Functionalized polyacrylamide and preparation method thereof

Abstract

The invention relates to the field of polyacrylamide, in particular to functional polyacrylamide and a preparation method thereof.The functional polyacrylamide is prepared by copolymerization of an acrylamide monomer, an acryloylamino crown ether derivative, a nonionic monomer, an anionic monomer and / or a cationic monomer, an acrylamide structure and a crown ether structure are combined together to synthesize a crown ether monomer with a polymerizable acrylamide group, and the monomer is introduced into a polyacrylamide molecular chain to form a copolymerization product, so that during sewage treatment, heavy metal ions in water are effectively removed while suspended particles are aggregated as a flocculating agent, and the water quality is improved. The heavy metal content after treatment is reduced, and the water treatment agent with multiple effects is formed.

Description

Technical Field

[0001] The present invention relates to the field of polyacrylamide, and particularly to a functionalized polyacrylamide and a preparation method thereof. Background Art

[0002] Polyacrylamide is the most common water-soluble polymer, which is widely used in the fields of papermaking, water treatment, oil and gas exploitation, etc. Its excellent water solubility, viscosity-increasing ability, ultra-high molecular weight, etc. have attracted wide attention.

[0003] With the development of industrialization, the discharge of industrial wastewater containing heavy metals (such as arsenic, copper, chromium, cadmium, nickel, zinc, lead, mercury and manganese) has gradually increased; due to their non-biodegradability and long half-life, these heavy metals cause serious pollution in groundwater, surface water, soil and crops, seriously threatening the health of humans, animals and plants. At present, the research on the treatment technology of heavy metals in industrial wastewater includes physical and chemical methods and biological methods, and these methods have their own advantages and disadvantages. For example, physical and chemical methods have problems such as generating a large amount of sludge, low removal efficiency and high energy consumption; while biological methods strongly depend on pH and temperature, and have high requirements for energy and maintenance; in chemical methods, polyacrylamide is the most important and most used water treatment agent.

[0004] Therefore, a sewage treatment agent that can treat heavy metal ions in wastewater while realizing sewage treatment is a technical problem that needs to be solved currently. Summary of the Invention

[0005] The purpose of the present invention is to overcome the deficiencies of the prior art, and provide a functionalized polyacrylamide and a preparation method thereof. By combining the acrylamide structure with the crown ether structure, a kind of crown ether monomer with polymerizable acrylamide groups is synthesized. By introducing this monomer into the polyacrylamide molecular chain, a copolymer product is formed. When used in sewage treatment, as a flocculant, it can aggregate suspended particles while effectively removing heavy metal ions in water, reducing the heavy metal content after treatment, and forming a kind of water treatment agent with multiple effects in one agent.

[0006] The technical solution adopted by this application for this technical problem is as follows:

[0007] A functional polyacrylamide is prepared by copolymerizing acrylamide monomers with monomers having a crown ether structure, non-ionic monomers, anionic monomers and / or cationic monomers, and the structural formula is as follows:

[0008]

[0009] Wherein, a, b, c, d, and e are all natural numbers, and both a and b are greater than or equal to 1, and at least one of c, d, and e is greater than or equal to 1;

[0010] R1 has a crown ether structure; R2 is any one of methyl and H; R3, R4, and R5 are side group structures provided by any one of anionic monomers, cationic monomers, and nonionic monomers.

[0011] Further, the anionic monomer is selected from one or more of unsaturated organic acids and alkali metal salts thereof, such as fumaric acid, methacrylic acid, vinyl sulfonic acid, p-vinylbenzenesulfonic acid, maleic acid, vinylbenzenesulfonic acid, allyl sulfonic acid, allylbenzenesulfonic acid, 2-acrylamide-2-methylpropanesulfonic acid and alkali metal salts thereof; the cationic monomer is selected from one or more of unsaturated quaternary ammonium salts, such as methacryloyloxyethyl trimethylammonium chloride, 2-acrylamide-2-methylpropyl trimethylammonium chloride, dimethylethyl allyl ammonium chloride, dimethyl diallyl ammonium chloride, acryloyloxyethyl trimethyl ammonium chloride, acryloyloxyethyl dimethylbenzyl ammonium chloride, methacryloyloxyethyl dimethylbenzyl ammonium chloride; the nonionic monomer is selected from one or more of acrylamide derivatives without strong electric groups, such as methacrylamide, ethylacrylamide, hydroxymethylacrylamide, dimethylacrylamide, diethylacrylamide, hydroxyethylacrylamide, dimethylaminopropyl methacrylamide, and vinylpyrrolidone.

[0012] Furthermore, the initiation system of the functional polyacrylamide includes an oxidant, a reducing agent, and an azo initiator;

[0013] The reducing agent is selected from one or more of sodium bisulfite, sodium thiosulfate, and sodium pyrosulfite; the oxidizing agent is selected from one or more of persulfate, potassium persulfate, sodium persulfate, hydrogen peroxide, benzoyl peroxide, potassium bromate, and tert-butyl hydroperoxide; the azo initiator is selected from one or more of azobisisobutyronitrile, azobisisovaleronitrile, azobisisoheptanenitrile, dimethyl azobisisobutyrate, azobisisobutylamidine hydrochloride, 2,2'-azo[2-(2-imidazoline-2-yl)propane] dihydrochloride, azobis(2,5-dimethyl-6-carboxy)hexanenitrile, and 4,4'-azobis(4-cyanovaleric acid).

