A flocculant production and processing technology

Abstract

The invention discloses a flocculant production and processing technology, belonging to the technical field of wastewater treatment. The invention uses natural guar gum as raw material, has the advantages of wide source, low cost, biodegradability, etc., and conforms to the current trend of environmental protection and resource conservation; the invention has a simple preparation process, low cost, and is easy to implement.

Description

Technical Field

[0001] The invention relates to the technical field of wastewater treatment, and in particular to a flocculant production and processing technology. Background Art

[0002] Flocculants are an important chemical agent widely used in water treatment. They are mainly used for the aggregation and precipitation of soluble pollutants and to improve the removal efficiency of suspended solids in water bodies. Flocculants can be generally divided into two categories according to their chemical composition: inorganic flocculants and organic flocculants. Currently, common inorganic polymer coagulants can be roughly divided into aluminum-based, iron-based, and composite polymer coagulants with silicon polymers as skeletons. Aluminum-based and iron-based inorganic polymer coagulants achieve efficient adsorption and sedimentation treatment of wastewater by changing the polymerization state of aluminum and iron ions in the water environment to give them a higher molecular weight; however, the effect of inorganic flocculants is affected by environmental factors such as ion composition, temperature, pH, and so on in the water, and their adaptability may be insufficient.

[0003] Organic flocculants are divided into synthetic organic polymer flocculants and natural polymer flocculants. Organic polymer flocculants are the first choice because they are easy to handle, have low dosage requirements, are less sensitive to system pH, have greater cohesion between floccules, and are easy to synthesize, but most of them are toxic.

[0004] Chinese patent document CN110040834A discloses a non-toxic and environmentally friendly all-natural composite flocculant and its application. The composite flocculant is a solid composite flocculant prepared by mass percentage of 20%-40% chitosan, 15%-30% citric acid, less than 20% oxalic acid, 30-60% sodium diacetate, and 1%-5% guar gum. The present invention provides an application of the above composite flocculant. The components in the composite flocculant according to the present invention work synergistically and show good flocculation performance. Moreover, the composite flocculant according to the present invention is in solid form, and the effect will not decrease if used within one year after being prepared into a liquid composite flocculant, so it is convenient for transportation and long-term storage, and solves the problem of fast degradation of polyacrylamide, a commonly used flocculant. The patent directly uses guar gum and other substances for compounding, which solves the problem of fast degradation of polyacrylamide, but the patent has the defect that guar gum is easy to agglomerate in water when used as a flocculant, thereby affecting its flocculation effect. Summary of the invention

[0005] The main purpose of the present invention is to propose a flocculant production and processing technology, which uses natural flocculant guar gum as a raw material, and grafts ionic liquid-modified polyacrylamide onto guar gum molecules. The ionic liquid can synergistically play a flocculation role with polyacrylamide and guar gum, thereby forming a multi-adsorption layer network structure. The network structure has better adsorption bridging performance and significantly improves the flocculation effect of guar gum.

[0006] To achieve the above object, the present invention proposes a flocculant production and processing technology, comprising the following steps:

[0007] S1, mixing guar gum and water and heating until the guar gum is completely dissolved, adding diethylenetriamine and epichlorohydrin, heating to continue the reaction, cooling, filtering, and freeze-drying the solid to obtain amino guar gum;

[0008] S2, dispersing the amino guar gum in water, adding acrylamide-2-methylpropane sulfonic acid, adjusting the pH value to 8-10, heating for reaction, cooling to room temperature, distilling off the solvent under reduced pressure, and drying the residue to obtain acrylamide-modified guar gum;

[0009] S3. Under the protection of N2, acrylamide-modified guar gum and initiator are added into water, 1-allyl-methylimidazole chloride is added dropwise, and the mixture is heated for reaction. After the reaction is completed, the mixture is cooled, the solvent is evaporated under reduced pressure, and then the mixture is mixed with bentonite and stirred to obtain the flocculant.

