Phosphorus removal agent and preparation method thereof

Abstract

The present invention proposes a kind of phosphorus remover and preparation method thereof, and its preparation method includes:Myristamidopropyl PG-dimethylammonium chloride phosphate and brominated tetradecylpyridine are mixed and prepared into an aqueous solution, heated to 70-80 DEG C, sodium bentonite is added, and insulation stirring is processed for 1-3h, centrifugation, drying, and crushing to obtain organic bentonite;Iron salt and lanthanum salt are configured into an aqueous solution, organic bentonite is added, under ultrasonic conditions, stirring is processed for 5-10h, centrifugation, drying, and crushing to obtain phosphorus remover.The phosphorus remover prepared by the present invention not only has a high phosphorus removal rate, and phosphorus removal is rapid, and the moisture content of the precipitate obtained after phosphorus removal is also lower, and it is easy to carry out solid-liquid separation, with good application prospects.

Description

Technical Field

[0001] The present invention relates to the technical field of sewage treatment preparations, in particular to a phosphorus removal agent and a preparation method thereof. Background Art

[0002] Phosphorus-containing wastewater cannot be discharged directly into the environment. It needs to undergo phosphorus removal treatment until the phosphorus content meets the discharge standards before it can be discharged. The current methods of phosphorus removal in water bodies mainly include biological phosphorus removal, chemical reaction phosphorus removal, and adsorption and precipitation phosphorus removal. Among them, the adsorption and precipitation method has the advantages of low cost, high efficiency, and repeatability.

[0003] Bentonite is a wastewater treatment agent with abundant reserves and low cost. It has good dispersibility in water, but its surface carries a negative charge, and the main source of phosphorus pollution in water bodies is in the form of free phosphate ions or hydrogen phosphate ions, which are also negatively charged ions. In this case, it is difficult for bentonite to efficiently adsorb and precipitate phosphorus in water bodies. Therefore, under normal circumstances, a method of modifying bentonite is adopted to improve its binding ability and adsorption of phosphorus in water bodies. Currently, common modification methods mainly include activation modification, inorganic modification and organic modification. Among them, the organic modification method can introduce positive charges to the surface of the phosphorus remover, thereby improving its adsorption of phosphorus. However, due to the introduction of organic groups, the interface structure between the bentonite surface and water is also affected, which has a certain negative impact on the phosphorus adsorption process. In view of this, how to select a suitable organic modifier to balance the phosphorus removal effect of the phosphorus remover and the mass transfer effect at the interface with the water layer has become one of the technical problems that need to be solved urgently. Summary of the Invention

[0004] In view of this, the present invention proposes a phosphorus removal agent and a preparation method thereof, wherein bentonite is modified by combining organic modification with inorganic modification to obtain a modified bentonite phosphorus removal agent with rapid phosphorus removal and stable separation effects.

[0005] The technical solution of the present invention is achieved as follows: The present invention provides a method for preparing a phosphorus removal agent, the steps of which include:

[0006] Step 1: Myristamidopropyl PG-dimethylammonium chloride phosphate and tetradecylpyridine bromide are mixed to prepare an aqueous solution, heated to 70-80° C., and sodium bentonite is added. The mixture is stirred at 70-80° C. for 1-3 hours, and then centrifuged, dried, and crushed to 200 mesh to obtain organic bentonite.

[0007] Step 2: prepare an aqueous solution of iron salt and lanthanum salt, add organic bentonite, stir and treat under ultrasonic conditions for 5-10 hours, centrifuge, dry and crush to obtain a phosphorus removal agent.

