CN114685711B

CN114685711B - Modified flocculant and preparation method thereof

Info

Publication number: CN114685711B
Application number: CN202210602876.8A
Authority: CN
Inventors: 郑江波; 夏彤; 张文强
Original assignee: Dongying Beilu Biotechnology Co ltd
Current assignee: Dongying Beilu Biotechnology Co ltd
Priority date: 2022-05-31
Filing date: 2022-05-31
Publication date: 2022-08-30
Anticipated expiration: 2042-05-31
Also published as: CN114685711A

Abstract

The invention provides a modified flocculant and a preparation method thereof, relating to the technical field of sewage treatment, and the method comprises the following steps: adding acrylamide, a cationic monomer, a multi-arm prepolymer, a modified monomer and an anionic monomer into deionized water, and uniformly stirring to obtain a water-phase reaction medium; wherein the multi-arm prepolymer is prepared from 3-acryloyloxy propyl trichlorosilane and perfluoro-1-octanol; the modified monomer is N-p-hydroxyphenyl acrylamide containing a cationic group; stirring and uniformly mixing an oily solvent, an emulsifier and a water phase reaction medium to obtain a mixed solution with the viscosity of more than 1000mPa & s; and adding an initiator into the mixed solution to initiate polymerization reaction under the nitrogen atmosphere, and adding a phase inversion agent after the polymerization reaction is finished to obtain the modified flocculant. The modified flocculant prepared by the invention has the removal rate of more than 95% on suspended matters, ammonia nitrogen content, copper, chromium and lead ions in the printing and dyeing wastewater, and the clarity of the treatment liquid is high.

Description

Modified flocculant and preparation method thereof

Technical Field

The invention relates to the technical field of sewage treatment, and particularly relates to a modified flocculant and a preparation method thereof.

Background

The printing and dyeing wastewater is industrial wastewater which seriously pollutes the environment, particularly the printing and dyeing wastewater is difficult to treat by using reactive dye, and because the structure of the reactive dye contains a large amount of sizing agents, auxiliary agents, oiling agents, acid, alkali, fiber impurities, inorganic salts and the like in the dyeing and pre-and post-treatment processes, the printing and dyeing wastewater has the characteristics of high pollutant concentration, multiple types, high chromaticity, difficult degradation and the like, and therefore, a plurality of technologies are used for treating the printing and dyeing wastewater.

At present, various kinds of flocculating agents are used for treating printing and dyeing wastewater, such as inorganic flocculating agents including aluminum chloride, aluminum sulfate, ferrous sulfate and the like, but the inorganic flocculating agents have poor decolorizing effect on the printing and dyeing wastewater, large sludge amount and undesirable treatment effect. The inorganic polymeric flocculant is very effective in removing suspended matters in the wastewater, but has low removal rate for high chroma of the printing and dyeing wastewater, and has little effect particularly when the amount of soluble dye substances in the wastewater is large; the conventional organic polymer flocculant can reduce the volume of a precipitation flocculating constituent, has a certain effect on suspended matters and colorimetric substances, but has lower removal rate of the suspended matters, the chromaticity and the COD, so that the standard discharge difficulty of the chromaticity and the COD index is higher.

Disclosure of Invention

The invention provides a modified flocculant and a preparation method thereof. The modified flocculant has multiple side arms, has an excellent pretreatment effect on printing and dyeing sewage, can effectively adsorb suspended matters, organic impurities and heavy metal ions, and has high clarity of treatment liquid.

In a first aspect, the present invention provides a preparation method of a modified flocculant, the preparation method comprising the steps of:

(1) adding acrylamide, a cationic monomer, a multi-arm prepolymer, a modified monomer and an anionic monomer into deionized water, and uniformly stirring to obtain a water-phase reaction medium; the multi-arm prepolymer is prepared from 3-acryloyloxy propyl trichlorosilane and perfluoro-1-octanol; the modified monomer is N-p-hydroxyphenyl acrylamide containing a cationic group;

(2) uniformly stirring and mixing an oily solvent, an emulsifier and the water-phase reaction medium to obtain a mixed solution; wherein the viscosity of the mixed solution is more than 1000 mPa.s; the emulsifier is a compound of sorbitol polyether-30 tetraoleate, triethanolamine monooleate and sorbitan monostearate; the compound ratio is sorbitol polyether-30 tetraoleate: triethanolamine monooleate: sorbitan monostearate =1:1: 2;

(3) and adding an initiator into the mixed solution to initiate polymerization reaction under the nitrogen atmosphere, and adding a phase inversion agent after the polymerization reaction is finished to obtain the modified flocculant.

Preferably, the cationic monomer is at least one of methacryl propyl trimethyl ammonium chloride and (3-acrylamide propyl) trimethyl ammonium chloride.

Preferably, the anionic monomer is at least one of 2-acrylamide-based 2-methyl propyl sodium sulfonate and 3-propyl-2-enoyl oxypropane-1-sodium sulfonate.

