A preparation method of modified polyferric sulfate for treating industrial wastewater

Abstract

The invention discloses a preparation method of modified polyferric sulfate for treating industrial wastewater, and belongs to the technical field of industrial wastewater treatment. Ferric sulfate is dissolved in distilled water by stirring, and sodium hydroxide aqueous solution is slowly added at 20°C for aging to obtain polyferric sulfate; modified polyacrylamide is prepared into polyacrylamide aqueous solution; the obtained polyferric sulfate and the obtained polyacrylamide aqueous solution are fully stirred to mix uniformly to prepare modified polyferric sulfate. There is a chemical reaction between the polyacrylamide and the auxiliary agent in the modified polyacrylamide of the present invention, and the auxiliary agent contains a quaternary ammonium salt structure, and the modified polyferric sulfate of the present invention is obtained by mixing modified polyacrylamide and polyferric sulfate. Therefore, the use of the modified polyferric sulfate of the present invention can not only improve the removal rate of chemical oxygen demand, suspended matter and other harmful impurities in industrial wastewater, but also effectively eliminate pathogenic bacteria in industrial wastewater to avoid health hazards.

Description

Technical Field

[0001] The invention belongs to the technical field of industrial wastewater treatment, and in particular relates to a method for preparing modified polyferric sulfate for treating industrial wastewater. Background Art

[0002] With the industrialization of human society, water pollution caused by industrial wastewater has a negative impact on the ecological environment and human life. Polyferric sulfate is an inorganic polymer flocculant developed in recent years. Compared with traditional flocculants such as ferric chloride, aluminum sulfate, ferric chloride sulfate, etc., it has the advantages of low production cost, small dosage in the purification process, wide applicable pH range, high impurity (turbidity, chemical oxygen demand, suspended solids, etc.) removal rate, low residue concentration, and good decolorization effect.

[0003] Pollutants such as suspended solids, organic matter, heavy metal ions and pathogenic bacteria in industrial wastewater can cause great harm to human health. Among them, the public health problems caused by pathogenic bacterial infections are particularly serious. Various pathogens and intestinal bacteria seriously endanger the health of humans and animals. Although polyferric sulfate can partially separate and remove bacteria in water, it cannot effectively inhibit or kill these bacteria. Therefore, it is extremely important to enhance the antibacterial properties of polyferric sulfate, efficiently remove harmful microorganisms such as algae, bacteria and pathogens, and develop modified polyferric sulfate with dual functions of flocculation and antibacterial. Summary of the invention

[0004] The purpose of the present invention is to overcome the defects of the prior art and provide a method for preparing modified polyferric sulfate for treating industrial wastewater.

[0005] The purpose of the present invention can be achieved through the following technical solutions:

[0006] A method for preparing modified polyferric sulfate for treating industrial wastewater comprises the following steps:

[0007] (1) adding ferric sulfate into distilled water, stirring to dissolve, slowly adding sodium hydroxide aqueous solution at 20° C., aging to obtain polyferric sulfate;

[0008] (2) preparing the modified polyacrylamide into a polyacrylamide aqueous solution;

[0009] (3) The polyferric sulfate obtained in step (1) and the polyacrylamide aqueous solution obtained in step (2) are fully stirred to mix them uniformly to prepare modified polyferric sulfate.

[0010] Furthermore, in the step (1), the ratio of ferric sulfate to distilled water is 13.3 g:15-40 mL, and the mass fraction of the sodium hydroxide aqueous solution is 21.9%.

[0011] Furthermore, the aging temperature in step (1) is 20-60°C.

[0012] Furthermore, the aging time in step (1) is 2-6 hours.

[0013] Furthermore, the mass concentration of the polyacrylamide aqueous solution in step (2) is 0.1-1%.

[0014] Furthermore, in the step (3), the mass ratio of the polyferric sulfate to the polyacrylamide aqueous solution is (10-1000):1.

[0015] Furthermore, the modified polyacrylamide in step (2) comprises the following raw materials in parts by weight: 100 parts of polyacrylamide, 1-2 parts of auxiliary agent, and 0.01-0.02 parts of initiator.

[0016] Polyacrylamide is made of acrylamide monomers. Polyacrylamide can effectively remove suspended solids, organic matter, heavy metals and other harmful substances in industrial wastewater, and is often used in industrial wastewater treatment. The polyacrylamide in the modified polyferric sulfate works synergistically with the polyferric sulfate, giving the modified polyferric sulfate a higher wastewater treatment capacity.

