CN103102459B - Preparation method of gelatin grafted acrylamide cation polymeric flocculant - Google Patents

Abstract

The invention relates to a preparation method of a gelatin grafted acrylamide cation polymeric flocculant. Current flocculant in leather wastewater treatment is easy to cause secondary pollution to the environment. The method comprises the following steps of: firstly, adding dried gelatin into deionized water; uniformly stirring and adding a catalyst; reacting for 40-60 minutes in the presence of nitrogen; then, adding acrylamide; after reaction, preparing a grafted copolymer; and then, adding a glutaraldehyde liquor and a dimethylamine liquor into the grafted copolymer, stirring and reacting for 2-4.5 hours at 45-65 DEG C, and cooling and discharging to obtain the product. The gelatin grafted acrylamide cation polymeric flocculant prepared by the method provided by the invention is good in flocculating effect, quicker in sedimentation rate, low in cost and small in pollution, and can be completely biologically degraded.

Description

A kind of preparation method of gelatin grafted acrylamide cationic polymer flocculant

technical field

The invention belongs to the technical field of sewage treatment, and relates to a preparation method of a flocculant, in particular to a preparation method of a gelatin-grafted acrylamide cationic polymer flocculant.

Background technique

While the leather industry produces huge economic and social benefits, it also causes certain pollution to the environment. During the tanning process, only 20% of the skin weight of the raw material is converted into finished leather, and the rest is discarded as solid waste such as cutting, cutting, grinding and trimming scraps during the tanning process. At the same time, the sewage discharged by leather enterprises contains a large amount of COD, chromium and suspended solids. These are all important factors that cause serious pollution in the leather industry.

Synthetic organic polymer flocculants used in the treatment of tannery wastewater mainly include anionic and nonionic organic polymer flocculants such as polyacrylamide and its derivatives, sodium polyacrylate, polysulfostyrene, poly Ethylene oxide, urea-formaldehyde resin and polyvinyl alcohol, etc.

The problem of residual toxic monomers in polyacrylamide polymer flocculants has not yet been effectively resolved. A similar situation also exists in the preparation of urea-formaldehyde resin and polyvinyl alcohol. These two types of flocculants are high polymers with low relative molecular weight, and their flocculation performance is relatively poor.

At present, most of the flocculants used in the treatment of tannery wastewater are organic synthetic polymer flocculants, among which polyacrylamide polymer flocculants are the most widely used. Although this type of flocculant has the structural characteristics of relatively large molecular weight and many active functional groups in the molecular chain, it has a fatal weakness. Most of them are slightly toxic and affect human health, and their residues are not easy to be biodegraded. Cause secondary pollution, but restrict the sustainable and healthy development of the leather industry. Therefore, on the basis of graft copolymers, using the advantages of natural polymer raw materials to synthesize grafted polymer flocculants is an idea worth exploring.

Contents of the invention

The object of the present invention is to provide a preparation method of gelatin-grafted acrylamide cationic polymer flocculant against the deficiencies of the prior art.

The concrete steps of the inventive method are as follows:

Step (1). Graft copolymerization reaction: Add dry gelatin to deionized water, stir evenly, then add catalyst, under nitrogen protection condition, 35℃～55℃ for 40～60 minutes, then add acrylamide, 45℃～ React at 70°C for 3 to 6 hours to obtain a graft copolymer; add 50 to 150 grams of dry gelatin, 2 to 20 grams of catalyst, and 150 to 500 grams of acrylamide per liter of deionized water;

Described gelatin is the gelatin of 100～280 bloom;

As preferably, described gelatin is the gelatin of 250 bloom;

The catalyst is one or more of cerium ammonium nitrate, hydrogen peroxide, sodium bisulfite, and persulfate; when multiple, the ratio is any ratio;

Described catalyst is the mixture that sodium bisulfite and persulfate are mixed in any ratio;

Described persulfate is all persulfates;

Step (2). Amination reaction: Add glutaraldehyde solution and dimethylamine solution to the prepared graft copolymer, stir and react at 45-65°C for 2-4.5 hours, cool and discharge, and obtain gelatin grafted copolymer. Branched acrylamide cationic polymer flocculant;

The mass ratio of glutaraldehyde solution to dry gelatin added to the reaction system is 0.13-1:1, and the mass ratio of dimethylamine solution to dry gelatin is 0.13-1:1;

The mass content of glutaraldehyde in the described glutaraldehyde solution is 35～50%;

The mass content of dimethylamine in the dimethylamine solution is 33-40%.