Preferably, the multi-arm prepolymer is prepared by the following steps:

and adding perfluoro-1-octanol into acetone, dropwise adding 3-acryloyloxy propyl trichlorosilane at 5-10 ℃ in a nitrogen atmosphere for reaction, and performing rotary evaporation treatment after the reaction is finished to obtain the multi-arm prepolymer.

Preferably, the molar ratio of the 3-acryloyloxypropyl trichlorosilane to the perfluoro-1-octanol is 1 (3-3.5);

the dosage of the acetone is 5-7% of the sum of the dosages of the 3-acryloyl oxy propyl trichlorosilane and the perfluoro-1-octanol.

Preferably, the reaction time for preparing the multi-arm prepolymer is 3-4 h; the rotary evaporation treatment time is 1-2 h, the temperature of the rotary evaporation treatment is 65-75 ℃, and the pressure is-0.1 to-0.09 MPa.

Preferably, the modified monomer is prepared from epichlorohydrin, trimethylamine and N-p-hydroxyphenyl acrylamide in an alkaline environment;

the mol ratio of the epoxy chloropropane to the trimethylamine to the N-p-hydroxyphenyl acrylamide is 1 (1-1.5) to 1.

Preferably, the modified monomer is prepared by the following steps:

uniformly mixing epoxy chloropropane and a sodium hydroxide aqueous solution with the mass fraction of 20%, then adding trimethylamine to react for 2-3 h, then continuously adding sodium hydroxide and N-p-hydroxyphenyl acrylamide, and reacting for 2-3 h to obtain the modified monomer;

wherein the reaction temperature is 65-70 ℃, and the amount of the sodium hydroxide aqueous solution with the mass fraction of 20% is 16-20% of the sum of the amounts of the epichlorohydrin and the trimethylamine; the dosage of the sodium hydroxide is 4-5% of that of the N-p-hydroxyphenyl acrylamide.

Preferably, in the step (1), the pH of the aqueous phase reaction medium is 4.2-4.7.

Preferably, in the step (2), the rotation speed of the stirring and uniform mixing is 10000-15000 rpm, and the viscosity of the mixed solution is 1001-3000 mPa & s;

in the step (3), initiating a polymerization reaction at 20-22 ℃ and reacting for 5-6 h; and stirring and uniformly mixing the phase inversion agent and the phase inversion agent for 1-2 hours to obtain the modified flocculant.

Preferably, in step (1), the pH of the aqueous reaction medium is adjusted with acetic acid.

Preferably, the oily solvent is kerosene, diesel, benzene, toluene or white oil.

Preferably, the initiator is ammonium persulfate and sodium bisulfite; the mass ratio of ammonium persulfate to sodium bisulfite is (1-5) to (1-5);

the phase transfer agent is polyethylene glycol monooleate.

Preferably, the perfluoro-1-octanol is 1H, 1H-pentadecafluoro-1-octanol.

The oily solvent is white oil.

Preferably, the modified flocculant is prepared from the following raw materials in parts by weight: 20-40 parts of acrylamide, 120-160 parts of cationic monomer, 4-10 parts of multi-arm prepolymer, 20-40 parts of modified monomer, 25-50 parts of anionic monomer, 500-611 parts of deionized water, 270-310 parts of oily solvent, 30-40 parts of emulsifier, 0.2-1 part of initiator and 20-30 parts of phase transfer agent.

In a second aspect, the invention provides a modified flocculant prepared by the preparation method of any one of the first aspect.

Compared with the prior art, the invention at least has the following beneficial effects:

(1) the multi-arm modified emulsion flocculant is prepared by an inverse emulsion polymerization process, has a strong pretreatment effect on printing and dyeing sewage, can effectively adsorb suspended matters, organic impurities and heavy metal ions, can adsorb and decolor, and is high in clarity and chroma removal rate of treated liquid.

(2) The modified flocculant provided by the invention is a water-in-oil type emulsion, has high dissolution speed in printing and dyeing wastewater and strong stability, is not layered or settled after being stored for a long time, can be directly added into a wastewater pool, and does not need dissolution equipment.

(3) According to the invention, the multi-arm prepolymer containing three side arms is prepared by reacting 3-acryloyloxy propyl trichlorosilane with perfluoro-1-octanol, the side arms have a large amount of fluorine, so that a large amount of fiber impurities and suspended matters can be adsorbed, the large side arms can increase the sweeping net capture area and the adsorption bridging effect of the modified flocculant, and the bonding capability of the adsorption bridging and metal ions such as copper, chromium, lead, zinc, aluminum and the like is stronger than that of hydrogen bonds, so that the chromaticity can be greatly reduced.

(4) According to the invention, the N-p-hydroxyphenyl acrylamide is modified, so that a cationic group is introduced into the modified monomer, and the structure has an effective adsorption bridging effect on organic matters in wastewater, can adsorb organic matters in wastewater, and reduces the content of the organic matters in wastewater.

