High-molecular-weight polyacrylamide with strong anti-shearing force and large adsorption area as well as preparation method and application of high-molecular-weight polyacrylamide

Abstract

The invention discloses high-molecular-weight polyacrylamide with strong anti-shearing force and large adsorption area, which is prepared from the following components in parts by weight: 90 to 100 parts of acrylamide, 10 to 15 parts of acrylic acid, 15 to 20 parts of 2-acrylamide-2-methylpropanesulfonic acid, 0.01 to 0.03 part of EDTA-2Na (Ethylene Diamine Tetraacetic Acid), 0.1 to 0.3 part of butylated hydroxyanisole, 0.1 to 0.3 part of N, N-dimethylformamide, 0.1 to 0.3 part of N, N-dimethylformamide and the balance of water. The invention discloses a water-based cleaning agent which is prepared from the following components in parts by weight: 0.2 to 0.5 part of N, N '-methylene bisacrylamide, 0.025 to 0.03 part of ammonium persulfate, 0.025 to 0.03 part of sodium hydrogen sulfite, 0.005 to 0.008 part of 2-hydroxyl-4'-(2-hydroxyethoxy)-2-methyl propiophenone and 360 to 375 parts of deionized water. The invention also provides a preparation method and application of the high molecular weight polyacrylamide. The polyacrylamide provided by the invention has strong anti-shearing force and large adsorption area, can more efficiently capture and wrap pollutant particles, and greatly enhances the adsorption capacity and flocculation efficiency of suspended colloids, organic impurities and heavy metal ions.

Description

Technical Field

[0001] This invention belongs to the field of wastewater treatment technology, specifically relating to a high molecular weight polyacrylamide with strong shear resistance and large adsorption area, its preparation method, and its application. Background Technology

[0002] Polyacrylamide (PAM), an indispensable high-efficiency flocculant and thickener in water treatment, oil extraction, and papermaking, relies heavily on the molecular weight and structure of its polymer. Theoretically, higher molecular weight and longer molecular chains result in greater bridging ability and thickening effect. However, in practical industrial applications, conventional linear or low-branched polyacrylamide prepared using existing technologies exhibits two key technical bottlenecks. First, it suffers from severe shear resistance. These polymers primarily exhibit simple linear extension structures, making their relatively brittle backbone prone to breakage under high-shear conditions, such as rapid stirring exceeding 1500 rpm, intense turbulence during pipeline transport, or the mechanical shearing of centrifugal pump impellers. This irreversible mechanical degradation directly leads to a significant decrease in polymer molecular weight of 30% to 40%, with the solution often exhibiting a viscosity retention rate of less than 50%. This means that its core function as a thickener or flocculant is essentially lost after high-shear processes, severely impacting process continuity and treatment stability. The second bottleneck lies in the limited adsorption area of ​​the linear molecular structure. The active adsorption sites (such as amide groups or ionic groups) of traditional linear polyacrylamide are mainly distributed at both ends and side chains of the long molecular chain, and its total adsorption capacity is limited by the extent of molecular chain extension in water. When facing complex wastewater systems with high turbidity, high chemical oxygen demand, or containing a large number of oil droplets and heavy metal ions, the limited specific surface area and site density of the linear molecular chain easily reach adsorption saturation. Once saturated, the polymer can no longer capture and trap more pollutant particles, leading to a rapid decline in flocculation effect, resulting in problems such as small flocs and slow settling, making it difficult to meet the requirements of high-standard effluent.

[0003] Although the industry has proposed some solutions to these problems, such as solely pursuing the synthesis of products with higher molecular weights or adding antioxidants to the formulation to slow down chemical degradation, these methods are all marginal improvements and fail to fundamentally break the bottleneck. Simply increasing the molecular weight makes the polymer more prone to entanglement, more difficult to dissolve in solution, and increases its sensitivity to mechanical shear; while antioxidants mainly act on chemical oxidative degradation and are powerless against physical mechanical shear. However, these solutions fail to address the fundamental contradiction between "easily broken linear chains" and "insufficient adsorption sites" at the source of molecular structure design.