[0008] Unlike other quaternary ammonium salt-type cationic surfactants, one molecule of myristamidopropyl PG-dimethylammonium chloride phosphate has multiple adsorption sites with bentonite, which leads to the formation of hydrophobic groups with different carbon chain lengths and different distribution patterns on the surface of bentonite. When the carbon chain length is longer, there are cations on the carbon chain, which can improve the binding with phosphorus in sewage. When the carbon chain is shorter, multiple short carbon chains with regular distribution are formed, and hydrophobic layers are formed between these regularly distributed short carbon chains. In order to minimize the interfacial effect of these hydrophobic layers, tetradecylpyridine bromide is also used. Due to the steric effect of the pyridine ring structure, the long carbon chain structures therein have a certain directionality, which is used to attract the surrounding short carbon chains, thereby reducing the interfacial effect and improving the material exchange efficiency between bentonite and water. On the other hand, this solution also undergoes inorganic modification after organic modification, utilizing functional groups such as nitrogen and oxygen on the carbon chain structure of myristamidopropyl PG-dimethylammonium chloride phosphate to coordinate and fix metal ions, further enhancing the phosphorus adsorption and removal efficiency. Furthermore, since some of these metal ions do not enter the interlayers of the bentonite, the phosphorus adsorption response is rapid. Furthermore, experiments have shown that the phosphorus removal agent of the present invention produces a very low water content in the precipitate after phosphorus removal, making solid-liquid separation easier.

[0009] In some embodiments, the mass ratio of myristamidopropyl PG-dimethylammonium chloride phosphate:tetradecylpyridinium bromide:sodium bentonite is (0.1-0.2):(0.05-0.1):1.

[0010] In some embodiments, the mass ratio of coramidopropyl PG-dimethylammonium chloride phosphate to tetradecylpyridinium bromide is 2:1.

[0011] In some embodiments, in step 2, in the aqueous solution, the concentration of iron ions is 20-40 mmol / L, the concentration of lanthanum ions is 40-80 mmol / L, and the amount of organic bentonite added is 50-100 g / L.

[0012] In some embodiments, in step 1 and step 2, the drying temperature is 50-70°C.

[0013] In some embodiments, the iron salt is at least one of ferric chloride, ferric nitrate, and ferric sulfate, and the lanthanum salt is at least one of lanthanum chloride and lanthanum nitrate.

[0014] On the other hand, the present invention also provides a phosphorus removal agent prepared by the above preparation method.

[0015] The phosphorus removal agent and preparation method of the present invention have the following beneficial effects compared with the prior art:

[0016] The present invention adopts an organic combined with inorganic modification method to modify sodium bentonite, and the obtained modified bentonite has a high-efficiency phosphorus removal effect. Experiments have found that the phosphorus removal efficiency in 1 minute reaches more than 90%, and the moisture content of the solid separation after treatment is between 40-50%, which is easy to separate and recover. DETAILED DESCRIPTION

[0017] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0018] 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 embodiments of the present invention belong. If the definitions set forth in this section are contrary to or otherwise inconsistent with definitions set forth in the patents, patent applications, published patent applications, and other publications incorporated herein by reference, the definitions listed in this section take precedence over the definitions incorporated herein by reference.

[0019] Example 1

[0020] Weigh 10 g of myristamidopropyl PG-dimethylammonium chloride phosphate, 5 g of tetradecylpyridine bromide, and 100 ml of water, mix them evenly to obtain an organic modified aqueous solution, heat it to 70°C, then add 100 g of sodium bentonite, keep it warm and stir for 1 hour, centrifuge and grind it to less than 200 mesh to obtain organic bentonite;

[0021] 20 mmol of ferric chloride and 40 mmol of lanthanum chloride were added to 1 L of water, stirred and dissolved, and then 50 g of organic bentonite was added under ultrasonic conditions. The mixture was stirred for 5 h, centrifuged and dried, and crushed to less than 200 mesh to obtain a phosphorus removal agent.

[0022] Example 2

[0023] 15 g of myristamidopropyl PG-dimethylammonium chloride phosphate, 7.5 g of tetradecylpyridine bromide and 100 ml of water were weighed and mixed to obtain an organic modified aqueous solution. The solution was heated to 75°C and then 100 g of sodium bentonite was added. The solution was stirred at this temperature for 2 h, centrifuged and dried, and crushed to a size of less than 200 mesh to obtain an organic bentonite.

[0024] 30 mmol of ferric chloride and 60 mmol of lanthanum chloride were added to 1 L of water, stirred and dissolved, and then 70 g of organic bentonite was added under ultrasonic conditions. The mixture was stirred for 7 h, centrifuged and dried, and crushed to less than 200 mesh to obtain a phosphorus removal agent.