[0010] Preferably, in step S1, the mass ratio of guar gum, diethylenetriamine and epichlorohydrin is 20-30:10-15:5-8.

[0011] Preferably, in step S2, the mass ratio of the amino guar gum to 2-acrylamide-2-methylpropane sulfonic acid is 2-3:3-4; the heating temperature is 50-75° C.; and the reaction time is 2-4 h.

[0012] Preferably, in step S3, the initiator is one of benzoyl peroxide and azobisisobutyronitrile; the mass ratio of acrylamide-modified guar gum, 1-allyl-methylimidazole chloride and bentonite is 1.5-2.5:1-2:5-10; the amount of the initiator added is 1-2% of the total mass of amino guar gum and 1-allyl-methylimidazole chloride; the dripping speed is 1-2 drops / second; the heating temperature is 60-80°C, and the heating time is 4-6h.

[0013] The present invention also claims protection for a flocculant prepared using the above flocculant production and processing technology.

[0014] Compared with the prior art, the present invention has the following beneficial effects:

[0015] 1) The present invention provides a flocculant, which uses natural guar gum as a raw material, has the advantages of wide sources, low cost, and biodegradability, and is in line with the current trend of environmental protection and resource conservation; the present invention has a simple preparation process, low cost, and is easy to implement;

[0016] 2) The raw material guar gum of the present invention is a natural organic polymer flocculant, but its flocculation effect is limited. Its molecular structure contains multiple active hydroxyl groups, and it can react with diethylenetriamine under the action of epichlorohydrin to generate amino guar gum; then acrylamide-2-methylpropane sulfonic acid is grafted onto the guar gum molecule to obtain acrylamide-modified tara gum; the modified tara gum has better dispersibility and will not agglomerate. In addition, the grafted acrylamide-2-methylpropane sulfonic acid can provide carbon-carbon double bonds, which is beneficial to subsequent reactions. By reacting with ionic liquid 1-allyl-methylimidazole chloride, ionic liquid-modified polyacrylamide can be obtained. The ionic liquid-modified polyacrylamide is grafted onto the guar gum, and the ionic liquid can synergistically exert a flocculation effect with polyacrylamide and guar gum, thereby forming a multi-adsorption layer network structure, which has better adsorption bridging performance and improves the flocculation effect of the guar gum;

[0017] 3) The bentonite used in the present invention is mainly composed of montmorillonite, which not only has good adsorption capacity for organic matter, but also can provide a carrier for flocculation and precipitation, thereby improving the coagulation and sedimentation performance of flocs. Combining it with guar gum is beneficial to improving the flocculation effect of the flocculant. DETAILED DESCRIPTION

[0018] To avoid redundancy, the items used in the following examples are all commercially available products unless otherwise specified, and the methods used are all conventional methods unless otherwise specified.

[0019] The sources of some raw materials used in the present invention are as follows:

[0020] Guar gum, content 99%, was purchased from Jinan Daorong Chemical Co., Ltd.

[0021] Bentonite, 325 mesh, was purchased from Sishui County Hengjian Bentonite Co., Ltd.

[0022] Example 1

[0023] A flocculant production and processing process comprises the following steps:

[0024] S1, 25.6g guar gum was mixed with 400mL water and heated to 60°C until the guar gum was completely dissolved, 10-15g diethylenetriamine and 5-8g epichlorohydrin were added, the mixture was reacted at 60°C for 2h, then cooled and filtered, and the solid was freeze-dried to obtain amino guar gum;

[0025] S2, dispersing 22.3 g of amino guar gum in 200 mL of water, adding 35.5 g of acrylamide-2-methylpropane sulfonic acid, adjusting the pH value to 9, reacting at 65 ° C for 3 h, cooling to room temperature, distilling off the solvent under reduced pressure, and drying the residue to obtain acrylamide-modified guar gum;

[0026] S3. Under N2 protection, add 20 g of acrylamide-modified guar gum and 0.5 g of benzoyl peroxide into 300 mL of water, add 15.5 g of 1-allyl-methylimidazole chloride at a rate of 2 drops / second, heat at 70°C for 5 h, cool after the reaction is completed, evaporate the solvent under reduced pressure, mix with 80 g of bentonite and stir to obtain the flocculant.

