CN116135897A - Polyacrylamide copolymer, and preparation method and application thereof - Google Patents

Abstract

The invention relates to a polyacrylamide copolymer, its preparation method and application. The polyacrylamide copolymer comprises a first structural unit and a second structural unit, the structures of the first structural unit and the second structural unit are as follows, wherein R _{and R} are each independently selected from hydrogen and methyl; R ₂ is selected from methylene, ethylene and propylene; R ₃ and R ₄ are each independently selected from methyl and ethyl; R ₆ is an alkyl group containing 8 to 14 carbon atoms. The polyacrylamide copolymer of the present invention has good pH responsiveness, and has excellent flocculation ability for both hydrophilic and hydrophobic suspended particles. As a flocculant, it can effectively expand the use conditions and conditions of existing polyacrylamide flocculants. scope.

Description

Polyacrylamide copolymer, preparation method and application thereof

Technical Field

The invention relates to a polyacrylamide copolymer, in particular to a polyacrylamide copolymer which can be used as a flocculant.

Background Art

At present, in mineral processing, water waste and pollution have become a major problem. In order to reduce pollution and promote resource recycling, it is of great significance to study efficient and simple water treatment technology. Compared with ion exchange, adsorption, advanced oxidation and other technologies, flocculation precipitation is not only easy to operate and simple in process, but also has low processing cost and high processing efficiency. Therefore, it has attracted the attention of various industries and is widely used in oil production industry, mineral processing and wastewater treatment.

Flocculants are the core of flocculation technology. The main flocculants can be divided into three categories: inorganic flocculants, organic polymer flocculants and biological flocculants. Compared with inorganic flocculants and biological flocculants, polyacrylamide (PAM) organic polymer flocculants are widely used due to their simple production process, wide range of applications, and long-term storage. The flocculation effect of polyacrylamide with different molecular weights varies greatly. High molecular weight polyacrylamide often has better flocculation effect and faster flocculation speed. However, if the dosage is too high, the flocculant will generate electrostatic repulsion with the particles, which will seriously reduce the effect of use. Therefore, many modified polyacrylamide flocculants have been studied and successfully applied.

Among the many modifications, hydrophobic modification has gradually attracted attention. The introduction of hydrophobic monomers through graft polymerization can not only increase the molecular weight of molecular polymers, but also improve the hydrophobic association and adsorption bridging capabilities of flocculants. Polyacrylamide flocculants that have undergone hydrophobic modification have a strong ability to remove oil droplets and hydrophobic suspended solids in water. However, the flocs produced by the flocculation of general hydrophobically modified polyacrylamide are loose and easy to break. Other amphoteric substances and particles with different hydrophilicity and hydrophobicity in the system hinder the flocculation of polyacrylamide, which greatly limits the scope of application of flocculants.

Summary of the invention

In view of the above analysis, one embodiment of the present invention aims to provide a polyacrylamide copolymer to solve the problem of limited application range of existing polyacrylamide flocculants.

On the one hand, an embodiment of the present invention provides a polyacrylamide copolymer, comprising a first structural unit and a second structural unit, wherein the first structural unit is:

The second structural unit is:

Wherein, _R1 and _R5 are each independently selected from hydrogen and methyl; _R2 is selected from methylene, ethylene and propylene; _R3 and _R4 are each independently selected from methyl and ethyl; _R6 is an alkyl group containing 8 to 14 carbon atoms.

According to one embodiment of the present invention, _R1 and _R5 are each independently selected from hydrogen and methyl; _R2 is methylene or ethylene; _R3 and _R4 are each independently selected from methyl and ethyl; _R6 is a straight-chain alkyl group containing 8 to 14 carbon atoms.

According to one embodiment of the present invention, the weight average molecular weight of the polyacrylamide copolymer is 70,000-100,000.

According to one embodiment of the present invention, the molar ratio of the first structural unit to the second structural unit is 1.9:1 to 5.7:1; and/or,

The intrinsic viscosity of the polyacrylamide copolymer is 380-580 mL/g.

One embodiment of the present invention further provides a method for preparing the above-mentioned polyacrylamide copolymer, comprising reacting reaction raw materials to obtain the polyacrylamide copolymer; the reaction raw materials include a first polymerizable monomer, a second polymerizable monomer and an alkyl glucoside; the second polymerizable monomer includes acrylamide and/or methacrylamide, and the first polymerizable monomer and the alkyl glucoside have the following structural formulas:

烷基葡萄糖苷：

First polymerizable monomer:

Alkyl Glucoside:

Wherein, _R1 is selected from hydrogen and methyl; _R2 is selected from methylene, ethylene and propylene; _R3 and _R4 are each independently selected from methyl and ethyl; _R6 is an alkyl group containing 8 to 14 carbon atoms.