[0014] Furthermore, the functionalized polyacrylamide is applied in the water treatment process, and can effectively enrich the metal ions in the water and remove the metal ions by flocculation precipitation, and the crown ether side groups will not remain in the water to cause secondary pollution.

[0015] A method for preparing a functional polyacrylamide, used for preparing the above-mentioned functional polyacrylamide, comprises the following steps:

[0016] Step 1: Use an amino crown ether derivative and an acryloyl halide compound to synthesize an acryloyl amino crown ether derivative through an acylation reaction, and the structural formula thereof is as follows:

[0017]

[0018] Among them, R1 has a crown ether structure, and R1 may carry;

[0019] Step 2: Weigh acrylamide, anionic monomer, cationic monomer, non-ionic monomer, and the acryloylamino crown ether derivative obtained in Step 1, uniformly mix them in deionized water, and adjust the pH value between 7 and 8 to obtain a mixed solution;

[0020] Step 3: Preparation of initiator: Weigh 0.00001 - 0.0001 parts of oxidant, 0.00002 - 0.0001 parts of reductant, and 0.0001 - 0.0005 parts of azo initiator, and respectively prepare them into aqueous solutions;

[0021] Step 4; Cool the solution obtained in Step 2 to -2 - 3 °C, add the aqueous solution obtained in Step 3 in an inert gas, maintain the inert atmosphere until the viscosity of the system increases, seal until the temperature rise ends, and keep warm for 2 hours to obtain a gel-like product;

[0022] Step 5: Take out the gel-like product obtained in Step 4, granulate, dry, and pulverize to obtain a functional polyacrylamide product.

[0023] Furthermore, the monomer with a crown ether structure is prepared by the following steps:

[0024] Step 1a: Take an amino crown ether derivative and an acryloyl halide compound, react in a mixed solvent at 2 - 5 °C for 1 - 4 hours;

[0025] Step 1b: Distill the reactant obtained in Step 1a, remove the solvent and excess acryloyl halide compound to obtain an acryloylamino crown ether derivative.

[0026] Furthermore, the acryloyl halide compound is preferably acryloyl chloride.

[0027] Furthermore, in the reaction system of Step 1a, the molar ratio of the acryloyl halide compound to the amino crown ether derivative is 1.2:1, and the mixed solvent is dichloromethane and triethylamine with a mass ratio of 1:1.

[0028] The principle is as follows:

[0029]

[0030] Furthermore, in Step 2, a chelating agent is also included to eliminate the influence of trace metal ions in the monomer on polymerization, and the chelating agent is selected as disodium ethylenediaminetetraacetate.

[0031] Further, by weight, the mixed solution contains 20 - 60 parts of acrylamide, 0 - 25 parts of anionic monomer, 0 - 25 parts of cationic monomer, 0 - 25 parts of non-ionic monomer, 0.002 - 0.05 parts of chelating agent, 0.2 - 10 parts of the monomer with a crown ether structure obtained in Step 1, and 60 - 80 parts of deionized water.

[0032] Further, by weight, in Step 3, the three aqueous solutions respectively contain 0.00001 - 0.0001 parts of oxidizing agent, 0.00002 - 0.0001 parts of reducing agent, and 0.0001 - 0.0005 parts of azo initiator.

[0033] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0034] Compared with ordinary polyacrylamide, by introducing a crown ether structure into the side chain of polyacrylamide, when the polyacrylamide is used as a water treatment agent, it can not only play a flocculation role, but also effectively enrich and flocculate and remove metal ions in the solution, achieving multiple effects with one agent and endowing more functions and more beneficial effects in water treatment.

[0035] After treating the water simulating heavy metal pollution with the product of the present invention, the lead content in the water is less than 1 ppm, and the removal efficiency is high, which is better than the requirements of the latest environmental protection regulations. Description of the Drawings

[0036] Figure 1 is the nuclear magnetic resonance hydrogen spectrum of the functionalized polyacrylamide in Example 1 of the present invention;

[0037] Figure 2 is the nuclear magnetic resonance hydrogen spectrum of the functionalized polyacrylamide in Example 2 of the present invention;

[0038] Figure 3 is the nuclear magnetic resonance hydrogen spectrum of the functionalized polyacrylamide in Example 3 of the present invention;

[0039] Figure 4 is the nuclear magnetic resonance hydrogen spectrum of the functionalized polyacrylamide in Example 4 of the present invention;

[0040] Figure 5 is the nuclear magnetic resonance hydrogen spectrum of the functionalized polyacrylamide in Example 5 of the present invention;

[0041] Figure 6 is the nuclear magnetic resonance hydrogen spectrum of the functionalized polyacrylamide in Example 6 of the present invention. Detailed Embodiments

[0042] In order to make the objectives, technical solutions and advantages of the present invention more clear and understandable, the present invention will be further described in detail below in conjunction with specific embodiments. The reagents and raw materials used in the embodiments and comparative examples of the present invention can be obtained through commercial channels without special instructions.

