Modified nano calcium hydroxide emulsion for water treatment and preparation method thereof

Abstract

The invention relates to the technical field of water treatment, in particular to a modified nano calcium hydroxide emulsion for water treatment and a preparation method thereof.The preparation method comprises the following steps that calcium hydroxide is weighed and placed in water to be stirred, and a saturated lime water solution is prepared; preparing calcium chloride, carboxyethyl cellulose and water into a mixed solution; adding a crystal form control agent, gradually dropwise adding a sodium hydroxide solution while stirring until no new precipitate is generated, and carrying out ultrasonic oscillation to obtain slurry; centrifugally washing precipitates in the slurry for 3-5 times by using saturated lime water; carrying out vacuum drying for 10-15 hours at the temperature of 100-110 DEG C to obtain modified calcium hydroxide powder; adding the modified calcium hydroxide powder and a sodium polyacrylate dispersing agent into water, and stirring and dissolving to obtain the modified nano calcium hydroxide emulsion. The modified nano calcium hydroxide emulsion prepared by selecting and matching specific raw materials and processes has certain flocculation adsorption capacity while reducing agglomeration of nano particles, and the purification effect is improved.

Description

Technical Field

[0001] The present application relates to the technical field of water treatment, and in particular to a modified nano calcium hydroxide emulsion for water treatment and a preparation method thereof. Background Art

[0002] Water treatment is a measure to treat domestic sewage, industrial wastewater, etc. to meet discharge standards or for reuse. Calcium hydroxide is easy to make and low in cost. It is a commonly used sewage treatment agent with high alkalinity and precipitation. It can be used to adjust pH, remove heavy metal ions and organic matter, soften water, etc.

[0003] At present, most of the calcium hydroxide supplied on the market is solid powder. In the field of sewage treatment, the use effect of powdered calcium hydroxide is poor. The strong hygroscopicity of calcium hydroxide powder can cause burns to human skin. When calcium hydroxide powder is used, a large amount of dust will be generated, which is easy to pollute the atmospheric environment. In addition, the powdered calcium hydroxide on the market often contains impurities such as undigested overburned calcium oxide, raw calcium carbonate and silicon dioxide, which are easy to block pipes and cause serious wear and tear on sewage treatment equipment when used. At the same time, nano calcium hydroxide is widely favored due to its small particles and good uniformity.

[0004] Calcium hydroxide emulsion can avoid dust and environmental pollution, making it a better choice for water treatment. However, nanoparticles are very easy to agglomerate during the preparation of nano calcium hydroxide emulsion, which places high demands on the preparation of nano calcium hydroxide emulsion. Summary of the invention

[0005] The present application aims to overcome at least one of the defects of the prior art and provide a modified nano calcium hydroxide emulsion for water treatment and a preparation method thereof. The modified nano calcium hydroxide emulsion prepared by selecting specific raw materials and processes has a certain flocculation and adsorption capacity while reducing the agglomeration of nanoparticles, thereby further improving its water purification effect in water treatment.

[0006] In the first aspect, the present application embodiment provides a method for preparing a modified nano calcium hydroxide emulsion for water treatment, which is achieved by the following technical solutions:

[0007] A method for preparing a modified nano calcium hydroxide emulsion for water treatment comprises the following steps:

[0008] (1) 1 L of deionized water was heated to boiling and then naturally cooled to room temperature, 10 g of calcium hydroxide was weighed and placed in the cooled water and stirred for 0.5 hour to prepare a saturated lime water solution;

[0009] (2) preparing a mixed solution of calcium chloride, carboxyethyl cellulose and deionized water in a weight ratio of (8-12):(1-2):(30-50), and uniformly dispersing the solution by ultrasonication;

[0010] (3) adding a crystal form control agent, gradually adding a sodium hydroxide solution dropwise while stirring until no new precipitate is generated, and ultrasonically shaking for 1-2 hours to obtain a modified calcium hydroxide slurry;

[0011] (4) using the saturated lime water described in step (1) to centrifuge and wash the precipitate in the modified calcium hydroxide slurry at a speed of 1500-2500 r / min for 3-5 times; vacuum drying the washed precipitate at a temperature of 100-110° C. for 10-15 hours to obtain a modified calcium hydroxide powder;

[0012] (5) heating deionized water to boiling and then naturally cooling to room temperature, adding the modified calcium hydroxide powder and sodium polyacrylate dispersant, stirring and dissolving to obtain a modified nano calcium hydroxide emulsion;

[0013] Wherein, the crystal form control agent in step (3) includes styrylphenyl polyoxyethylene ether and N,N-methylenebisacrylamide.

