A coagulant for treating sewage and a method for preparing the same

Abstract

The present application relates to the technical field of coagulant preparation, in particular to a coagulant for treating sewage and a preparation method thereof.The present application provides a preparation method of a coagulant for treating sewage, which comprises two steps of S1 coagulant reaction liquid preparation and S2 coagulant preparation.The coagulant is an inorganic-organic composite coagulant generated by mixing titanium chloride, magnesium chloride and methacryloyloxyethyl trimethyl ammonium chloride (DMC) in a certain proportion and reacting at low temperature.The coagulant has high flocculation and sewage removal capacity, is stable in nature, and can be used in sewage with different pH and different temperatures.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of coagulant preparation, in particular to a coagulant for treating sewage and a preparation method thereof. BACKGROUND

[0002] Coagulant is generally a chemical substance, which can destroy the stability of fine particles in liquid, make them contact and coagulate together to form flocculation, and then sink and separate, so as to achieve the purpose of sewage purification.

[0003] The commonly used coagulants in sewage treatment can be roughly divided into organic polymer coagulants, inorganic coagulants, microbial coagulants and active coagulants. Among them, inorganic coagulants are widely used in the field of water treatment due to their environmental protection, non-toxicity, economy, practicality, convenience, good treatment effect and wide application range. However, the inorganic coagulant flocculation has poor stability, poor water quality adaptability, and the treatment effect is greatly affected by water temperature; some inorganic coagulants have strong corrosiveness, which may cause corrosion to equipment and pipelines during use.

[0004] Therefore, it is necessary to invent a coagulant with good stability, suitable for various water qualities and little affected by water temperature. SUMMARY

[0005] In view of the above technical problems, the present application aims to provide a coagulant for sewage treatment and a preparation method thereof. The coagulant prepared by the method has good stability, is suitable for various water qualities and is little affected by water temperature.

[0006] The present application discloses a preparation method of a coagulant for treating sewage, comprising the following steps:

[0007] S1. Coagulant reaction liquid preparation: adding anhydrous ethanol and acetone into a reactor to obtain a mixed solution, then cooling, then slowly adding titanium tetrachloride into the cooled mixed solution, stirring to obtain a reaction liquid; then adding magnesium chloride solution and methacryloyloxyethyl trimethyl ammonium chloride (DMC) into the reaction liquid in sequence, continuing to stir to react until the reaction is completed to obtain a coagulant reaction liquid;

[0008] S2. Coagulant preparation: obtaining the coagulant by sequentially performing rotary evaporation, drying and grinding on the coagulant reaction liquid obtained in step S1.

[0009] Preferably, in the S1 coagulant reaction liquid preparation step, the mass ratio of the anhydrous ethanol and acetone is (18-22):1.

[0010] Preferably, in the S1 coagulant reaction liquid preparation step, the cooling is to be reduced to -10-0℃.

[0011] Preferably, in the S1 coagulant reaction solution preparation step, the mass ratio of titanium tetrachloride to anhydrous ethanol is 1: (30-50).

[0012] Preferably, in the S1 coagulant reaction solution preparation step, the mass fraction of the magnesium chloride solution is 1-5%; the mass ratio of titanium tetrachloride to magnesium chloride is 1: (0.05-0.3).

[0013] Preferably, in the S1 coagulant reaction solution preparation step, the mass ratio of titanium tetrachloride to methacryloyloxyethyl trimethyl ammonium chloride (DMC) is 1: (0.1-0.15).

[0014] Preferably, in the S1 coagulant reaction solution preparation step, the total reaction time is 3-5 h.

[0015] Preferably, in the S2 coagulant preparation step, the rotary evaporation method is reduced-pressure rotary evaporation; and the drying method is freeze-drying.

[0016] Preferably, in the freeze-drying process, the freeze-drying temperature is -50 to -70℃; and the freeze-drying time is 10-12 h.

[0017] A coagulant for treating sewage, which is prepared by any one of the above-mentioned preparation methods of a coagulant for treating sewage.

