阅读说明：本技术 一种聚丙烯酸钠插层水滑石复合材料及其制备方法与应用 (Sodium polyacrylate intercalated hydrotalcite composite material and preparation method and application thereof ) 是由 陈飞飞 陈蒙 杨锋 李伟 张然 于 2019-10-09 设计创作，主要内容包括：本发明涉及水滑石复合材料制备技术领域,公开了一种聚丙烯酸钠插层水滑石复合材料及其制备方法与应用。该方法包括：用水对纯丙烯酸溶液进行稀释后用氢氧化钠溶液滴定,加入纯异丙醇溶液搅拌后倒入五颈烧瓶中；将过硫酸铵溶液逐滴滴入五颈烧瓶中进行聚合反应,滴定完成后,继续冷凝回流反应；蒸馏得到聚丙烯酸钠；用水将得到的聚丙烯酸钠溶解后加入五颈烧瓶中,将Mg(NO<Sub>3</Sub>)<Sub>2</Sub>·6H<Sub>2</Sub>O和Al(NO<Sub>3</Sub>)<Sub>3</Sub>·9H<Sub>2</Sub>O混合溶液以及NaOH溶液滴入五颈烧瓶中进行反应,滴加完成后继续冷凝回流反应；将所得产物水热后离心、水洗、干燥。本发明制备的聚丙烯酸钠插层水滑石复合材料对水中铅离子的吸附效率与原水滑石相比有了极大的提升。(The invention relates to the technical field of hydrotalcite composite material preparation, and discloses a sodium polyacrylate intercalated hydrotalcite composite material, and a preparation method and application thereof. The method comprises the following steps: diluting a pure acrylic acid solution with water, titrating with a sodium hydroxide solution, adding a pure isopropanol solution, stirring, and pouring into a five-neck flask; dropwise adding an ammonium persulfate solution into a five-neck flask for polymerization reaction, and continuing to perform condensation reflux reaction after the titration is finished; distilling to obtain sodium polyacrylate; dissolving the obtained sodium polyacrylate with water, adding into a five-neck flask, and adding Mg (NO) 3 ) 2 ·6H 2 O and Al (NO) 3 ) 3 ·9H 2 Dripping the O mixed solution and the NaOH solution into a five-neck flask for reaction, and continuing to perform condensation reflux reaction after the dripping is finished; and (4) centrifuging, washing and drying the obtained product after hydrothermal treatment. The sodium polyacrylate intercalated hydrotalcite composite material prepared by the invention can be used for treating lead ions in waterCompared with the original water talc, the adsorption efficiency is greatly improved.)

1. A preparation method of a sodium polyacrylate intercalated hydrotalcite composite material is characterized by comprising the following steps:

s1, diluting a pure acrylic acid solution with water, titrating with a sodium hydroxide solution, adding a pure isopropanol solution, stirring the obtained mixed solution, and pouring the mixed solution into a five-neck flask with a reflux condenser tube and a dropping funnel;

s2, dropwise adding an ammonium persulfate solution into the five-neck flask through the dropping funnel for polymerization reaction, and continuing to perform condensation reflux for polymerization reaction after the titration is finished;

s3, distilling the product obtained in the step S2 to obtain sodium polyacrylate;

s4, dissolving the sodium polyacrylate obtained in the step S3 into sodium polyacrylate solution with water, adding the sodium polyacrylate solution into a reaction kettle with a reflux condensation pipeInto a five-necked flask of a dropping funnel, Mg (NO) was added₃)₂·6H₂O and Al (NO)₃)₃·9H₂Dripping the O mixed solution and the NaOH solution into a five-neck flask through a dropping funnel for reaction, and continuing to perform condensation reflux reaction after the dripping is finished;

s5, centrifuging the product obtained in the step S4 after hydrothermal treatment, taking out a lower layer sample, adding water to dissolve the lower layer sample, centrifuging again, and repeating the centrifuging operation;

and S6, washing and drying the product obtained in the step S5.

