Phosphorus-containing wastewater treatment agent and method for preparing the same

Abstract

This invention provides a phosphorus-containing wastewater treatment agent, comprising, by weight: 3-10 parts sodium polyphosphate, 0.1-1 parts alkylepoxycarboxylic acid, 5-10 parts ethylenediaminetetraacetic acid, 3-10 parts EDTMPS, 0.1-3 parts polyacrylamide, 5-15 parts iron(III) oxide, 10-30 parts polyaluminum chloride, 10-30 parts modified bentonite, and 0.5-5 parts aminated carbon nanotubes. The preparation method includes the following steps: adding magnetic iron(III) oxide nanoparticles to a polyaluminum chloride solution to obtain a precipitating composite agent; dissolving chitosan in acetic acid solution and adding sodium-based bentonite to obtain modified bentonite; adding water to the remaining materials and mixing well; adding aminated carbon nanotubes and the precipitating composite agent in portions; adding modified bentonite and mixing well to obtain a premix; treating the premix to obtain the product. This product can efficiently and stably adsorb suspended particles and phosphates in water, accelerate the floc settling rate, and enhance phosphorus removal efficiency.

Description

Technical Field

[0001] This invention relates to the field of water treatment agent technology, and more specifically, to a phosphorus-containing wastewater treatment agent and its preparation method. Background Technology

[0002] As is well known, phosphorus is an essential element for life in nature and influences the primary productivity of aquatic ecosystems. It is also a controlling factor in eutrophication of most water bodies, making the control of phosphorus concentration in wastewater particularly important. Phosphorus usually exists in water bodies in the form of low-concentration phosphates, and currently, there are strict limits worldwide on the phosphorus concentration in discharged wastewater.

[0003] Phosphorus removal from industrial wastewater not only reduces phosphorus emissions and prevents eutrophication, but also enables the resource utilization of phosphorus. Currently, the main methods for treating phosphorus-containing wastewater include biological, chemical, and adsorption methods. Biological phosphorus removal has a low removal rate and the treatment system is relatively complex. Chemical phosphorus removal generates a large amount of sludge, and the selection of chemical agents is difficult, easily causing secondary pollution. Adsorption is one of the effective methods for phosphorus removal. Current research focuses on developing new adsorption materials and modifying traditional adsorption materials. Improving the treatment efficiency of adsorbents and reducing the total phosphorus concentration in wastewater is particularly important. Summary of the Invention

[0004] The purpose of this invention is to provide a phosphorus-containing wastewater treatment agent and its preparation method, which can efficiently and stably adsorb suspended particles and phosphates in water, accelerate the settling rate of flocs, and enhance phosphorus removal efficiency.

[0005] The embodiments of the present invention are achieved through the following technical solutions:

[0006] A phosphorus-containing wastewater treatment agent, by weight, comprises: 3-10 parts sodium polyphosphate, 0.1-1 parts alkylepoxycarboxylic acid, 5-10 parts ethylenediaminetetraacetic acid, 3-10 parts EDTMPS, 0.1-3 parts polyacrylamide, 5-15 parts iron(III) oxide, 10-30 parts polyaluminum chloride, 10-30 parts modified bentonite, and 0.5-5 parts aminated carbon nanotubes.

[0007] A method for preparing a phosphorus-containing wastewater treatment agent includes the following steps:

[0008] S1. Add magnetic nanoparticles of iron oxide to a polyaluminum chloride solution, stir magnetically and age for a period of time to obtain a precipitated composite agent;

[0009] S2. Dissolve chitosan in acetic acid solution to obtain chitosan solution; then add sodium bentonite to the above chitosan solution and stir continuously for a period of time, let it stand for a period of time, and dry it to obtain chitosan modified bentonite.

[0010] S3. After thoroughly mixing the remaining materials, add water and mix well. Then add some aminated carbon nanotubes and some precipitating composite agent, and stir continuously to disperse them fully. Then add the remaining aminated carbon nanotubes and precipitating composite agent in several batches, and after fully dispersing, add modified bentonite and mix well to obtain the premix.