[0043] The objective of the present invention is to combine the acrylamide structure with the crown ether structure to synthesize a class of crown ether monomers with polymerizable acrylamide groups. By introducing this monomer into the polyacrylamide molecular chain, a copolymer product is formed, enabling effective removal of heavy metal ions in water while aggregating suspended particles as a flocculant during sewage treatment, reducing the heavy metal content after treatment, and forming a class of water treatment agents with multiple effects in one agent.

[0044] Preparation of simulated water: Prepare simulated water with a lead ion content of 50 ppm using lead acetate, and add 0.5% bentonite to simulate suspended particles.

[0045] Example 1:

[0046] A functionalized polyacrylamide, which is prepared by copolymerizing acrylamide, acryloylaminomethyl 15-crown-5, and acrylic acid. Its structural formula is shown as follows;

[0047]

[0048] Among them, a, b, and c are all natural numbers greater than or equal to 1.

[0049] A method for preparing the above-mentioned functionalized polyacrylamide, comprising the following steps:

[0050] Preparation of a monomer with a crown ether structure:

[0051] Take aminomethyl 15-crown-5 and acryloyl chloride, and react in a mixed solution of dichloromethane and triethylamine at 3°C for 4 hours; among them, the molar ratio of acryloyl chloride to aminomethyl 15-crown-5 is 1.2:1, and the mass ratio of dichloromethane to triethylamine is 1:1;

[0052] After distilling off the solvent and excess acryloyl chloride from the reactants, acryloylaminomethyl 15-crown-5 is obtained.

[0053] The reaction mechanism is as follows:

[0054]

[0055] Then weigh 25 parts of acrylamide, 5 parts of acrylic acid, 3 parts of acryloylaminomethyl 15-crown-5, 0.002 parts of disodium ethylenediaminetetraacetate, 0.00005 parts of potassium persulfate, 0.00006 parts of sodium bisulfite, 0.0002 parts of azobisisobutyronitrile, and 60 parts of deionized water;

[0056] Acrylamide, acrylic acid, acrylamidomethyl 15-crown-5, and disodium ethylenediaminetetraacetate were added to deionized water to form a homogeneous solution, and the pH value was adjusted to be between 7 and 8 to obtain a mixed solution.

[0057] Potassium persulfate, sodium bisulfite, and azobisisobutyronitrile were respectively prepared as aqueous solutions.

[0058] The obtained mixed solution was cooled to -2 to 3 °C, transferred to a heat-insulating container, and nitrogen was introduced for 30 min to form an inert atmosphere.

[0059] The aqueous solutions of potassium persulfate, sodium bisulfite, and azobisisobutyronitrile were slowly added to the reaction system, and nitrogen was introduced until the system began to heat up. After the heating ended, it was kept warm for 1 h, and the colloidal product was collected.

[0060] The obtained colloid was pelletized, dried, and pulverized to obtain functionalized polyacrylamide.

[0061] The nuclear magnetic resonance hydrogen spectrum of the functionalized polyacrylamide is as Figure 1 shown.

[0062] The functionalized polyacrylamide was prepared as an aqueous solution of 6000 ppm, added to simulated water, and the ratio of the aqueous solution to the simulated water was 1:2. After stirring, it was allowed to stand and settle, and the supernatant was taken to measure the lead ion content, as shown in the attached table.

[0063] As Figure 1 shown in the product NMR spectrum, the highest peak is the solvent peak of water, 3.49 - 4.12 is the hydrogen on the crown ether, 1.4 - 2.5 is the hydrogen on the main chain, and the active hydrogen does not appear in water.

[0064] Example 2:

[0065] A functionalized polyacrylamide, which is copolymerized from acrylamide, acrylamidomethyl 18-crown-6, vinylpyrrolidone, and 2-acrylamido-2-methylpropanesulfonic acid, and its structural formula is as shown in the following figure;

[0066]

[0067] Among them, a, b, c, and e are all natural numbers greater than or equal to 1.

[0068] A method for preparing the above-mentioned functionalized polyacrylamide, comprising the following steps:

[0069] Prepare a monomer with a crown ether structure:

[0070] Take aminomethyl 18-crown-6 and acryloyl chloride, and react them in a mixed solution of dichloromethane and triethylamine at 5 °C for 1 hour. Among them, the molar ratio of acryloyl chloride to aminomethyl 18-crown-6 is 1.2:1, and the mass ratio of dichloromethane to triethylamine is 1:1.

[0071] After distilling off the solvent and excess acryloyl chloride from the reactants, acryloylaminomethyl 18-crown-6 is obtained.

[0072] The mechanism for preparing the monomer with a crown ether structure is the same as that in Example 1.

[0073] Then weigh 20 parts of acrylamide, 15 parts of 2-acrylamido-2-methylpropanesulfonic acid, 3 parts of vinylpyrrolidone, 2 parts of acryloylaminomethyl 18-crown-6, 0.004 parts of disodium ethylenediaminetetraacetate, 0.00007 parts of potassium bromate, 0.00009 parts of sodium thiosulfate, 0.00015 parts of azodiisopentanenitrile, and 70 parts of deionized water.