As a preference, the mass content of glutaraldehyde in the glutaraldehyde solution is 45%, and the mass content of dimethylamine in the dimethylamine solution is 40%.

The beneficial effects that the present invention has:

1. The gelatin-grafted acrylamide cationic polymer flocculant of the present invention has the following advantages: (1) the dosage is small, and when the flocculant addition is 1.5-4 mg/L, the flocculation effect is better; (2) the flocculation effect is good, The flocs are formed quickly, the particles are large, and the sedimentation rate is fast; (3) low cost; (4) less pollution.

2. The graft copolymerization polymer flocculant has some excellent characteristics of both natural polymer compounds and synthetic polymer compounds, which are mainly reflected in the enhanced flocculation ability, increased molecular chain stability, and easier cationization. There are a large number of polar groups and surface active points on its molecular chain, so it can produce flocculation effect through adsorption bridging or electrical neutralization of polymers. At the same time, it is completely biodegradable and has good "environmental acceptability", so it is in line with the current national requirements for promoting green environmental protection projects.

Detailed ways

Example 1:

Step (1). Graft copolymerization reaction: Add 50.0 grams of dry 100 bloom gelatin to 1L of deionized water, stir evenly, then add 2 grams of ammonium cerium nitrate, react at 35°C for 60 minutes under nitrogen protection, and then add 150 gram of acrylamide, reacted for 6 hours at 45°C to obtain a graft copolymer;

Step (2). Amination reaction: 50.0 grams of 35% glutaraldehyde solution and 50.0 grams of 33% dimethylamine solution were added to the prepared graft copolymer and stirred at 45°C After reacting for 4.5 hours, cooling and discharging, the gelatin-grafted acrylamide cationic polymer flocculant was prepared.

Example 2:

Step (1). Graft copolymerization reaction: Add 100 grams of dry 250 bloom gelatin to 1L deionized water, stir evenly, then add 10 grams of hydrogen peroxide, react at 50°C for 45 minutes under nitrogen protection, and then add 300 gram of acrylamide, reacted for 4.5 hours at 57°C to obtain a graft copolymer;

Step (2). Amination reaction: 13 grams of glutaraldehyde solution with a mass content of 50% and 13 grams of dimethylamine solution with a mass content of 40% are added to the prepared graft copolymer, stirred at 55°C React for 3.5 hours, cool and discharge to prepare gelatin grafted acrylamide cationic polymer flocculant.

Example 3:

Step (1). Graft copolymerization reaction: Add 150 grams of dry 280 bloom gelatin to 1L deionized water, stir evenly, then add 20 grams of sodium bisulfite, react at 55°C for 40 minutes under nitrogen protection, and then add 500 grams of acrylamide were reacted for 3 hours at 70° C. to obtain a graft copolymer;

Step (2). Amination reaction: adding 75 grams of glutaraldehyde solution with a mass content of 45% and 75 grams of dimethylamine solution with a mass content of 37% into the prepared graft copolymer, stirring at 65°C React for 2 hours, cool and discharge to prepare gelatin-grafted acrylamide cationic polymer flocculant.

Example 4:

Step (1). Graft copolymerization reaction: Add 60 grams of dry 150 bloom gelatin to 1L deionized water, stir evenly, then add 6 grams of sodium persulfate, react at 40°C for 55 minutes under nitrogen protection, and then add 200 gram of acrylamide, reacted for 5.5 hours at 50°C to obtain a graft copolymer;

Step (2). Amination reaction: adding 48 grams of glutaraldehyde solution with a mass content of 40% and 48 grams of dimethylamine solution with a mass content of 35% into the prepared graft copolymer, stirring at 50°C React for 4 hours, cool and discharge to prepare gelatin grafted acrylamide cationic polymer flocculant.