[0025] Example 3

[0026] 20 g of myristamidopropyl PG-dimethylammonium chloride phosphate, 10 g of tetradecylpyridine bromide and 100 ml of water were weighed and mixed to obtain an organic modified aqueous solution, heated to 80°C, and then 100 g of sodium bentonite was added. After stirring at this temperature for 3 h, the solution was centrifuged and crushed to less than 200 mesh to obtain organic bentonite.

[0027] 40 mmol of ferric chloride and 80 mmol of lanthanum chloride were added to 1 L of water, stirred and dissolved, and then 100 g of organic bentonite was added under ultrasonic conditions. The mixture was stirred for 10 hours, centrifuged and dried, and crushed to less than 200 mesh to obtain a phosphorus removal agent.

[0028] Example 4

[0029] 15 g of myristamidopropyl PG-dimethylammonium chloride phosphate, 5 g of tetradecylpyridine bromide and 100 ml of water were weighed and mixed to obtain an organic modified aqueous solution. The solution was heated to 75°C and then 100 g of sodium bentonite was added. The solution was stirred at this temperature for 2 h, centrifuged and dried, and crushed to a size of less than 200 mesh to obtain an organic bentonite.

[0030] 30 mmol of ferric chloride and 60 mmol of lanthanum chloride were added to 1 L of water, stirred and dissolved, and then 70 g of organic bentonite was added under ultrasonic conditions. The mixture was stirred for 7 h, centrifuged and dried, and crushed to less than 200 mesh to obtain a phosphorus removal agent.

[0031] Example 5

[0032] 15 g of myristamidopropyl PG-dimethylammonium chloride phosphate, 10 g of tetradecylpyridine bromide and 100 ml of water were weighed and mixed to obtain an organic modified aqueous solution. The solution was heated to 75°C and then 100 g of sodium bentonite was added. The solution was stirred at this temperature for 2 h, centrifuged and dried, and crushed to a size of less than 200 mesh to obtain an organic bentonite.

[0033] 30 mmol of ferric chloride and 60 mmol of lanthanum chloride were added to 1 L of water, stirred and dissolved, and then 70 g of organic bentonite was added under ultrasonic conditions. The mixture was stirred for 7 h, centrifuged and dried, and crushed to less than 200 mesh to obtain a phosphorus removal agent.

[0034] Example 6

[0035] 5 g of myristamidopropyl PG-dimethylammonium chloride phosphate, 2.5 g of tetradecylpyridine bromide and 100 ml of water were weighed and mixed to obtain an organic modified aqueous solution. The solution was heated to 75°C and then 100 g of sodium bentonite was added. The solution was stirred at this temperature for 2 h, centrifuged and dried, and crushed to a size of less than 200 mesh to obtain an organic bentonite.

[0036] 30 mmol of ferric chloride and 60 mmol of lanthanum chloride were added to 1 L of water, stirred and dissolved, and then 70 g of organic bentonite was added under ultrasonic conditions. The mixture was stirred for 7 h, centrifuged and dried, and crushed to less than 200 mesh to obtain a phosphorus removal agent.

[0037] Example 7

[0038] 30 g of myristamidopropyl PG-dimethylammonium chloride phosphate, 15 g of tetradecylpyridine bromide and 100 ml of water were weighed and mixed to obtain an organic modified aqueous solution. The solution was heated to 75°C and then 100 g of sodium bentonite was added. The solution was stirred at this temperature for 2 h, centrifuged and dried, and crushed to a size of less than 200 mesh to obtain an organic bentonite.

[0039] 30 mmol of ferric chloride and 60 mmol of lanthanum chloride were added to 1 L of water, stirred and dissolved, and then 70 g of organic bentonite was added under ultrasonic conditions. The mixture was stirred for 7 h, centrifuged and dried, and crushed to less than 200 mesh to obtain a phosphorus removal agent.

