CN102603970B - Preparation method of cationic polyacrylamide - Google Patents

Abstract

The invention relates to a preparation method of cationic polyacrylamide. In the present invention, a certain amount of solubilizer and complexing agent are added to acrylamide (AM) and two cationic monomer aqueous solutions to adjust the pH value of the reaction system, and then a certain amount of initiator is added. It is formed by polymerization reaction. The invention has the advantages that the polymerization reaction time is short, the types of additives are few, and the prepared product has high purity and is non-toxic and harmless. The cationic polyacrylamide obtained in the present invention has multi-functionality, the molecular weight can reach 1 million to 12 million, and the residual acrylamide monomer concentration is extremely low. It is suitable for drinking water, sewage treatment and sludge dehydration treatment, and has a good application prospect .

Description

A kind of preparation method of cationic polyacrylamide

technical field

The invention relates to a method for preparing an aqueous solution polymer, in particular to a method for preparing a cationic polyacrylamide.

Background technique

At present, the flocculants used in sewage treatment plants mainly include inorganic flocculants and organic polymer flocculants. Polyacrylamide flocculant is an important organic polymer flocculant, including cationic polyacrylamide (CPAM), anionic polyacrylamide (APAM), nonionic polyacrylamide (NPAM) and zwitterionic polyacrylamide; among them, Cationic polyacrylamide (CPAM) is its high-end product. It has the advantages of excellent turbidity removal and decolorization performance. Most of the products produced by the current preparation method are affected by the use of too many additives, which affects the purity of the product and the synthesis reaction is insufficient. The monomer content is relatively large, and the residual monomer content of acrylamide after refining is still greater than 0.05%. It is not suitable for drinking water treatment, but only suitable for industrial sewage, urban domestic sewage treatment and sludge dehydration treatment of urban sewage treatment plants.

The existing cationic polyacrylamide is prepared by using acrylamide as raw material through copolymerization or modification reaction with cationic monomers. For example, in the patent "Preparation Method of High Molecular Weight Instant Cationic Polyacrylamide" whose publication number is CN101353392A, the patent is to dissolve acrylamide and comonomer in deionized water; , poured on a flat surface and spread into flakes, and high-purity nitrogen gas is passed through, and then ultraviolet light is irradiated on the spread into flakes. The disadvantages of this method are: 1. The reaction polymerization time is long, preferably 3 to 6 hours; 2. In addition to the initiator, six kinds of auxiliary agents such as chelating agent, chain extender and chain transfer agent are added in the additive in the reaction aqueous solution. , surfactants, etc., and each additive also includes one or several substances, and the total dosage of various additives can be as high as 1.95% of the total monomer mass. Various additives will eventually remain in the synthetic product, which is not easy to remove and seriously affect the purity of the product; 3. Some substances in the additives are highly toxic and not suitable for production and application, such as the chain extender boric acid itself can be used as a trauma Disinfectant, oral administration can cause acute poisoning, mainly manifested as gastrointestinal symptoms, such as nausea, vomiting, abdominal pain, diarrhea, etc. It cannot be used as a raw material for water treatment agents and is used in water treatment. It has the potential to cause pollution to water bodies Toxicity; chain regulator diethylenetriamine, triethylenediamine, its vapor or mist are corrosive to the nose, throat and mucous membranes, production personnel need to wear gas masks.

Contents of the invention

The technical problem to be solved by the present invention is to provide a method of cationic polyacrylamide, the polymerization reaction time is short in the preparation process of the method, the types of additives are added and the dosage is low, and the prepared product is high in purity, non-toxic and harmless.

The technical problem to be solved by the present invention is realized by such technical scheme, and it comprises the following steps:

The first step is to weigh 20% to 80% of the monomer acrylamide and 20% to 80% of the two cationic monomers according to the total mass percentage of the monomer; add distilled water and stir until it is completely dissolved to prepare the mass of the total monomer Monomer aqueous solution with a concentration of 20% to 50%;

In the second step, add 0.05% to 0.5% of urea with the total mass of the monomers to the aqueous monomer solution prepared above, and then add 0.01% to 0.2% of the ethylenediaminetetraacetic acid complexing agent with the total mass of the monomers. Weak base or weak acid adjusts the pH value of the system to 8-9, fills high-purity nitrogen to remove oxygen, and quickly adds 0.1% to 3% of the total mass of the monomer Initiator, the initiator includes the oxidizing agent potassium persulfate or ammonium persulfate and The reducing agent is sodium sulfite, the mass ratio of the oxidizing agent to the reducing agent is in the range of 0.5 to 2, and at the same time, it is stirred evenly, and then filled with high-purity nitrogen to remove oxygen and then sealed;

The third step is to put the above-mentioned prepared mixture into the ultraviolet light reaction device at the indoor ambient temperature, and initiate it under ultraviolet light irradiation. After irradiating for 10 minutes to 90 minutes, let it stand and mature for more than 1 hour to obtain a colorless and transparent cationic polyacrylamide colloid;

In the fourth step, the cationic polyacrylamide viscous colloid is shredded and granulated, repeatedly washed and refined with absolute ethanol, dried and ground to obtain a white solid powder of cationic polyacrylamide.