[0004] Therefore, designing and synthesizing a high molecular weight polyacrylamide with a special dense branched structure through advanced polymerization technology, utilizing its three-dimensional spherical or dendritic structure to disperse shear force and provide a huge specific surface area, thereby simultaneously achieving a qualitative change in shear resistance and a leap in adsorption efficiency, has become the key to breaking through the current limitations of complex industrial working conditions and promoting the technological upgrading of water treatment and related industries. Summary of the Invention

[0005] One object of the present invention is to provide a high molecular weight polyacrylamide with strong shear resistance and large adsorption area.

[0006] Another object of the present invention is to provide a method for preparing the high molecular weight polyacrylamide.

[0007] Another object of the present invention is to provide the application of the high molecular weight polyacrylamide.

[0008] To achieve the above-mentioned objectives, this invention provides a high molecular weight polyacrylamide with strong shear resistance and a large adsorption area, which comprises the following components by weight: Acrylamide 90-100 parts, acrylic acid 10-15 parts, 2-acrylamide-2-methylpropanesulfonic acid 15-20 parts, EDTA-2Na 0.01-0.03 parts, butylated hydroxyanisole 0.1-0.3 parts, N,N'-methylenebisacrylamide 0.2-0.5 parts, ammonium persulfate 0.025-0.03 parts, sodium bisulfite 0.025-0.03 parts, 2-hydroxy-4'-(2-hydroxyethoxy)-2-methylphenylacetone 0.005-0.008 parts, deionized water 360-375 parts.

[0009] Preferably, the high molecular weight polyacrylamide comprises the following components by weight: 90 parts acrylamide, 10-15 parts acrylic acid, 20 parts 2-acrylamide-2-methylpropanesulfonic acid, 0.01 parts EDTA-2Na, 0.1 parts butylated hydroxyanisole, 0.2 parts N,N'-methylenebisacrylamide, 0.025 parts ammonium persulfate, 0.025 parts sodium bisulfite, 0.005 parts 2-hydroxy-4'-(2-hydroxyethoxy)-2-methylphenylacetone, and 375 parts deionized water.

[0010] Preferably, the high molecular weight polyacrylamide comprises the following components by weight: 100 parts acrylamide, 10 parts acrylic acid, 20 parts 2-acrylamide-2-methylpropanesulfonic acid, 0.02 parts EDTA-2Na, 0.2 parts butylated hydroxyanisole, 0.3 parts N,N'-methylenebisacrylamide, 0.03 parts ammonium persulfate, 0.025 parts sodium bisulfite, 0.006 parts 2-hydroxy-4'-(2-hydroxyethoxy)-2-methylphenylacetone, and 370 parts deionized water.

[0011] Preferably, the high molecular weight polyacrylamide comprises the following components by weight: 95 parts acrylamide, 10 parts acrylic acid, 15 parts 2-acrylamide-2-methylpropanesulfonic acid, 0.03 parts EDTA-2Na, 0.3 parts butylated hydroxyanisole, 0.5 parts N,N'-methylenebisacrylamide, 0.03 parts ammonium persulfate, 0.03 parts sodium bisulfite, 0.008 parts 2-hydroxy-4'-(2-hydroxyethoxy)-2-methylphenylacetone, and 360 parts deionized water.

[0012] Preferably, the molecular weight of the polyacrylamide is 16.5-18 million.

[0013] The present invention also provides a method for preparing the high molecular weight polyacrylamide, which includes the following steps: S1. Dissolve acrylamide, acrylic acid, and 2-acrylamide-2-methylpropanesulfonic acid in deionized water, stir until completely dissolved, and adjust the pH of the solution to 6.5-7.0; S2. Add EDTA-2Na and butylated hydroxyanisole, stir for 10 minutes, then add N,N'-methylenebisacrylamide, continue stirring for 5 minutes, and purge with nitrogen to remove oxygen. S3. Add ammonium persulfate and sodium bisulfite, control the temperature at 30-35℃, react for 2 hours, then add 2-hydroxy-4'-(2-hydroxyethoxy)-2-methylphenylacetone, irradiate with ultraviolet light for 40-60 minutes, and simultaneously raise the temperature to 50℃ and keep the reaction at this temperature for 2 hours to complete the polymerization and form a colloid. S4. The colloid is granulated, dried, crushed, and sieved to obtain the polyacrylamide product.