2. The method according to claim 1, wherein in step S1, when the pure acrylic acid solution is diluted with water, the volume ratio of water to the pure acrylic acid solution is 1-1.5: 1;

preferably, the concentration of the sodium hydroxide solution is 28 to 32 mass%;

preferably, the solution is titrated with sodium hydroxide solution to a pH of 7-8;

preferably, the volume ratio of the diluted acrylic acid solution to the pure isopropanol solution in the five-necked flask is 3.2-4: 1.

3. The method according to claim 1, wherein in step S2, the concentration of the ammonium persulfate solution is 5-7 mass%;

preferably, the volume ratio of the ammonium persulfate solution to the pure isopropanol solution added into the five-neck flask is 3.8-4.2: 1;

preferably, the titration time for dropping the ammonium persulfate solution into the five-neck flask is controlled to be 1.5-2 hours;

preferably, the reaction temperature of the polymerization reaction is 75-85 ℃;

preferably, the ammonium persulfate solution titration is completed and the time for continuing the condensing reflux is 0.8-1.5 hours.

4. The method according to claim 1, wherein in step S3, the distillation temperature is 58-65 ℃.

5. The method according to claim 1, wherein in step S4, the concentration of the sodium polyacrylate solution after being dissolved with water is 0.45-0.55 g/mL; in Mg (NO)₃)₂·6H₂O and Al (NO)₃)₃·9H₂O mixed solution of said Mg (NO)₃)₂·6H₂The concentration of O solution is 0.09-0.1g/mL, and the Al (NO) is₃)₃·9H₂The concentration of the O solution is 0.071-0.075 g/mL; the concentration of the NaOH solution is 0.03-0.035 g/mL;

preferably, the sodium polyacrylate solution and Mg (NO) are added into a five-neck flask₃)₂·6H₂O and Al (NO)₃)₃·9H₂The volume ratio of the O mixed solution is 1: 4.5-5.5.

6. The method of claim 1, wherein in step S4, the reaction pH is controlled to 9-10 by adding NaOH solution dropwise;

preferably, the reaction temperature of the reaction is 38-45 ℃;

preferably, the reaction time for continuing the condensation reflux reaction is 2.8 to 4 hours.

7. The method according to claim 1, wherein in step S5, the hydrothermal temperature is 85-95 ℃ and the hydrothermal time is 3.8-5 hours;

preferably, the centrifugation rate of each centrifugation is 3800-;

preferably, the centrifugation is repeated until the pH of the supernatant is 7-8 and the centrifugation is stopped.

8. The method as claimed in claim 1, wherein the drying temperature is 78-85 ℃ and the drying time is 20-30 hours in step S6.

9. The sodium polyacrylate intercalated hydrotalcite composite material prepared by the method of any one of claims 1 to 8, comprising sodium polyacrylate and hydrotalcite, wherein the sodium polyacrylate is attached between the layered plate structures of the hydrotalcite.

10. The use of the sodium polyacrylate intercalated hydrotalcite composite material according to claim 9 for adsorbing lead ions in water.

Technical Field

The invention relates to the technical field of hydrotalcite composite material preparation, in particular to a sodium polyacrylate intercalated hydrotalcite composite material and a preparation method and application thereof.

Background

With the development of industrial technology and the frequent occurrence of heavy metal water pollution events, the ecological environment of the earth is seriously affected, and the discharge of the dye and the heavy metal waste liquid brings a serious challenge to the survival of the plant and the animal. The raw water talc has certain adsorption and energy absorption on certain dyes and heavy metals, but has extremely poor lead ion adsorption performance, and the raw water talc is modified aiming at the characteristic that the raw water talc has poor lead ion adsorption performance, so that the adsorption effect of the hydrotalcite on the lead ions is improved.

Disclosure of Invention

The invention aims to overcome the problem of poor lead ion adsorption performance of hydrotalcite in the prior art, and provides a sodium polyacrylate intercalated hydrotalcite composite material, and a preparation method and application thereof.