The initiator used in the present invention can also be an organic initiator or an inorganic-organic composite initiator.

The materials used in the present invention are all commercially available with low price and can be purchased directly.

Since the initiating system selected by the present invention is ultraviolet light with a shorter wavelength, its energy is greater than the chemical bond energy of the monomer, which can initiate monomer polymerization in a long period of time, and the reaction rate is greatly improved after adding initiator and auxiliary agent, and the required With low dosage of initiator and auxiliary agent, a product with high purity and uniform molecular weight distribution can be obtained. The present invention has the following advantages:

1. The polymerization reaction time is short. Since the present invention uses ultraviolet light to initiate polymerization, ultraviolet light can accelerate the breaking of chemical bonds through free radical polymerization, so the initiation polymerization time can be greatly shortened, and the initiation polymerization time is at least 10 minutes.

2. The initiators and additives required for the synthesis are few in type and low in dosage, with few residues in the product and high purity of the product; the additives used are non-toxic and harmless, and the product is safe to use and suitable for drinking water treatment.

Detailed ways

The present invention will be further described below in conjunction with embodiment:

Example 1:

In the first step, weigh 7g of monomer acrylamide, 2g of dimethyldiallyl ammonium chloride, and 1g of acryloyloxyethyltrimethylammonium chloride into a jar, add 23.3ml of distilled water, and stir well , prepare the monomer aqueous solution that the mass concentration of total monomer is 30%;

In the second step, add 0.02 g of urea as a solubilizer (0.2% of the total mass of the monomer) to the aqueous monomer solution prepared above, and then add 0.004 g of ethylenediaminetetraacetic acid complexing agent (0.2% of the total mass of the monomer) 0.04% of the mass), adjust the pH=9; pass nitrogen to remove oxygen, add 0.144g of inorganic initiator (the mass ratio of potassium persulfate to sodium sulfite is 1:2), the dosage is 1.44% of the total mass of the monomer, stir evenly, Nitrogen was added to remove oxygen, and then airtight.

The third step is to put the above-prepared mixture into the ultraviolet light reaction device at the ambient temperature of the room. After irradiating ultraviolet light for 15 minutes, a colorless and transparent cationic polyacrylamide colloid is obtained; the residual monomer content of acrylamide is 0.1870 %, it can be directly used for sludge dewatering after dilution.

In the fourth step, the cationic polyacrylamide colloid is crushed and granulated, refined, dried, and ground to obtain a white solid powder of cationic polyacrylamide; the measured molecular weight is 4747241, and the cationic degree is 10.86%. High-purity product with amide residual monomer content of 0.0153%. It is suitable for drinking water treatment and sludge dehydration treatment.

Example 2

In the first step, weigh 8g of monomer acrylamide, 1g of methacryloyloxyethyltrimethylammonium chloride, and 1g of dimethyldiallylammonium chloride into a jar, add 10ml of distilled water, and stir Uniform, prepare the monomer aqueous solution whose mass concentration of total monomer is 50%;

In the second step, add 0.05g of urea as a solubilizer (0.5% of the total mass of the monomer) to the aqueous monomer solution prepared above, and then add 0.02g of ethylenediaminetetraacetic acid complexing agent (0.5% of the total mass of the monomer) 0.2% of the mass), adjust the pH=8; pass nitrogen to remove oxygen, add 0.015g of inorganic initiator (the mass ratio of ammonium persulfate to sodium sulfite is 2:1, the dosage is 0.15% of the total mass of the monomer), stir evenly, Then pass nitrogen gas to remove oxygen, and then airtight;

The third step is to put the above-prepared mixture into the ultraviolet light reaction device at the indoor ambient temperature. After 10 minutes of ultraviolet light irradiation, a colorless and transparent cationic polyacrylamide colloid is obtained; the residual monomer content of acrylamide is 0.2262 %, it can be directly used for sludge dewatering after dilution.