[0014] Preferably, in step S1, the pH is adjusted using NaOH with a mass concentration of 10%.

[0015] Preferably, in step S2, the nitrogen gas is introduced for 30 minutes.

[0016] Preferably, in step S3, the ultraviolet irradiation wavelength is 365nm and the power is 200W.

[0017] The present invention also provides the application of the high molecular weight polyacrylamide as a flocculant and thickener for wastewater treatment.

[0018] Compared with existing technologies, this invention achieves a fundamental enhancement of shear resistance and a significant expansion of adsorption area. Regarding shear resistance enhancement, the key lies in overcoming the fragile structure of traditional linear molecules and constructing a unique three-dimensional network structure of "main chain-branch chain-crosslinking nodes." The ultra-high molecular weight main chain serves as the backbone of the entire molecule, providing the basic chain length and bridging ability. Through a carefully designed multifunctional crosslinking agent, numerous branches are grafted onto the main chain, forming stable "elastic support nodes." When encountering high shear forces generated by high-speed stirring, pumping, etc., this structure exhibits excellent mechanical adaptability: the flexible branches can absorb and dissipate energy through reversible elastic deformation, thus replacing the direct breakage of rigid linear chains; simultaneously, the crosslinking nodes distributed throughout the molecule can efficiently disperse concentrated shear stress throughout the entire three-dimensional network, avoiding molecular chain breakage caused by stress accumulation at local points, thereby achieving a high retention rate of molecular weight under high shear conditions. Regarding the expansion of adsorption area, the polyacrylamide of this invention achieves dual optimization of site density and spatial configuration. By precisely introducing highly active adsorption groups such as carboxyl and sulfonic acid groups at the ends of numerous branches, the density of adsorption sites per unit molecular weight is significantly increased, far exceeding that of linear molecules. More importantly, this three-dimensional branched structure exhibits a unique "umbrella-like" or "dendritic" extended conformation in aqueous solution. Compared to the single-chain extension of linear molecules, its effective specific surface area is increased by orders of magnitude, as if expanding from a line into a three-dimensional network. This allows for more efficient capture and encapsulation of pollutant particles, greatly enhancing the adsorption capacity and flocculation efficiency for suspended colloids, organic impurities, and heavy metal ions. Detailed Implementation

[0019] To facilitate understanding of the present invention, a more complete description will be given below with reference to specific embodiments. However, the present invention can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to provide a thorough and complete understanding of the disclosure of the present invention.

[0020] In the description of this invention, unless otherwise explicitly defined, terms such as heating, cleaning, weighing, and freezing should be interpreted broadly. Those skilled in the art can reasonably determine the specific meaning of the above terms in this invention in conjunction with the specific content of the technical solution.

[0021] In the description of this invention, references to terms such as "some embodiments" and "examples" indicate that the specific methods or materials described in connection with that embodiment or example are included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiments or examples. Furthermore, the specific methods and materials described may be combined in any suitable manner in one or more embodiments or examples.

[0022] 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 invention pertains. The terminology used herein in the description of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention.

[0023] Unless otherwise specified, the experimental methods used in the following examples and comparative examples are conventional methods, and the materials and reagents used are commercially available unless otherwise specified.

[0024] Example 1 Dissolve 90g acrylamide, 15g acrylic acid, and 20g 2-acrylamide-2-methylpropanesulfonic acid in 375g deionized water and stir until completely dissolved. Add 10% NaOH to adjust the pH of the solution to 6.5.

[0025] Add 0.01g EDTA-2Na and 0.1g butylated hydroxyanisole, stir for 10 minutes, then add 0.2g N,N'-methylenebisacrylamide, continue stirring for 5 minutes, and purge with nitrogen for 30 minutes to remove oxygen.