[0017] Furthermore, the auxiliary agent is prepared by the following steps:

[0018] S1. Under nitrogen protection, sodium carbonate, 3-chloro-1,2-propylene glycol and deionized water were added to a three-necked flask, and N-methyl-2-hydroxyethylamine was slowly added after stirring. After mixing, the temperature was raised to 70°C, and the mixture was reacted at 70°C for 3 hours. After the reaction was completed, the mixture was cooled to room temperature, distilled under reduced pressure, washed with deionized water for 3 times, and dried at 110°C for 12 hours to obtain intermediate 1; the dosage ratio of N-methyl-2-hydroxyethylamine, 3-chloro-1,2-propylene glycol, sodium carbonate and deionized water was 8.8 mL:8.4 mL:11.7 g:120 mL;

[0019] Under sodium carbonate and heating conditions, the molar ratio of N-methyl-2-hydroxyethylamine and 3-chloro-1,2-propylene glycol is controlled to be 1.05-1.1:1, and the -NH- of N-methyl-2-hydroxyethylamine and the -Cl of 3-chloro-1,2-propylene glycol undergo a nucleophilic substitution reaction. The reaction process is as follows:

[0020]

[0021] S2. Under nitrogen protection, add 8-chloro-1-octene, triethylamine and diethyl ether to a dry brown three-necked flask, stir evenly, then slowly add the mixed solution of intermediate 1 and diethyl ether, mix evenly, heat to 80°C, react at 80°C for 4h, cool to room temperature after the reaction, and distill under reduced pressure to obtain an auxiliary agent. The dosage ratio of 8-chloro-1-octene, intermediate 1, triethylamine and diethyl ether is 12.9g:11.9g:16mL:200mL.

[0022] Under triethylamine and heating conditions, the molar ratio of 8-chloro-1-octene to intermediate 1 is controlled to be 1.05-1.1:1, and the -Cl of 8-chloro-1-octene reacts with the tertiary amine group of intermediate 1 to undergo a nucleophilic substitution reaction. The reaction process is as follows:

[0023]

[0024] The additive contains a quaternary ammonium salt structure, which is a broad-spectrum fungicide. The quaternary ammonium salt structure can dissociate into a quaternary ammonium salt cation containing a positive charge. + Ions can be adsorbed onto the cell walls of negatively charged bacteria, destroying the cell membrane, denaturing proteins, and hindering the replication and reproduction of DNA, thereby achieving an antibacterial effect. The multiple hydroxyl groups in the additive can improve the adsorption and net-catching ability of modified polyacrylamide to a certain extent. Under the action of the initiator, the terminal carbon-carbon double bond of the additive can produce a chemical reaction with the unreacted carbon-carbon double bond at the end of the polyacrylamide, so that the additive can be grafted onto the macromolecular chain of polyacrylamide, exerting a long-lasting and efficient antibacterial effect.

[0025] The grafting of additives enables modified polyacrylamide to effectively remove harmful substances such as suspended matter, organic matter and heavy metals in industrial wastewater, and kill pathogenic bacteria in industrial wastewater to avoid harming the health of humans and animals.

[0026] Furthermore, the initiator is one or more of ammonium persulfate, potassium persulfate, benzoyl peroxide, and azobisisobutyronitrile.

[0027] The beneficial effects of the present invention are as follows: a chemical reaction exists between the polyacrylamide in the modified polyacrylamide of the present invention and the auxiliary agent, and the auxiliary agent contains a quaternary ammonium salt structure, and the modified polyferric sulfate of the present invention is obtained by mixing the modified polyacrylamide and the polyferric sulfate. Therefore, the use of the modified polyferric sulfate of the present invention can not only improve the removal rate of chemical oxygen demand, suspended matter and other harmful impurities in industrial wastewater, but also effectively eliminate pathogenic bacteria in the industrial wastewater to avoid health hazards. DETAILED DESCRIPTION

[0028] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0029] Example 1

[0030] Preparation of auxiliary agent, the specific steps are as follows:

[0031] S1. Under nitrogen protection, 11.7 g of sodium carbonate, 8.4 mL of 3-chloro-1,2-propylene glycol and 120 mL of deionized water were added to a 250 mL three-necked flask, and 8.8 mL of N-methyl-2-hydroxyethylamine was slowly added after stirring. After mixing, the temperature was raised to 70° C., and the mixture was reacted at 70° C. for 3 h. After the reaction was completed, the mixture was cooled to room temperature, distilled under reduced pressure, washed with deionized water 3 times, and dried at 110° C. for 12 h to obtain intermediate 1.

[0032] S2. Under nitrogen protection, add 12.9 g of 8-chloro-1-octene, 16 mL of triethylamine and 110 mL of ether into a dry 500 mL brown three-necked flask, stir evenly and then slowly add a mixed solution of 11.9 g of intermediate 1 and 90 mL of ether. After mixing evenly, heat to 80°C and react at 80°C for 4 h. After the reaction is completed, cool to room temperature and distill under reduced pressure to obtain an auxiliary agent.