According to one embodiment of the present invention, the alkyl glucoside includes one, two or three of octyl glucoside, dodecyl glucoside and tetradecyl glucoside; and/or,

The mass of the alkyl glucoside is 2 to 14%, further 6 to 10% of the mass of the reaction raw materials; and or,

The reaction temperature of the reaction raw materials is 40 to 60° C.; and/or the reaction time is 2 to 7 hours.

According to one embodiment of the present invention, the preparation method comprises:

dispersing the reaction raw materials in water to form a raw material solution; and

A redox initiator is added to the raw material solution, and the reaction is carried out at 40 to 60° C. for 2 to 7 hours to obtain a colloidal polymer.

According to one embodiment of the present invention, the mass of the reaction raw material is 20-45% of the mass of the raw material solution; and/or,

The mass of the redox initiator is 0.2-1.2% of the mass of the reaction raw materials; and/or,

The redox initiators include potassium persulfate and sodium bisulfite.

One embodiment of the present invention further provides a pH-sensitive polyacrylamide flocculant, comprising the above-mentioned polyacrylamide copolymer.

One embodiment of the present invention further provides the use of the above-mentioned polyacrylamide copolymer in wastewater treatment.

The polyacrylamide copolymer of one embodiment of the present invention has good pH response capability and excellent flocculation ability for both hydrophilic and hydrophobic suspended particles. As a flocculant, it can effectively expand the use conditions and scope of existing polyacrylamide flocculants.

In the present invention, the above-mentioned technical solutions can also be combined with each other to achieve more preferred combination solutions. Other features and advantages of the present invention will be described in the subsequent description, and some advantages can become obvious from the description, or can be understood by practicing the present invention. The purpose and other advantages of the present invention can be achieved and obtained through the contents particularly pointed out in the description.

DETAILED DESCRIPTION

The preferred embodiments of the present invention are described in detail below, which are used to illustrate the principles of the present invention but not to limit the scope of the present invention.

An embodiment of the present invention provides a polyacrylamide copolymer, comprising a first structural unit and a second structural unit, wherein the first structural unit is:

The second structural unit is:

Wherein, R ₁ and R ₅ are each independently selected from hydrogen and methyl; R ₂ is selected from an alkylene group containing 1 to 3 carbon atoms, such as methylene (-CH ₂ -), ethylene (-CH ₂ CH ₂ -), propylene (-CH ₂ CH ₂ CH ₂ - or -CH ₂ (CH ₃ )CH-); R ₃ and R ₄ are each independently selected from methyl and ethyl; R ₆ is an alkyl group containing 8 to 14 carbon atoms.

The polyacrylamide copolymer of one embodiment of the present invention includes a hydrophobic group (dodecyl glucoside group) and a pH sensitive group (tertiary amine group), so that the copolymer has pH sensitivity on the basis of being hydrophobically modified, and has a certain responsiveness to pH. Specifically, the pH sensitive group is reactive and can undergo protonation or deprotonation reactions in environments with different pH. Thus, the polyacrylamide copolymer of one embodiment of the present invention can not only improve its own solubility, but also change the electrical properties of the flocculant itself as a flocculant, and has excellent removal ability for particles and pollutants with different hydrophilicity and hydrophobicity, effectively expanding the use conditions and scope of existing polyacrylamide flocculants.

In one embodiment, R ₁ and R ₅ are each independently selected from hydrogen and methyl; R ₂ is ethylene; and R ₃ and R ₄ are both ethyl.

In one embodiment, R ₆ is a straight chain alkyl group containing 8, 9, 10, 11, 12, 13 or 14 carbon atoms, such as -(CH ₂ ) ₈ , -(CH ₂ ) ₁₂ , -(CH ₂ ) ₁₄ .

In one embodiment, the molar ratio of the first structural unit to the second structural unit of the polyacrylamide copolymer is 1.9:1 to 5.7:1, and can further be 3:1 to 5:1. For example, the molar ratio of the first structural unit to the second structural unit can be 1.92:1, 2:1, 2.5:1, 3:1, 3.5:1, 4:1, 4.5:1, 5:1, 5.5:1, 5.67:1, etc.