(5) The anionic monomer in the modified flocculant provided by the invention can effectively adsorb heavy metal ions, reduce the content of the heavy metal ions and improve the transparency of supernatant liquid.

Detailed Description

In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer and more complete, the technical solutions in the embodiments of the present invention are described below, it is obvious that the described embodiments are a part of the embodiments of the present invention, but not all embodiments, and all other embodiments obtained by a person of ordinary skill in the art without creative efforts based on the embodiments of the present invention belong to the protection scope of the present invention.

The invention provides a preparation method of a modified flocculant, which comprises the following steps:

(1) adding acrylamide, a cationic monomer, a multi-arm prepolymer, a modified monomer and an anionic monomer into deionized water, and uniformly stirring to obtain a water-phase reaction medium; wherein the multi-arm prepolymer is prepared from 3-acryloyloxy propyl trichlorosilane and perfluoro-1-octanol; the modified monomer is N-p-hydroxyphenyl acrylamide containing a cationic group;

(2) stirring and uniformly mixing an oily solvent, an emulsifier and a water-phase reaction medium to obtain a mixed solution; wherein the viscosity of the mixed solution is more than 1000 mPa.s;

the emulsifier is a compound of sorbitol polyether-30 tetraoleate, triethanolamine monooleate and sorbitan monostearate; the compound ratio is sorbitol polyether-30 tetraoleate: triethanolamine monooleate: sorbitan monostearate =1:1: 2;

In the present invention, since oxygen acts as a polymerization inhibitor and affects the polymerization reaction of polyacrylamide, the polymerization is carried out under a nitrogen atmosphere. Specifically, before the initiator is added for polymerization, nitrogen gas needs to be introduced for 30-40 min (for example, 30min, 35min or 40 min) to remove oxygen and ensure that the polymerization reaction is normally performed.

In the invention, experiments prove that the emulsifier compound has better emulsifying property to water-in-oil emulsion, more stable system and more stable reaction.

According to some preferred embodiments, the cationic monomer is at least one of methacrylpropyltrimethylammonium chloride, (3-acrylamidopropyl) trimethylammonium chloride.

At least one of them is a mixture of any one or more of them mixed in any ratio.

According to some preferred embodiments, the anionic monomer is at least one of sodium 2-acrylamido 2-methylpropanesulfonate, sodium 3-prop-2-enoyloxypropane-1-sulfonate.

According to some preferred embodiments, the multi-arm prepolymer is prepared by:

adding perfluoro-1-octanol into acetone, dropwise adding 3-acryloyloxy propyl trichlorosilane at 5-10 ℃ (for example, 5 ℃, 6 ℃, 8 ℃ or 10 ℃) in a nitrogen atmosphere for reaction, and performing rotary steaming treatment after the reaction is finished to obtain the multi-arm prepolymer.

Specifically, the 3-acryloyloxypropyl trichlorosilane is added dropwise within 20 to 30min (for example, 20min, 22min, 25min, 28min or 30 min).

According to some more preferred embodiments, the molar ratio of 3-acryloyloxypropyltrichlorosilane to perfluoro-1-octanol is 1 (3 to 3.5) (e.g., may be 1:3, 1: 3.1, 1: 3.2, 1: 3.3, 1: 3.4, or 1: 3.5);

the amount of acetone is 5 to 7% (for example, 5%, 5.5%, 6%, 6.5% or 7%) of the sum of the amounts of 3-acryloyloxypropyltrichlorosilane and perfluoro-1-octanol.

According to some more preferred embodiments, the reaction time for preparing the multi-arm prepolymer is 3 to 4 hours (e.g., can be 3 hours, 3.2 hours, 3.5 hours, 3.8 hours, or 4 hours); the rotary evaporation treatment time is 1-2 h (for example, 1h, 1.5h or 2 h), the rotary evaporation treatment temperature is 65-75 ℃ (for example, 65 ℃, 68 ℃, 70 ℃, 72 ℃ or 75 ℃) and the pressure is-0.1-0.09 MPa (for example, -0.1 MPa, -0.095 MPa or-0.09 MPa).

According to the invention, the multi-arm prepolymer containing three side arms is prepared by the reaction of 3-acryloyloxy propyl trichlorosilane and perfluoro-1-octanol, the side arms have a large amount of fluorine, so that a large amount of fiber impurities and suspended matters can be adsorbed, and the large side arms can increase the rolling and sweeping capacity and the adsorption and bridging effects of the polymer.

According to some more preferred embodiments, the perfluoro-1-octanol is 1H, 1H-pentadecafluoro-1-octanol.

