Anionic polyacrylamide and preparation method thereof

Abstract

The present application relates to the field of wastewater treatment technology, and specifically discloses an anionic polyacrylamide and a preparation method thereof. An anionic polyacrylamide comprises the following raw materials in parts by weight: 70-90 parts of acrylamide, 10-20 parts of acrylic acid, 0.01-0.03 parts of initiator, 0.5-1 parts of methacryloxypropyltrimethoxysilane, 1-3 parts of ethylene glycol, 5-8 parts of carbonamide, and 100-110 parts of water. An anionic polyacrylamide of the present application can be used for flocculation and sedimentation treatment of wastewater, with excellent solubility and flocculation efficiency. The mutual synergistic combination of methacryloxypropyltrimethoxysilane and carbonamide improves the solubility of anionic polyacrylamide in the aqueous phase medium, and at the same time, methacryloxypropyltrimethoxysilane can promote anionic polyacrylamide to better bind impurities in wastewater, thereby improving the flocculation efficiency of anionic polyacrylamide.

Description

Technical Field

[0001] The present application relates to the technical field of wastewater treatment, and more specifically, to an anionic polyacrylamide and a preparation method thereof. Background Art

[0002] Anionic polyacrylamide is a high molecular polymer. The polar groups of anionic polyacrylamide can produce a certain adsorption effect on suspended particles. Through charge neutralization or bridging between particles, it promotes the sedimentation of particles in the suspension, and ultimately achieves flocculation, sedimentation and clarification of the wastewater.

[0003] However, the commonly used anionic polyacrylamide polymers have the problems of poor water solubility and long dissolution time, which affects the flocculation efficiency of anionic polyacrylamide, wastes a lot of manpower, material and financial resources, and cannot meet the needs of industrial production. Summary of the invention

[0004] In order to improve the water solubility of anionic polyacrylamide, the present application provides an anionic polyacrylamide and a preparation method thereof.

[0005] In the first aspect, the present application provides an anionic polyacrylamide, which adopts the following technical solution:

[0006] An anionic polyacrylamide comprises the following raw materials in parts by weight: 70-90 parts of acrylamide, 10-20 parts of acrylic acid, 0.01-0.03 parts of initiator, 0.5-1 parts of methacryloxypropyltrimethoxysilane, 1-3 parts of ethylene glycol, 5-8 parts of carbonamide and 100-110 parts of water.

[0007] By adopting the above technical scheme, the unsaturated double bonds and silylmethoxy groups in the methacryloxypropyltrimethoxysilane molecule can undergo free radical polymerization reaction with acrylamide monomers, and the silyloxy groups form silanol groups, which can better combine with inorganic substances in wastewater, further improving the flocculation and precipitation efficiency of the anionic polyacrylamide system and further improving the solubility of anionic polyacrylamide. Carbon amide is a small molecule with high molecular mobility, which further improves the water solubility of anionic polyacrylamide. Ethylene glycol is added to the anionic polyacrylamide system to improve the fluidity of the anionic polyacrylamide system, reduce the self-condensation reaction of methacryloxypropyltrimethoxysilane, and reduce the formation of insoluble colloid particles in the anionic polyacrylamide system, thereby improving the water solubility and solubility of anionic polyacrylamide and improving the flocculation efficiency of anionic polyacrylamide.

[0008] Preferably, the anionic polyacrylamide raw material also includes 1-3 parts of nano silicon dioxide.

[0009] By adopting the above technical scheme, nano silicon dioxide has the characteristics of high specific surface area, good stability, heat resistance and salt resistance. Nano silicon dioxide is grafted to the surface of anionic polyacrylamide through the active group of methacryloxypropyltrimethoxysilane. The silicon-oxygen bond of nano silicon dioxide and anionic polyacrylamide form chemical bonds for cross-linking, thereby improving the stability and heat resistance of anionic polyacrylamide, and further improving the durability of the flocculation effect of anionic polyacrylamide.