In one embodiment, the weight average molecular weight of the polyacrylamide copolymer may be 70,000 to 100,000, such as 75,000, 80,000, 85,000, 90,000, 95,000, etc.

In one embodiment, the intrinsic viscosity of the polyacrylamide copolymer is 380 to 580 mL/g, for example, 385 mL/g, 390 mL/g, 400 mL/g, 420 mL/g, 450 mL/g, 470 mL/g, 490 mL/g, 500 mL/g, 520 mL/g, 550 mL/g, and 570 mL/g.

In one embodiment, the polyacrylamide copolymer may be a random copolymer or a block copolymer.

One embodiment of the present invention provides a method for preparing a polyacrylamide copolymer, wherein the polyacrylamide copolymer is prepared by co-solution polymerization.

In one embodiment, a method for preparing a polyacrylamide copolymer comprises reacting reaction raw materials to obtain a polyacrylamide copolymer; wherein the reaction raw materials include a first polymerizable monomer (also referred to as a pH-sensitive monomer), a second polymerizable monomer, and an alkyl glucoside containing a hydrophobic group; the second polymerizable monomer includes acrylamide and/or methacrylamide, and the structural formulas of the first polymerizable monomer and the alkyl glucoside are as follows:

烷基葡萄糖苷：

First polymerizable monomer:

Alkyl Glucoside:

Herein, the above definitions apply to R ₁ , R ₂ , R ₃ , R ₄ and R ₆ .

The preparation method of one embodiment of the present invention has a simple process. While the first polymerized monomer and the second polymerized monomer are being polymerized, dodecyl glucoside is reacted with the amide group of the second polymerized monomer to obtain a polyacrylamide copolymer, that is, two reactions are achieved through one process, simplifying the preparation process. Further, in the process of free radical copolymerization initiated by the initiator, the amino group on the amide group and the hydroxyl group on the alkyl glycoside are reaction activation groups with very low activation energy. The two will graft and remove water molecules, and this reaction runs through the entire polymerization reaction stage.

In another embodiment, dodecyl glucoside may be first reacted with the second polymerizable monomer and then copolymerized with the first polymerizable monomer.

In one embodiment, the first polymerizable monomer includes one or more of diethylaminoethyl methacrylate, diethylaminoethyl acrylate, dimethylaminoethyl methacrylate, dimethylaminoethyl acrylate, 2-(ethyl(methyl)amino)ethyl methacrylate, and 2-(ethyl(methyl)amino)ethyl acrylate.

In one embodiment, the alkyl glucoside includes one, two or three of octyl glucoside, dodecyl glucoside and tetradecyl glucoside.

In one embodiment, the mass of the first polymerizable monomer is 38-57% of the total mass of the reaction raw materials, and can further be 40-50%, for example 38.8%, 40%, 42%, 45%, 48%, 50%, 52%, 55%, 56.1%.

In one embodiment, the mass of the second polymerizable monomer is 43-62% of the total mass of the reaction raw materials, and can further be 45-55%, for example 43.9%, 45%, 47%, 49%, 50%, 52%, 54%, 58%, 60%, 61.2%.

In one embodiment, the mass of the alkyl glucoside is 2-14% of the total mass of the reaction raw materials, further 6-14%, further 6-10%, for example 3%, 4%, 5%, 6%, 8%, 9%, preferably 10%. The mass content of the alkyl glucoside is kept within the above range, which can not only further improve the hydrophobic association effect of the obtained polyacrylamide copolymer, but also make the polyacrylamide copolymer have a higher solubility, which is conducive to its use as a flocculant.

In one embodiment, the reaction temperature of the reaction raw materials can be 40 to 60° C., such as 45° C., 50° C., 55° C., etc., preferably 50° C., and the reaction raw materials can be kept at a temperature of 40 to 60° C. by water bath heating. The reaction temperature within the above range can not only increase the polymerization reaction rate, but also does not reduce the intrinsic viscosity of the polymer, and can keep the intrinsic viscosity of the obtained polymer within a suitable range.

In one embodiment, the reaction time of the reaction raw materials can be 2 to 7 hours, such as 3 hours, 4 hours, 5 hours, 6 hours, preferably 5 hours. The reaction time of 2 to 7 hours can not only make the polymerization reaction fully proceed, but also will not cause the product to crosslink, which is conducive to improving the conversion rate.

In one embodiment, the preparation method of the polyacrylamide copolymer comprises:

Dissolving the reaction raw materials in water to form a raw material solution;

Adding a redox initiator to the raw material solution, reacting at 40 to 60° C. for 2 to 7 hours to obtain a colloidal polymer; and

The colloidal polymer is washed with anhydrous ethanol, dried and then ground into powder to obtain polyacrylamide copolymer powder.