[0033] Example 2

[0034] The specific steps for preparing modified polyacrylamide are as follows:

[0035] 100 parts of polyacrylamide and 1 part of the auxiliary agent of Example 1 were mixed uniformly in deionized water, and then 0.01 parts of benzoyl peroxide were added under stirring. The temperature was raised to 60° C. and stirring was continued for 3 hours. The mixture was cooled to room temperature and dried to obtain modified polyacrylamide.

[0036] Example 3

[0037] The specific steps for preparing modified polyacrylamide are as follows:

[0038] 100 parts of polyacrylamide and 1.2 parts of the auxiliary agent of Example 1 were mixed uniformly in deionized water, and then 0.012 parts of potassium persulfate were added under stirring. The mixture was heated to 60° C. and stirred for 3 hours. The mixture was cooled to room temperature and dried to obtain modified polyacrylamide.

[0039] Example 4

[0040] The specific steps for preparing modified polyacrylamide are as follows:

[0041] 100 parts of polyacrylamide and 2 parts of the auxiliary agent of Example 1 were mixed uniformly in deionized water, and then 0.02 parts of ammonium persulfate were added under stirring. The temperature was raised to 60° C. and stirring was continued for 3 hours. The mixture was cooled to room temperature and dried to obtain modified polyacrylamide.

[0042] Example 5

[0043] Preparation of modified polyferric sulfate, the specific steps are as follows:

[0044] (1) 13.3 g of ferric sulfate was added to 15 mL of distilled water, stirred to dissolve, and a 21.9 wt % sodium hydroxide aqueous solution was slowly added at 20° C., and aged at 20° C. for 2 h to obtain polyferric sulfate;

[0045] (2) preparing the modified polyacrylamide of Example 2 into a polyacrylamide aqueous solution with a mass concentration of 0.1%;

[0046] (3) The polyferric sulfate obtained in step (1) and the polyacrylamide aqueous solution obtained in step (2) are fully stirred to mix them evenly, wherein the mass ratio of the polyferric sulfate to the polyacrylamide aqueous solution is 10:1, thereby preparing modified polyferric sulfate.

[0047] Example 6

[0048] Preparation of modified polyferric sulfate, the specific steps are as follows:

[0049] (1) 13.3 g of ferric sulfate was added to 40 mL of distilled water, stirred to dissolve, and a 21.9 wt % sodium hydroxide aqueous solution was slowly added at 20° C., and aged at 60° C. for 6 h to obtain polyferric sulfate;

[0050] (2) preparing the modified polyacrylamide of Example 3 into a polyacrylamide aqueous solution with a mass concentration of 1%;

[0051] (3) The polyferric sulfate obtained in step (1) and the polyacrylamide aqueous solution obtained in step (2) are stirred thoroughly to mix them evenly, wherein the mass ratio of the polyferric sulfate to the polyacrylamide aqueous solution is 1000:1, thereby preparing modified polyferric sulfate.

[0052] Example 7

[0053] Preparation of modified polyferric sulfate, the specific steps are as follows:

[0054] (1) 13.3 g of ferric sulfate was added to 40 mL of distilled water, stirred to dissolve, and a 21.9 wt % sodium hydroxide aqueous solution was slowly added at 20° C., and aged at 20° C. for 4 h to obtain polyferric sulfate;

[0055] (2) preparing the modified polyacrylamide of Example 4 into a polyacrylamide aqueous solution with a mass concentration of 0.5%;

[0056] (3) The polyferric sulfate obtained in step (1) and the polyacrylamide aqueous solution obtained in step (2) are stirred thoroughly to mix them evenly, wherein the mass ratio of the polyferric sulfate to the polyacrylamide aqueous solution is 100:1, thereby preparing modified polyferric sulfate.

[0057] Comparative Example 1

[0058] The specific steps for preparing modified polyacrylamide are as follows:

[0059] The auxiliary agent in Example 4 was replaced by 5-chloro-2-methyl-1-isothiazoline-3-one to prepare modified polyacrylamide.

[0060] Comparative Example 2

[0061] Preparation of polyferric sulfate, the specific steps are as follows:

[0062] The remaining steps remain unchanged, only the modified polyacrylamide of Example 7 is replaced by the modified polyacrylamide of Comparative Example 1 to prepare polyferric sulfate.

[0063] Comparative Example 3

[0064] Preparation of polyferric sulfate, the specific steps are as follows:

[0065] The remaining steps remain unchanged, except that the modified polyacrylamide in Example 7 is replaced by polyacrylamide that has not undergone any modification treatment to prepare polyferric sulfate.

[0066] Comparative Example 4

[0067] Preparation of polyferric sulfate, the specific steps are as follows:

[0068] The remaining steps remain unchanged, only step (2) and step (3) of Example 7 are removed to prepare polyferric sulfate.