[0014] According to a method for preparing a modified nano calcium hydroxide emulsion for water treatment according to an embodiment of the present application, there are at least the following beneficial effects:

[0015] The preparation method of the present application adopts a liquid phase method to prepare nano calcium hydroxide. The raw materials are dispersed at the molecular level in the solution, and the reaction conditions are mild and easy to control, the equipment is simple and easy to operate, and the prepared nano materials have uniform composition and high purity. Carboxyethyl cellulose and calcium ions are mixed in a liquid phase system to form an inorganic-polymer homogeneous system. Carboxyethyl cellulose can enhance steric resistance and electrostatic repulsion to expand the distance between particles and weaken the effect of van der Waals attraction. Carboxyethyl cellulose polymers can form an interpenetrating network. At the same time, the coating and entanglement on the surface of particles can also inhibit the growth of particles. Strong complexation and chelation are formed between polar groups and metal ions, so that the agglomeration of nano particles can be more effectively controlled and the dispersibility of nano calcium hydroxide particles can be improved.

[0016] In the preparation method of the present application, step (3) uses ultrasonic vibration. Ultrasonic waves can produce cavitation effect, destroy large particles formed by agglomeration, make nano calcium hydroxide particles more easily form monodisperse particles, reduce the agglomeration of nano calcium hydroxide particles, and improve the yield of modified nano calcium hydroxide emulsion.

[0017] In the preparation method of the present application, styrylphenyl polyoxyethylene ether and N,N-methylenebisacrylamide are added as crystal form control agents in step (3). Styrylphenyl polyoxyethylene ether and N,N-methylenebisacrylamide are preferentially adsorbed on different crystal faces of calcium hydroxide crystals, which can regulate the formation of calcium hydroxide crystals and make the particle size distribution of the prepared modified nano calcium hydroxide particles narrower.

[0018] The carboxyethyl cellulose added in step (2) of the present application also has a flocculation effect and can chelate with metal ions in the wastewater to accelerate the precipitation of impurities in the water.

[0019] The sodium polyacrylate dispersant in step (5) of the present application forms a steric hindrance layer on the surface of the modified calcium hydroxide powder particles through intermolecular interactions. This steric hindrance effect can effectively prevent the aggregation of particles and significantly improve their dispersibility.

[0020] The use of saturated lime water for washing in step (4) of the preparation method of the present application can not only better remove impurities, but also improve the purity of the modified nano calcium hydroxide emulsion, maintain the stability of the calcium hydroxide crystal form, and improve its purification effect on water quality.

[0021] According to some embodiments of the present application, the weight ratio of the styrylphenyl polyoxyethylene ether to N,N-methylenebisacrylamide is (2-4): 1. Excessive content of styrylphenyl polyoxyethylene ether will lead to an increase in the diameter of calcium hydroxide particles, and excessive content of N,N-methylenebisacrylamide will cause the morphology of calcium hydroxide to change. Controlling the content of the two in an appropriate ratio can better regulate the formation of calcium hydroxide crystals.

[0022] According to some embodiments of the present application, the concentration of the sodium hydroxide solution in step (3) is 0.5-1 g / L.

[0023] Furthermore, the dripping rate of the sodium hydroxide solution in step (3) is 1-3 mL / min. Controlling the dripping rate of the sodium hydroxide solution can make the formation of calcium hydroxide crystals more complete, the crystal form more controllable, and the particle size of the prepared nano calcium hydroxide particles more consistent.

[0024] According to some embodiments of the present application, the reaction temperature in step (3) is 15-20°C.