[0074] Add acrylamide, 2-acrylamido-2-methylpropanesulfonic acid, vinylpyrrolidone, acryloylaminomethyl 18-crown-6, and disodium ethylenediaminetetraacetate to deionized water to prepare a homogeneous solution, and adjust the pH value to be between 7 and 8 to obtain a mixed solution.

[0075] Prepare aqueous solutions of potassium bromate, sodium thiosulfate, and azodiisopentanenitrile respectively.

[0076] Cool the obtained mixed solution to -2 to 3 °C, transfer it to a heat-insulating container, and introduce nitrogen for 30 minutes to form an inert atmosphere.

[0077] Slowly add the aqueous solutions of potassium bromate, sodium thiosulfate, and azodiisopentanenitrile to the reaction system, introduce nitrogen until the system starts to heat up, keep the temperature for 1 hour after the heating ends, and collect the colloidal product.

[0078] Cut, dry, and crush the obtained colloid to obtain functionalized polyacrylamide.

[0079] The nuclear magnetic resonance hydrogen spectrum of the functionalized polyacrylamide is as Figure 2 shown.

[0080] Prepare an aqueous solution of the functionalized polyacrylamide with a concentration of 6000 ppm, add it to simulated water, and the ratio of the aqueous solution to the simulated water is 1:2. Stir and then let it stand for sedimentation. Take the supernatant and test the lead ion content as shown in the attached table.

[0081] As Figure 2The product NMR spectrum is shown. The highest peak is the solvent peak of water. The hydrogens on the crown ether are in the range of 3.49 - 4.12, the hydrogens on the main chain are in the range of 1.4 - 2.5, the hydrogens of pyrrolidone are at 1.9 and 2.2, and there is also a peak of the hydrogen on 2 - acrylamido - 2 - methylpropanesulfonic acid at 1.47. The active hydrogen does not show a peak in water.

[0082] Example 3:

[0083] A functionalized polyacrylamide, which is prepared by copolymerizing acrylamide, 4 - acrylamidoaminobenzo - 18 - crown - 6, and methacryloyloxyethyltrimethylammonium chloride. Its structural formula is shown as follows;

[0084]

[0085] Among them, a, b, and d are all natural numbers greater than or equal to 1.

[0086] A method for preparing the above - mentioned functionalized polyacrylamide, comprising the following steps:

[0087] Prepare a monomer with a crown ether structure:

[0088] Take 4'-aminobenzo - 18 - crown - 6 and acryloyl chloride, and react in a mixed solution of dichloromethane and triethylamine at 4°C for 2 hours. Among them, the molar ratio of acryloyl chloride to 4 - acrylamidoaminobenzo - 18 - crown - 6 is 1.2:1, and the mass ratio of dichloromethane to triethylamine is 1:1;

[0089] After distilling off the solvent and excess acryloyl chloride from the reactants, acryloyl - 4 - aminomethyl - 18 - crown - 6 is obtained.

[0090] The mechanism for preparing the monomer with a crown ether structure is the same as that in Example 1.

[0091] Then weigh 30 parts of acrylamide, 7 parts of methacryloyloxyethyltrimethylammonium chloride, 3 parts of acryloyl - 4 - aminomethyl - 18 - crown - 6, 0.005 part of disodium ethylenediaminetetraacetate, 0.00008 part of sodium persulfate, 0.00009 part of sodium metabisulfite, 0.0002 part of 2,2'-azobis(2 - methylheptanenitrile), and 65 parts of deionized water;

[0092] Add acrylamide, methacryloyloxyethyltrimethylammonium chloride, acryloyl - 4 - aminomethyl - 18 - crown - 6, and disodium ethylenediaminetetraacetate to deionized water to prepare a homogeneous solution, and adjust the pH value to be between 7 and 8 to obtain a mixed solution;

[0093] Prepare aqueous solutions of sodium persulfate, sodium metabisulfite, and 2,2'-azobis(2 - methylheptanenitrile) respectively;

[0094] Cool the obtained mixed solution to -2 to 3 °C, transfer it to a heat-insulated container, and introduce nitrogen for 30 min to form an inert atmosphere;

[0095] Slowly add an aqueous solution of sodium persulfate, sodium metabisulfite, and 2,2'-azobis(2-methylbutyronitrile) to the reaction system, and introduce nitrogen until the system starts to heat up. After the heating is completed, keep it warm for 1 h, and collect the colloidal product;

[0096] Cut, dry, and pulverize the obtained colloid to obtain functionalized polyacrylamide.

[0097] The nuclear magnetic resonance hydrogen spectrum of the functionalized polyacrylamide is as Figure 3 shown.

[0098] Prepare an aqueous solution of the functionalized polyacrylamide at 6000 ppm, add it to the simulated water, and the ratio of the aqueous solution to the simulated water is 1:2. After stirring, let it stand for sedimentation, take the supernatant, and test the lead ion content therein, as shown in the attached table.

