CN1321909C - Flocculation agent of powder amphoteric polyacrylic amide prepared by water solution polymer and its preparation method - Google Patents

Abstract

The present invention relates to a powder amphoteric polyacrylamide flocculant prepared by water solution polymerization and a preparing method thereof. The flocculant is a terpolymer which is formed by that a structural unit (I), a structural unit (II) and structural unit (III) are mutually linked, wherein the R is equal to H or CH3, and the X is equal to H or Na. A sorbitan fatty acid ester/polyethylene glycol sorbitan fatty acid ester based compounded surfactant is added in the process of preparing the flocculant in the present invention; in the meantime of treating operation after alkalization, a colloid product which is obtained by water solution polymerization is make easy to granulate and shape; the powder amphoteric polyacrylamide flocculant has great molecular weight and high dissolving speed.

Description

Method for preparing powdery amphoteric polyacrylamide flocculant by aqueous solution polymerization

technical field

The invention relates to the technical field of wastewater treatment using high molecular polymers to flocculate suspended impurities, in particular to a method for preparing powdery amphoteric polyacrylamide by aqueous solution polymerization.

Background technique

In the process of water treatment, the polymer flocculant widely used at present is a cationic flocculant containing quaternary ammonium salt or hydrochloride of ester type (such as dimethylaminomethacrylate) in the composition of polyacrylamide. This kind of flocculant has problems such as high moisture content of dewatered filter cake and weak floc strength (ie low recovery rate of suspended solids) for the production of rich organic matter and the treatment of domestic wastewater, so it is difficult to obtain sufficient dehydration effect. Japanese special open Zhao No. 58-215454 patent discloses a kind of cationic macromolecular flocculant and anionic macromolecular flocculant shared method; People such as Li Wanjie proposed a method in "Water Treatment Technology" 20 (1) in 1994: 33 A method of using a Mannich modified amphoteric polyacrylamide flocculant. The Chinese invention patent ZL97123344.6 authorized by Shen Jiarui and Peng Xiaohong in 2000 discloses an amphoteric polyacrylamide flocculant and its preparation method. Due to the simultaneous action of anion and cation in these methods, the dehydration effect has been improved to a certain extent. However, there are still some problems: 1. The selection of the mixing ratio of the components and the mixing operation of the above-mentioned anionic and cationic polymer common flocculants are very cumbersome; 2. The amphoteric polyacrylamide modified by Mannich In flocculants, cations are easy to decompose when the pH value is high, so the storage stability is not good, and it is not suitable for treating wastewater with high pH value, thus limiting its application range; 3. Amphoteric polyacrylamide prepared by patent ZL97123344.6 Colloids are difficult to granulate because of their high viscosity and poor resilience, so they are not suitable for the preparation of powder products.

Contents of the invention

The purpose of the present invention is to provide a method for preparing powdery amphoteric polyacrylamide flocculants by aqueous solution polymerization, which overcomes the shortcomings of flocculant colloids in the existing amphoteric polyacrylamide preparation technology, which are highly viscous and difficult to granulate. Anhydrous fatty acid ester and polyoxyethylene sorbitan fatty acid ester composite surfactant, the prepared amphoteric polyacrylamide colloid is not sticky, has good resilience, is easy to granulate and does not need post-addition anti-sticking agent treatment, and is easy to operate The process is simple, the energy consumption is low, the application range is wide, and the dehydration effect is good.

Powdered amphoteric polyacrylamide flocculant is composed of structural unit (I)

(R can be H and CH ₃ )

and structural unit (II)

(X can be H and Na)

and structural unit (III)

It is a terpolymer in which the ratio of anion and cationic groups formed by interlinking is 1:1 to 1:20. The pure aqueous solution with a mass percent concentration of 1% has a viscosity range of 250 to 20,000 mPa·s.

The method for preparing powdery amphoteric polyacrylamide flocculant by aqueous solution polymerization of the present invention comprises the following steps:

Step 1. In the reaction kettle, add deionized water and 10-80mol% acrylamide, and start stirring;

Add 10-80mol% of acryloyloxyethyltrimethylammonium chloride or methacryloyloxyethyltrimethylammonium chloride, 1-30mol% of acrylic acid or sodium acrylate, and stir evenly to make the monomer The total mass percentage concentration is 15-60%, and the pH value of the aqueous solution is 4.0-8.0.