[0025] According to some embodiments of the present application, the weight ratio of the sodium polyacrylate dispersant to the modified calcium hydroxide powder in step (5) is (1-2): (8-15). The characteristics of the sodium polyacrylate dispersant can not only further improve the fluidity of the powder, but also improve the stability of the modified nano calcium hydroxide emulsion. However, excessive use of the dispersant will also lead to excessive viscosity of the system and decreased leveling. The calcium hydroxide of the present application is subjected to a series of treatments, and only a small amount of sodium polyacrylate dispersant is used to achieve a good dispersion effect. According to a specific ratio, the dispersibility and high viscosity of the emulsion can be more balanced, thereby improving the water purification effect of the modified nano calcium hydroxide emulsion.

[0026] In a second aspect, the embodiments of the present application provide a modified nano calcium hydroxide emulsion for water treatment prepared by the above-mentioned preparation method.

[0027] A modified nano calcium hydroxide emulsion for water treatment according to an embodiment of the present application has at least the following beneficial effects:

[0028] The modified nano calcium hydroxide emulsion obtained in the present application has fine particle size, low impurity content, is safe and pollution-free, has a stable structure, and is suitable for use in water treatment.

[0029] According to some embodiments of the present application, the mass concentration of calcium hydroxide in the modified nano calcium hydroxide emulsion is 20-25%.

[0030] According to some embodiments of the present application, the specific surface area of ​​the modified nano calcium hydroxide particles in the modified nano calcium hydroxide emulsion is 50-60 m 2 / g.

[0031] According to some embodiments of the present application, the particle size of the modified nano calcium hydroxide particles in the modified nano calcium hydroxide emulsion is 200-300 nm.

[0032] In the third aspect, the present application embodiment provides the application of the modified nano calcium hydroxide emulsion for water treatment in water treatment. The modified nano calcium hydroxide emulsion of the present application is applied to sewage treatment or water supply treatment, and the pH value of industrial water and wastewater can be adjusted. Especially under acidic conditions, the acidic environment can be neutralized by adding calcium hydroxide emulsion, so that the pH value of water reaches a suitable range, thereby avoiding corrosion to equipment and pipelines and protecting water treatment equipment; the nano modified calcium hydroxide emulsion can react with heavy metal ions in wastewater to form precipitation, thereby reducing the concentration of heavy metal ions in wastewater; in addition, the nano modified calcium hydroxide can also neutralize organic matter in wastewater, which helps the precipitation and removal of these organic matter; agricultural water usually contains high hardness and iron, manganese and other ions, which are harmful to the growth of crops. The nano modified calcium hydroxide emulsion can be used for softening of agricultural water, by adjusting the hardness of water and removing harmful ions, improving water quality, and promoting the healthy growth of crops; in addition, the carboxyethyl cellulose in the modified nano calcium hydroxide emulsion can provide flocculation, further enhancing the effect of water treatment. DETAILED DESCRIPTION

[0033] To make the purpose, technical solution and advantages of the present application clearer, the following will be further described in detail in conjunction with specific embodiments. The embodiments described here are only part of the embodiments of the present application and cannot be understood as limiting the scope of protection of the present application.

[0034] Example 1

[0035] Preparation of a modified nano calcium hydroxide emulsion for water treatment:

[0036] (1) 1 L of deionized water was heated to boiling and then naturally cooled to room temperature, 10 g of calcium hydroxide was weighed and placed in the cooled water and stirred for 0.5 hour to prepare a saturated lime water solution;

[0037] (2) preparing a mixed solution of calcium chloride, carboxyethyl cellulose and deionized water in a weight ratio of 10:2:40, and uniformly dispersing the solution by ultrasonication;

[0038] (3) adding styrylphenyl polyoxyethylene ether and N,N-methylenebisacrylamide in a weight ratio of 3:1, and gradually adding 0.8 g / L sodium hydroxide solution at a rate of 2 mL / min while stirring at a temperature of 18°C ​​until no new precipitate is generated, and ultrasonically vibrating for 1.5 h to obtain a modified calcium hydroxide slurry;

[0039] (4) using the saturated lime water described in step (1) to centrifuge and wash the precipitate in the modified calcium hydroxide slurry at a speed of 2000 r / min for 4 times; drying the washed precipitate in a vacuum drying oven at a temperature of 105° C. for 12 hours to obtain modified calcium hydroxide powder;

[0040] (5) Deionized water is heated to boiling and then naturally cooled to room temperature, and a sodium polyacrylate dispersant and the modified calcium hydroxide powder are added in a weight ratio of 2:12, and stirred to dissolve to obtain a modified nano calcium hydroxide emulsion with a mass concentration of 20% of calcium hydroxide.