In order to achieve the above object, one aspect of the present invention provides a method for preparing a sodium polyacrylate intercalated hydrotalcite composite material, comprising the following steps:

s1, diluting a pure acrylic acid solution with water, titrating with a sodium hydroxide solution, adding a pure isopropanol solution, stirring the obtained mixed solution, and pouring the mixed solution into a five-neck flask with a reflux condenser tube and a dropping funnel;

s2, dropwise adding an ammonium persulfate solution into the five-neck flask through the dropping funnel for polymerization reaction, and continuing to perform condensation reflux for polymerization reaction after the titration is finished;

s3, distilling the product obtained in the step S2 to obtain sodium polyacrylate;

s4, dissolving the sodium polyacrylate obtained in the step S3 into sodium polyacrylate solution by water, adding the sodium polyacrylate solution into a five-neck flask provided with a reflux condenser and a dropping funnel, and adding Mg (NO)₃)₂·6H₂O and Al (NO)₃)₃·9H₂Dripping the O mixed solution and the NaOH solution into a five-neck flask through a dropping funnel for reaction, and continuing to perform condensation reflux reaction after the dripping is finished;

s5, centrifuging the product obtained in the step S4 after hydrothermal treatment, taking out a lower layer sample, adding water to dissolve the lower layer sample, centrifuging again, and repeating the centrifuging operation;

and S6, washing and drying the product obtained in the step S5.

Preferably, in the step S1, the volume ratio of water to the pure acrylic acid solution is 1-1.5:1 when the pure acrylic acid solution is diluted with water.

Preferably, in step S1, the concentration of the sodium hydroxide solution is 28 to 32 mass%.

Preferably, in step S1, the pH of the solution is titrated with sodium hydroxide solution to 7-8.

Preferably, in step S1, the volume ratio of the diluted acrylic acid solution to the pure isopropanol solution in the five-necked flask is 3.2-4: 1.

Preferably, in step S2, the concentration of the ammonium persulfate solution is 5 to 7 mass%.

Preferably, in step S2, the volume ratio of the ammonium persulfate solution to the pure isopropanol solution added to the five-necked flask is 3.8-4.2: 1.

Preferably, in step S2, the titration time for dropping the ammonium persulfate solution into the five-necked flask is controlled to be 1.5 to 2 hours.

Preferably, in step S2, the reaction temperature of the polymerization reaction is 75-85 ℃.

Preferably, in step S2, the ammonium persulfate solution titration is completed and the condensing reflux is continued for 0.8-1.5 hours.

Preferably, in step S3, the distillation temperature is 58-65 ℃.

Preferably, in step S4, the concentration of the sodium polyacrylate solution after being dissolved by water is 0.45-0.55 g/mL; in Mg (NO)₃)₂·6H₂O and Al (NO)₃)₃·9H₂O mixed solution of said Mg (NO)₃)₂·6H₂The concentration of the O solution is 009-0.1g/mL, said Al (NO)₃)₃·9H₂The concentration of the O solution is 0.071-0.075 g/mL; the concentration of the NaOH solution is 0.03-0.035 g/mL.

Preferably, in step S4, the sodium polyacrylate solution and Mg (NO) are added to the five-necked flask₃)₂·6H₂O and Al (NO)₃)₃·9H₂The volume ratio of the O mixed solution is 1: 4.5-5.5.

Preferably, in step S4, the reaction pH is controlled to 9-10 by dropwise addition of NaOH solution.

Preferably, in step S4, the reaction temperature of the reaction is 38 to 45 ℃.

Preferably, in step S4, the reaction time for continuing the condensation reflux reaction is 2.8 to 4 hours.

Preferably, in step S5, the hydrothermal temperature is 85 to 95 ℃, and the hydrothermal time is 3.8 to 5 hours.

Preferably, in step S5, the centrifugation rate of each centrifugation is 3800-.

Preferably, in step S5, the centrifugation operation is repeated until the pH of the supernatant is 7-8, and the centrifugation is stopped.

Preferably, in step S6, the drying temperature is 78-85 ℃, and the drying time is 20-30 hours.

In a second aspect, the present invention provides a sodium polyacrylate intercalated hydrotalcite composite material prepared by the method described above, the composite material comprising sodium polyacrylate and hydrotalcite, and the sodium polyacrylate is attached between the layered plate structures of the hydrotalcite.

The third aspect of the invention provides the application of the sodium polyacrylate intercalated hydrotalcite composite material in the adsorption of lead ions in water.