[0018] Compared with the prior art, the coagulant for treating sewage provided by the present application has the following beneficial effects:

[0019] The coagulant for treating sewage provided by the present application is a titanium-magnesium composite coagulant, which is prepared by mixing titanium tetrachloride and magnesium chloride, methacryloyloxyethyl trimethyl ammonium chloride (DMC) in a certain proportion, and then reacting at low temperature with a mixed solution of anhydrous ethanol and acetone mixed in a certain proportion as a solvent. The titanium-magnesium composite coagulant thus prepared has higher coagulation performance, larger floc size and lower settling time; the magnesium ions can improve the electric neutralization capacity and adsorption capacity of the titanium gel coagulant, and improve the complexing capacity of the coagulant for organic matter. Since the DMC is also added in the coagulant, the titanium-magnesium composite coagulant has more stable properties, has good flocculation capacity in water of different pH and different temperature, and the amount of the coagulant used for treating the same volume of sewage is smaller after the addition of the DMC. DETAILED DESCRIPTION

[0020] The following examples are provided for better understanding of the present application, and do not limit the content and protection scope of the present application. Any product identical or similar to the present application obtained by the inspiration of the present application or by combining the present application with other prior art features falls within the protection scope of the present application.

[0021] When specific experimental procedures or conditions are not mentioned in the examples, the procedures or conditions are performed according to the conventional experimental procedures described in the literature in the art. When the manufacturers of the reagents or instruments are not mentioned, the reagents or instruments are conventional reagent products that can be commercially available.

[0022] Example 1: A preparation method of a coagulant for treating sewage, comprising the following steps:

[0023] S1 Coagulant reaction liquid preparation: 30 kg of anhydrous ethanol and 1.7 kg of acetone were added to a reactor and stirred to obtain a mixed solution, and then the temperature of the mixed solution was reduced to -10°C. When the temperature of the mixed solution was stabilized at -10°C, 1 kg of titanium tetrachloride was slowly added dropwise into the cooled mixed solution, and the temperature of the mixed solution was kept at -4°C during the dropwise addition. After the complete dropwise addition of titanium tetrachloride, the reaction was stirred for 0.5 h to obtain a transparent reaction liquid. Then, 50 g of a 1% magnesium chloride solution and 100 g of methacryloyloxyethyl trimethyl ammonium chloride (DMC) were sequentially added dropwise into the reaction liquid, and the stirring reaction was continued for 2.5 h. After the reaction was completed, a coagulant reaction liquid was obtained.

[0024] S2 Coagulant preparation: The coagulant reaction liquid obtained in step S1 was subjected to rotary evaporation under reduced pressure to obtain a coagulant in a gel form. The coagulant in the gel form was placed in a freeze dryer and dried at a temperature of -50°C for 10 h. The coagulant in a block form after drying was taken out of the freeze dryer and ground to obtain a coagulant.

[0025] Example 2: A preparation method of a coagulant for treating sewage, comprising the following steps:

[0026] S1 Coagulant reaction liquid preparation: 35 kg of anhydrous ethanol and 1.84 kg of acetone were added to a reactor and stirred to obtain a mixed solution, and then the temperature of the mixed solution was reduced to -8°C. When the temperature of the mixed solution was stabilized at -8°C, 1 kg of titanium tetrachloride was slowly added dropwise into the cooled mixed solution, and the temperature of the mixed solution was kept at -8°C during the dropwise addition. After the complete dropwise addition of titanium tetrachloride, the reaction was stirred for 0.6 h to obtain a transparent reaction liquid. Then, 100 g of a 2% magnesium chloride solution and 110 g of methacryloyloxyethyl trimethyl ammonium chloride (DMC) were sequentially added dropwise into the reaction liquid, and the stirring reaction was continued for 2.9 h. After the reaction was completed, a coagulant reaction liquid was obtained.

[0027] S2 Coagulant preparation: The coagulant reaction liquid obtained in step S1 was subjected to rotary evaporation under reduced pressure to obtain a coagulant in a gel form. The coagulant in the gel form was placed in a freeze dryer and dried at a temperature of -55°C for 10.5 h. The coagulant in a block form after drying was taken out of the freeze dryer and ground to obtain a coagulant.

