrium concentration of methylene blue (mg / L), V is the volume of methylene blue solution (mL), and m is the mass of water treatment agent (mg). Specific test results are as follows: Figure 2 As shown.

[0079] The water treatment agent from Example 2 was subjected to transmission electron microscopy and elemental distribution testing. The test results are as follows: Figure 3 As shown, aluminum and iron atoms are uniformly distributed in the water treatment agent of this application, and a certain degree of ion migration and diffusion can occur during the adsorption process, thereby improving the flocculation and adsorption effect.

[0080] It can be seen that the water treatment agent of this application has a high adsorption effect on high-concentration wastewater, especially high-COD biological wastewater, with a removal rate of over 60%. Furthermore, the water treatment agent of this application contains multiple adsorption sites, which can reduce the influence of concentration polarization during the adsorption process, resulting in a higher adsorption saturation capacity, and enabling deep adsorption treatment of high-concentration wastewater.

[0081] Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A method for preparing a composite water treatment agent, characterized in that: Includes the following steps: 1) Add ferric chloride hexahydrate and polysaccharide to L-aspartic acid solution and stir until homogeneous to obtain base solution; the polysaccharide is composed of carrageenan and xanthan gum in a mass ratio of 1:(0.1-0.15); 2) Take wood pulp, deionized water, and tetrabutylphosphine hydroxide and mix them evenly. Then add sepiolite and aluminum lactate, and grind them thoroughly to obtain a dispersion. 3) Slowly add the base liquid to the dispersion, then add the mixed monomers and initiator, age at 50-65℃ overnight, wash, dry and grind to obtain the final product.

2. The preparation method of the composite water treatment agent according to claim 1, characterized in that: In the base solution, the mass ratio of L-aspartic acid, ferric chloride hexahydrate, and polysaccharide is (0.2-0.25):(0.55-0.65):

1.

3. The preparation method of the composite water treatment agent according to claim 1, characterized in that: The mass fraction of wood pulp in the dispersion is 1.5-3%.

4. The method for preparing the composite water treatment agent according to claim 1, characterized in that: The wood pulp undergoes pretreatment, which involves impregnating the raw wood pulp in an impregnation solution, then draining and drying it; the impregnation solution includes modified cyclodextrin and deionized water.

5. The method for preparing the composite water treatment agent according to claim 4, characterized in that: The modified cyclodextrin is prepared by reacting β-cyclodextrin with allyl glycidyl ether.

6. The method for preparing the composite water treatment agent according to claim 4, characterized in that: The mass fraction of modified cyclodextrin in the impregnation solution is 2-5%.

7. The method for preparing the composite water treatment agent according to claim 1, characterized in that: The mixed monomers include acrylic acid and N,N'-methylenebisacrylamide.

8. A composite water treatment agent, characterized in that: It is prepared by any one of the preparation methods described in claims 1-7.

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