[0099] As Figure 3 shown is the NMR spectrum of the product. The highest peak is the solvent peak of water. The hydrogen on the crown ether is at 3.49 - 4.12, the hydrogen on the main chain is at 1.4 - 2.5, the hydrogen on the benzene ring is around 6.7 - 7.2, and there are also peaks of hydrogen on the cationic monomer at 3.3 - 3.5 and 4.5. The active hydrogen does not appear in water.

[0100] Example 4:

[0101] A functionalized polyacrylamide, which is prepared by copolymerizing acrylamide, acryloylaminomethyl 15-crown-5, and methacrylamide, and its structural formula is as shown in the following figure;

[0102]

[0103] Among them, a, b, and e are all natural numbers greater than or equal to 1.

[0104] A method for preparing the above-mentioned functionalized polyacrylamide, comprising the following steps:

[0105] Prepare a monomer with a crown ether structure:

[0106] Take aminomethyl 15-crown-5 and acryloyl chloride, and react in a mixed solution of dichloromethane and triethylamine at 2 °C for 3 hours; among them, the molar ratio of acryloyl chloride to aminomethyl 15-crown-5 is 1.2:1, and the mass ratio of dichloromethane to triethylamine is 1:1;

[0107] After distilling off the solvent and excess acryloyl chloride from the reactants, acryloylaminomethyl 15-crown-5 is obtained.

[0108] The reaction mechanism is as follows:

[0109]

[0110] Then, weigh 25 parts of acrylamide, 7.5 parts of methacrylamide, 3 parts of acrylamidomethyl 15-crown-5, 0.005 part of disodium ethylenediaminetetraacetate, 0.0001 part of potassium persulfate, 0.0001 part of sodium bisulfite, 0.0005 part of azobisisobutyronitrile, and 75 parts of deionized water;

[0111] Add acrylamide, methacrylamide, acrylamidomethyl 15-crown-5, and disodium ethylenediaminetetraacetate to deionized water to prepare a homogeneous solution, and adjust the pH value to be between 7 and 8 to obtain a mixed solution;

[0112] Prepare aqueous solutions of potassium persulfate, sodium bisulfite, and azobisisobutyronitrile respectively;

[0113] Cool the obtained mixed solution to -2 to 3 °C, transfer it to a heat-insulating container, and introduce nitrogen for 30 min to form an inert atmosphere;

[0114] Slowly add the aqueous solutions of potassium persulfate, sodium bisulfite, and azobisisobutyronitrile to the reaction system, introduce nitrogen until the system starts to heat up, keep the temperature for 1 h after the heating ends, and collect the colloidal product;

[0115] Cut, dry, and pulverize the obtained colloid to obtain functionalized polyacrylamide.

[0116] The nuclear magnetic resonance hydrogen spectrum of the functionalized polyacrylamide is as Figure 4 shown.

[0117] Prepare an aqueous solution of the functionalized polyacrylamide at 6000 ppm, add it to simulated water, and the ratio of the aqueous solution to the simulated water is 1:2. Stir and then let it stand for sedimentation. Take the supernatant and test the lead ion content in it, as shown in the attached table.

[0118] As Figure 4 shown is the nuclear magnetic spectrum of the product. The highest peak is the solvent peak of water, the hydrogen on the crown ether is at 3.49 - 4.12, the hydrogen on the main chain is at 1.4 - 2.5, the peak of the side methyl of methacrylamide is at 1.2, and the active hydrogen does not peak in water.

[0119] Example 5:

[0120] A functionalized polyacrylamide is copolymerized from acrylamide, acrylamidomethyl 18-crown-6, dimethyldiallylammonium chloride, and p-vinylbenzenesulfonic acid, and its structural formula is as shown in the following figure;

[0121]

[0122] Among them, a, b, c, and d are all natural numbers greater than or equal to 1.

[0123] A method for preparing the above functionalized polyacrylamide, comprising the following steps:

[0124] Preparing a monomer with a crown ether structure:

[0125] Taking aminomethyl 18-crown-6 and acryloyl chloride, reacting in a mixed solution of dichloromethane and triethylamine at 3 °C for 2 hours; wherein, the molar ratio of acryloyl chloride to aminomethyl 18-crown-6 is 1.2:1, and the mass ratio of dichloromethane to triethylamine is 1:1;

[0126] After distilling off the solvent and excess acryloyl chloride from the reactants, acryloylaminomethyl 18-crown-6 is obtained.

[0127] The mechanism for preparing the monomer with a crown ether structure is the same as in Example 1.

[0128] Then weigh 30 parts of acrylamide, 25 parts of p-vinylbenzenesulfonic acid, 12.5 parts of dimethyldiallylammonium chloride, 5 parts of acryloylaminomethyl 18-crown-6, 0.035 parts of disodium ethylenediaminetetraacetate, 0.00005 parts of potassium bromate, 0.00007 parts of sodium thiosulfate, 0.0001 parts of azodiisopentanenitrile, and 70 parts of deionized water;

[0129] Adding acrylamide, p-vinylbenzenesulfonic acid, dimethyldiallylammonium chloride, acryloylaminomethyl 18-crown-6, and disodium ethylenediaminetetraacetate to deionized water to form a homogeneous solution, and adjusting the pH value to be between 7 and 8 to obtain a mixed solution;

[0130] Preparing aqueous solutions of potassium bromate, sodium thiosulfate, and azodiisopentanenitrile respectively;

[0131] Cooling the obtained mixed solution to -2 to 3 °C, transferring it to a heat-insulating container, and introducing nitrogen for 30 minutes to form an inert atmosphere;

[0132] Slowly adding the aqueous solutions of potassium bromate, sodium thiosulfate, and azodiisopentanenitrile to the reaction system, introducing nitrogen until the system starts to heat up, keeping warm for 1 h after the heating ends, and collecting the colloidal product;

[0133] Performing pelletizing, drying, and pulverizing on the obtained colloid to obtain the functionalized polyacrylamide.