[0010] Preferably, the anionic polyacrylamide raw material also includes 5-10 parts of polyethylene oxide.

[0011] By adopting the above technical solution, polyethylene oxide is added to the anionic polyacrylamide system to strengthen the flocculation effect of the anionic polyacrylamide and improve the flocculation efficiency of the anionic polyacrylamide. At the same time, the anionic polyacrylamide polymer can be evenly dispersed in the aqueous medium, further improving the solubility and water-soluble properties of the anionic polyacrylamide.

[0012] Preferably, the anionic polyacrylamide raw material also includes 3-5 parts of sodium alginate.

[0013] By adopting the above technical solution, sodium alginate can improve the viscosity of the anionic polyacrylamide system, and can react with divalent and trivalent cations in the wastewater to form a gel, thereby achieving a flocculation effect and improving the flocculation efficiency of the anionic polyacrylamide.

[0014] Preferably, the anionic polyacrylamide raw material also includes 0.3-0.5 parts of sodium ethylenediaminetetraacetate.

[0015] By adopting the above technical solution, sodium ethylenediaminetetraacetate can promote the uniform and stable dispersion of anionic polyacrylamide polymer activity in aqueous solution, improve the solubility and dispersion stability of anionic polyacrylamide, and further improve the flocculation efficiency of anionic polyacrylamide. At the same time, sodium ethylenediaminetetraacetate can eliminate impure metal ions in the polyacrylamide system, increase the molecular weight of polyacrylamide polymer, further improve the solubility of anionic polyacrylamide, and improve the flocculation efficiency of anionic polyacrylamide.

[0016] Preferably, the nano-silicon dioxide particle size is 20nm-40nm.

[0017] By adopting the above technical solution, controlling the particle size of nano-silicon dioxide within a suitable range can reduce the phenomenon of nano-silicon dioxide particle agglomeration, thereby enabling the nano-silicon dioxide to be evenly dispersed in the anionic polyacrylamide system.

[0018] In a second aspect, the present application provides a method for preparing anionic polyacrylamide, using the following technical solution: A method for preparing anionic polyacrylamide, comprising the following specific steps:

[0019] Acrylamide, acrylic acid, carbon amide and water are mixed to form a mixed liquid. Under the protection of nitrogen, an initiator is added to the mixed liquid to mix, react at 60-70°C, and then methacryloxypropyltrimethoxysilane and ethylene glycol are added in sequence to prepare anionic polyacrylamide.

[0020] By adopting the above technical solution, the prepared anionic polyacrylamide has excellent water solubility and dissolution, and the flocculation efficiency of the anionic polyacrylamide is further improved.

[0021] Preferably, nano-silica is mixed with a solvent in advance, and then methacryloxypropyltrimethoxysilane is added, reacted at 50-60° C., and then dried to obtain modified nano-silica, and then the modified nano-silica is mixed with ethylene glycol and added to the mixed solution to obtain anionic polyacrylamide.

[0022] By adopting the above technical scheme, the surface of nano-silica is modified in advance by methacryloxypropyltrimethoxysilane, the active groups on the surface of nano-silica are increased, the nano-silica is grafted to the surface of the anionic polyacrylamide polymer, the cross-linking degree of the anionic polyacrylamide system is increased, and the flocculation efficiency of the anionic polyacrylamide is further improved.

[0023] In summary, this application has the following beneficial effects:

[0024] 1. Since the present application adopts methacryloxypropyltrimethoxysilane and carbon amide to be added to the anionic polyacrylamide system, the water solubility and dissolution of the anionic polyacrylamide are improved, thereby improving the flocculation efficiency of the anionic polyacrylamide.