[0011] S4. Keep the premixed material at a constant temperature for a period of time, then gradually increase the temperature and keep it at that temperature for a period of time; take out the treated mixture, cool it, grind it, and sieve it to obtain the product.

[0012] The technical solutions of the embodiments of the present invention have at least the following advantages and beneficial effects:

[0013] 1. The treatment agent of this invention can efficiently and stably adsorb suspended particles and phosphates in water by using magnetic, chemical adsorption and electrostatic attraction, thereby accelerating the settling rate of flocs and enhancing phosphorus removal efficiency.

[0014] 2. The treatment agent of this invention utilizes the porous nature and hollow tubular structure of carbon nanotubes, allowing modified bentonite and precipitating composite agents to fill the internal voids and surface of the carbon nanotubes more efficiently, loading more modified bentonite, thereby achieving better purification effect on phosphorus-containing wastewater. In addition, this invention amination of carbon nanotubes improves the dispersion effect of carbon nanotubes, avoids secondary aggregation of carbon nanotubes, and makes them more dispersible in wastewater, thus achieving a more efficient adsorption effect. Detailed Implementation

[0015] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Where specific conditions are not specified in the embodiments, conventional conditions or conditions recommended by the manufacturer shall apply. Reagents or instruments whose manufacturers are not specified are all conventional products that can be purchased commercially.

[0016] The following is a detailed description of a phosphorus-containing wastewater treatment agent and its preparation method provided by an embodiment of the present invention.

[0017] A phosphorus-containing wastewater treatment agent, by weight, comprises: 3-10 parts sodium polyphosphate, 0.1-1 parts alkylepoxycarboxylic acid, 5-10 parts ethylenediaminetetraacetic acid, 3-10 parts EDTMPS, 0.1-3 parts polyacrylamide, 5-15 parts iron(III) oxide, 10-30 parts polyaluminum chloride, 10-30 parts chitosan-modified bentonite, and 0.5-5 parts aminated carbon nanotubes.

[0018] Further, it includes: 3-5 parts sodium polyphosphate, 0.1-0.5 parts alkyl epoxycarboxylic acid, 5-8 parts ethylenediaminetetraacetic acid, 3-8 parts EDTMPS, 0.1-1 part polyacrylamide, 10-15 parts iron oxide, 15-25 parts polyaluminum chloride, 15-25 parts chitosan-modified bentonite, and 0.5-2 parts aminated carbon nanotubes.

[0019] Further, it includes: 4 parts sodium polyphosphate, 0.3 parts alkyl epoxy carboxylic acid, 6 parts ethylenediaminetetraacetic acid, 5 parts EDTMPS, 0.5 parts polyacrylamide, 15 parts iron oxide, 20 parts polyaluminum chloride, 20 parts chitosan-modified bentonite, and 1 part aminated carbon nanotubes.

[0020] This invention employs a co-precipitation method to prepare magnetic iron oxide nanoparticles, which are then added to a polyaluminum chloride solution and aged with magnetic stirring for 3-5 hours to obtain a magnetic-chemical precipitation composite agent. Simultaneously with the chemical reaction with phosphate, tiny suspended particles and small-diameter colloids in the water can be adsorbed by the aluminum phosphate flocs. Furthermore, the cationic hydroxyl complexes generated from the hydrolysis of aluminum ions enhance adsorption through a charge neutralization reaction with the negatively charged phosphate, achieving phosphorus removal. In addition, the magnetic iron oxide nanoparticles form magnetic flocs with magnetic powder as the core in the liquid phase, facilitating the chemical adsorption and precipitation of orthophosphate. Under the action of an external magnetic field, the floc settling rate accelerates, enhancing phosphorus removal efficiency.

[0021] Chitosan and bentonite are chemically bonded together, resulting in a larger interlayer spacing and specific surface area, which allows for more efficient adsorption. Furthermore, chitosan contains -OH and -NH2 groups, which convert to -NH3 under acidic conditions. + It can interact with phosphorus through electrostatic attraction; and the -OH and -NH2 groups on chitosan also form hydrogen bonds with phosphorus, which enhances the phosphorus adsorption capacity of the modified bentonite.