In one embodiment, the mass of the reaction raw materials accounts for 20-45% of the mass of the raw material solution, such as 25%, 28%, 30%, 32%, 35%, 38%, 40%, 42%, preferably 30%. Maintaining the mass concentration of the reaction raw materials within the above range can not only increase the polymerization reaction rate, but also facilitate the purification and dissolution of the product.

In one embodiment, the mass of the redox initiator is 0.2-1.2% of the total mass of the reaction raw materials, such as 0.3%, 0.5%, 0.6%, 0.8%, 1.0%, preferably 1.0%. The mass of the redox initiator is kept within the above range, so that the number of reaction centers can be kept within an appropriate range without causing a decrease in molecular weight, which is beneficial to the control of the molecular weight of the obtained polymer.

In one embodiment, the redox initiator includes an oxidant and a reductant. When used, the oxidant is first added to the raw material solution, and then the reductant is added.

In one embodiment, the molar ratio of the oxidizing agent to the reducing agent may be 1:2, the oxidizing agent may be, for example, potassium persulfate, and the reducing agent may be, for example, sodium bisulfite.

In the preparation method of one embodiment of the present invention, after the redox initiator is added to the reaction system, nitrogen is introduced into the system to remove the air therein, especially oxygen, so as to avoid the occurrence of inhibition caused by oxygen destroying the free radical polymerization. The nitrogen introduction time can be more than 10 minutes, and further can be 10 to 20 minutes, for example, 12 minutes, 15 minutes, 18 minutes, preferably 15 minutes. The nitrogen introduction time can discharge the air in the reaction system to the greatest extent without causing waste.

In one embodiment, the preparation method of the polyacrylamide copolymer comprises:

(1) Deionized water is added to a reaction device, and the first polymerization monomer, the second polymerization monomer and alkyl glucoside are added to the reaction device and stirred thoroughly to obtain a raw material solution.

(2) adding a redox initiator potassium persulfate-sodium bisulfite to the above raw material solution, stirring the mixture thoroughly, introducing high-purity nitrogen into the reaction device to remove air from the device and sealing the device; the order of adding the initiators is to first add the oxidizing agent potassium persulfate and then add the reducing agent sodium bisulfite.

(3) The sealed reaction device after the above treatment is placed in a constant temperature water bath and stirred to initiate a polymerization reaction. After the polymerization is completed, a milky white colloidal polymer compound is generated. The reaction device is taken out and cooled to room temperature.

(4) The cooled white colloidal substance is repeatedly washed and purified with ethanol, dried at 70° C. for 24 hours to form a solid, and then ground into powder to obtain a pH-sensitive polyacrylamide copolymer.

In one embodiment, the stirring in step (3) can be performed by mechanical stirring, and the stirring speed can be controlled at 70 to 100 rpm, such as 75 rpm, 80 rpm, 85 rpm, 90 rpm, 95 rpm, etc.

In one embodiment, the washing and purification time in step (4) can be 2 hours, so that the unreacted monomers can be completely washed away.

The preparation method of the polyacrylamide copolymer according to one embodiment of the present invention has simple process, convenient operation, mild reaction conditions and stable reaction.

The polyacrylamide copolymer of one embodiment of the present invention can be used as a flocculant. Under acidic conditions, the tertiary amine is protonated and positively charged, so the turbidity of the flocculant aqueous solution is extremely low and it is positively charged. Under alkaline conditions, the increase in pH causes the protonation effect to disappear. In order to make the polymer present a low-energy state distribution in water, the polymer chain will shrink and curl, and the hydrophobic part will aggregate to form micelles, which will lead to an increase in the turbidity of the solution and a negative charge. Therefore, the polyacrylamide copolymer flocculant has good pH response ability.

The polyacrylamide copolymer flocculant of one embodiment of the present invention can be used for wastewater treatment, especially tailings water treatment. The flocculant can condense fine kaolin and molybdenite in the ore dressing wastewater into large flocs for sedimentation through charge neutralization, adsorption bridging and hydrophobic association, and has excellent flocculation and turbidity removal capabilities.

The preparation and application of the polyacrylamide copolymer according to one embodiment of the present invention are further described below in conjunction with specific examples. The intrinsic viscosity involved in the examples is measured by the intrinsic viscosity test method GB12005.1-89 polyacrylamide intrinsic viscosity determination method; the weight average molecular weight is measured by gel permeation chromatography (GPC).