[0025] 2. This application uses nano-silicon dioxide to add to the anionic polyacrylamide system to improve the heat resistance and flocculation durability of the anionic polyacrylamide system and improve the flocculation efficiency of the anionic polyacrylamide. Polyethylene oxide can promote the uniform dispersion of the active components of the anionic polyacrylamide in the water phase, improve the solubility and water solubility of the polyacrylamide, and further improve the flocculation efficiency of the anionic polyacrylamide. DETAILED DESCRIPTION

[0026] The present application is further described in detail below in conjunction with embodiments.

[0027] The initiator is ammonium persulfate.

[0028] The weight average molecular weight of polyethylene oxide is 20,000.

[0029] Example

[0030] Example 1

[0031] Anionic polyacrylamide comprises the following raw materials in parts by weight: 80 kg acrylamide, 15 kg acrylic acid, 0.02 kg initiator, 0.8 kg methacryloxypropyltrimethoxysilane, 2 kg ethylene glycol, 7 kg carbonamide and 105 kg water.

[0032] The preparation method of anionic polyacrylamide comprises the following specific steps: acrylamide, acrylic acid and water are mixed, stirred at a speed of 300 r / min for 10 minutes, carbon amide is added, and stirring is continued for 5 minutes to form a mixed solution, nitrogen is introduced for 20 minutes, an initiator is added to the mixed solution, mixed, reacted at 60°C for 10 minutes, and then methacryloxypropyltrimethoxysilane and ethylene glycol are added, mixed, and reacted for 20 minutes to form polyacrylamide colloid, thereby preparing anionic polyacrylamide.

[0033] Example 2-3

[0034] The difference between Example 2-3 and Example 1 is that the contents of the components in the anionic polyacrylamide raw material are different, as shown in Table 1.

[0035]

[0036]

[0037] Example 4

[0038] The difference between Example 4 and Example 1 is that the anionic polyacrylamide raw material also includes 2 kg of nano-silicon dioxide, and the particle size of the nano-silicon dioxide is 30 nm.

[0039] The preparation method of anionic polyacrylamide comprises the following specific steps:

[0040] S1: Mix nano-silica with anhydrous ethanol, then add methacryloxypropyltrimethoxysilane to form a composite liquid, adjust the pH value of the composite liquid to 5 with hydrochloric acid and sodium hydroxide, ultrasonically disperse for 30 minutes, introduce nitrogen, react at 50°C for 4 hours, then wash with anhydrous ethanol, and dry at 60°C to obtain modified nano-silica.

[0041] S2: acrylamide, acrylic acid and water are mixed, stirred at a speed of 300r / min for 10min, carbon amide is added, and stirring is continued for 5min to form a mixed solution, and then nitrogen is introduced for 20min, and then an initiator is added to the mixed solution and mixed, and the mixture is reacted at 60°C for 10min, and then modified nano-silica and ethylene glycol are added and mixed, and the reaction is continued for 20min to form polyacrylamide colloid and obtain anionic polyacrylamide.

[0042] Example 5

[0043] The difference between Example 5 and Example 4 is that the amount of nano-silicon dioxide used in the anionic polyacrylamide raw material is 1 kg and the particle size is 20 nm.

[0044] Example 6

[0045] The difference between Example 6 and Example 4 is that the amount of nano-silicon dioxide used in the anionic polyacrylamide raw material is 3 kg and the particle size is 40 nm.

[0046] Example 7

[0047] The difference between Example 7 and Example 4 is that the anionic polyacrylamide raw material also includes 8 kg of polyethylene oxide.

[0048] The preparation method of anionic polyacrylamide comprises the following specific steps:

[0049] S1: Mix nano-silica with anhydrous ethanol, then add methacryloxypropyltrimethoxysilane to form a composite liquid, adjust the pH value of the composite liquid to 5 with hydrochloric acid and sodium hydroxide, ultrasonically disperse for 30 minutes, introduce nitrogen, react at 50°C for 4 hours, then wash with anhydrous ethanol, and dry at 60°C to obtain modified nano-silica.