Step 2. Add 1-150ppm of ethylenediaminetetraacetic acid and its sodium salt, 0.01-1% of water-soluble azo initiator relative to the total mass of monomers and 3-60‰ of sorbitan fat relative to the total mass of monomers Ester and polyoxyethylene sorbitan fatty acid ester series composite surfactants, the hydrophilic-lipophilic balance value is 5.0-10.0, start stirring, control the temperature to 10-60°C, and blow nitrogen for 5-20 minutes.

Step 3. Add 0.0001-0.1% of water-soluble oxidizing agent relative to the total mass of the monomer and 0.001-5% of water-soluble reducing agent relative to the total mass of the monomer, and stir evenly.

Step 4. Keep the same temperature, continue to polymerize for 2-24 hours, and discharge the material. After the colloid is granulated, dried and pulverized, the powdery amphoteric polyacrylamide flocculant of the present invention is obtained.

Aqueous solution polymerization prepares the method for powdery amphoteric polyacrylamide flocculant, comprises following steps and its optimal process condition:

Step 1. In the reaction kettle, add deionized water and 20-75mol% acrylamide, and start stirring;

Add 15-70mol% of acryloyloxyethyltrimethylammonium chloride or methacryloyloxyethyltrimethylammonium chloride, 2-20mol% of acrylic acid or sodium acrylate, and stir evenly to make the monomer The total mass percentage concentration is 18-45%, and the pH value of the aqueous solution is 4.0-8.0.

Step 2. Add 10-100ppm of ethylenediaminetetraacetic acid and its sodium salt, 0.05-0.5% of water-soluble azo initiator relative to the total mass of monomers and 6-30‰ of sorbitan fat relative to the total mass of monomers Ester and polyoxyethylene sorbitan fatty acid ester series composite surfactants, the hydrophilic-lipophilic balance value is 5.0-10.0, start stirring, control the temperature to 20-50°C, and blow nitrogen for 5-20 minutes.

Step 3. Add 0.001-0.05% of water-soluble oxidizing agent relative to the total mass of the monomer and 0.005-2% of water-soluble reducing agent relative to the total mass of the monomer, and stir evenly.

Step 4. Keep the same temperature, continue to polymerize for 8-16 hours, and discharge the material. After the colloid is granulated, dried and crushed, the powdery amphoteric polyacrylamide flocculant of the present invention is obtained.

The method of the present invention is that acrylic acid or sodium acrylate, acrylamide and acryloyloxyethyltrimethylammonium chloride or methacryloyloxyethyltrimethylammonium chloride monomer mixture copolymerization, for acrylic acid It is a ternary copolymerization product of monomers, and it can be post-neutralized according to the needs of the actual situation.

Compared with the prior art, the present invention has the following advantages:

1. The preparation method of the present invention uses a sorbitan fatty acid ester/polyoxyethylene sorbitan fatty acid ester series composite surfactant, and the colloidal product after polymerization is not sticky, has good resilience, and is easy to granulate and form.

2. The flocculant prepared by the method of the present invention has higher molecular weight and faster dissolution rate.

3. The flocculant prepared by the method of the present invention utilizes the synergistic effect of anion and cationic groups to make it have a larger floc diameter and a lower filter cake moisture content, which is different from the CPA-III type cationic polypropylene widely used in China now. Compared with amide flocculants, the diameter of flocs increases by 1.0-4.0mm, and the water content of filter cakes decreases by 1.0-6.5 percentage points. It can save fuel by 10-65% when burning filter cakes, and can be widely used in pH value It is 2 to 12 kinds of wastewater, and has stable performance, good flocculation and dehydration effects, energy saving, and is conducive to protecting the ecological environment, and has obvious economic and social benefits.

Detailed ways

Embodiment one

Step 1. In a jacketed reactor with a capacity of 1 liter, add 500 grams of deionized water and 13.6 grams of 20mol% acrylamide, and start stirring;

Add 130.1 g of 70 mol% acryloyloxyethyltrimethylammonium chloride and 9.0 g of 10 mol% sodium acrylate, and stir evenly.