[0041] Example 2

[0042] Preparation of a modified nano calcium hydroxide emulsion for water treatment:

[0043] (1) 1 L of deionized water was heated to boiling and then naturally cooled to room temperature, 10 g of calcium hydroxide was weighed and placed in the cooled water and stirred for 0.5 hour to prepare a saturated lime water solution;

[0044] (2) preparing a mixed solution of calcium chloride, carboxyethyl cellulose and deionized water in a weight ratio of 8:2:30, and uniformly dispersing the solution by ultrasonication;

[0045] (3) adding styrylphenyl polyoxyethylene ether and N,N-methylenebisacrylamide in a weight ratio of 4:1, and gradually adding 1 g / L sodium hydroxide solution at a rate of 1 mL / min at a temperature of 20° C. while stirring until no new precipitate is generated, and ultrasonically vibrating for 1 h to obtain a modified calcium hydroxide slurry;

[0046] (4) using the saturated lime water described in step (1) to centrifuge and wash the precipitate in the modified calcium hydroxide slurry at a speed of 2500 r / min for 3 times; drying the washed precipitate in a vacuum drying oven at a temperature of 110° C. for 10 hours to obtain modified calcium hydroxide powder;

[0047] (5) Deionized water is heated to boiling and then naturally cooled to room temperature, and a sodium polyacrylate dispersant and the modified calcium hydroxide powder are added in a weight ratio of 2:8, and stirred to dissolve to obtain a modified nano calcium hydroxide emulsion with a mass concentration of 25% of calcium hydroxide.

[0048] Example 3

[0049] Preparation of a modified nano calcium hydroxide emulsion for water treatment:

[0050] (1) 1 L of deionized water was heated to boiling and then naturally cooled to room temperature, 10 g of calcium hydroxide was weighed and placed in the cooled water and stirred for 0.5 hour to prepare a saturated lime water solution;

[0051] (2) preparing a mixed solution of calcium chloride, carboxyethyl cellulose and deionized water in a weight ratio of 12:1:50, and uniformly dispersing the solution by ultrasonication;

[0052] (3) adding styrylphenyl polyoxyethylene ether and N,N-methylenebisacrylamide in a weight ratio of 2:1, and gradually adding 0.5 g / L sodium hydroxide solution at a rate of 3 mL / min while stirring at a temperature of 15 ° C. until no new precipitate is generated, and ultrasonically vibrating for 2 h to obtain a modified calcium hydroxide slurry;

[0053] (4) using the saturated lime water described in step (1) to centrifuge and wash the precipitate in the modified calcium hydroxide slurry at a speed of 1500 r / min for 5 times; drying the washed precipitate in a vacuum drying oven at a temperature of 100° C. for 15 hours to obtain modified calcium hydroxide powder;

[0054] (5) Deionized water is heated to boiling and then naturally cooled to room temperature, and a sodium polyacrylate dispersant and the modified calcium hydroxide powder are added in a weight ratio of 1:15, and stirred to dissolve to obtain a modified nano calcium hydroxide emulsion with a mass concentration of 23% of calcium hydroxide.

[0055] Comparative Example 1

[0056] Preparation of a modified nano calcium hydroxide emulsion for water treatment:

[0057] (1) 1 L of deionized water was heated to boiling and then naturally cooled to room temperature, 10 g of calcium hydroxide was weighed and placed in the cooled water and stirred for 0.5 hour to prepare a saturated lime water solution;

[0058] (2) preparing a mixed solution of calcium chloride and deionized water in a weight ratio of 10:2:40, and uniformly dispersing the solution by ultrasonication;

[0059] (3) adding styrylphenyl polyoxyethylene ether and N,N-methylenebisacrylamide in a weight ratio of 3:1, and gradually adding 0.8 g / L sodium hydroxide solution at a rate of 2 mL / min while stirring at a temperature of 18°C ​​until no new precipitate is generated, and ultrasonically vibrating for 1.5 h to obtain a modified calcium hydroxide slurry;