[0134] The nuclear magnetic resonance hydrogen spectrum of the functionalized polyacrylamide is as Figure 5 shown.

[0135] The functionalized polyacrylamide was configured into an aqueous solution with a concentration of 6000 ppm and added to the simulated water. The ratio of the aqueous solution to the simulated water was 1:2. After stirring, it was allowed to stand for sedimentation, and the supernatant was taken to test the lead ion content, as shown in the attached table.

[0136] As Figure 5 shown in the product NMR spectrum, the highest peak is the solvent peak of water, the hydrogen on the crown ether is at 3.49 - 4.12, the hydrogen on the main chain is at 1.4 - 2.5, the hydrogen on the benzene ring is around 7.6 - 7.8, and there is a peak of hydrogen on the cationic monomer at 3.3. The active hydrogen does not appear in the water peak.

[0137] Example 6:

[0138] A functionalized polyacrylamide, which is copolymerized from acrylamide, 4 - acrylamidobenzo - 18 - crown - 6, and acryloyloxyethyltrimethylammonium chloride, and its structural formula is shown as follows;

[0139]

[0140] Among them, a, c, and d are all natural numbers greater than or equal to 1.

[0141] A method for preparing the above - mentioned functionalized polyacrylamide, comprising the following steps:

[0142] Preparing a monomer with a crown ether structure:

[0143] Taking 4'-aminobenzo - 18 - crown - 6 and acryloyl chloride, reacting in a mixed solution of dichloromethane and triethylamine at 2°C for 4 hours; among them, the molar ratio of acryloyl chloride to 4 - acrylamidobenzo - 18 - crown - 6 is 1.2:1, and the mass ratio of dichloromethane to triethylamine is 1:1;

[0144] After distilling off the solvent and excess acryloyl chloride from the reactants, acryloyl - 4 - aminomethyl - 18 - crown - 6 is obtained.

[0145] The mechanism for preparing the monomer with a crown ether structure is the same as that in Example 1.

[0146] Then, 27 parts of acrylamide, 17 parts of acryloyloxyethyltrimethylammonium chloride, 6.5 parts of acryloyl - 4 - aminomethyl - 18 - crown - 6, 0.04 part of disodium ethylenediaminetetraacetate, 0.00005 part of sodium persulfate, 0.00007 part of sodium metabisulfite, 0.0003 part of 2,2'-azobis(2 - methylheptanenitrile), and 70 parts of deionized water were weighed;

[0147] Acrylamide, acryloyloxyethyltrimethylammonium chloride, acryloyl - 4 - aminomethyl - 18 - crown - 6, and disodium ethylenediaminetetraacetate were added to deionized water to form a homogeneous solution, and the pH value was adjusted between 7 and 8 to obtain a mixed solution;

[0148] Sodium persulfate, sodium metabisulfite, and 2,2'-azobis(2-methylheptanenitrile) were respectively prepared as aqueous solutions.

[0149] The obtained mixed solution was cooled to -2 to 3 °C, transferred to a heat-insulating container, and nitrogen was introduced for 30 min to form an inert atmosphere.

[0150] The aqueous solutions of sodium persulfate, sodium metabisulfite, and 2,2'-azobis(2-methylheptanenitrile) were slowly added to the reaction system. Nitrogen was passed until the system began to warm up. After the temperature rise ended, it was kept warm for 1 h, and the colloidal product was collected.

[0151] The obtained colloid was pelletized, dried, and pulverized to obtain functionalized polyacrylamide.

[0152] The 1H NMR spectrum of the functionalized polyacrylamide is as Figure 6 shown.

[0153] The functionalized polyacrylamide was prepared as an aqueous solution of 6000 ppm, added to simulated water, and the ratio of the aqueous solution to simulated water was 1:2. After stirring, it was allowed to stand and settle. The supernatant was taken, and the lead ion content in it was measured, as shown in the attached table.

[0154] As Figure 6 shown in the product NMR spectrum, the highest peak is the solvent peak of water, 3.49 - 4.12 is the hydrogen on the crown ether, 1.4 - 2.5 is the hydrogen on the main chain, around 6.7 - 7.2 is the hydrogen on the benzene ring, and there are peaks of hydrogen on the cationic monomer at 3.3, 3.5, and 4.5. The active hydrogen does not appear in water.