Example 1

(1) Add 25 mL of deionized water to a reaction device, and add 6.05 g of acrylamide, 2.41 g of diethylaminoethyl methacrylate, and 2.32 g of dodecyl glucoside solution (mass fraction 40%) to the reaction device in sequence and stir until the three substances are dissolved in the deionized water to obtain a solution of the reaction raw materials with a mass fraction of 30%. At the same time, the mass of dodecyl glucoside is 10% of the total mass of the three reaction raw materials.

(2) First, add 0.052g of potassium persulfate to the above solution, then add 0.040g of sodium bisulfite to the solution, stir thoroughly to dissolve both, the mass of the redox initiator is 1.0% of the total mass of the reaction raw materials. Continue to pass high-purity nitrogen into the reaction device for 15 minutes, evacuate the air in the reaction device and seal it.

(3) The reaction device was placed in a constant temperature water bath at 50°C and the mechanical stirring speed was 75 rpm. After stirring for 5 hours, a milky white colloidal substance appeared in the reaction device. The reaction device was removed and cooled to room temperature.

(4) The white colloidal substance was repeatedly washed and purified with ethanol, and dried at a constant temperature of 70° C. for 24 hours to obtain a solid product, which was ground into powder to obtain a pH-sensitive polyacrylamide copolymer. The weight average molecular weight of the copolymer was measured to be 100,000, and the intrinsic viscosity was 575.88 mL/g.

Example 2

(1) 14 mL of deionized water was added to a reaction device, and 4.00 g of acrylamide, 2.09 g of diethylaminoethyl methacrylate and 0.6 g of dodecyl glucoside solution (mass fraction 40%) were added to the reaction device in sequence and stirred until the three substances were dissolved in the deionized water to obtain a solution of the reaction raw materials with a mass fraction of 20%. At the same time, the mass of dodecyl glucoside was 3.8% of the total mass of the three reaction raw materials.

(2) First, add 0.021 g of potassium persulfate to the above solution, then add 0.016 g of sodium bisulfite to the solution, stir thoroughly to dissolve both, the mass of the redox initiator is 0.4% of the total mass of the reaction raw materials. Continue to pass high-purity nitrogen into the reaction device for 15 minutes, evacuate the air in the reaction device and seal it.

(3) The reaction device was placed in a constant temperature water bath at 40°C and the mechanical stirring speed was 70 rpm. After stirring for 6 hours, a milky white colloidal substance appeared in the reaction device. The reaction device was removed and cooled to room temperature.

(4) The white colloidal substance was repeatedly washed and purified with ethanol, and dried at a constant temperature of 70° C. for 24 hours to obtain a solid product, which was ground into powder to obtain a pH-sensitive polyacrylamide copolymer, and its intrinsic viscosity was measured to be 385.70 mL/g.

Example 3

(1) 12 mL of deionized water was added to a reaction device, and 4.00 g of acrylamide, 2.00 g of diethylaminoethyl methacrylate and 2.45 g of dodecyl glucoside solution (mass fraction 40%) were added to the reaction device in sequence and stirred until the three substances were dissolved in the deionized water to obtain a solution of the reaction raw materials with a mass fraction of 40%. At the same time, the mass of dodecyl glucoside was 14% of the total mass of the three reaction raw materials.

(2) First, add 0.090g of potassium persulfate to the above solution, then add 0.064g of sodium bisulfite to the solution, stir thoroughly to dissolve both, the mass of the redox initiator is 2.0% of the total mass of the reaction raw materials. Continue to pass high-purity nitrogen into the reaction device for 15 minutes, evacuate the air in the reaction device and seal it.

(3) The reaction device was placed in a constant temperature water bath at 60°C and the mechanical stirring speed was 85 rpm. After stirring for 4 hours, a milky white colloidal substance appeared in the reaction device. The reaction device was removed and cooled to room temperature.

(4) The white colloidal substance was repeatedly washed and purified with ethanol, and dried at a constant temperature of 70° C. for 24 hours to obtain a solid product, which was ground into powder to obtain a pH-sensitive polyacrylamide copolymer, and its intrinsic viscosity was measured to be 492.59 mL/g.

Example 4

(1) 23 mL of deionized water was added to a reaction device, and 6.00 g of acrylamide, 2.40 g of diethylaminoethyl methacrylate and 1.35 g of dodecyl glucoside solution (mass fraction 40%) were added to the reaction device in sequence and stirred until the three substances were dissolved in the deionized water to obtain a solution of the reaction raw materials with a mass fraction of 30%. At the same time, the mass of dodecyl glucoside was 6.0% of the total mass of the three reaction raw materials.