In the fourth step, the cationic polyacrylamide colloid is crushed and granulated, refined, dried, and ground to obtain a white solid powder of cationic polyacrylamide; the measured molecular weight is 1280500, and the cationic degree is 3.37%. It is a high-purity product with amide residual monomer content of 0.0197%, suitable for drinking water treatment and sludge dehydration treatment.

Example 3

In the first step, weigh 7g of monomer acrylamide, 1.5g of methacryloxyethyltrimethylammonium chloride, and 1.5g of dimethyldiallylammonium chloride into a jar, add 30ml of distilled water , stir evenly, prepare the monomer aqueous solution that the mass concentration of total monomer is 25%;

In the second step, add 0.005g of urea as a solubilizer (0.05% of the total mass of the monomer) to the aqueous monomer solution prepared above, and then add 0.001g of ethylenediaminetetraacetic acid complexing agent (0.05% of the total mass of the monomer) 0.01% of the mass of the monomer), adjust the pH=6; pass through nitrogen to remove oxygen, add 0.12g of organic initiator azobisisobutylamidine hydrochloride V50 (the amount is 1.2% of the total mass of the monomer), stir evenly, and pass through Into nitrogen to remove oxygen, then airtight;

The third step is to put the above-prepared mixture into the ultraviolet light reaction device at the indoor ambient temperature. After irradiating with ultraviolet light for 60 minutes, a colorless and transparent cationic polyacrylamide colloid is obtained; the residual monomer content of acrylamide is 0.1221 %; It can be directly used for sludge dehydration after dilution.

In the fourth step, the cationic polyacrylamide colloid is crushed, granulated, refined, dried, and ground to obtain a white solid powder of cationic polyacrylamide; the measured molecular weight is 4051330, and the cationic degree is 10.98%. It is a high-purity product with amide residual monomer content of 0.0107%, suitable for drinking water treatment and sludge dehydration treatment.

Example 4

In the first step, weigh 2g of monomer acrylamide, 4g of dimethyldiallyl ammonium chloride, and 4g of acryloyloxyethyltrimethylammonium chloride into a jar, add 30ml of distilled water, and stir evenly. Prepare the monomer aqueous solution that the mass concentration of total monomer is 25%;

In the second step, add 0.024g of urea as a solubilizer (0.24% of the total mass of the monomer) to the aqueous monomer solution prepared above, and then add 0.02g of ethylenediaminetetraacetic acid complexing agent (0.24% of the total mass of the monomer) 0.2% of the mass), adjust the pH=8; pass through nitrogen to remove oxygen, add 0.12g of inorganic-organic compound initiator (the mass ratio of potassium persulfate, sodium sulfite and v50 is 1:1:8, and the dosage is 1% of the total mass of the monomer 1.2%), stir evenly, then pass in nitrogen to remove oxygen, and then airtight;

The third step is to put the above-prepared mixture into the ultraviolet light reaction device at the indoor ambient temperature. After 60 minutes of ultraviolet light irradiation, a colorless and transparent cationic polyacrylamide colloid is obtained; the residual monomer content of acrylamide is 0.1416 %, it can be directly used for sludge dewatering after dilution.

In the fourth step, the cationic polyacrylamide colloid is crushed, granulated, refined, dried, and ground to obtain a white solid powder of cationic polyacrylamide; the measured molecular weight is 7051330, and the cationic degree is 51.86%. It is a high-purity product with amide residual monomer content of 0.0113%, suitable for drinking water treatment and sludge dehydration treatment.

Example 5

In the first step, weigh 6g of monomer acrylamide, 2g of methacryloyloxyethyltrimethylammonium chloride, and 2g of acryloyloxyethyltrimethylammonium chloride into a jar, add 40ml of distilled water, Stir evenly, prepare the monomer aqueous solution that the mass concentration of total monomer is 20%;

In the second step, add 0.005g of urea as a solubilizer (0.05% of the total mass of the monomer) to the aqueous monomer solution prepared above, and then add 0.001g of ethylenediaminetetraacetic acid complexing agent (0.05% of the total mass of the monomer) 0.01% of the mass), adjust the pH=8; pass through nitrogen to remove oxygen, add 0.25g of inorganic-organic compound initiator (the mass ratio of ammonium persulfate, sodium sulfite and V-50 is 2:2:1, and the dosage is the total monomer 2.5% of the mass), stir evenly, then pass in nitrogen to deoxygenate, and then airtight;

The third step is to put the above-mentioned prepared mixture into the ultraviolet light reaction device at the indoor ambient temperature, and after 60 minutes of ultraviolet light irradiation, a colorless and transparent cationic polyacrylamide colloid is obtained; the residual monomer content of acrylamide is 0.0866 %, it can be directly used for sludge dewatering after dilution.