[0022] This invention utilizes the porous nature and hollow tubular structure of carbon nanotubes, enabling modified bentonite and precipitating composites to fill the internal voids and surface of the carbon nanotubes more efficiently, loading more modified bentonite and thus achieving better purification effects on phosphorus-containing wastewater. In addition, this invention amination of carbon nanotubes improves their dispersion effect, avoids secondary aggregation of carbon nanotubes, and results in better dispersibility in wastewater, allowing for more efficient adsorption.

[0023] Sodium polyphosphate, sodium alkylepoxycarboxylate, ethylenediaminetetraacetic acid, EDTMPS, and polyacrylamide are used to sterilize and descale the wastewater, effectively removing suspended solids, reducing wastewater color, and preventing the wastewater after phosphorus removal treatment from corroding the equipment.

[0024] A method for preparing a phosphorus-containing wastewater treatment agent includes the following steps:

[0025] S1. Ferric oxide magnetic nanoparticles were prepared by co-precipitation method, added to polyaluminum chloride solution, and aged by magnetic stirring at 30-50℃ for 3-5 hours to obtain precipitated composite agent;

[0026] S2. Dissolve chitosan in acetic acid solution to prepare a 1-5% (w / w) chitosan solution, then add a certain mass of sodium-based bentonite to the above chitosan solution and stir continuously for 3-5 hours to fully impregnate it. After standing for 24-48 hours, dry it at 70-90℃ to obtain chitosan-modified bentonite.

[0027] S3. After thoroughly mixing the remaining materials, add water and mix well. Then add a portion of aminated carbon nanotubes and a portion of precipitating composite agent, and stir continuously to ensure thorough dispersion. Then add the remaining aminated carbon nanotubes and magnetic-chemical precipitating composite agent in several portions, and after thorough dispersion treatment, add modified bentonite and mix well to obtain the premix. Among them, aminated carbon nanotubes and precipitating composite agent are each added at least twice, and each time the amount is equal.

[0028] S4. Place the premixed material in a constant temperature oven at 60℃~70℃ for 2~3 hours, then gradually increase the temperature to 80℃~90℃ at a heating rate of 1-5℃ / min, and bake for 6~10 hours; take out the processed mixture, cool, grind, and sieve to obtain the product.

[0029] Example 1

[0030] A phosphorus-containing wastewater treatment agent, by weight, comprises: 4 parts sodium polyphosphate, 0.3 parts alkylepoxycarboxylic acid, 6 parts ethylenediaminetetraacetic acid, 5 parts EDTMPS, 0.5 parts polyacrylamide, 15 parts iron(III) oxide, 20 parts polyaluminum chloride, 20 parts chitosan-modified bentonite, and 1 part aminated carbon nanotubes.

[0031] A method for preparing a phosphorus-containing wastewater treatment agent includes the following steps:

[0032] S1. Ferric oxide magnetic nanoparticles were prepared by co-precipitation method, added to polyaluminum chloride solution, and aged under magnetic stirring at 40℃ for 4h to obtain precipitated composite agent;

[0033] S2. Chitosan is dissolved in a 5% (v / v) acetic acid solution to prepare a 2% (w / w) chitosan solution. Then, a certain mass of sodium-based bentonite is added to the chitosan solution and stirred continuously for 4 hours to fully impregnate it. After standing for 30 hours, it is dried at 80°C to obtain chitosan-modified bentonite.

[0034] S3. After thoroughly mixing the remaining materials, add water and mix well. Then add some aminated carbon nanotubes and some precipitating composite agent, and stir continuously to disperse them fully. Then add the remaining aminated carbon nanotubes and precipitating composite agent in two equal portions, and after fully dispersing, add modified bentonite and mix well to obtain the premix.

[0035] S4. Place the premixed material in a constant temperature oven at 65℃ for 2.5 hours, then gradually increase the temperature to 85℃ and bake for 8 hours; remove the processed mixture, cool, grind, and sieve to obtain the product.