[0050] S2: acrylamide, acrylic acid and water are mixed, stirred at a speed of 300r / min for 10min, carbon amide is added, and stirring is continued for 5min to form a mixed solution, and then nitrogen is introduced for 20min, and then an initiator is added to the mixed solution and mixed, and the mixture is reacted at 60°C for 10min, and then modified nano-silica, polyethylene oxide and ethylene glycol are added and mixed, and the reaction is continued for 20min to form polyacrylamide colloid and obtain anionic polyacrylamide.

[0051] Example 8

[0052] The difference between Example 8 and Example 7 is that the amount of polyethylene oxide used in the anionic polyacrylamide raw material is 5 kg.

[0053] Example 9

[0054] The difference between Example 9 and Example 7 is that the amount of polyethylene oxide used in the anionic polyacrylamide raw material is 10 kg.

[0055] Example 10

[0056] The difference between Example 10 and Example 7 is that the anionic polyacrylamide raw material also includes 4 kg of sodium alginate.

[0057] The preparation method of anionic polyacrylamide comprises the following specific steps:

[0058] S1: Mix nano-silica with anhydrous ethanol, then add methacryloxypropyltrimethoxysilane to form a composite liquid, adjust the pH value of the composite liquid to 5 with hydrochloric acid and sodium hydroxide, ultrasonically disperse for 30 minutes, introduce nitrogen, react at 50°C for 4 hours, then wash with anhydrous ethanol, and dry at 60°C to obtain modified nano-silica.

[0059] S2: acrylamide, acrylic acid and water are mixed, stirred at a speed of 300r / min for 10min, carbon amide is added, and stirring is continued for 5min to form a mixed solution, and then nitrogen is introduced for 20min, and then an initiator is added to the mixed solution and mixed, and the mixture is reacted at 60°C for 10min, and then modified nano-silica, polyethylene oxide, sodium alginate and ethylene glycol are added and mixed, and the reaction is continued for 20min to form polyacrylamide colloid and obtain anionic polyacrylamide.

[0060] Embodiment 11

[0061] The difference between Example 11 and Example 10 is that the amount of sodium alginate used in the anionic polyacrylamide raw material is 3 kg.

[0062] Example 12

[0063] The difference between Example 12 and Example 10 is that the amount of sodium alginate used in the anionic polyacrylamide raw material is 5 kg.

[0064] Example 13

[0065] The difference between Example 13 and Example 10 is that the anionic polyacrylamide raw material further includes 0.4 kg of sodium ethylenediaminetetraacetate.

[0066] The preparation method of anionic polyacrylamide comprises the following specific steps:

[0067] S1: Mix nano-silica with anhydrous ethanol, then add methacryloxypropyltrimethoxysilane to form a composite liquid, adjust the pH value of the composite liquid to 5 with hydrochloric acid and sodium hydroxide, ultrasonically disperse for 30 minutes, introduce nitrogen, react at 50°C for 4 hours, then wash with anhydrous ethanol, and dry at 60°C to obtain modified nano-silica.

[0068] S2: acrylamide, acrylic acid and water are mixed, stirred at a speed of 300r / min for 10min, carbon amide is added, and stirring is continued for 5min to form a mixed solution, and then nitrogen is introduced for 20min, and then an initiator is added to the mixed solution and mixed, and the mixture is reacted at 60°C for 10min, and then modified nano-silica, polyethylene oxide, sodium ethylenediaminetetraacetic acid, sodium alginate and ethylene glycol are added and mixed, and the reaction is continued for 20min to form polyacrylamide colloid and obtain anionic polyacrylamide.

[0069] Embodiment 14

[0070] The difference between Example 14 and Example 13 is that the amount of sodium ethylenediaminetetraacetate used in the anionic polyacrylamide raw material is 0.3 kg.

[0071] Embodiment 15

[0072] The difference between Example 15 and Example 13 is that the amount of sodium ethylenediaminetetraacetate used in the anionic polyacrylamide raw material is 0.5 kg.