According to the invention, the raw water talc is modified, and the sodium polyacrylate is inserted between the laminated plate structures of the raw water talc to obtain the sodium polyacrylate intercalated hydrotalcite composite material, and the adsorption rate and the adsorption effect of the composite material on lead ions in water are greatly improved compared with those of the raw water talc.

Drawings

FIG. 1 is an XRD pattern of a sodium polyacrylate intercalated hydrotalcite composite material prepared in example 1 of the present invention;

FIG. 2 is an infrared spectrum of the sodium polyacrylate intercalated hydrotalcite composite material prepared in example 1 of the present invention.

Detailed Description

The following detailed description of embodiments of the invention refers to the accompanying drawings. It should be understood that the detailed description and specific examples, while indicating the present invention, are given by way of illustration and explanation only, not limitation.

The endpoints of the ranges and any values disclosed herein are not limited to the precise range or value, and such ranges or values should be understood to encompass values close to those ranges or values. For ranges of values, between the endpoints of each of the ranges and the individual points, and between the individual points may be combined with each other to give one or more new ranges of values, and these ranges of values should be considered as specifically disclosed herein.

The invention provides a preparation method of a sodium polyacrylate intercalated hydrotalcite composite material, which comprises the following steps:

s1, diluting a pure acrylic acid solution with water, titrating with a sodium hydroxide solution, adding a pure isopropanol solution, stirring the obtained mixed solution, and pouring the mixed solution into a five-neck flask with a reflux condenser tube and a dropping funnel;

s2, dropwise adding an ammonium persulfate solution into the five-neck flask through the dropping funnel for polymerization reaction, and continuing to perform condensation reflux for polymerization reaction after the titration is finished;

s3, distilling the product obtained in the step S2 to obtain sodium polyacrylate;

s4, dissolving the sodium polyacrylate obtained in the step S3 into sodium polyacrylate solution by water, adding the sodium polyacrylate solution into a five-neck flask provided with a reflux condenser and a dropping funnel, and adding Mg (NO)₃)₂·6H₂O and Al (NO)₃)₃·9H₂O mixed solution and NaOH solutionDripping the mixture into a five-neck flask through a dropping funnel for reaction, and continuing to perform condensation reflux reaction after the dripping is finished;

s5, centrifuging the product obtained in the step S4 after hydrothermal treatment, taking out a lower layer sample, adding water to dissolve the lower layer sample, centrifuging again, and repeating the centrifuging operation;

and S6, washing and drying the product obtained in the step S5.

In the method of the present invention, steps S1-S3 are the preparation process of sodium polyacrylate, and steps S4-S6 are the preparation process of sodium polyacrylate intercalated hydrotalcite. In the preparation process of the sodium polyacrylate, isopropanol is used as a chain transfer agent in the polymerization reaction process of acrylic acid and sodium hydroxide to adjust the molecular weight; ammonium persulfate is used as a chain initiator to control the polymerization reaction. After the sodium polyacrylate is prepared, the sodium polyacrylate and Mg (NO) are mixed₃)₂·6H₂O and Al (NO)₃)₃·9H₂And O, reacting, regulating and controlling the pH value in the reaction process by using sodium hydroxide, and then carrying out hydrothermal, centrifugation, washing, drying and other processes to obtain the sodium polyacrylate intercalated hydrotalcite composite material.

In the method of the present invention, in order to facilitate the polymerization reaction, in step S1, the pure acrylic acid solution needs to be diluted with water, and when the pure acrylic acid solution is diluted with water, the volume ratio of water to the pure acrylic acid solution is 1-1.5: 1; specifically, the volume ratio of water to pure acrylic acid solution may be 1:1, 1.1:1, 1.2:1, 1.3:1, 1.4:1, or 1.5: 1; preferably, the volume ratio of water to pure acrylic acid solution is 1.25: 1. Herein, the pure acrylic acid solution is a chemically pure reagent.

In the method of the present invention, in step S1, the sodium hydroxide solution is used to titrate the acrylic acid solution, on one hand, to mix the sodium hydroxide solution with the acrylic acid solution to facilitate the polymerization reaction between the sodium hydroxide solution and the acrylic acid solution, and on the other hand, to adjust the pH of the solution to allow the polymerization reaction to occur in a suitable acid-base environment.