[0069] Performance Testing

[0070] 1000 mL of industrial wastewater from 6 groups of the same batch was taken into a beaker, and 2.0 mL of modified polyferric sulfate of Examples 5-7 and 2.0 mL of polyferric sulfate of Comparative Examples 2-4 were added respectively. After stirring, the mixture was allowed to stand, and the supernatant was taken. The water quality parameters before and after treatment were measured, and the removal rate was calculated. The results are shown in Table 1:

[0071] Table 1

[0072]

[0073] It can be seen from the results in Table 1 that the modified polyferric sulfate prepared in Examples 5-7 of the present invention has a more excellent wastewater treatment capacity.

[0074] Then 1000 mL of industrial wastewater from 4 groups of the same batch was taken into a beaker, and 15% of the modified polyferric sulfate of Examples 5-7 and 15% of the polyferric sulfate of Comparative Example 2 were added respectively, and stirred evenly. The antibacterial rates of Escherichia coli and Staphylococcus aureus were tested. The test results are shown in Table 2 below:

[0075] Table 2

[0076]

[0077]

[0078] It can be seen from Table 2 that the modified polyferric sulfate prepared in Examples 5-7 of the present invention has an excellent and stable antibacterial effect. When the auxiliary agent is replaced with an antibacterial agent (5-chloro-2-methyl-1-isothiazoline-3-one) that has no chemical reaction with polyacrylamide, although a higher initial antibacterial effect can be obtained, the antibacterial activity is unstable and tends to decrease gradually over time.

[0079] In the description of the specification, the description with reference to the terms "one embodiment", "example", "specific example", etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0080] The above contents are merely examples and explanations of the present invention. Those skilled in the art may make various modifications or additions to the specific embodiments described or replace them in a similar manner. As long as they do not deviate from the invention or exceed the scope defined by the claims, they shall all fall within the protection scope of the present invention.

Claims

1. A method for preparing modified polyferric sulfate for treating industrial wastewater, characterized in that: The following steps are involved: (1) adding ferric sulfate to distilled water, stirring, adding sodium hydroxide aqueous solution at 20° C., aging, and obtaining polyferric sulfate; (2) preparing the modified polyacrylamide into a polyacrylamide aqueous solution; (3) fully stirring the polyferric sulfate obtained in step (1) and the polyacrylamide aqueous solution obtained in step (2) to mix them evenly, thereby preparing modified polyferric sulfate; Wherein, the modified polyacrylamide in step (2) comprises the following raw materials in parts by weight: 100 parts of polyacrylamide, 1-2 parts of auxiliary agent, and 0.01-0.02 parts of initiator; The auxiliary agent is grafted onto the polyacrylamide macromolecular chain under the action of an initiator, and the auxiliary agent is prepared by the following steps: S1. Under nitrogen protection, sodium carbonate, 3-chloro-1,2-propylene glycol and deionized water were added to a flask, and N-methyl-2-hydroxyethylamine was added after stirring. The temperature was raised to 70°C for reaction for 3 hours, and the mixture was cooled, distilled under reduced pressure, washed and dried to obtain intermediate 1. The dosage ratio of N-methyl-2-hydroxyethylamine, 3-chloro-1,2-propylene glycol, sodium carbonate and deionized water was 8.8 mL: 8.4 mL: 11.7 g: 120 mL. S2. Under nitrogen protection, add 8-chloro-1-octene, triethylamine and diethyl ether into a flask, stir and add intermediate 1 and diethyl ether, heat to 80°C and react for 4 hours, cool and distill under reduced pressure to obtain an auxiliary agent; the dosage ratio of 8-chloro-1-octene, intermediate 1, triethylamine and diethyl ether is 12.9 g:11.9 g:16 mL:200 mL.

2. The method for preparing a modified polyferric sulfate for treating industrial wastewater according to claim 1, characterized in that: In the step (1), the ratio of ferric sulfate to distilled water is 13.3 g:15-40 mL, and the mass fraction of the sodium hydroxide aqueous solution is 21.9%.

3. The method for preparing a modified polyferric sulfate for treating industrial wastewater according to claim 1, characterized in that: The aging temperature in step (1) is 20-60°C.

4. The method for preparing modified polyferric sulfate for treating industrial wastewater according to claim 1, characterized in that: The aging time in step (1) is 2-6 hours.

5. The method for preparing modified polyferric sulfate for treating industrial wastewater according to claim 1, characterized in that: The mass concentration of the polyacrylamide aqueous solution in step (2) is 0.1-1%.

6. The method for preparing modified polyferric sulfate for treating industrial wastewater according to claim 1, characterized in that: In the step (3), the mass ratio of the polyferric sulfate to the polyacrylamide aqueous solution is (10-1000):

1.

7. The method for preparing modified polyferric sulfate for treating industrial wastewater according to claim 1, characterized in that: The initiator is one or more of ammonium persulfate, potassium persulfate, benzoyl peroxide, and azobisisobutyronitrile.

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