[0028] Example 3: A preparation method of a coagulant for treating sewage, comprising the following steps:

[0029] S1 Coagulant reaction liquid preparation: 40 kg of anhydrous ethanol and 2.0 kg of acetone were added to a reactor and stirred to obtain a mixed solution, then the temperature of the mixed solution was reduced to -6℃, and when the temperature of the mixed solution was stabilized at -6℃, 1 kg of titanium tetrachloride was slowly added to the cooled mixed solution, and the temperature of the mixed solution was kept at -6℃ during the addition; after the addition of titanium tetrachloride was completed, the reaction was stirred for 0.7 h to obtain a transparent reaction liquid; then 150 g of a 3% by mass magnesium chloride solution and 120 g of methacryloyloxyethyl trimethyl ammonium chloride (DMC) were sequentially added dropwise to the reaction liquid, and the stirring reaction was continued for 3.3 h, and the coagulant reaction liquid was obtained after the reaction was completed.

[0030] S2 Coagulant preparation: The coagulant reaction liquid obtained in step S1 was subjected to rotary evaporation under reduced pressure to obtain a gel-like coagulant; the gel-like coagulant was placed in a freeze dryer and dried at a temperature of -60℃ for 11 h; the dried block-shaped coagulant was taken out of the freeze dryer and ground to obtain the coagulant.

[0031] Example 4: A preparation method of a coagulant for treating sewage, comprising the following steps:

[0032] SS1 Coagulant reaction liquid preparation: 45 kg of anhydrous ethanol and 2.14 kg of acetone were added to a reactor and stirred to obtain a mixed solution, then the temperature of the mixed solution was reduced to -4℃, and when the temperature of the mixed solution was stabilized at -4℃, 1 kg of titanium tetrachloride was slowly added to the cooled mixed solution, and the temperature of the mixed solution was kept at -4℃ during the addition; after the addition of titanium tetrachloride was completed, the reaction was stirred for 0.8 h to obtain a transparent reaction liquid; then 200 g of a 4% by mass magnesium chloride solution and 130 g of methacryloyloxyethyl trimethyl ammonium chloride (DMC) were sequentially added dropwise to the reaction liquid, and the stirring reaction was continued for 3.7 h, and the coagulant reaction liquid was obtained after the reaction was completed.

[0033] S2 Coagulant preparation: The coagulant reaction liquid obtained in step S1 was subjected to rotary evaporation under reduced pressure to obtain a gel-like coagulant; the gel-like coagulant was placed in a freeze dryer and dried at a temperature of -65℃ for 11.5 h; the dried block-shaped coagulant was taken out of the freeze dryer and ground to obtain the coagulant.

[0034] Example 5: A preparation method of a coagulant for treating sewage, comprising the following steps:

[0035] S1 coagulant reaction liquid preparation: 50 kg of anhydrous ethanol and 2.27 kg of acetone were added into a reactor to obtain a mixed solution, then the temperature of the mixed solution was reduced to 0℃, when the temperature of the mixed solution was stable at 0℃, 1 kg of titanium tetrachloride was slowly added into the cooled mixed solution, and the temperature of the mixed solution was kept at 0℃ during the adding process; after the adding of titanium tetrachloride was completed, the reaction was stirred for 1.0 h to obtain a transparent reaction liquid; then 300 g of a 5% magnesium chloride solution and 150 g of methacryloyloxyethyl trimethyl ammonium chloride (DMC) were added into the reaction liquid in sequence, and the reaction was continuously stirred for 4.0 h, and the coagulant reaction liquid was obtained after the reaction was completed.

[0036] S2 coagulant preparation: the coagulant reaction liquid obtained in the step S1 was subjected to rotary evaporation under reduced pressure to obtain a coagulant in a gel form; the coagulant in the gel form was placed in a freeze dryer and dried at a temperature of -70℃ for 12 h; the dried coagulant in a block form was taken out from the freeze dryer, ground and the coagulant was obtained.

[0037] Comparative Example 1: no DMC was added in the step S1, and the other dosages, reaction conditions and reaction steps were the same as those in Example 4.

[0038] Comparative Example 2: no magnesium chloride solution was added in the step S1, and the other dosages, reaction conditions and reaction steps were the same as those in Example 4.

[0039] Comparative Example 3: no magnesium chloride solution and DMC were added in the step S1, and the other dosages, reaction conditions and reaction steps were the same as those in Example 4.

[0040] The coagulants obtained in Examples 1-5 and Comparative Examples 1-3 were added into sewage with different pH values, and the solid suspended substance contents before and after the addition were detected, and the experimental results are shown in the following table:

[0041]

[0042] From the above table, it can be seen that the solid suspended substance in the sewage prepared by Examples 1-5 is significantly reduced, and the coagulants prepared by Comparative Examples 1-3 also have a certain sewage treatment capacity, but the sewage treatment capacity is obviously insufficient compared with the coagulants prepared by Examples. The experimental data in the above table also shows that the coagulants prepared by the method provided by the present application have good flocculation capacity in sewage with different pH values. The preparation conditions and raw material ratio of Example 4 are the best.