(2) First, add 0.051 g of potassium persulfate to the above solution, then add 0.038 g of sodium bisulfite to the solution, stir thoroughly to dissolve both, the mass of the redox initiator is 1.0% of the total mass of the reaction raw materials. Continue to pass high-purity nitrogen into the reaction device for 15 minutes, evacuate the air in the reaction device and seal it.

(3) The reaction device was placed in a constant temperature water bath at 50°C and the mechanical stirring speed was 75 rpm. After stirring for 5 hours, a milky white colloidal substance appeared in the reaction device. The reaction device was removed and cooled to room temperature.

(4) The white colloidal substance was repeatedly washed and purified with ethanol, and dried at a constant temperature of 70° C. for 24 hours to obtain a solid product, which was ground into powder to obtain a pH-sensitive polyacrylamide copolymer, and its intrinsic viscosity was measured to be 435.25 mL/g.

Application Example 1

Turbidity Removal from Kaolin Suspension

(1) Weigh 0.20 g of the polyacrylamide copolymer prepared in Example 1 and dissolve it in 100 mL of deionized water to prepare a flocculant solution with a concentration of 2 g/L.

(2) Weigh 5 portions of 1.0 g of fine-grained kaolin respectively, disperse them in 5 beakers containing 200 mL of deionized water, stir them thoroughly to obtain 5 portions of suspensions, and adjust the pH of the suspensions with sodium hydroxide and hydrochloric acid solutions to 2, 4, 6, 8, and 10, respectively.

(3) Add 4 mL of flocculant solution to each of the five beakers, stir for 10 minutes to allow the flocculant to fully contact the kaolin particles, and then let it stand for 5 minutes to wait for flocculation.

The turbidity removal rates of kaolin suspension at pH values of 2, 4, 6, 8 and 10 were 99.46%, 99.65%, 99.48%, 98.82% and 86.28%, respectively.

Turbidity Removal of Molybdenite Suspension

(1) Weigh 0.20 g of the polyacrylamide copolymer prepared in Example 1 and dissolve it in 100 mL of deionized water to prepare a flocculant solution with a concentration of 2 g/L.

(2) Weigh 5 portions of 1.0 g of fine-grained molybdenite, disperse them in 5 beakers containing 200 mL of deionized water, and stir them thoroughly to obtain 5 portions of suspensions. Use sodium hydroxide and hydrochloric acid solutions to adjust the pH values of the suspensions to 2, 4, 6, 8, and 10, respectively.

(3) Add 4 mL of flocculant solution to each of the five beakers, stir for 10 min to allow the flocculant to fully contact the molybdenite particles, and then let it settle for 5 min to wait for flocculation.

The turbidity removal rates of molybdenite suspension at pH values of 2, 4, 6, 8 and 10 were 99.21%, 99.72%, 99.47%, 98.33% and 98.98%, respectively.

Application Example 2

Turbidity Removal from Kaolin Suspension

(1) Weigh 0.20 g of the polyacrylamide copolymer prepared in Example 2 and dissolve it in 100 mL of deionized water to prepare a flocculant solution with a concentration of 2 g/L.

(2) Weigh 5 portions of 1.0 g of fine-grained kaolin respectively, disperse them in 5 beakers containing 200 mL of deionized water, stir them thoroughly to obtain 5 portions of suspensions, and adjust the pH of the suspensions with sodium hydroxide and hydrochloric acid solutions to 2, 4, 6, 8, and 10, respectively.

(3) Add 4 mL of flocculant solution to each of the five beakers, stir for 10 minutes to allow the flocculant to fully contact the kaolin particles, and then let it stand for 5 minutes to wait for flocculation.

The turbidity removal rates of kaolin suspension at pH values of 2, 4, 6, 8, and 10 were 68.27%, 68.73%, 67.84%, 67.29%, and 67.07%, respectively.

Turbidity Removal of Molybdenite Suspension

(1) Weigh 0.20 g of the polyacrylamide copolymer prepared in Example 2 and dissolve it in 100 mL of deionized water to prepare a flocculant solution with a concentration of 2 g/L.