Step 2. Add 40 grams of aqueous solution containing 0.064 gram of disodium EDTA, 50 grams of aqueous solution containing 0.100 gram of 2,2'-azo (2-amidinopropane) dihydrochloride, 2.0 gram of sorbitol Anhydrous monooleate and 0.29 g of polyoxyethylene sorbitan trioleate were started to stir, the temperature was controlled to 35° C. in a super constant temperature water bath, and nitrogen gas was passed for 15 minutes.

Step 3. Add 25 grams of aqueous solution containing 0.011 gram of ammonium persulfate and 25 grams of aqueous solution containing 0.032 gram of sodium formaldehyde sulfoxylate, stir well.

Step 4. Keep the same temperature, continue to polymerize for 16 hours, and discharge the material. After the colloid is granulated, dried and pulverized, a powdery amphoteric polyacrylamide flocculant of the present invention is obtained.

Embodiment two

Step 1. In a jacketed reactor with a capacity of 1 liter, add 300 grams of deionized water and 48.9 grams of 40mol% acrylamide, and start stirring;

Add 178.7 g of 50 mol% methacryloxyethyltrimethylammonium chloride and 12.4 g of 10 mol% acrylic acid, and stir evenly.

Step 2. Add 60 grams of aqueous solution containing 0.016 gram of disodium edetate, 50 grams of aqueous solution of 2'-azo (2-amidinopropane) dihydrochloride containing 0.240 gram, 1.5 gram of sorbitol Anhydrous monooleate and 0.9 g of polyoxyethylene sorbitan monooleate were started to stir, and the temperature was controlled to 30° C. in a super constant temperature water bath, and nitrogen gas was passed for 10 minutes.

Step 3. Add 25 grams of aqueous solution containing 0.024 gram of ammonium persulfate and 25 grams of aqueous solution containing 0.120 gram of urea, and stir evenly.

Step 4. Keep the same temperature, continue to polymerize for 12 hours, and discharge the material. After the colloid is granulated, dried and pulverized, a powdery amphoteric polyacrylamide flocculant of the present invention is obtained.

Embodiment Three

Step 1. In a jacketed reactor with a capacity of 1 liter, add 500 grams of deionized water and 60.8 grams of 60mol% acrylamide, and start stirring;

Add 88.9 g of 30 mol% methacryloyloxyethyltrimethylammonium chloride and 13.4 g of 10 mol% sodium acrylate, and stir evenly.

Step 2. Add 40 grams of aqueous solution containing 0.032 gram of disodium edetate, 50 grams of aqueous solution of 2'-azo (2-amidinopropane) dihydrochloride containing 0.266 gram, 3.5 gram of sorbitol Anhydride monolaurate and 0.6 g of polyoxyethylene sorbitan monooleate were started to stir, and the temperature was controlled to 48° C. in a super constant temperature water bath, and nitrogen gas was passed for 5 minutes.

Step 3. Add 25 grams of aqueous solution containing 0.011 gram of ammonium persulfate and 25 grams of aqueous solution containing 0.032 gram of sodium formaldehyde sulfoxylate, stir well.

Step 4. Keep the same temperature, continue to polymerize for 4 hours, and discharge the material. After the colloid is granulated, dried and pulverized, a powdery amphoteric polyacrylamide flocculant of the present invention is obtained.

Embodiment Four

Step 1. In a jacketed reactor with a capacity of 1 liter, add 300 grams of deionized water and 93.4 grams of 75mol% acrylamide, and start stirring;

Add 51.0 g of 15 mol% acryloyloxyethyltrimethylammonium chloride and 12.6 g of 10 mol% acrylic acid, and stir evenly.

Step 2. Add 40 grams of an aqueous solution containing 0.008 grams of ethylenediamine tetraacetic acid, 50 grams of an aqueous solution containing 0.266 grams of 2,2'-azo(2-amidinopropane) dihydrochloride, and 1.4 grams of sorbitan tris Oleate and 1.8 g of polyoxyethylene sorbitan trioleate were started to stir, and the temperature was controlled to 23° C. in a super constant temperature water bath, and nitrogen gas was passed for 20 minutes.

Step 3. Add 25 grams of aqueous solution containing 0.012 gram of potassium persulfate and 25 grams of aqueous solution containing 0.026 gram of sodium bisulfite, stir well.

Step 4. Keep the same temperature, continue to polymerize for 24 hours, and discharge the material. After the colloid is granulated, dried and pulverized, a powdery amphoteric polyacrylamide flocculant of the present invention is obtained.