Example 5:

Step (1). Graft copolymerization reaction: Add 80 grams of dry 200 bloom gelatin to 1L deionized water, stir evenly, then add 15 grams of potassium persulfate, react at 45°C for 50 minutes under nitrogen protection, and then add 250 gram of acrylamide, reacted for 5 hours at 60°C to obtain a graft copolymer;

Step (2). Amination reaction: adding 48 grams of glutaraldehyde solution with a mass content of 40% and 48 grams of dimethylamine solution with a mass content of 35% into the prepared graft copolymer, stirring at 60°C React for 3 hours, cool and discharge to prepare gelatin grafted acrylamide cationic polymer flocculant.

Embodiment 6:

Step (1). Graft copolymerization reaction: add 120 grams of dry 250 bloom gelatin to 1L deionized water, stir evenly, then add 6 grams of sodium bisulfite and 6 grams of sodium persulfate, under nitrogen protection conditions, 48 ° C React for 50 minutes, then add 350 grams of acrylamide, and react for 4 hours at 65°C to obtain a graft copolymer;

Step (2). Amination reaction: 48 grams of glutaraldehyde solution with a mass content of 45% and 48 grams of dimethylamine solution with a mass content of 40% are added to the prepared graft copolymer, stirred at 60°C React for 3 hours, cool and discharge to prepare gelatin grafted acrylamide cationic polymer flocculant.

Embodiment 7:

Step (1). Graft copolymerization reaction: add 140 grams of dry 230 bloom gelatin to 1L deionized water, stir evenly, then add 8 grams of hydrogen peroxide and 8 grams of sodium persulfate, and react at 52 ° C under nitrogen protection conditions After 43 minutes, add 450 grams of acrylamide and react at 65°C for 3.5 hours to obtain a graft copolymer;

Step (2). Amination reaction: adding 28 grams of glutaraldehyde solution with a mass content of 48% and 28 grams of dimethylamine solution with a mass content of 38% into the prepared graft copolymer, stirring at 63°C React for 2.5 hours, cool and discharge to prepare gelatin grafted acrylamide cationic polymer flocculant.

Claims (5)

1. a preparation method for gelatin graft acrylamide cation polymeric flocculant, is characterized in that the method comprises the following steps:

Step (1). graft copolymerization: dry gelatin is added in deionized water, stirs, then add catalyzer, under nitrogen protection condition, 35 DEG C ~ 55 DEG C are reacted 40 ~ 60 minutes, then add acrylamide, react 3 ~ 6 hours at 45 DEG C ~ 70 DEG C, obtained graft copolymer; 50 ~ 150 grams of dry gelatin, 2 ~ 20 grams of catalyzer, 150 ~ 500 grams of acrylamides are added in often liter of deionized water;

Described catalyzer is one or more in ceric ammonium nitrate, hydrogen peroxide, sodium bisulfite, persulphate; When for time multiple, ratio be arbitrarily than;

Step (2). aminated reaction: glutaraldehyde solution and dimethylamine solution are added in obtained graft copolymer, stirring reaction 2 ~ 4.5 hours at 45 ~ 65 DEG C, cooling discharging, obtained gelatin graft acrylamide cation polymeric flocculant;

The mass ratio of the glutaraldehyde solution added in reaction system and dry gelatin is 0.13 ~ 1:1, and the mass ratio of dimethylamine solution and dry gelatin is 0.13 ~ 1:1;

Gelatin described in step (1) is the gelatin of 100 ~ 280bloom.

2. the preparation method of a kind of gelatin graft acrylamide cation polymeric flocculant as claimed in claim 1, is characterized in that the gelatin described in step (1) is the gelatin of 250bloom.

3. the preparation method of a kind of gelatin graft acrylamide cation polymeric flocculant as claimed in claim 1, is characterized in that the catalyzer described in step (1) is the mixture that sodium bisulfite and persulphate are mixed by any ratio.

4. the preparation method of a kind of gelatin graft acrylamide cation polymeric flocculant as claimed in claim 1, it is characterized in that the mass content of glutaraldehyde in the glutaraldehyde solution described in step (2) is 35 ~ 50%, in described dimethylamine solution, the mass content of dimethylamine is 33 ~ 40%.

5. the preparation method of a kind of gelatin graft acrylamide cation polymeric flocculant as claimed in claim 1, the mass content that it is characterized in that glutaraldehyde in the glutaraldehyde solution described in step (2) is 45%, and in dimethylamine solution, the mass content of dimethylamine is 40%.