[0060] (4) using the saturated lime water described in step (1) to centrifuge and wash the precipitate in the modified calcium hydroxide slurry at a speed of 2000 r / min for 4 times; drying the washed precipitate in a vacuum drying oven at a temperature of 105° C. for 12 hours to obtain modified calcium hydroxide powder;

[0061] (5) Deionized water is heated to boiling and then naturally cooled to room temperature, and a sodium polyacrylate dispersant and the modified calcium hydroxide powder are added in a weight ratio of 2:12, and stirred to dissolve to obtain a modified nano calcium hydroxide emulsion with a mass concentration of 20% of calcium hydroxide.

[0062] Comparative Example 2

[0063] Preparation of a modified nano calcium hydroxide emulsion for water treatment:

[0064] (1) 1 L of deionized water was heated to boiling and then naturally cooled to room temperature, 10 g of calcium hydroxide was weighed and placed in the cooled water and stirred for 0.5 hour to prepare a saturated lime water solution;

[0065] (2) preparing a mixed solution of calcium chloride, carboxyethyl cellulose and deionized water in a weight ratio of 10:2:40, and uniformly dispersing the solution by ultrasonication;

[0066] (3) adding styrylphenyl polyoxyethylene ether and N,N-methylenebisacrylamide in a weight ratio of 3:1, and gradually adding 0.8 g / L sodium hydroxide solution at a rate of 2 mL / min while stirring at a temperature of 18°C ​​until no new precipitate is generated, and ultrasonically vibrating for 1.5 h to obtain a modified calcium hydroxide slurry;

[0067] (4) using the saturated lime water described in step (1) to centrifuge and wash the precipitate in the modified calcium hydroxide slurry at a speed of 2000 r / min for 4 times; drying the washed precipitate in a vacuum drying oven at a temperature of 105° C. for 12 hours to obtain modified calcium hydroxide powder;

[0068] (5) Deionized water is heated to boiling and then naturally cooled to room temperature, and the modified calcium hydroxide powder is added thereto, stirred and dissolved to obtain a modified nano calcium hydroxide emulsion with a mass concentration of 20% of calcium hydroxide.

[0069] Comparative Example 3

[0070] Preparation of a modified nano calcium hydroxide emulsion for water treatment:

[0071] (1) 1 L of deionized water was heated to boiling and then naturally cooled to room temperature, 10 g of calcium hydroxide was weighed and placed in the cooled water and stirred for 0.5 hour to prepare a saturated lime water solution;

[0072] (2) preparing a mixed solution of calcium chloride, carboxyethyl cellulose and deionized water in a weight ratio of 10:2:40, and uniformly dispersing the solution by ultrasonication;

[0073] (3) at a temperature of 18° C., gradually adding 0.8 g / L sodium hydroxide solution at a rate of 2 mL / min while stirring until no new precipitate is generated, and ultrasonically vibrating for 1.5 h to obtain a modified calcium hydroxide slurry;

[0074] (4) using the saturated lime water described in step (1) to centrifuge and wash the precipitate in the modified calcium hydroxide slurry at a speed of 2000 r / min for 4 times; drying the washed precipitate in a vacuum drying oven at a temperature of 105° C. for 12 hours to obtain modified calcium hydroxide powder;

[0075] (5) Deionized water is heated to boiling and then naturally cooled to room temperature, and a sodium polyacrylate dispersant and the modified calcium hydroxide powder are added in a weight ratio of 2:12, and stirred to dissolve to obtain a modified nano calcium hydroxide emulsion with a mass concentration of 20% of calcium hydroxide.