[0026] Add 0.025 g of ammonium persulfate and 0.025 g of sodium bisulfite, control the temperature at 30 °C, and react for 2 hours to form a main chain structure containing initial branch sites. Then, transfer the reactants to a UV reactor (wavelength 365 nm, power 200 W), add 0.005 g of 2-hydroxy-4'-(2-hydroxyethoxy)-2-methylphenylacetone, irradiate with UV light for 40 minutes, and simultaneously raise the temperature to 50 °C. Maintain the reaction temperature for 2 hours to complete the polymerization and form a colloid.

[0027] The colloid is granulated, dried, crushed, and sieved to obtain polyacrylamide products.

[0028] The molecular weight of polyacrylamide is 17 million.

[0029] Example 2 Dissolve 100g acrylamide, 10g acrylic acid, and 20g 2-acrylamide-2-methylpropanesulfonic acid in 370g deionized water and stir until completely dissolved. Add 10% NaOH and adjust the pH of the solution to 7.0.

[0030] Add 0.02g EDTA-2Na and 0.2g butylated hydroxyanisole, stir for 10 minutes, then add 0.3g N,N'-methylenebisacrylamide, continue stirring for 5 minutes, and purge with nitrogen for 30 minutes to remove oxygen.

[0031] Add 0.03 g of ammonium persulfate and 0.025 g of sodium bisulfite, control the temperature at 35 °C, and react for 2 hours to form a main chain structure containing initial branch sites. Then, transfer the reactants to a UV reactor (wavelength 365 nm, power 200 W), add 0.006 g of 2-hydroxy-4'-(2-hydroxyethoxy)-2-methylphenylacetone, irradiate with UV light for 60 minutes, and simultaneously raise the temperature to 50 °C. Maintain the reaction temperature for 3 hours to complete the polymerization and form a colloid.

[0032] The colloid is granulated, dried, crushed, and sieved to obtain polyacrylamide products.

[0033] The molecular weight of polyacrylamide is 18 million.

[0034] Example 3 Dissolve 95g acrylamide, 10g acrylic acid, and 15g 2-acrylamide-2-methylpropanesulfonic acid in 360g deionized water and stir until completely dissolved. Add 10% NaOH and adjust the pH of the solution to 7.0.

[0035] Add 0.03g EDTA-2Na and 0.3g butylated hydroxyanisole, stir for 10 minutes, then add 0.5g N,N'-methylenebisacrylamide, continue stirring for 5 minutes, and purge with nitrogen for 30 minutes to remove oxygen.

[0036] Add 0.03 g of ammonium persulfate and 0.03 g of sodium bisulfite, control the temperature at 35 °C, and react for 2 hours to form a main chain structure containing initial branching sites. Then, transfer the reactants to a UV reactor (wavelength 365 nm, power 200 W), add 0.008 g of 2-hydroxy-4'-(2-hydroxyethoxy)-2-methylphenylacetone, irradiate with UV light for 60 minutes, and simultaneously raise the temperature to 50 °C. Maintain the reaction temperature for 4 hours to complete the polymerization and form a colloid.

[0037] The colloid is granulated, dried, crushed, and sieved to obtain polyacrylamide products.

[0038] The molecular weight of polyacrylamide is 16.5 million.

[0039] Performance testing Simulating pure shear scenarios such as centrifugal pump delivery and high-speed stirring, the viscosity retention rates of polyacrylamide and commercially available ordinary PAM in Examples 1-3 were tested at different rotation speeds.

[0040] The test data is shown in Table 1 below.

[0041] Table 1. Polyacrylamide viscosity retention rate

[0042] The sludge treatment effects of polyacrylamide in Examples 1-3 and commercially available ordinary PAM were tested through an adsorption experiment on high-turbidity municipal sludge (SS (suspended solids) = 15 g / L, COD (chemical oxygen demand) = 900 mg / L).

[0043] The experimental results are shown in Table 2 below.

[0044] Table 2. Sludge Treatment Effect

[0045] As can be seen from Tables 1 and 2, compared with commercially available ordinary PAM, the polyacrylamide in Examples 1-3 of this invention has stronger shear resistance and significantly improved sludge treatment effect.

[0046] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Therefore, any simple modifications, equivalent changes, and alterations made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the scope of the present invention.