In a preferred embodiment, the multi-arm prepolymer is prepared by the following steps: adding 1H, 1H-pentadecafluoro-1-octanol and acetone into a four-neck flask with a stirrer and a thermometer, introducing nitrogen for 30min, then starting an ice water bath to control the temperature, dropwise adding 3-acryloxypropyl trichlorosilane under the nitrogen protection condition, reacting for 3H, and then finishing, and carrying out rotary evaporation purification on the obtained crude product to remove the acetone to obtain a multi-arm prepolymer; the chemical reaction formula is shown as follows:

。

according to some preferred embodiments, the modifying monomer is prepared from epichlorohydrin, trimethylamine, and N-p-hydroxyphenyl acrylamide in an alkaline environment;

the molar ratio of epichlorohydrin to trimethylamine to N-p-hydroxyphenyl acrylamide is 1 (1-1.5): 1 (for example, 1:1: 1, 1: 1.1:1, 1: 1.2:1, 1: 1.3:1, 1: 1.4:1 or 1:1.5: 1).

According to some preferred embodiments, the modifying monomer is prepared by:

uniformly mixing epoxy chloropropane and a sodium hydroxide aqueous solution with the mass fraction of 20%, then adding trimethylamine to react for 2-3 h (for example, 2h, 2.5h or 3 h), then continuously adding sodium hydroxide and N-p-hydroxyphenyl acrylamide, and obtaining a modified monomer after reacting for 2-3 h (for example, 2h, 2.5h or 3 h);

wherein, the reaction temperature is 65-70 ℃ (for example, 65 ℃, 68 ℃ or 70 ℃), and the usage of the sodium hydroxide aqueous solution with the mass fraction of 20% is 16-20% (for example, 16%, 16.5%, 17%, 18%, 19% or 20%) of the sum of the usage of the epichlorohydrin and the trimethylamine; the amount of sodium hydroxide is 4-5% (for example, 4%, 4.5% or 5%) of the amount of N-p-hydroxyphenyl acrylamide.

The 20% aqueous solution of sodium hydroxide added first is to provide the alkaline environment required for the first reaction step, and the solid sodium hydroxide added later is to sufficiently perform the reaction.

In the invention, the N-p-hydroxyphenyl acrylamide is modified to introduce cationic groups into the modified monomer, and the structure has an effective adsorption bridging effect on organic matters in wastewater, can adsorb the organic matters in the wastewater and reduce the content of the organic matters in the wastewater.

In a preferred embodiment, the modifying monomer is prepared by: adding epoxy chloropropane and a sodium hydroxide aqueous solution with the mass fraction of 20% into a four-neck flask with a stirrer, a condenser pipe and a thermometer, placing the four-neck flask into a 70 ℃ water bath kettle, slowly adding trimethylamine, adding solid sodium hydroxide after reacting for 2h, adding N-p-hydroxyphenyl acrylamide, and ending the reaction after reacting for 2h to obtain a modified monomer; the chemical reaction formula is shown as follows:

according to some preferred embodiments, in step (1), the pH of the aqueous reaction medium is between 4.2 and 4.7 (e.g., it may be 4.2, 4.3, 4.5, 4.6 or 4.7).

According to some more preferred embodiments, in step (1), the pH of the aqueous reaction medium is adjusted with acetic acid.

In the invention, the pH value is adjusted to avoid the influence of the pH value of the reaction medium on the decomposition rate of the subsequent initiator, thereby ensuring the normal operation of the polymerization reaction. In order to uniformly mix and sufficiently disperse acrylamide, a cationic monomer, a multi-arm prepolymer, a modified monomer and an anionic monomer and to obtain a more accurate pH value, the rotation speed for uniformly stirring is limited to 500 to 1000rpm (for example, 500rpm, 600rpm, 700rpm, 800rpm, 900rpm or 1000 rpm).

According to some preferred embodiments, in the step (2), the rotation speed for stirring and mixing is 10000 to 15000rpm (for example, 10000rpm, 11000rpm, 12000rpm, 13000rpm, 14000rpm or 15000rpm may be set), and the viscosity of the mixed solution is 1001 to 3000mPa · s (for example, 1001mPa · s, 1500mPa · s, 2000mPa · s, 2500mPa · s or 3000mPa · s);

in the step (3), the polymerization reaction is initiated at 20-22 ℃ (for example, 20 ℃, 20.5 ℃, 21 ℃, 21.5 ℃ or 22 ℃) and is reacted for 5-6 h (for example, 5h, 5.5h or 6 h); and stirring and uniformly mixing for 1-2 h (for example, 1h, 1.2h, 1.5h, 1.8h or 2 h) after the phase inversion agent is added to obtain the modified flocculant.

In the present invention, in order to avoid too low an emulsifying viscosity, demulsification may occur during the reaction; meanwhile, in order to avoid the problem that the reaction speed is affected by the difficulty of the initiator entering the emulsion when the emulsion viscosity is too high, the viscosity of the mixed solution is limited to be more than 1000 mPas, preferably 1001 to 3000 mPas.

According to some preferred embodiments, the oily solvent is kerosene, diesel, benzene, toluene or white oil.

According to some more preferred embodiments, the oily solvent is a white oil.

According to some preferred embodiments, the initiator is ammonium persulfate and sodium bisulfite; the mass ratio of ammonium persulfate to sodium bisulfite is (1-5) to (1-5) (for example, 1:1, 1:2, 1:3, 1:4, 1: 5, 2:1, 2:3, 2: 5, 3:1, 3:2, 3:4, 3: 5, 4:1, 4:3, or 5: 1);

the phase transfer agent is polyethylene glycol monooleate.