Embodiment five

Step 1. In a jacketed reactor with a capacity of 1 liter, add 200 grams of deionized water and 36.7 grams of 45mol% acrylamide, and start stirring;

Add 111.2 g of 50 mol% acryloxyethyltrimethylammonium chloride and 4.1 g of 5 mol% acrylic acid, and stir evenly.

Step 2. Add 40 grams of aqueous solution containing 0.032 gram of disodium EDTA, 50 grams of aqueous solution containing 0.533 gram of 2,2'-azo [2-(N-n-butyl) amidinopropane] dihydrochloride gram, 0.7 gram of sorbitan monooleate and 0.26 gram of polyoxyethylene sorbitan monopalmitate, started stirring, controlled the temperature to 40°C in a super constant temperature water bath, and passed nitrogen for 10 minutes.

Step 3. Add 25 grams of an aqueous solution containing 0.012 grams of potassium persulfate and 25 grams of an aqueous solution containing 2.580 grams of urea, and stir evenly.

Step 4. Keep the same temperature, continue to polymerize for 8 hours, and discharge the material. After the colloid is granulated, dried and pulverized, a powdery amphoteric polyacrylamide flocculant of the present invention is obtained.

Embodiment six

Step 1. In a jacketed reactor with a capacity of 1 liter, add 250 grams of deionized water and 101.3 grams of 50mol% acrylamide, and start stirring;

Add 177.6 grams of 30 mol% methacryloyloxyethyltrimethylammonium chloride and 41.1 grams of 20 mol% acrylic acid, and stir evenly.

Step 2. Add 80 grams of aqueous solution containing 0.016 gram of ethylenediamine tetraacetic acid, 50 grams of aqueous solution containing 0.533 gram of 2,2'-azo (2-amidinopropane) dihydrochloride, 5.6 gram of sorbitan three Oleate and 4.0 g of polyoxyethylene sorbitan monooleate were started to stir, the temperature was controlled to 27° C. in a super constant temperature water bath, and nitrogen gas was passed for 10 minutes.

Step 3. Add 25 grams of aqueous solution containing 0.005 gram of ammonium persulfate and 25 grams of aqueous solution containing 0.016 gram of sodium bisulfite, stir well.

Step 4. Keep the same temperature, continue to polymerize for 12 hours, and discharge the material. After the colloid is granulated, dried and pulverized, a powdery amphoteric polyacrylamide flocculant of the present invention is obtained.

Embodiment seven

Step 1. In a jacketed reactor with a capacity of 1 liter, add 200 grams of deionized water and 78.6 grams of 58mol% acrylamide, and start stirring;

Add 74.0 g of 20 mol% acryloxyethyltrimethylammonium chloride, 79.3 g of 20mol% methacryloxyethyltrimethylammonium chloride and 3.7 g of 2mol% sodium acrylate, and stir evenly.

Step 2. Add 60 grams of aqueous solution containing 0.016 gram of disodium edetate, 50 grams of aqueous solution containing 0.400 gram of 2,2,-azo [2-(N-benzyl) amidinopropane] dihydrochloride , 1.2 grams of sorbitan trioleate and 1.2 grams of polyoxyethylene sorbitan monostearate, start stirring, control the temperature to 37 ° C in a super constant temperature water bath, and pass nitrogen for 15 minutes.

Step 3. Add 25 grams of aqueous solution containing 0.120 gram of ammonium persulfate and 25 grams of aqueous solution containing 0.360 gram of sodium formaldehyde sulfoxylate, stir well.

Step 4. Keep the same temperature, continue to polymerize for 16 hours, and discharge the material. After the colloid is granulated, dried and pulverized, a powdery amphoteric polyacrylamide flocculant is obtained.