[0036] Example 2

[0037] The difference between this embodiment and Embodiment 1 is that: a phosphorus-containing wastewater treatment agent, by weight, comprises: 5 parts sodium polyphosphate, 0.5 parts alkyl epoxy carboxylic acid, 7 parts ethylenediaminetetraacetic acid, 6 parts EDTMPS, 1 part polyacrylamide, 10 parts iron oxide, 15 parts polyaluminum chloride, 15 parts modified bentonite, and 0.5 parts aminated carbon nanotubes.

[0038] Example 3

[0039] The difference between this embodiment and Embodiment 1 is that: a phosphorus-containing wastewater treatment agent, by weight, includes: 8 parts sodium polyphosphate, 0.6 parts alkyl epoxy carboxylic acid, 8 parts ethylenediaminetetraacetic acid, 9 parts EDTMPS, 0.2 parts polyacrylamide, 15 parts iron oxide, 25 parts polyaluminum chloride, 25 parts modified bentonite, and 4 parts aminated carbon nanotubes.

[0040] Example 4

[0041] The difference between this embodiment and Embodiment 1 is that: a phosphorus-containing wastewater treatment agent, by weight, comprises: 7 parts sodium polyphosphate, 0.8 parts alkyl epoxy carboxylic acid, 6 parts ethylenediaminetetraacetic acid, 8 parts EDTMPS, 0.3 parts polyacrylamide, 8 parts iron oxide, 18 parts polyaluminum chloride, 20 parts modified bentonite, and 1.5 parts aminated carbon nanotubes.

[0042] Example 5

[0043] The difference between this embodiment and Embodiment 1 is that: a phosphorus-containing wastewater treatment agent, by weight, comprises: 9 parts sodium polyphosphate, 0.9 parts alkyl epoxy carboxylic acid, 9 parts ethylenediaminetetraacetic acid, 7 parts EDTMPS, 0.1 parts polyacrylamide, 13 parts iron oxide, 22 parts polyaluminum chloride, 22 parts modified bentonite, and 0.5 parts aminated carbon nanotubes.

[0044] Example 6

[0045] The difference between this embodiment and Embodiment 1 is that: a phosphorus-containing wastewater treatment agent, by weight, comprises: 3 parts sodium polyphosphate, 0.1 parts alkyl epoxy carboxylic acid, 6 parts ethylenediaminetetraacetic acid, 3 parts EDTMPS, 0.2 parts polyacrylamide, 14 parts iron oxide, 18 parts polyaluminum chloride, 16 parts modified bentonite, and 0.5 parts aminated carbon nanotubes.

[0046] Comparative Example 1

[0047] The difference between this comparative example and Example 1 is that: a phosphorus-containing wastewater treatment agent does not include: modified bentonite and aminated carbon nanotubes.

[0048] Comparative Example 2

[0049] The difference between this comparative example and Example 1 is that this is a phosphorus-containing wastewater treatment agent that does not include: iron tetroxide and polyaluminum chloride.

[0050] Experimental Example 1

[0051] The performance of the treatment agents prepared in Examples 1-3 and Comparative Examples 1-2 of this invention was tested.

[0052] Experimental method: This experiment used phosphorus-containing wastewater in the factory area as the test object. The total phosphorus in the wastewater was 28.4 mg / L, COD was 4650 mg / L, BOD was 2545 mg / L, and ammonia nitrogen was 34.5 mg / L.

[0053] The wastewater was divided into five equal parts, and the treatment agents prepared in Examples 1-3 and Comparative Examples 1-2 of this invention were added to each part. The concentration of the agent was 100 ppm (mass ratio). The supernatant of the wastewater after treatment was then tested, and the results are shown in Table 1.

[0054] Table 1

[0055]

[0056]

[0057] As shown in Table 1, the treatment agent prepared in the embodiments of the present invention can effectively reduce the total phosphorus, COD, BOD and ammonia nitrogen values ​​in phosphorus-containing wastewater; while the treatment effect of the comparative example on phosphorus-containing wastewater is far inferior to that of the treatment agent in the embodiments of the present invention.