According to some preferred embodiments, the parts by weight of the raw materials used to prepare the modified flocculant are as follows: acrylamide 20 to 40 parts (for example, 20 parts, 22 parts, 25 parts, 28 parts, 30 parts, 32 parts, 35 parts, 38 parts, or 40 parts) cationic monomer 120 to 160 parts (for example, 120 parts, 125 parts, 130 parts, 135 parts, 140 parts, 145 parts, 150 parts, 155 parts, or 160 parts), multi-arm prepolymer 4 to 10 parts (for example, 4 parts, 5 parts, 6 parts, 8 parts, 9 parts, or 10 parts), modifying monomer 20 to 40 parts (for example, 20 parts, 22 parts, 25 parts, 28 parts, 30 parts, 32 parts, 35 parts, 38 parts, or 40 parts), anionic monomer 25 to 50 parts (for example, 25 parts, 28 parts, 30 parts, 32 parts, 35 parts, 40 parts, 45 parts, 48 parts, or 50 parts), deionized water 500 to 611 parts (for example, 500 parts, 510 parts, 520 parts, 560 parts, 580 parts, 550 parts, 600 parts, 610 parts, or 611 parts), oily solvent 270 parts (for example, 310 parts, can be 270 parts, 272 parts, 275 parts, 280 parts, 285 parts, 290 parts, 295 parts, 300 parts, 305 parts or 310 parts), 30 to 40 parts of emulsifier (for example, can be 30 parts, 32 parts, 35 parts, 38 parts or 40 parts), 0.2 to 1 part of initiator (for example, can be 0.2 parts, 0.4 parts, 0.5 parts, 0.6 parts, 0.8 parts or 1 part), 20 to 30 parts of phase transfer agent (for example, can be 20 parts, 22 parts, 25 parts, 26 parts, 28 parts or 30 parts).

More specifically, when the modified flocculant is prepared according to the above weight parts, the mass parts of acetic acid is 0.1-2 parts (for example, 0.1 part, 0.2 part, 0.5 part, 1 part, 1.2 parts, 1.5 parts, 1.8 parts or 2 parts) which is adopted, namely, the mass ratio of acrylamide to acetic acid adopted when the flocculant is prepared is (20-40): 0.1-2); when the modified flocculant is prepared according to the parts by weight, 0.2-1 part of initiator is 0.1-0.5 part of ammonium persulfate and 0.1-0.5 part of sodium bisulfite.

Experiments prove that the prepared modified flocculant can realize the rapid sedimentation of the printing and dyeing wastewater by limiting the raw material proportion of acrylamide, a cationic monomer, a multi-arm prepolymer, a modified monomer, an anionic monomer and the like in the range, the removal rate of suspended matters, ammonia nitrogen content, copper, chromium and lead ions in the printing and dyeing wastewater reaches more than 95%, and the clarity of the treatment solution is high.

In a preferred embodiment, according to the weight parts of the raw materials, uniformly stirring and mixing acrylamide, a cationic monomer, a multi-arm prepolymer, a modified monomer, an anionic monomer and deionized water at 500-1000 rpm, adjusting the pH value to 4.2-4.7 by using acetic acid, and then adding ammonium persulfate to uniformly mix; then continuously adding the oily solvent and the emulsifier at the stirring speed of 10000-15000 rpm, and uniformly mixing until the viscosity of an emulsification system reaches over 1000mPa & s; and then introducing nitrogen to remove oxygen for 30-40 min, pumping sodium bisulfite at 20-22 ℃ at a stirring speed of 400-600 rpm to initiate polymerization reaction, finishing the reaction after 5-6 h, adding a phase inversion agent, and stirring for 1-2 h to obtain the modified flocculant.

The invention also provides a modified flocculant prepared by the preparation method provided by the invention.

In order to more clearly illustrate the technical scheme and advantages of the invention, a modified flocculant and a preparation method thereof are described in detail by using several examples.

In the following examples, the mass of the raw materials used in the preparation process is expressed in parts by weight; wherein the emulsifier is composed of sorbitol polyether-30 tetraoleate: triethanolamine monooleate: sorbitan monostearate =1:1: 2.

Example 1

Preparing a multi-arm prepolymer: adding 600 parts of 1H, 1H-pentadecafluoro-1-octanol and 43 parts of acetone into a four-neck flask with a stirrer and a thermometer, introducing nitrogen for 30min, starting an ice water bath, controlling the temperature to be 8 ℃, dropwise adding 120 parts of 3-acryloyloxypropyltrichlorosilane under the condition of nitrogen protection, reacting for 3H, and then finishing, and carrying out rotary evaporation purification on the obtained crude product at 70 ℃ and under the condition of-0.09 MPa for 1H to remove the acetone so as to obtain the multi-arm prepolymer.