The powdery amphoteric polyacrylamide flocculant prepared in each example was used to treat the biochemical sludge of Guangzhou Datansha Sewage Treatment Plant. is 4.7%, the pH value is 7.5, and the addition amount of the sample to the solid content in the biochemical sludge is 1.00%, and the processing data are shown in Table 1 and Table 2 below:

Table 1

DAC or DMC/AA or AANa/AM composition (mol%) Colloidal charge density (meq/g)pH3pH11 1% aqueous solution viscosity (mPa·s) 0.1% aqueous solution dissolution rate (min) Embodiment one 70/10/20 2.90-0.20 6200 40 Embodiment two 50/10/40 2.77-0.16 3750 46 Embodiment three 30/10/60 1.82-0.06 5920 52 Embodiment four 15/10/75 0.75-0.05 4450 38 Embodiment five 50/5/45 2.79-0.45 8150 50 Embodiment six 30/20/50 1.48-0.03 3500 63 Embodiment seven 40/2/58 2.23-0.92 4200 55

Note: DAC = acryloyloxyethyltrimethylammonium chloride

DMC = methacryloyloxyethyltrimethylammonium chloride

AA = acrylic acid

AANa = sodium acrylate

AM = acrylamide

The data in Table 1 shows that because the flocculant of the present invention has a high viscosity, its dosage can be reduced, thereby saving the dosage, and because of its fast dissolution rate, it is beneficial to practical application.

Table 2

Addition rate (%) Floc diameter (mm) Moisture content of dehydrated filter cake (%) Filterability Embodiment 1 1.00 7.0 75.10 good Example 2 1.00 6.0 76.45 good Example three 1.00 7.0 74.26 good Embodiment four 1.00 4.0 77.89 good Example five 1.00 7.5 73.04 good Embodiment six 1.00 4.5 78.91 good Embodiment Seven 1.00 5.0 78.78 good

The data in Table 2 illustrate the application effect of the flocculant of the present invention: the flocculant of the present invention has larger flocs, and the water content of the dewatered filter cake is lower, so the filterability is better, and the flocculation and dehydration effect is better.

Claims (2)

1, a kind of aqueous solution polymerization prepares the method for powdery amphoteric polyacrylamide flocculant, it is characterized in that comprising the steps:

Step 1. adds the acrylamide of deionized water and 10～80mol% in reactor, start stirring;

The acryloxy ethyl-trimethyl salmiac or the methacryloxyethyl trimethyl ammonium chloride monomer that add 10～80mol%, the vinylformic acid of 1～30mol% or sodium acrylate monomers, stir, making monomer total mass per-cent total concn is 15～60%, and pH value of water solution is 4.0～8.0;

Step 2. adds ethylenediamine tetraacetic acid (EDTA) or its sodium salt of 1～150ppm, the water-soluble azo initiator of relative monomer total mass 0.01～1% and the sorbitan-fatty acid ester and the polyoxyethylene sorbitan fatty acid ester complexed surfactant of relative monomer total mass 3～60 ‰, the hydrophile-lipophile balance value of described complexed surfactant is 5.0～10.0, start stirring, temperature control to 10～60 ℃, logical nitrogen 5～20 minutes;

Step 3. adds the water-soluble oxidizers of relative monomer total mass 0.0001～0.1% and the water-soluble reductive agent of relative monomer total mass 0.001～5%, stirs;

Step 4. keeps same temperature, continues polymerization 2～24 hours, discharging, and colloid promptly gets the powdery amphoteric polyacrylamide flocculant after granulation, drying, pulverizing.

2. method according to claim 1 is characterized in that:

Step 1. adds the acrylamide of deionized water and 20～75mol% in reactor, start stirring;

The acryloxy ethyl-trimethyl salmiac or the methacryloxyethyl trimethyl ammonium chloride monomer that add 15～70mol%, the vinylformic acid of 2～20mol% or sodium acrylate monomers, stir, making monomer total mass per-cent total concn is 18～45%, and pH value of water solution is 4.0～8.0;

Step 2. adds ethylenediamine tetraacetic acid (EDTA) or its sodium salt of 10～100ppm, the water-soluble azo initiator of relative monomer total mass 0.05～0.5% and the sorbitan-fatty acid ester and the polyoxyethylene sorbitan fatty acid ester complexed surfactant of relative monomer total mass 6～30 ‰, the hydrophile-lipophile balance value of described complexed surfactant is 5.0～10.0, start stirring, temperature control to 20～50 ℃, logical nitrogen 5～20 minutes;

Step 3. adds the water-soluble oxidizers of relative monomer total mass 0.001～0.05% and the water-soluble reductive agent of relative monomer total mass 0.005～2%, stirs;

Step 4. keeps same temperature, continues polymerization 8～16 hours, discharging, and colloid promptly gets the powdery amphoteric polyacrylamide flocculant after granulation, drying, pulverizing.