(2) Weigh 5 portions of 1.0 g of fine-grained molybdenite, disperse them in 5 beakers containing 200 mL of deionized water, and stir them thoroughly to obtain 5 portions of suspensions. Use sodium hydroxide and hydrochloric acid solutions to adjust the pH values of the suspensions to 2, 4, 6, 8, and 10, respectively.

(3) Add 4 mL of flocculant solution to each of the five beakers, stir for 10 min to allow the flocculant to fully contact the molybdenite particles, and then let it stand for 5 min to wait for flocculation.

The turbidity removal rates of molybdenite suspension at pH values of 2, 4, 6, 8, and 10 were 69.66%, 69.59%, 68.94%, 68.42%, and 67.88%, respectively.

Application Example 3

Turbidity Removal from Kaolin Suspension

(1) Weigh 0.20 g of the polyacrylamide copolymer prepared in Example 3 and dissolve it in 100 mL of deionized water to prepare a flocculant solution with a concentration of 2 g/L.

(2) Weigh 5 portions of 1.0 g of fine-grained kaolin respectively, disperse them in 5 beakers containing 200 mL of deionized water, stir them thoroughly to obtain 5 portions of suspensions, and adjust the pH of the suspensions with sodium hydroxide and hydrochloric acid solutions to 2, 4, 6, 8, and 10, respectively.

(3) Add 4 mL of flocculant solution to each of the five beakers, stir for 10 minutes to allow the flocculant to fully contact the kaolin particles, and then let it stand for 5 minutes to wait for flocculation.

The turbidity removal rates of kaolin suspension at pH values of 2, 4, 6, 8, and 10 were 88.74%, 88.82%, 88.40%, 88.16%, and 87.73%, respectively.

Turbidity Removal of Molybdenite Suspension

(1) Weigh 0.20 g of the polyacrylamide copolymer prepared in Example 3 and dissolve it in 100 mL of deionized water to prepare a flocculant solution with a concentration of 2 g/L.

(2) Weigh 5 portions of 1.0 g of fine-grained molybdenite, disperse them in 5 beakers containing 200 mL of deionized water, and stir them thoroughly to obtain 5 portions of suspensions. Use sodium hydroxide and hydrochloric acid solutions to adjust the pH values of the suspensions to 2, 4, 6, 8, and 10, respectively.

(3) Add 4 mL of flocculant solution to each of the five beakers, stir for 10 min to allow the flocculant to fully contact the molybdenite particles, and then let it settle for 5 min to wait for flocculation.

The turbidity removal rates of molybdenite suspension at pH values of 2, 4, 6, 8, and 10 were 89.24%, 89.45%, 88.93%, 88.62%, and 88.37%, respectively.

Application Example 4

Turbidity Removal from Kaolin Suspension

(1) Weigh 0.20 g of the polyacrylamide copolymer prepared in Example 4 and dissolve it in 100 mL of deionized water to prepare a flocculant solution with a concentration of 2 g/L.

(2) Weigh 5 portions of 1.0 g of fine-grained kaolin respectively, disperse them in 5 beakers containing 200 mL of deionized water, stir them thoroughly to obtain 5 portions of suspensions, and adjust the pH of the suspensions with sodium hydroxide and hydrochloric acid solutions to 2, 4, 6, 8, and 10, respectively.

(3) Add 4 mL of flocculant solution to each of the five beakers, stir for 10 minutes to allow the flocculant to fully contact the kaolin particles, and then let it stand for 5 minutes to wait for flocculation.

The turbidity removal rates of kaolin suspension at pH values of 2, 4, 6, 8, and 10 were 90.62%, 90.70%, 90.43%, 90.27%, and 90.15%, respectively.

Turbidity Removal of Molybdenite Suspension

(1) Weigh 0.20 g of the polyacrylamide copolymer prepared in Example 4 and dissolve it in 100 mL of deionized water to prepare a flocculant solution with a concentration of 2 g/L.

(2) Weigh 5 portions of 1.0 g of fine-grained molybdenite, disperse them in 5 beakers containing 200 mL of deionized water, and stir them thoroughly to obtain 5 portions of suspensions. Use sodium hydroxide and hydrochloric acid solutions to adjust the pH values of the suspensions to 2, 4, 6, 8, and 10, respectively.

(3) Add 4 mL of flocculant solution to each of the five beakers, stir for 10 min to allow the flocculant to fully contact the molybdenite particles, and then let it settle for 5 min to wait for flocculation.

The turbidity removal rates of molybdenite suspension at pH values of 2, 4, 6, 8, and 10 were 90.24%, 90.18%, 90.05%, 89.87%, and 89.72%, respectively.