[0043] The coagulants obtained in Examples 1-5 and Comparative Examples 1-3 were added into sewage with different water temperatures, and the solid suspended substance contents before and after the addition were detected, and the experimental results are shown in the following table:

[0044]

[0045] From the above table, it can be seen that the sewage treatment capacity of the coagulant prepared in Examples 1-5 is not affected by water temperature, indicating that the coagulant is stable in property. The preparation conditions and raw material ratio of Example 4 are optimal.

[0046] The coagulants obtained in Examples 1-5 and Comparative Examples 1-3 were used to treat 1L of sewage with a solid suspended matter content of 500mg / L, and the amount of coagulant required for complete treatment was determined, and the experimental results are shown in the following table:

[0047]

[0048] From the above table, it can be seen that the coagulants prepared in Examples 1-5 require less amount of coagulant for treating sewage with the same content.

[0049] In summary, the coagulant for sewage treatment provided by the present application is a coagulant with good stability, which can be applied to various water qualities and is not affected by water temperature, and the amount of coagulant required is less. The coagulant is an inorganic-organic composite coagulant, which has the advantages of simple preparation method, good flocculation capacity, small amount of sludge produced, simple post-treatment, etc.

[0050] Obviously, the above examples are merely examples for clearly illustrating the present application, and are not intended to limit the embodiments. Based on the above description, other different forms of changes or variations can be made by those of ordinary skill in the art. Here, it is not necessary and impossible to enumerate all the embodiments. The obvious changes or variations derived therefrom are still within the protection scope of the present application.

Claims

1. A method for preparing a coagulant for treating sewage, characterized by, The method comprises the following steps: S1: preparing a coagulant reaction solution, adding anhydrous ethanol and acetone in a reactor to obtain a mixed solution, then cooling, slowly adding titanium tetrachloride into the cooled mixed solution, stirring to obtain a reaction solution, then adding a magnesium chloride solution and methacryloyloxyethyl trimethyl ammonium chloride into the reaction solution in sequence, continuing to stir, and obtaining the coagulant reaction solution after the reaction is completed; S2: preparing a coagulant, performing rotary evaporation, drying, and grinding on the coagulant reaction solution obtained in S1 in sequence to obtain the coagulant; In the step S1 of preparing the coagulant reaction solution, the temperature is cooled to -10-0 ℃; the mass ratio of titanium tetrachloride to magnesium chloride is 1:(0.05-0.3); and the mass ratio of titanium tetrachloride to methacryloyloxyethyl trimethyl ammonium chloride is 1:(0.1-0.15).

2. The method for preparing a coagulant for treating wastewater according to claim 1, characterized in that, In the step S1 of preparing the coagulant reaction solution, the mass ratio of anhydrous ethanol to acetone is (18-22):

1.

3. The method for preparing a coagulant for treating wastewater according to claim 1, characterized in that, In the step S1 of preparing the coagulant reaction solution, the mass ratio of titanium tetrachloride to anhydrous ethanol is 1:(30-50).

4. The method for preparing a coagulant for treating wastewater according to claim 1, characterized in that, In the step S1 of preparing the coagulant reaction solution, the mass fraction of the magnesium chloride solution is 1-5%.

5. A method for preparing a coagulant for treating wastewater according to claim 1, characterized in that, In the step S1 of preparing the coagulant reaction solution, the total reaction time is 3-5 h.

6. The method of claim 1, wherein the coagulant is prepared by mixing the polyaluminum chloride and the polymeric flocculant in a ratio of 1:1 to 1:

3. 5 In the step S2 of preparing the coagulant, the rotary evaporation method is reduced-pressure rotary evaporation; and the drying method is freeze-drying.

7. The method of claim 6, wherein the coagulant is prepared by adding the polyaluminum chloride to the water to be treated. In the freeze-drying process, the freeze-drying temperature is -50--70 ℃; and the freeze-drying time is 10-12 h.

8. A coagulant for treating sewage, which is prepared by the method according to any one of claims 1-7.

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