[0040] Comparative Example 1

[0041] Weigh 15 g of myristamidopropyl PG-dimethylammonium chloride phosphate and 100 ml of water, mix well to obtain an organic modified aqueous solution, heat to 75°C, then add 100 g of sodium bentonite, keep warm and stir for 2 hours, centrifuge and grind to less than 200 mesh to obtain organic bentonite;

[0042] 30 mmol of ferric chloride and 60 mmol of lanthanum chloride were added to 1 L of water, stirred and dissolved, and then 70 g of organic bentonite was added under ultrasonic conditions. The mixture was stirred for 7 h, centrifuged and dried, and crushed to less than 200 mesh to obtain a phosphorus removal agent.

[0043] Comparative Example 2

[0044] Weigh 7.5 g of tetradecylpyridine bromide and 100 ml of water, mix them evenly to obtain an organic modified aqueous solution, heat it to 75°C, then add 100 g of sodium bentonite, keep it warm and stir for 2 hours, centrifuge and grind it to less than 200 mesh to obtain organic bentonite;

[0045] 30 mmol of ferric chloride and 60 mmol of lanthanum chloride were added to 1 L of water, stirred and dissolved, and then 70 g of organic bentonite was added under ultrasonic conditions. The mixture was stirred for 7 h, centrifuged and dried, and crushed to less than 200 mesh to obtain a phosphorus removal agent.

[0046] Comparative Example 3

[0047] 15 g of myristamidopropyl PG-dimethylammonium chloride phosphate, 7.5 g of tetradecylpyridine bromide and 100 ml of water were weighed and mixed to obtain an organic modified aqueous solution. The solution was heated to 75°C and then 100 g of sodium bentonite was added. The solution was stirred at this temperature for 2 h, centrifuged and dried, and crushed to a size of less than 200 mesh to obtain an organic bentonite.

[0048] 90 mmol of ferric chloride was added to 1 L of water, and after stirring to dissolve, 70 g of organic bentonite was added under ultrasonic conditions, and the mixture was stirred for 7 hours. The mixture was centrifugally dried and crushed to less than 200 meshes to obtain a phosphorus removal agent.

[0049] Comparative Example 4

[0050] 15 g of myristamidopropyl PG-dimethylammonium chloride phosphate, 7.5 g of tetradecylpyridine bromide and 100 ml of water were weighed and mixed to obtain an organic modified aqueous solution. The solution was heated to 75°C and then 100 g of sodium bentonite was added. The solution was stirred at this temperature for 2 h, centrifuged and dried, and crushed to a size of less than 200 mesh to obtain an organic bentonite.

[0051] 90 mmol of lanthanum chloride was added to 1 L of water, and after stirring to dissolve, 70 g of organic bentonite was added under ultrasonic conditions, and the mixture was stirred for 7 h. The mixture was centrifugally dried and crushed to less than 200 mesh to obtain a phosphorus removal agent.

[0052] Comparative Example 5

[0053] 15 g of myristamidopropyl PG-dimethylammonium chloride phosphate, 7.5 g of tetradecylpyridine bromide and 100 ml of water were weighed and mixed to obtain an organic modified aqueous solution. The solution was heated to 75°C and then 100 g of sodium bentonite was added. The solution was stirred at this temperature for 2 h, centrifuged and dried, and crushed to a size of less than 200 mesh to obtain an organic bentonite.

[0054] 30 mmol of ferric chloride and 60 mmol of lanthanum chloride were added to 1 L of water, stirred and dissolved, and then 70 g of organic bentonite was added. The mixture was stirred for 7 h, centrifuged and dried, and crushed to less than 200 mesh to obtain a phosphorus removal agent.

[0055] The phosphorus removal effects of the phosphorus removal agents prepared in the above examples and comparative examples were tested. Dry potassium dihydrogen phosphate was dissolved and mixed with deionized water to prepare a 5 mg / L phosphorus-containing solution, which was used as a substrate for the phosphorus removal test.

[0056] The phosphorus removal agents described in the examples and comparative examples were added at dosages of 50 mg / L, 100 mg / L, and 200 mg / L, and the phosphorus concentrations of the phosphorus-containing solutions were measured at different time points. The dephosphorized mixed solution was then filtered, and the water content of the filtered phosphorus removal agent was weighed and calculated, yielding the test data shown in the table below.