[0155] Comparative Example 1:

[0156] A method for preparing the above-mentioned functionalized polyacrylamide includes the following steps:

[0157] Weigh 25 parts of acrylamide, 5 parts of acrylic acid, 0.002 parts of disodium ethylenediaminetetraacetate, 0.00005 parts of potassium persulfate, 0.00009 parts of sodium bisulfite, 0.0002 parts of 2,2'-azobis(2-methylpropionitrile), and 70 parts of deionized water;

[0158] Acrylamide, acrylic acid, and disodium ethylenediaminetetraacetate were added to deionized water to prepare a homogeneous solution, and the pH value was adjusted to be between 7 and 8 to obtain a mixed solution;

[0159] Potassium persulfate, sodium bisulfite, and 2,2'-azobis(2-methylpropionitrile) were respectively prepared as aqueous solutions;

[0160] The obtained mixed solution was cooled to -2 to 3 °C, transferred to a heat-insulating container, and nitrogen was introduced for 30 min to form an inert atmosphere;

[0161] Slowly add an aqueous solution of potassium persulfate, sodium bisulfite, and azodiisobutyronitrile to the reaction system, and pass nitrogen until the system starts to heat up. After the heating is completed, keep the temperature for 1 h, and collect the colloidal product;

[0162] Cut, dry, and pulverize the obtained colloid to obtain functionalized polyacrylamide.

[0163] Prepare an aqueous solution of the functionalized polyacrylamide at 6000 ppm, add it to the simulated water, with the ratio of the aqueous solution to the simulated water being 1:2. After stirring, let it stand for sedimentation, take the supernatant, and test the lead ion content therein, as shown in the attached table.

[0164] Comparative Example 2:

[0165] A method for preparing the above-mentioned functionalized polyacrylamide includes the following steps:

[0166] Weigh 20 parts of acrylamide, 15 parts of 2-acrylamido-2-methylpropanesulfonic acid, 3 parts of vinylpyrrolidone, 0.004 parts of disodium ethylenediaminetetraacetate, 0.00007 parts of potassium bromate, 0.00009 parts of sodium thiosulfate, 0.00015 parts of azodiisovaleronitrile, and 70 parts of deionized water;

[0167] Add acrylamide, 2-acrylamido-2-methylpropanesulfonic acid, vinylpyrrolidone, and disodium ethylenediaminetetraacetate to deionized water to prepare a homogeneous solution, and adjust the pH value to be between 7 and 8 to obtain a mixed solution;

[0168] Prepare aqueous solutions of potassium bromate, sodium thiosulfate, and azodiisovaleronitrile respectively;

[0169] Cool the obtained mixed solution to -2 to 3 °C, transfer it to a heat-insulating container, and pass nitrogen for 30 min to form an inert atmosphere;

[0170] Slowly add the aqueous solutions of potassium bromate, sodium thiosulfate, and azodiisovaleronitrile to the reaction system, and pass nitrogen until the system starts to heat up. After the heating is completed, keep the temperature for 1 h, and collect the colloidal product;

[0171] Cut, dry, and pulverize the obtained colloid to obtain functionalized polyacrylamide.

[0172] Prepare an aqueous solution of the functionalized polyacrylamide at 6000 ppm, add it to the simulated water, with the ratio of the aqueous solution to the simulated water being 1:2. After stirring, let it stand for sedimentation, take the supernatant, and test the lead ion content therein, as shown in the attached table.

[0173] Comparative Example 3:

[0174] A method for preparing the above-mentioned functionalized polyacrylamide includes the following steps:

[0175] Weigh 30 parts of acrylamide, 7 parts of methacryloyloxyethyl trimethyl ammonium chloride, 0.005 part of disodium ethylenediaminetetraacetate, 0.00008 part of sodium persulfate, 0.00009 part of sodium metabisulfite, 0.0002 part of 2,2'-azobis(2-methylheptonitrile) and 65 parts of deionized water;

[0176] Add acrylamide, methacryloyloxyethyl trimethyl ammonium chloride, and disodium ethylenediaminetetraacetate into deionized water to prepare a homogeneous solution, and adjust the pH value between 7 and 8 to obtain a mixed solution;

[0177] Prepare aqueous solutions of sodium persulfate, sodium metabisulfite, and 2,2'-azobis(2-methylheptonitrile) respectively;

[0178] Cool the obtained mixed solution to -2 to 3 °C, transfer it to a heat-insulating container, and introduce nitrogen for 30 minutes to form an inert atmosphere;

[0179] Slowly add the aqueous solutions of sodium persulfate, sodium metabisulfite, and 2,2'-azobis(2-methylheptonitrile) to the reaction system, introduce nitrogen until the system starts to heat up, keep the temperature for 1 hour after the heating ends, and collect the colloidal product;

[0180] Cut, dry, and crush the obtained colloid to obtain functionalized polyacrylamide.

[0181] Prepare an aqueous solution of the functionalized polyacrylamide at 6000 ppm, add it to the simulated water, and the ratio of the aqueous solution to the simulated water is 1:2. Stir and then let it stand for sedimentation. Take the supernatant and test the lead ion content as shown in the attached table.