[0058] In summary, the fast-acting water treatment agent of this invention has a significant effect on treating total phosphorus in phosphorus-containing wastewater, and can also effectively remove total COD, BOD and ammonia nitrogen from the wastewater. The agent dosage is small, and it can also effectively remove suspended solids in the wastewater and reduce the color of the wastewater. It is suitable for the pretreatment, end-of-pipe treatment and emergency treatment of high-concentration organic wastewater.

[0059] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A phosphorus-containing wastewater treatment agent, characterized by, By weight, it comprises: 3-10 parts sodium polyphosphate, 0.1-1 parts alkylepoxycarboxylic acid, 5-10 parts ethylenediaminetetraacetic acid, 3-10 parts EDTMPS, 0.1-3 parts polyacrylamide, 5-15 parts iron oxide, 10-30 parts polyaluminum chloride, 10-30 parts modified bentonite, and 0.5-5 parts aminated carbon nanotubes; wherein the modified bentonite is chitosan-modified bentonite.

2. The phosphorus-containing wastewater treatment agent according to claim 1, characterized in that, By weight, it includes: 3-5 parts sodium polyphosphate, 0.1-0.5 parts alkyl epoxycarboxylic acid, 5-8 parts ethylenediaminetetraacetic acid, 3-8 parts EDTMPS, 0.1-1 part polyacrylamide, 10-15 parts iron oxide, 15-25 parts polyaluminum chloride, 15-25 parts modified bentonite, and 0.5-2 parts aminated carbon nanotubes.

3. The phosphorus-containing wastewater treatment agent according to claim 2, characterized by By weight, it includes: 4 parts sodium polyphosphate, 0.3 parts alkyl epoxy carboxylic acid, 6 parts ethylenediaminetetraacetic acid, 5 parts EDTMPS, 0.5 parts polyacrylamide, 15 parts iron oxide, 20 parts polyaluminum chloride, 20 parts modified bentonite, and 1 part aminated carbon nanotubes.

4. A process for the preparation of a phosphorus-containing wastewater treatment agent according to any one of claims 1 to 3, characterized in that, Includes the following steps: S1. Add magnetic nanoparticles of iron oxide to a polyaluminum chloride solution, stir magnetically and age for a period of time to obtain a precipitated composite agent; S2. Dissolve chitosan in acetic acid solution to obtain chitosan solution; then add sodium bentonite to the above chitosan solution and stir continuously for a period of time, let it stand for a period of time, and dry it to obtain chitosan modified bentonite. S3. After thoroughly mixing the remaining materials, add water and mix well. Then add some aminated carbon nanotubes and some precipitating composite agent, and stir continuously to disperse them fully. Then add the remaining aminated carbon nanotubes and precipitating composite agent in several batches, and after fully dispersing, add modified bentonite and mix well to obtain the premix. S4. Keep the premixed material at a constant temperature for a period of time, then gradually increase the temperature and keep it at that temperature for a period of time; take out the treated mixture, cool it, grind it, and sieve it to obtain the product.

5. The method for preparing the phosphorus-containing wastewater treatment agent according to claim 4, characterized in that, In S1, during aging, magnetic stirring is applied at 30~50℃ for 3-5 hours.

6. The method for preparing the phosphorus-containing wastewater treatment agent according to claim 4, characterized in that, In S2, the mass concentration of the chitosan solution is 1-5%.

7. The method for preparing the phosphorus-containing wastewater treatment agent according to claim 4, characterized in that, In S3, aminated carbon nanotubes and precipitating composite agents are each added at least twice, and each time in equal amounts.

8. The method for preparing the phosphorus-containing wastewater treatment agent according to claim 4, characterized in that, In S4, the premixed material is kept at a constant temperature of 60℃~70℃ for 2~3 hours; then the temperature is gradually increased to 80℃~90℃ and kept at that temperature for 6~10 hours.

9. The method for preparing the phosphorus-containing wastewater treatment agent according to claim 4, characterized in that, In S4, the heating rate is 1-5℃ / min.

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