Preparation of modified monomer: 185 parts of epoxy chloropropane and 65 parts of sodium hydroxide aqueous solution with the mass fraction of 20% are added into a four-neck flask with a stirrer, a condenser tube and a thermometer, the four-neck flask is placed into a 70 ℃ water bath kettle, 140 parts of trimethylamine is slowly added, 13 parts of sodium hydroxide and 326 parts of N-p-hydroxyphenyl acrylamide are added after 2 hours of reaction, and the modified monomer is obtained after 2 hours of reaction.

Preparing a modified flocculant: stirring and uniformly mixing 20 parts of acrylamide, 120 parts of methacryl propyl trimethyl ammonium chloride, 4 parts of multi-arm prepolymer, 20 parts of modified monomer, 25 parts of 2-acrylamide 2-methyl sodium propane sulfonate and 600 parts of deionized water at 600rpm, adding 0.5 part of acetic acid to adjust the pH value to 4.5, and then adding 0.2 part of ammonium persulfate to uniformly mix; then, continuously adding 270 parts of white oil and 30 parts of emulsifier at the stirring speed of 12000rpm, and uniformly mixing until the viscosity of an emulsification system reaches more than 1000mPa & s; then introducing nitrogen for 30min, pumping 0.3 part of sodium bisulfite at the temperature of 20 ℃ at the stirring speed of 400rpm to initiate polymerization reaction, finishing the reaction after 5h, adding 20 parts of phase inversion agent, and stirring for 1.5h to obtain the modified flocculant.

Example 2

Example 2 is substantially the same as example 1 except that:

preparing a modified flocculant: uniformly stirring and mixing 30 parts of acrylamide, 140 parts of (3-acrylamidopropyl) trimethyl ammonium chloride, 7 parts of multi-arm prepolymer, 30 parts of modified monomer, 35 parts of 3-propyl-2-enoyloxypropane-1-sodium sulfonate and 550 parts of deionized water at 600rpm, adding 1 part of acetic acid to adjust the pH value to 4.5, and then adding 0.3 part of ammonium persulfate to uniformly mix; then, continuously adding 290 parts of white oil and 35 parts of emulsifier at the stirring speed of 12000rpm, and uniformly mixing until the viscosity of an emulsification system reaches more than 1000mPa & s; then nitrogen is introduced for 30min, 0.4 part of sodium bisulfite is pumped in at the temperature of 20 ℃ under the stirring speed of 400rpm to initiate polymerization reaction, after 5h, the reaction is finished, and 25 parts of phase inversion agent is added and stirred for 1.5h to obtain the modified flocculant.

Example 3

Example 3 is essentially the same as example 1, except that:

preparing a modified flocculant: uniformly stirring and mixing 40 parts of acrylamide, 160 parts of methacryl propyl trimethyl ammonium chloride, 10 parts of multi-arm prepolymer, 40 parts of modified monomer, 50 parts of 2-acrylamide 2-methyl sodium propanesulfonate and 500 parts of deionized water at 600rpm, adding 0.4 part of acetic acid to adjust the pH value to 4.5, and then adding 0.4 part of ammonium persulfate to uniformly mix; then, continuously adding 310 parts of white oil and 40 parts of emulsifier at the stirring speed of 12000rpm, and uniformly mixing until the viscosity of an emulsification system reaches more than 1000mPa & s; then introducing nitrogen for 30min, pumping 0.5 part of sodium bisulfite at 20 ℃ at the stirring speed of 400rpm to initiate polymerization reaction, ending the reaction after 5h, adding 30 parts of phase inversion agent, and stirring for 1.5h to obtain the modified flocculant.

Example 4

Example 4 is essentially the same as example 1, except that:

preparing a modified flocculant: stirring and uniformly mixing 20 parts of acrylamide, 120 parts of methacryl propyl trimethyl ammonium chloride, 4 parts of multi-arm prepolymer, 20 parts of modified monomer, 25 parts of 2-acrylamide 2-methyl sodium propane sulfonate and 600 parts of deionized water at 500rpm, adding 0.5 part of acetic acid to adjust the pH value to 4.2, and then adding 0.2 part of ammonium persulfate to uniformly mix; then, continuously adding 270 parts of white oil and 30 parts of emulsifier at the stirring speed of 10000rpm, and uniformly mixing until the viscosity of an emulsification system reaches 3000mPa & s; then nitrogen is introduced for 40min, 0.3 part of sodium bisulfite is pumped in at the temperature of 22 ℃ under the stirring speed of 600rpm to initiate polymerization reaction, after 6h, the reaction is finished, and 20 parts of phase inversion agent is added and stirred for 2h to obtain the modified flocculant.