[0027] Example 2

[0028] S1, 20.3 g of guar gum was mixed with 400 mL of water and heated to 60° C. until the guar gum was completely dissolved, 10.2 g of diethylenetriamine and 5.3 g of epichlorohydrin were added, the mixture was reacted at 60° C. for 2 h, then cooled and filtered, and the solid was freeze-dried to obtain amino guar gum;

[0029] S2, dispersing 20 g of amino guar gum in 200 mL of water, adding 30 g of acrylamide-2-methylpropane sulfonic acid, adjusting the pH value to 8, reacting at 50 ° C for 4 h, cooling to room temperature, distilling off the solvent under reduced pressure, and drying the residue to obtain acrylamide-modified guar gum;

[0030] S3. Under N2 protection, 15 g of acrylamide-modified guar gum and 0.25 g of azobisisobutyronitrile were added to 300 mL of water, 10.3 g of 1-allyl-methylimidazole chloride was added dropwise at a rate of 1 drop / second, and the mixture was heated at 60°C for 6 h. After the reaction was completed, the mixture was cooled, the solvent was evaporated under reduced pressure, and then mixed with 50 g of bentonite and stirred to obtain the flocculant.

[0031] Example 3

[0032] S1, 30g guar gum was mixed with 400mL water and heated to 60°C until the guar gum was completely dissolved, 15g diethylenetriamine and 7.8g epichlorohydrin were added, the reaction was continued at 60°C for 2h, then cooled and filtered, and the solid was freeze-dried to obtain amino guar gum;

[0033] S2, dispersing 30g of amino guar gum in 200mL of water, adding 49.5% acrylamide-2-methylpropanesulfonic acid, adjusting the pH value to 10, reacting at 75°C for 2h, cooling to room temperature, distilling off the solvent under reduced pressure, and drying the residue to obtain acrylamide-modified guar gum;

[0034] S3. Under N2 protection, add 25 g of acrylamide-modified guar gum and 0.9 g of benzoyl peroxide into water, add 20 g of 1-allyl-methylimidazole chloride at a rate of 2 drops / second, heat at 80°C for 4 h, cool after the reaction is completed, evaporate the solvent under reduced pressure, and mix with 100 g of bentonite and stir to obtain the flocculant.

[0035] Comparative Example 1

[0036] A flocculant production and processing process is similar to Example 1, except that 1-allyl-methylimidazole chloride is not added, and specifically comprises the following steps:

[0037] S1, 25.6g guar gum was mixed with 400mL water and heated to 60°C until the guar gum was completely dissolved, 10-15g diethylenetriamine and 5-8g epichlorohydrin were added, the mixture was reacted at 60°C for 2h, then cooled and filtered, and the solid was freeze-dried to obtain amino guar gum;

[0038] S2, dispersing 22.3 g of amino guar gum in 200 mL of water, adding 35.5 g of acrylamide-2-methylpropane sulfonic acid, adjusting the pH value to 9, reacting at 65 ° C for 3 h, cooling to room temperature, distilling off the solvent under reduced pressure, and drying the residue to obtain acrylamide-modified guar gum;

[0039] S3, 20 g of acrylamide-modified guar gum and 80 g of bentonite are mixed and stirred uniformly to obtain the flocculant.

[0040] Comparative Example 2

[0041] A flocculant production and processing process, the difference is that the flocculant is a mixture of amino guar gum and bentonite, specifically comprising the following steps:

[0042] S1, 25.6g guar gum was mixed with 400mL water and heated to 60°C until the guar gum was completely dissolved, 10-15g diethylenetriamine and 5-8g epichlorohydrin were added, the mixture was reacted at 60°C for 2h, then cooled and filtered, and the solid was freeze-dried to obtain amino guar gum;

[0043] S2. Mix 20 g of amino guar gum and 80 g of bentonite and stir evenly to obtain the flocculant.