[0073] Comparative Example

[0074] Comparative Example 1

[0075] The difference between Comparative Example 1 and Example 1 is that methacryloxypropyltrimethoxysilane is not used in the anionic polyacrylamide raw material.

[0076] Comparative Example 2

[0077] The difference between Comparative Example 2 and Example 1 is that no carbon amide is used in the anionic polyacrylamide raw material.

[0078] Comparative Example 3

[0079] The difference between Comparative Example 3 and Example 1 is that ethylene glycol is not used in the anionic polyacrylamide raw material.

[0080] Performance testing

[0081] The following performance tests were performed on the anionic polyacrylamide provided in Examples 1-15 and Comparative Examples 1-3 of the present application. The specific test results are shown in Table 2.

[0082] Detection Methods

[0083] 1. Solubility

[0084] 0.2 g of the anionic polyacrylamide sample prepared in the example of the present application was mixed with 50 ml of distilled water, and stirred continuously at a speed of 100 r / min. The time required for the anionic polyacrylamide colloid sample to be completely dissolved was recorded to determine the solubility of the anionic polyacrylamide.

[0085] 2. Flocculation

[0086] Take 20 ml of anionic polyacrylamide and add it to 1000 ml of coal slime water. Stir at 100 r / min for 10 min to make the anionic polyacrylamide evenly distributed in the coal slime water. Observe the sedimentation of the coal slime water and record the sedimentation amount of the coal slime water at sedimentation times of 60 min, 180 min, and 360 min.

[0087] Table 2: Performance test data table

[0088]

[0089]

[0090] The performance test results of the anionic polyacrylamide prepared by Examples 1-3 show that the anionic polyacrylamide prepared by the present application has excellent solubility and flocculation efficiency. When the sedimentation time is 180min, the flocculation efficiency has reached 89%, and the flocculation is basically completed. Under the synergistic combination of the various components of the present application, the prepared anionic polyacrylamide is better for flocculation and sedimentation of suspended matter in sludge wastewater. The present application modifies polyacrylamide by methacryloxypropyltrimethoxysilane, improves the molar mass of anionic polyacrylamide, shortens the dissolution time of anionic polyacrylamide, and thus improves the flocculation efficiency of anionic polyacrylamide. At the same time, carbonamide is combined with methacryloxypropyltrimethoxysilane to improve the mobility of molecules in the anionic polyacrylamide system, further improve the solubility of anionic polyacrylamide, and improve the flocculation efficiency of anionic polyacrylamide.

[0091] In Examples 4-6, nano-silicon dioxide was added to the anionic polyacrylamide system. From the test results, it can be seen that the flocculation effect of the anionic polyacrylamide was significantly improved, and the flocculation efficiency reached 91%. At the same time, when the sedimentation time was 360 minutes, it can be seen from the comparison of the performance test results of Example 4 and Example 1 that the flocculation effect was more durable, which further illustrates that the silicon-oxygen bond of the nano-silicon dioxide was grafted onto the molecular chain of the anionic polyacrylamide, thereby increasing the degree of cross-linking on the surface of the anionic polyacrylamide molecules and further improving the flocculation effect of the anionic polyacrylamide.

[0092] In Examples 7-9, polyethylene oxide was added to the anionic polyacrylamide system. From the test results, it can be seen that the solubility of anionic polyacrylamide is significantly improved. On the premise of improving the flocculation effect of anionic polyacrylamide, polyethylene oxide can also promote the uniform dispersion of anionic polyacrylamide in the aqueous solution, improve the dispersibility and solubility of anionic polyacrylamide, and further improve the flocculation efficiency of anionic polyacrylamide.

[0093] In Examples 10-12, sodium alginate was added to the anionic polyacrylamide system. From the test results, it can be seen that the comprehensive performance of the anionic polyacrylamide is improved. Sodium alginate can react with divalent and trivalent cations in the wastewater to form a gel, thereby improving the flocculation effect of the anionic polyacrylamide.