[0182] Except for the performance of the samples in the examples and comparative examples in the table

[0183] Lead content after treatment, ppm Example 1 0.21 Example 2 0.17 Example 3 0.23 Example 4 0.19 Example 5 0.21 Example 6 0.20 Comparative Example 1 43 Comparative Example 2 39 Comparative Example 3 47

[0184] Result analysis: It can be clearly seen from the above table that in the aqueous solutions treated by the six samples in the examples, the lead content is lower than 1 ppm, which is less than the requirements of the latest environmental protection regulations. In the comparative examples, there is basically no significant decrease. The small decrease is mainly due to the adsorption of a small amount of lead by bentonite and the subsequent flocculation and sedimentation by polyacrylamide.

[0185] It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

Claims

1. A functional polyacrylamide, characterized in that: The functional polyacrylamide is prepared by copolymerization of acrylamide monomer, acrylamide amino crown ether derivative, nonionic monomer, anionic monomer and / or cationic monomer, and has the following structural formula: Wherein, a, b, c, d, e are all natural numbers, and a and b are both greater than or equal to 1, and at least one of c, d, e is greater than or equal to 1; R1 has a crown ether structure; R2 is any one of methyl and H; R3, R4, and R5 are side group structures provided by any one of anionic monomers, cationic monomers, or nonionic monomers.

2. The functional polyacrylamide according to claim 1, characterized in that The anionic monomer is selected from one or more unsaturated organic acids and alkali metal salts thereof; the cationic monomer is selected from one or more unsaturated quaternary ammonium salts; and the nonionic monomer is selected from one or more acrylamide derivatives without strong electric groups.

3. The functional polyacrylamide according to claim 1, characterized in that: The initiation system of the functional polyacrylamide includes an oxidant, a reducing agent, and an azo initiator; The reducing agent is selected from one or more of sodium bisulfite, sodium thiosulfate, and sodium pyrosulfite; the oxidizing agent is selected from one or more of persulfate, potassium persulfate, sodium persulfate, hydrogen peroxide, benzoyl peroxide, potassium bromate, and tert-butyl hydroperoxide; the azo initiator is selected from one or more of azobisisobutyronitrile, azobisisovaleronitrile, azobisisoheptanenitrile, dimethyl azobisisobutyrate, azobisisobutylamidine hydrochloride, 2,2'-azo[2-(2-imidazoline-2-yl)propane] dihydrochloride, azobis(2,5-dimethyl-6-carboxy)hexanenitrile, and 4,4'-azobis(4-cyanovaleric acid).

4. The functional polyacrylamide according to any one of claims 1 to 3, characterized in that: Application in water treatment.

5. A method for preparing the functional polyacrylamide according to any one of claims 1 to 3, characterized in that: The following steps are involved: Step 1: Use an amino crown ether derivative and an acryloyl halide compound to synthesize an acryloyl amino crown ether derivative through an acylation reaction, and the structural formula thereof is as follows: wherein R1 has a crown ether structure; Step 2: weigh acrylamide, anionic monomer, cationic monomer, nonionic monomer, and the acryloylamino crown ether derivative obtained in step 1, mix them evenly in deionized water, and adjust the pH value to between 7 and 8 to obtain a mixed solution; Step 3: Initiator preparation: weigh 0.00001-0.0001 parts of oxidant, 0.00002-0.0001 parts of reducing agent, and 0.0001-0.0005 parts of azo initiator, and prepare them into aqueous solutions respectively; Step 4: Cool the solution obtained in step 2 to -2 to 3°C, add the aqueous solution obtained in step 3 in an inert gas, maintain the inert atmosphere until the viscosity of the system increases, seal until the heating is completed, and keep warm for 2 hours to obtain a gel product; Step 5: Take out the gel product obtained in step 4, granulate, dry and crush to obtain a functional polyacrylamide product.

6. The method for preparing functional polyacrylamide according to claim 5, characterized in that: The monomer having a crown ether structure is prepared by the following steps: Step 1a: Take an amino crown ether derivative and an acryloyl halide compound, react in a mixed solvent at 2-5° C. for 1-4 hours; Step 1b: distilling the reactant obtained in step 1a to remove the solvent and excess acryloyl halide compound to obtain an acryloylamino crown ether derivative.

7. The method for preparing functional polyacrylamide according to claim 6, characterized in that: In the reaction system of step 1a, the molar ratio of the acryloyl halide compound to the amino crown ether derivative is 1.2:1, and the mixed solvent is dichloromethane and triethylamine in a mass ratio of 1:

1.

8. The method for preparing functional polyacrylamide according to claim 5, characterized in that: The step 2 also includes a chelating agent, and the chelating agent is disodium ethylenediaminetetraacetate.

9. The method for preparing functional polyacrylamide according to claim 8, characterized in that: The mixed solution contains 20-60 parts of acrylamide, 0-25 parts of anionic monomers, 0-25 parts of cationic monomers, 0-25 parts of nonionic monomers, 0.002-0.05 parts of chelating agents, 0.2-10 parts of the monomer with crown ether structure obtained in step 1, and 60-80 parts of deionized water.

10. The method for preparing functional polyacrylamide according to claim 5, characterized in that: In step 3, the three aqueous solutions respectively contain 0.00001 to 0.0001 parts of an oxidant, 0.00002 to 0.0001 parts of a reducing agent, and 0.0001 to 0.0005 parts of an azo initiator.

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