[0076] Comparative Example 4

[0077] Preparation of a modified nano calcium hydroxide emulsion for water treatment:

[0078] (1) preparing a mixed solution of calcium chloride, carboxyethyl cellulose and deionized water in a weight ratio of 10:2:40, and uniformly dispersing the solution by ultrasonication;

[0079] (2) adding styrylphenyl polyoxyethylene ether and N,N-methylenebisacrylamide in a weight ratio of 3:1, and gradually adding 0.8 g / L sodium hydroxide solution at a rate of 2 mL / min while stirring at a temperature of 18°C ​​until no new precipitate is generated, and ultrasonically vibrating for 1.5 hours to obtain a modified calcium hydroxide slurry;

[0080] (3) using deionized water to centrifuge and wash the precipitate in the modified calcium hydroxide slurry at a speed of 2000 r / min for 4 times; drying the washed precipitate in a vacuum drying oven at a temperature of 105° C. for 12 hours to obtain a modified calcium hydroxide powder;

[0081] (4) Deionized water is heated to boiling and then naturally cooled to room temperature, and a sodium polyacrylate dispersant and the modified calcium hydroxide powder are added in a weight ratio of 2:12, and stirred to dissolve to obtain a modified nano calcium hydroxide emulsion with a mass concentration of 20% of calcium hydroxide.

[0082] Experimental example

[0083] Take the modified nano calcium hydroxide emulsion for water treatment prepared in Examples 1-3 and Comparative Examples 1-4, and measure the average particle size and average specific surface area of ​​the nano calcium hydroxide particles; prepare a potassium dihydrogen phosphate solution with an initial phosphorus concentration of 20 mg / L, a ferric chloride solution with an iron ion concentration of 0.1 mol / L, and a wastewater solution with a pH value of 3.0, respectively, and add equal amounts of the modified nano calcium hydroxide emulsion for water treatment prepared in Examples 1-3 and Comparative Examples 1-4, respectively. After treating at room temperature for 24 hours, the removal rate of phosphate in the solution, the removal rate of iron ions, and the pH value of the treated wastewater are respectively determined. The test data are shown in Table 1 below:

[0084] Table 1

[0085]

[0086]

[0087] As can be seen from Table 1, the modified nano calcium hydroxide emulsions for water treatment prepared in Examples 1-3 of the present application have finer particle sizes, larger specific surface areas, and higher purification efficiency for phosphates, iron ions, and acidic wastewater.

[0088] No carboxyethyl cellulose was added in the preparation method of Comparative Example 1, and the rest was the same as Example 1. The particle size of the modified nano calcium hydroxide emulsion for water treatment prepared in Comparative Example 1 increased, and the removal effect of phosphate and iron ions was significantly deteriorated, and the regulating effect of acidic wastewater was also deteriorated, indicating that the addition of carboxyethyl cellulose in the present application is very important, which can not only more effectively control the agglomeration of nanoparticles and improve the dispersibility of nano calcium hydroxide particles, but also has a flocculation effect, and can chelate with impurity ions in wastewater to accelerate the precipitation of impurities in water.

[0089] No sodium polyacrylate dispersant is used in the preparation raw materials of Comparative Example 2, and the rest are the same as Example 1. The particle size of the modified nano calcium hydroxide emulsion for water treatment prepared in Comparative Example 2 is increased, and the removal effect of phosphate and iron ions is significantly deteriorated, and the regulation effect of acidic wastewater is also deteriorated, indicating that the sodium polyacrylate dispersant in the present application forms a steric hindrance layer on the surface of the modified calcium hydroxide powder particles through intermolecular interactions. This steric hindrance effect can effectively prevent the aggregation of particles, and can significantly improve its dispersibility, thereby improving its purification efficiency for wastewater.

[0090] No crystal form control agent is used in the preparation raw materials of Comparative Example 3, and the rest are the same as Example 1. The particle size of the modified nano calcium hydroxide emulsion for water treatment prepared in Comparative Example 3 is increased, and the removal effect of phosphate and iron ions is significantly deteriorated, and the regulating effect of acidic wastewater is also deteriorated, indicating that styrylphenyl polyoxyethylene ether and N,N-methylenebisacrylamide are added as crystal form control agents in the present application, and styrylphenyl polyoxyethylene ether and N,N-methylenebisacrylamide are preferentially adsorbed on different crystal faces of calcium hydroxide crystals, which can regulate the formation of calcium hydroxide crystals, so that the particle size distribution of the prepared modified nano calcium hydroxide particles is narrower and the particle size is smaller, thereby improving the purification effect of the modified nano calcium hydroxide emulsion on water quality.