The above results show that the polyacrylamide copolymer flocculant of the embodiment of the present invention has a significant flocculation effect on both hydrophilic and hydrophobic suspended particles in a very wide pH range (e.g., pH 2 to 10). This is mainly due to the protonation effect of diethylaminoethyl methacrylate under acidic conditions, which enhances the charge attraction and bridging ability between the flocculant and the suspended particles, and the deprotonation under alkaline conditions, which enhances the hydrophobicity of the flocculant. At the same time, the introduction of the hydrophobic dodecyl glucoside group enhances the hydrophobic association ability between the flocculant and the suspended particles, causing the fine particles to agglomerate into larger flocs and settle, thereby enhancing the flocculation effect of the polyacrylamide copolymer.

In addition, Application Examples 1, 3, and 4 have better turbidity removal effects than Application Example 2, and Application Examples 1 and 4 have better turbidity removal effects than Application Example 3, indicating that the mass content of alkyl glucoside in polyacrylamide copolymers has a better flocculation effect in the range of 6 to 14%, especially 6 to 10%.

The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by any technician familiar with the technical field within the technical scope disclosed by the present invention should be covered within the protection scope of the present invention.

Claims (10)

1. A polyacrylamide copolymer comprising a first structural unit and a second structural unit, the first structural unit being:

the second structural unit is as follows:

wherein R is ₁ And R is ₅ Each independently selected from hydrogen and methyl; r is R ₂ Selected from the group consisting of methylene, ethylene and propylene; r is R ₃ And R is ₄ Each independently selected from methyl and ethyl; r is R ₆ Is an alkyl group having 8 to 14 carbon atoms.

2. The copolymer of claim 1, wherein R ₁ And R is ₅ Each independently selected from hydrogen and methyl; r is R ₂ Is methylene or ethylene; r is R ₃ And R is ₄ Each independently selected from methyl and ethyl; r is R ₆ Is a linear alkyl group having 8 to 14 carbon atoms.

3. The copolymer according to claim 1, wherein the weight average molecular weight of the polyacrylamide copolymer is 70000 to 100000.

4. The copolymer of claim 1, wherein the molar ratio of the first structural unit to the second structural unit is from 1.9:1 to 5.7:1; and/or the number of the groups of groups,

the intrinsic viscosity of the polyacrylamide copolymer is 380-580 mL/g.

5. The method for producing a polyacrylamide-based copolymer according to any one of claims 1 to 4, comprising producing the polyacrylamide-based copolymer by reacting reaction raw materials; the reaction raw materials comprise a first polymerization monomer, a second polymerization monomer and alkyl glucoside; the second polymeric monomer comprises acrylamide and/or methacrylamide, and the structural formulas of the first polymeric monomer and the alkyl glucoside are as follows:

first polymerized monomer:

alkyl glucoside:

Wherein R is ₁ Selected from hydrogen and methyl; r is R ₂ Selected from the group consisting of methylene, ethylene and propylene; r is R ₃ And R is ₄ Each independently selected from methyl and ethyl; r is R ₆ Is an alkyl group having 8 to 14 carbon atoms.

6. The method of claim 5, wherein the alkyl glucosides comprise one, two, or three of octyl glucoside, dodecyl glucoside, tetradecyl glucoside; and/or the number of the groups of groups,

the mass of the alkyl glucoside is 2-14% of the mass of the reaction raw material, and is further 6-10%; and/or, the number of the groups,

the reaction temperature of the reaction raw materials is 40-60 ℃; and/or the reaction time is 2 to 7 hours.

7. The method of claim 5, comprising:

dispersing the reaction raw materials in water to form a raw material solution; and

and adding a redox initiator into the raw material solution, and reacting for 2-7 hours at 40-60 ℃ to obtain the colloidal polymer.

8. The method according to claim 7, wherein the mass of the reaction raw material is 20 to 45% of the mass of the raw material solution; and/or the number of the groups of groups,

the mass of the redox initiator is 0.2-1.2% of the mass of the reaction raw materials; and/or the number of the groups of groups,

the redox initiator includes potassium persulfate and sodium bisulfite.

9. A pH sensitive polyacrylamide flocculant comprising a polyacrylamide copolymer according to any one of claims 1 to 4, or a polyacrylamide copolymer produced by a method according to any one of claims 5 to 8.

10. Use of the polyacrylamide copolymer according to any one of claims 1 to 4 or the polyacrylamide copolymer produced by the method according to any one of claims 5 to 8 in wastewater treatment.