Claims

1. A high molecular weight polyacrylamide with strong shear resistance and large adsorption area, characterized in that, The product comprises the following components by weight: 90-100 parts acrylamide, 10-15 parts acrylic acid, 15-20 parts 2-acrylamide-2-methylpropanesulfonic acid, 0.01-0.03 parts EDTA-2Na, 0.1-0.3 parts butylated hydroxyanisole, 0.2-0.5 parts N,N'-methylenebisacrylamide, 0.025-0.03 parts ammonium persulfate, 0.025-0.03 parts sodium bisulfite, 0.005-0.008 parts 2-hydroxy-4'-(2-hydroxyethoxy)-2-methylphenylacetone, and 360-375 parts deionized water.

2. The high molecular weight polyacrylamide according to claim 1, characterized in that, The high molecular weight polyacrylamide comprises the following components by weight: 90 parts acrylamide, 10-15 parts acrylic acid, 20 parts 2-acrylamide-2-methylpropanesulfonic acid, 0.01 parts EDTA-2Na, 0.1 parts butylated hydroxyanisole, 0.2 parts N,N'-methylenebisacrylamide, 0.025 parts ammonium persulfate, 0.025 parts sodium bisulfite, 0.005 parts 2-hydroxy-4'-(2-hydroxyethoxy)-2-methylphenylacetone, and 375 parts deionized water.

3. The high molecular weight polyacrylamide according to claim 1, characterized in that, The high molecular weight polyacrylamide comprises the following components by weight: 100 parts acrylamide, 10 parts acrylic acid, 20 parts 2-acrylamide-2-methylpropanesulfonic acid, 0.02 parts EDTA-2Na, 0.2 parts butylated hydroxyanisole, 0.3 parts N,N'-methylenebisacrylamide, 0.03 parts ammonium persulfate, 0.025 parts sodium bisulfite, 0.006 parts 2-hydroxy-4'-(2-hydroxyethoxy)-2-methylphenylacetone, and 370 parts deionized water.

4. The high molecular weight polyacrylamide according to claim 1, characterized in that, The high molecular weight polyacrylamide comprises the following components by weight: 95 parts acrylamide, 10 parts acrylic acid, 15 parts 2-acrylamide-2-methylpropanesulfonic acid, 0.03 parts EDTA-2Na, 0.3 parts butylated hydroxyanisole, 0.5 parts N,N'-methylenebisacrylamide, 0.03 parts ammonium persulfate, 0.03 parts sodium bisulfite, 0.008 parts 2-hydroxy-4'-(2-hydroxyethoxy)-2-methylphenylacetone, and 360 parts deionized water.

5. The high molecular weight polyacrylamide according to any one of claims 1 to 4, characterized in that, The polyacrylamide has a molecular weight of 16.5-18 million.

6. A method for preparing high molecular weight polyacrylamide as described in any one of claims 1 to 5, characterized in that, Includes the following steps: S1. Dissolve acrylamide, acrylic acid, and 2-acrylamide-2-methylpropanesulfonic acid in deionized water, stir until completely dissolved, and adjust the pH of the solution to 6.5-7.0; S2. Add EDTA-2Na and butylated hydroxyanisole, stir for 10 minutes, then add N,N'-methylenebisacrylamide, continue stirring for 5 minutes, and purge with nitrogen to remove oxygen. S3. Add ammonium persulfate and sodium bisulfite, control the temperature at 30-35℃, react for 2 hours, then add 2-hydroxy-4'-(2-hydroxyethoxy)-2-methylphenylacetone, irradiate with ultraviolet light for 40-60 minutes, and simultaneously raise the temperature to 50℃ and keep the reaction at this temperature for 2 hours to complete the polymerization and form a colloid. S4. The colloid is granulated, dried, crushed, and sieved to obtain the polyacrylamide product.

7. The method according to claim 6, characterized in that, In step S1, the pH is adjusted using NaOH with a mass concentration of 10%.

8. The method according to claim 6, characterized in that, In step S2, nitrogen gas is introduced for 30 minutes.

9. The method according to claim 6, characterized in that, In step S3, the ultraviolet irradiation wavelength is 365nm and the power is 200W.

10. The application of high molecular weight polyacrylamide as a flocculant and thickener in wastewater treatment as described in any one of claims 1 to 5.

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