[0094] In Examples 13-15, sodium ethylenediaminetetraacetate was added to the anionic polyacrylamide system. From the test results, it can be seen that the comprehensive performance of the anionic polyacrylamide is improved, which further illustrates that sodium ethylenediaminetetraacetate can improve the uniform and stable dispersion of the active polymer components of the anionic polyacrylamide in the anionic polyacrylamide system. At the same time, sodium ethylenediaminetetraacetate can also eliminate the impurity metal ions in the anionic polyacrylamide system and improve the flocculation efficiency of the anionic polyacrylamide.

[0095] By comparing the performance test results of Comparative Example 1 and Example 1, it can be seen that methacryloxypropyltrimethoxysilane is not used in Comparative Example 1. From the test results, it can be seen that the solubility and flocculation effect of anionic polyacrylamide are significantly reduced, further illustrating the promoting effect of methacryloxypropyltrimethoxysilane on the solubility and flocculation effect of anionic polyacrylamide.

[0096] By comparing the performance test results of Comparative Example 2 and Example 1, it can be seen that in Comparative Example 2, carbon amide is not used, and the comprehensive performance of the anionic polyacrylamide obtained is significantly reduced. The sedimentation effect is not completed within the sedimentation time of 360 minutes, and it is obviously observed that there are still certain suspended substances in the coal slime water, which further illustrates that carbon amide, as a small molecule substance, can significantly improve the solubility and flocculation efficiency of anionic polyacrylamide.

[0097] It can be seen from the performance test results of Comparative Example 3 and Example 1 that if ethylene glycol is not used in Comparative Example 3, the comprehensive performance of anionic polyacrylamide will also be affected, which further illustrates that ethylene glycol can improve the fluidity of anionic polyacrylamide in the anionic polyacrylamide system, reduce the formation of insoluble colloid particles, and further improve the water solubility and flocculation efficiency of anionic polyacrylamide.

[0098] This specific embodiment is merely an explanation of the present application and is not a limitation of the present application. After reading this specification, those skilled in the art may make modifications to the present embodiment without any creative contribution as needed, but such modifications are protected by the patent law as long as they are within the scope of the claims of the present application.

Claims

1. An anionic polyacrylamide, characterized in that The invention comprises the following raw materials in parts by weight: 70-90 parts of acrylamide, 10-20 parts of acrylic acid, 0.01-0.03 parts of initiator, 0.5-1 parts of methacryloxypropyltrimethoxysilane, 1-3 parts of ethylene glycol, 5-8 parts of carbonamide, and 100-110 parts of water; Acrylamide, acrylic acid, carbon amide and water are mixed to form a mixed liquid. Under the protection of nitrogen, an initiator is added to the mixed liquid to mix, react at 60-70°C, and then methacryloxypropyltrimethoxysilane and ethylene glycol are added in sequence to prepare anionic polyacrylamide.

2. An anionic polyacrylamide according to claim 1, characterized in that: The anionic polyacrylamide raw material also includes 1-3 parts of nano silicon dioxide, 5-10 parts of polyethylene oxide, 3-5 parts of sodium alginate, and 0.3-0.5 parts of sodium ethylenediaminetetraacetate; the preparation method of the anionic polyacrylamide includes the following specific steps: Preliminarily mixing nano-silica with a solvent, then adding methacryloxypropyltrimethoxysilane, reacting at 50-60°C, and then drying to obtain modified nano-silica; Acrylamide, acrylic acid, carbon amide and water are mixed to form a mixed liquid. Under the protection of nitrogen, an initiator is added to the mixed liquid for mixing, and the mixture is reacted at 60-70°C. Then, modified nano-silica, polyethylene oxide, sodium ethylenediaminetetraacetate, sodium alginate and ethylene glycol are added in sequence to prepare anionic polyacrylamide.

3. An anionic polyacrylamide according to claim 2, characterized in that: The particle size of the nano silicon dioxide is 20nm-40nm.

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