Example 5

Example 5 is essentially the same as example 1, except that:

preparing a modified flocculant: stirring and uniformly mixing 20 parts of acrylamide, 120 parts of methacryl propyl trimethyl ammonium chloride, 4 parts of multi-arm prepolymer, 20 parts of modified monomer, 25 parts of 2-acrylamide 2-methyl sodium propane sulfonate and 600 parts of deionized water at 1000rpm, adding 0.5 part of acetic acid to adjust the pH value to 4.7, and then adding 0.2 part of ammonium persulfate to uniformly mix; then, continuously adding 270 parts of white oil and 30 parts of emulsifier at the stirring speed of 15000rpm, and uniformly mixing until the viscosity of an emulsification system reaches more than 1000mPa & s; then introducing nitrogen for 30min, pumping 0.3 part of sodium bisulfite at 20 ℃ at the stirring speed of 400rpm to initiate polymerization reaction, ending the reaction after 5h, adding 20 parts of phase inversion agent, and stirring for 1h to obtain the modified flocculant.

Example 6

Example 6 is essentially the same as example 1, except that:

in the preparation of the multi-arm prepolymer: the molar ratio of the 3-acryloyloxypropyltrichlorosilane to the perfluoro-1-octanol is 1: 3.5; the temperature of the ice-water bath is controlled to be 10 ℃, and the dosage of the acetone is 5 percent of the sum of the dosages of the 3-acryloyloxy propyl trichlorosilane and the perfluoro-1-octanol.

Example 7

Example 7 is essentially the same as example 1, except that:

in the preparation of the multi-arm prepolymer: the temperature of the ice-water bath is controlled to be 5 ℃, and the dosage of the acetone is 7 percent of the sum of the dosages of the 3-acryloyloxy propyl trichlorosilane and the perfluoro-1-octanol.

Example 8

Example 8 is essentially the same as example 1, except that:

in the preparation of the modified monomer: the mol ratio of the epichlorohydrin to the trimethylamine to the N-p-hydroxyphenyl acrylamide is 1:1.5: 1.

Comparative example 1

Comparative example 1 is substantially the same as example 1 except that: 4 parts of multi-arm prepolymer is not added in the preparation of the modified flocculant, but 4 parts of deionized water is added instead, namely 604 parts of deionized water is added.

Comparative example 2

Comparative example 2 is substantially the same as example 1 except that: the preparation of the modified flocculant does not add 20 parts of modified monomer, but replaces 20 parts of deionized water, namely 620 parts of deionized water.

Comparative example 3

Comparative example 3 is substantially the same as example 1 except that: 25 parts of 2-acrylamide-based 2-methyl sodium propanesulfonate is not added in the preparation of the modified flocculant, but 25 parts of deionized water is added instead, namely 625 parts of deionized water.

Comparative example 4

Comparative example 4 is substantially the same as example 1 except that: 120 parts of methacryl propyl trimethyl ammonium chloride is not added in the preparation of the modified flocculant, but 120 parts of deionized water is added instead, namely 720 parts of deionized water is added.

Comparative example 5

Comparative example 5 is substantially the same as example 1 except that: the emulsifier adopted in the preparation of the modified flocculant is sorbitol polyether-30 tetraoleate: triethanolamine monooleate: sorbitan monostearate =2:2: 1.

Comparative example 6

Comparative example 6 is substantially the same as example 1 except that: the modified flocculant was prepared without adding 20 parts of the modifying monomer, but instead with 20 parts of N-p-hydroxyphenyl acrylamide.

The modified flocculants obtained in examples 1 to 8 and comparative examples 1 to 6 were used as samples, and water was used to prepare a 1 ‰ flocculant aqueous solution, and without pretreatment of the printing and dyeing wastewater, 1g of 1 ‰ flocculant aqueous solution was directly added to 100g of the printing and dyeing wastewater, and after mixing 3 times, the mixture was mixed well, and after waiting for 10 minutes, the detection data of the treated printing and dyeing wastewater was measured, and shown in table 1. Specifically, the performance evaluation test was performed on the modified flocculant according to the following evaluation criteria:

the heavy metal ions are measured according to the national environmental protection standard HJ 776-;

the ammonia nitrogen concentration is measured according to the national environmental protection standard HJ 536-2009 salicylic acid spectrophotometry for measuring ammonia nitrogen in water quality;

the content of suspended matters is measured according to the national standard GB 11901-89 gravimetric method for measuring suspended matters in water;

the turbidity is measured according to the national environmental protection standard HJ 1075 and 2019 turbidity measurement method for measuring the turbidity of water;

COD is measured according to the national environmental protection standard HJ828-2017 bichromate method for measuring chemical oxygen demand of water quality.

In the examples and comparative examples of the present invention, it was determined that the initial COD of a certain printing and dyeing wastewater before treatment was 2813mg/L, the suspended matter content was 2154mg/L, the copper ion concentration was 1279mg/L, the chromium ion concentration was 761mg/L, the lead ion concentration was 573mg/L, the ammonia nitrogen concentration was 1384mg/L, and the turbidity was 2472NTU, all according to the above-described method.

TABLE 1

In Table 1, "-" indicates that there is no corresponding data because comparative example 5 does not form a homogeneous emulsion and is not used for treating printing and dyeing wastewater.