[0057] When the dosage of phosphorus removal agent is 50 mg / L, the mass concentration of phosphorus changes as follows:

[0058]

[0059] When the dosage of phosphorus removal agent is 100 mg / L, the mass concentration of phosphorus changes as follows:

[0060]

[0061] When the dosage of phosphorus removal agent is 200 mg / L, the mass concentration of phosphorus changes as follows:

[0062]

[0063] It is not difficult to see that for water with a phosphorus concentration of 5 mg / L, when the phosphorus removal agent dosage is 100 mg / L, a phosphorus removal rate of more than 90% can be achieved within 1 minute. By comparing the data of Examples 4 and 5 with the data of Example 2, it can be seen that when the ratio of myristamidopropyl PG-dimethylammonium chloride phosphate to tetradecylpyridine bromide is 2:1, the phosphorus removal effect is optimal. When the ratio is higher than 2:1 or lower than 2:1, the effect is not as good as 2:1. According to the data of Comparative Examples 1 and 2, it can be seen that when only myristamidopropyl PG-dimethylammonium chloride phosphate is used to modify sodium bentonite, or when only tetradecylpyridine bromide is used to modify sodium bentonite, the phosphorus removal effect is not as good as when both are used in combination. When the solution used in the inorganic modification treatment lacks iron ions or lanthanum ions, the phosphorus removal effect is also affected to a certain extent. By comparing the data of Comparative Example 5 with that of Example 2, it can be seen that in the stepless modification process of the present application, the ultrasonic conditions also have a certain influence on the phosphorus removal effect and the speed of phosphorus removal.

[0064] For the above-mentioned 100 mg / L phosphorus removal agent, solid-liquid separation was performed after 3 minutes of phosphorus removal, and then the water content of the phosphorus removal agent was calculated to obtain the following data:

[0065] Grouping Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 Water content (%) 48 45 42 44 47 52 Grouping Example 7 Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Comparative Example 5 Water content (%) 41 52 57 44 46 49

[0066] It is not difficult to see from the above data that the phosphorus removal agent of the present invention can not only quickly remove phosphorus, but also has a low moisture content after phosphorus removal, which is convenient for solid-liquid separation and recovery, and has good application prospects.

[0067] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A method for preparing a phosphorus removal agent, characterized in that: The steps include: Step 1: Myristamidopropyl PG-dimethylammonium chloride phosphate and tetradecylpyridine bromide are mixed to prepare an aqueous solution, heated to 70-80° C., sodium bentonite is added, and the mixture is stirred at this temperature for 1-3 hours. The organic bentonite is obtained after centrifugation, drying, and crushing. Step 2: prepare an aqueous solution of iron salt and lanthanum salt, add organic bentonite, stir and treat under ultrasonic conditions for 5-10 hours, centrifuge, dry and crush to obtain a phosphorus removal agent.

2. The method for preparing the phosphorus removal agent according to claim 1, wherein In step 1, the mass ratio of myristamidopropyl PG-dimethylammonium chloride phosphate: tetradecylpyridinium bromide: sodium bentonite is (0.1-0.2): (0.05-0.1):

1.

3. The method for preparing the phosphorus removal agent according to claim 2, wherein: The mass ratio of coramidopropyl PG-dimethylammonium chloride phosphate:tetradecylpyridinium bromide is 2:

1.

4. The method for preparing the phosphorus removal agent according to claim 1, wherein In step 2, in the aqueous solution, the concentration of iron ions is 20-40 mmol / L, the concentration of lanthanum ions is 40-80 mmol / L, and the amount of organic bentonite added is 50-100 g / L.

5. The method for preparing the phosphorus removal agent according to claim 1, wherein In step 1 and step 2, the drying temperature is 50-70°C.

6. The method for preparing the phosphorus removal agent according to claim 1, wherein The iron salt is at least one of ferric chloride, ferric nitrate and ferric sulfate, and the lanthanum salt is at least one of lanthanum chloride and lanthanum nitrate.

7. A phosphorus removal agent, characterized in that: The method is prepared by any one of claims 1 to 6.

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