In the fourth step, the cationic polyacrylamide colloid is crushed and granulated, refined, dried, and ground to obtain a white solid powder of cationic polyacrylamide; the measured molecular weight is 6378830, and the cationic degree is 16.0%. It is a high-purity product with amide residual monomer content of 0.0087%, suitable for drinking water treatment and sludge dehydration treatment.

Example 6

The first step, weigh 4g of monomer acrylamide, 3g of methacryloxyethyltrimethylammonium chloride, 3g of dimethyldiallylammonium chloride into a jar, add 10ml of distilled water, stir Uniform, prepare the monomer aqueous solution whose mass concentration of total monomer is 50%;

In the second step, add 0.05g of urea as a solubilizer (0.5% of the total mass of the monomer) to the aqueous monomer solution prepared above, and then add 0.001g of ethylenediaminetetraacetic acid complexing agent (0.5% of the total mass of the monomer) 0.01% of the mass), adjust the pH=8; pass through nitrogen to remove oxygen, add 0.3g of inorganic-organic compound initiator (the mass ratio of ammonium persulfate, sodium sulfite and VA-044 is 1:1:8, and the dosage is the total monomer 3% of the mass), stir evenly, then pass in nitrogen to remove oxygen, and then seal it;

The third step is to put the above-prepared mixture into the ultraviolet light reaction device at the indoor ambient temperature. After 90 minutes of ultraviolet light irradiation, a colorless and transparent cationic polyacrylamide colloid is obtained; the residual monomer content of acrylamide is 0.0582 %, it can be directly used for sludge dewatering after dilution.

In the fourth step, the cationic polyacrylamide colloid is crushed and granulated, refined, dried, and ground to obtain a white solid powder of cationic polyacrylamide; the measured molecular weight is 11200730, and the cationic degree is 29.85%. It is a high-purity product with amide residual monomer content of 0.0068%, suitable for drinking water treatment and sludge dehydration treatment.

Example 7

Same as Example 3, but adding 0.25g of organic initiator azodiisopropylimidazoline hydrochloride VA-044 (the amount is 2.5% of the total mass of monomers), the obtained molecular weight is 6378830, and the cationic degree is 11.85%. It is a high-purity product with acrylamide residual monomer content of 0.0087%, suitable for drinking water treatment and sludge dehydration treatment.

In the above examples, the indoor ambient temperature used for the polymerization reaction is 5° C. to 45° C., and the above-mentioned ultraviolet light is generated by a high-pressure mercury lamp. The ultraviolet light has a wavelength of 220 nm to 2000 nm and a dominant wavelength of 365 nm.

Claims (2)

1. a preparation method for cationic polyacrylamide, is characterized in that, comprises the following steps:

The first step, takes 20%～80%, two kinds of cationic monomers 20%～80% of monomer acrylamide by monomer total mass per-cent; Add distilled water, and stir to dissolving completely, the monomer solution that the mass concentration that makes total monomer is 20%～50%;

Second step, in the monomer solution of above-mentioned preparation, add the urea with monomer total mass 0.05%～0.5%, add again the EDTA complex agent with monomer total mass 0.01%～0.2%, pH value 8～9 by weak base or weak acid regulation system, be filled with High Purity Nitrogen except oxygen, add fast the initiator with monomer total mass 0.1%～3%, this initiator comprises oxygenant Potassium Persulphate or ammonium persulphate and reductive agent S-WAT, oxygenant is 0.5～2 with the quality of reductive agent than scope, stir simultaneously, then be filled with High Purity Nitrogen except sealing after oxygen;

The 3rd step, under indoor environment temperature, puts into the mixture of above-mentioned preparation in UV-light reaction unit, under UV-irradiation, cause, irradiate after 10min～90min, standing slaking more than 1 hour, makes water white kation polyacrylamide colloid;

The 4th step, by described cationic polyacrylamide thickness colloid, through shredding granulation, dehydrated alcohol repeatedly wash refining, make cationic polyacrylamide white solid powder after drying, grinding.

2. the preparation method of cationic polyacrylamide according to claim 1, it is characterized in that adopting terpolymer, two kinds of described cationic monomers are optional two kinds in MethacryloyloxyethylTrimethyl Trimethyl Ammonium Chloride (DMC), acrylyl oxy-ethyl-trimethyl salmiac (DAC), dimethyl diallyl ammonium chloride (DMDAAC).