[0044] Comparative Example 3

[0045] A flocculant production and processing technology comprises the following steps: 20g of guar gum and 80g of bentonite are mixed and stirred uniformly to obtain the flocculant.

[0046] Performance Testing

[0047] Taking the printing and dyeing wastewater of a certain factory as the object, the flocculants prepared in Examples 1 to 3 and Comparative Examples 1 to 3 were used to test the flocculation effect of the printing and dyeing wastewater. The tests were carried out simultaneously in 6 sedimentation tanks, and the flocculant dosage was 0.2 g / L. After stirring, the wastewater was allowed to stand for 20 minutes. The chemical oxygen demand, suspended solids, decolorization rate, heavy metal ion removal rate and other parameters of the sewage before and after the addition of the flocculant were determined; the determination of COD (chemical oxygen demand) refers to HJ828-2017 "Determination of Chemical Oxygen Demand of Water Quality by Dichromate Method", and the determination of SS (suspended solids) refers to GB11901-1989 "Determination of Suspended Solids in Water Quality by Gravimetric Method". The decolorization rate was determined by UV-Vis spectrophotometer. The test results are shown in Table 1:

[0048] Table 1 Flocculant performance test results

[0049]

[0050] The above are only preferred embodiments of the present invention, and do not limit the patent scope of the present invention. For those skilled in the art, the present invention may have various changes and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the patent protection scope of the present invention.

Claims

1. A flocculant production and processing process, characterized in that: The steps include: S1, mixing guar gum and water and heating until the guar gum is completely dissolved, adding diethylenetriamine and epichlorohydrin, heating to continue the reaction, cooling, filtering, and freeze-drying the solid to obtain amino guar gum; S2, dispersing the amino guar gum in water, adding acrylamide-2-methylpropane sulfonic acid, adjusting the pH value to 8-10, heating for reaction, cooling to room temperature, distilling off the solvent under reduced pressure, and drying the residue to obtain acrylamide-modified guar gum; S3. Under the protection of N2, acrylamide-modified guar gum and initiator are added into water, 1-allyl-methylimidazole chloride is added dropwise, and the mixture is heated for reaction. After the reaction is completed, the mixture is cooled, the solvent is evaporated under reduced pressure, and then the mixture is mixed with bentonite and stirred to obtain the flocculant.

2. The flocculant production and processing process according to claim 1, characterized in that: In the step S1, the mass ratio of guar gum, diethylenetriamine and epichlorohydrin is 20-30:10-15:5-8.

3. The flocculant production and processing process according to claim 1, characterized in that: In the step S2, the mass ratio of the amino guar gum to the 2-acrylamide-2-methylpropane sulfonic acid is 2-3:3-4.

4. The flocculant production and processing process according to claim 1, characterized in that: In step S2, the heating temperature is 50-75° C. and the reaction time is 2-4 hours.

5. The flocculant production and processing process according to claim 1, characterized in that: In step S3, the initiator is one of benzoyl peroxide and azobisisobutyronitrile.

6. The flocculant production and processing process according to claim 1, characterized in that: In the step S3, the mass ratio of acrylamide-modified guar gum, 1-allyl-methylimidazole chloride, and bentonite is 1.5-2.5:1-2:5-10.

7. The flocculant production and processing process according to claim 1, characterized in that: The amount of the initiator added in step S3 is 1-2% of the total mass of the amino guar gum and 1-allyl-methylimidazole chloride.

8. The flocculant production and processing process according to claim 1, characterized in that: The dripping speed in step S3 is 1-2 drops / second.

9. The flocculant production and processing process according to claim 1, characterized in that: In step S3, the heating temperature is 60-80° C. and the heating time is 4-6 hours.

10. A flocculant, characterized in that: The invention is prepared by the production and processing technology of any one of claims 1 to 9.

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