[0091] In the preparation method of Comparative Example 4, deionized water is used instead of saturated lime water for washing, and the rest is the same as Example 1. The particle size of the modified nano calcium hydroxide emulsion for water treatment prepared in Comparative Example 4 is increased, and the removal effect of phosphate and iron ions is significantly deteriorated, and the regulating effect of acidic wastewater is also deteriorated, indicating that the preparation methods in this application are carefully set, and saturated lime water washing can not only better remove impurities, but also improve the purity of the modified nano calcium hydroxide emulsion, maintain the stability of the calcium hydroxide crystal form, and improve its purification effect on water quality.

[0092] Although the embodiments of the present application have been shown and described, those skilled in the art will appreciate that various changes, modifications, substitutions or variations may be made to the embodiments without departing from the principles and purpose of the present application, and that the technical solutions after these changes, modifications, substitutions or variations will fall within the scope of protection of the present application.

Claims

1. A method for preparing a modified nano calcium hydroxide emulsion for water treatment, characterized in that: The following steps are involved: (1) 1 L of deionized water was heated to boiling and then naturally cooled to room temperature, 10 g of calcium hydroxide was weighed and placed in the cooled water and stirred for 0.5 hour to prepare a saturated lime water solution; (2) preparing a mixed solution of calcium chloride, carboxyethyl cellulose and deionized water in a weight ratio of (8-12):(1-2):(30-50), and uniformly dispersing the solution by ultrasonication; (3) adding a crystal form control agent, gradually adding a sodium hydroxide solution dropwise while stirring until no new precipitate is generated, and ultrasonically shaking for 1-2 hours to obtain a modified calcium hydroxide slurry; (4) using the saturated lime water described in step (1) to centrifuge and wash the precipitate in the modified calcium hydroxide slurry at a speed of 1500-2500 r / min for 3-5 times; vacuum drying the washed precipitate at a temperature of 100-110° C. for 10-15 hours to obtain a modified calcium hydroxide powder; (5) heating deionized water to boiling and then naturally cooling to room temperature, adding the modified calcium hydroxide powder and sodium polyacrylate dispersant, stirring and dissolving to obtain a modified nano calcium hydroxide emulsion; Wherein, the crystal form control agent in step (3) includes styrylphenyl polyoxyethylene ether and N,N-methylenebisacrylamide.

2. A method for preparing a modified nano calcium hydroxide emulsion for water treatment according to claim 1, characterized in that, The weight ratio of the styrylphenyl polyoxyethylene ether to N,N-methylenebisacrylamide is (2-4):

1.

3. A method for preparing a modified nano calcium hydroxide emulsion for water treatment according to claim 1, characterized in that, The concentration of the sodium hydroxide solution in step (3) is 0.5-1 g / L.

4. A method for preparing a modified nano calcium hydroxide emulsion for water treatment according to claim 3, characterized in that, The dropping rate of the sodium hydroxide solution in step (3) is 1-3 mL / min.

5. A method for preparing a modified nano calcium hydroxide emulsion for water treatment according to claim 1, characterized in that, The weight ratio of the sodium polyacrylate dispersant to the modified calcium hydroxide powder in step (5) is (1-2):(8-15).

6. A method for preparing a modified nano calcium hydroxide emulsion for water treatment according to claim 1, characterized in that, The reaction temperature in step (3) is 15-20°C.

7. A modified nano calcium hydroxide emulsion for water treatment prepared by the method according to any one of claims 1 to 6.

8. A modified nano calcium hydroxide emulsion for water treatment according to claim 7, characterized in that, The mass concentration of calcium hydroxide in the modified nano calcium hydroxide emulsion is 20-25%.

9. A modified nano calcium hydroxide emulsion for water treatment according to claim 7, characterized in that, The specific surface area of ​​the modified nano calcium hydroxide particles in the modified nano calcium hydroxide emulsion is 50-60 m 2 / g, and the particle size of the modified nano calcium hydroxide particles in the modified nano calcium hydroxide emulsion is 200-300nm.

10. Use of the modified nano calcium hydroxide emulsion for water treatment as claimed in any one of claims 7 to 9 in water purification.

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