As can be seen from table 1, the modified flocculants prepared in embodiments 1 to 8 of the present invention have a multi-arm structure, form compact and uniform flocs with organic matter, heavy metal ions, inorganic suspended matter, etc. in the printing and dyeing wastewater through charge neutralization, adsorption, bridging, and sweeping actions, have a COD removal rate of 95% or more, a removal rate of suspended matter, ammonia nitrogen content, copper, chromium, and lead ions of 95% or more, a turbidity of 5NTU or less, and a treated liquid has a high clarity. Through the comparison example and the example 1, it can be found that when the multi-arm prepolymer is not added, the removal rate of suspended matters is greatly reduced and the removal rate of ions is also obviously reduced due to the fact that a multi-arm structure and a large amount of fluorine are not added; the flocculation effect of the prepared modified flocculant on printing and dyeing wastewater can be influenced without adding a modified monomer, an anionic monomer or a cationic monomer. To sum up, the modified flocculant prepared by the method has an excellent flocculation effect on treatment of printing and dyeing wastewater, realizes efficient adsorption of suspended matters, organic impurities and heavy metal ions, and has high clarity of treatment liquid.

Finally, it should be noted that: the above examples are only intended to illustrate the technical solution of the present invention, but not to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some technical features may be equivalently replaced; and such modifications or substitutions do not depart from the spirit and scope of the corresponding technical solutions of the embodiments of the present invention.

Claims

1. The preparation method of the modified flocculant is characterized by comprising the following steps of:

the modified monomer is prepared from epoxy chloropropane, trimethylamine and N-p-hydroxyphenyl acrylamide in an alkaline environment; the mol ratio of the epichlorohydrin to the trimethylamine to the N-p-hydroxyphenyl acrylamide is 1 (1-1.5) to 1;

the cationic monomer is at least one of methacryl propyl trimethyl ammonium chloride and (3-acrylamide propyl) trimethyl ammonium chloride; the anionic monomer is at least one of 2-acrylamide 2-methyl sodium propane sulfonate and 3-propyl-2-enoyl oxypropane-1-sodium sulfonate;

(2) uniformly stirring and mixing an oily solvent, an emulsifier and the water phase reaction medium to obtain a mixed solution; wherein the viscosity of the mixed solution is more than 1000 mPa.s;

(3) adding an initiator into the mixed solution to initiate polymerization reaction under the nitrogen atmosphere, and adding a phase inversion agent after the polymerization reaction is finished to obtain the modified flocculant; the phase transfer agent is polyethylene glycol monooleate;

the modified flocculant is prepared from the following raw materials in parts by weight: 20-40 parts of acrylamide, 120-160 parts of cationic monomer, 4-10 parts of multi-arm prepolymer, 20-40 parts of modified monomer, 25-50 parts of anionic monomer, 500-611 parts of deionized water, 270-310 parts of oily solvent, 30-40 parts of emulsifier, 0.2-1 part of initiator and 20-30 parts of phase transfer agent.

2. The method of claim 1, wherein:

the multi-arm prepolymer is prepared by the following steps:

3. The method of claim 2, wherein:

the molar ratio of the 3-acryloyloxypropyltrichlorosilane to the perfluoro-1-octanol is 1 (3-3.5);

the using amount of the acetone is 5-7% of the sum of the using amounts of the 3-acryloyloxypropyl trichlorosilane and the perfluoro-1-octanol; and/or

The reaction time for preparing the multi-arm prepolymer is 3-4 h; the rotary evaporation treatment time is 1-2 h, the temperature of the rotary evaporation treatment is 65-75 ℃, and the pressure is-0.1 to-0.09 MPa.

4. The method of claim 1, wherein:

the modified monomer is prepared by the following steps:

uniformly mixing epoxy chloropropane and a sodium hydroxide aqueous solution with the mass fraction of 20%, then adding trimethylamine to react for 2-3 h, then continuously adding sodium hydroxide and N-p-hydroxyphenyl acrylamide to react for 2-3 h, and obtaining the modified monomer;

5. The method of claim 1, wherein:

in the step (1), the pH value of the aqueous phase reaction medium is 4.2-4.7; and/or

In the step (2), the rotation speed of stirring and uniformly mixing is 10000-15000 rpm, and the viscosity of the mixed solution is 1001-3000 mPa & s;

6. The method of claim 5, wherein:

in step (1), the pH of the aqueous reaction medium is adjusted with acetic acid.

7. The method of claim 1, wherein:

the oily solvent is kerosene, diesel oil, benzene, toluene or white oil;

and/or

The initiator is ammonium persulfate and sodium bisulfite; the mass ratio of the ammonium persulfate to the sodium bisulfite is (1-5) to (1-5).

8. The method of claim 1, wherein:

the perfluoro-1-octanol is 1H, 1H-pentadecafluoro-1-octanol; and/or

The oily solvent is white oil.

9. A modified flocculant, characterized by being prepared by the preparation method of any one of claims 1 to 8.