In the method of the present invention, in step S1, the concentration of the sodium hydroxide solution is 28 to 32 mass%; specifically, the concentration of the sodium hydroxide solution may be 28 mass%, 29 mass%, 30 mass%, 31 mass%, or 32 mass%; preferably, the concentration of the sodium hydroxide solution is 30 mass%.

In the method of the present invention, in step S1, a sodium hydroxide solution is used to titrate the solution to pH 7-8; specifically, the pH of the solution may be titrated to 7.0, 7.2, 7.4, 7.6, 7.8, or 8; preferably, the solution is titrated with sodium hydroxide solution to a pH of 7.5.

In the process of the present invention, the isopropanol solution is used as a chain transfer agent in the polymerization reaction to adjust the molecular weight, so that an appropriate amount of isopropanol solution needs to be added to the five-necked flask before the reaction proceeds. The volume ratio of the diluted acrylic acid solution in the five-neck flask to the pure isopropanol solution is 3.2-4: 1; specifically, the volume ratio of the diluted acrylic acid solution to the pure isopropanol solution in the five-necked flask may be 3.2:1, 3.3:1, 3.4:1, 3.5:1, 3.6:1, 3.7:1, 3.8:1, 3.9:1, or 4: 1; preferably, the volume ratio of the diluted acrylic acid solution to the pure isopropanol solution in the five-necked flask is 3.6: 1. Herein, the pure isopropanol solution is an analytically pure reagent.

In the method, the ammonium persulfate solution is used as a chain initiator to control the polymerization reaction, and the reaction starts after the ammonium persulfate solution is added.

In step S2, the concentration of the ammonium persulfate solution is 5 to 7 mass%; specifically, the concentration of the ammonium persulfate solution may be 5 mass%, 5.5 mass%, 6 mass%, 6.5 mass%, or 7 mass%; preferably, the concentration of the ammonium persulfate solution is 6% by mass.

In step S2, the volume ratio of the ammonium persulfate solution to the pure isopropanol solution added into the five-neck flask is 3.8-4.2: 1; specifically, the volume ratio of the ammonium persulfate solution to the pure isopropanol solution added to the five-necked flask may be 3.8:1, 3.9:1, 4:1, 4.1:1 or 4.2: 1; preferably, the volume ratio of the ammonium persulfate solution to the pure isopropanol solution added to the five-necked flask is 4.0: 1.

In order to sufficiently and stably perform the polymerization reaction, it is preferable to add a solution of ammonium persulfate dropwise into the five-necked flask. In step S2, the titration time for dropping the ammonium persulfate solution into the five-necked flask is controlled to be 1.5-2 hours; specifically, the titration time may be 1.5 hours, 1.6 hours, 1.7 hours, 1.8 hours, 1.9 hours, or 2 hours; preferably, the titration time for dropping the ammonium persulfate solution into the five-necked flask is controlled to 1.8 hours.

In step S2, the reaction temperature of the polymerization reaction is 75-85 ℃; specifically, the reaction temperature of the polymerization reaction may be 75 ℃, 77 ℃, 79 ℃, 81 ℃, 83 ℃ or 85 ℃; preferably, the reaction temperature of the polymerization reaction is 80 ℃.

In order to ensure that the polymerization reaction is fully carried out, after the titration of the ammonium persulfate solution is finished, the condensation reflux is continuously carried out to continue the polymerization reaction. In step S2, completing titration of the ammonium persulfate solution, and continuing to perform condensation reflux for 0.8-1.5 hours; specifically, the time for continuing the condensing reflux may be 0.8 hour, 0.9 hour, 1 hour, 1.1 hour, 1.2 hours, 1.3 hours, 1.4 hours, or 1.5 hours; preferably, the ammonium persulfate solution titration is complete and the time for continuing the condensing reflux is 1 hour.

In the method of the present invention, after the polymerization reaction is completed, the obtained product is distilled to distill off water and isopropanol, the obtained sodium polyacrylate is left in a five-neck flask, and the distilled isopropanol can be recycled. The apparatus used for the distillation may be any conventional choice in the art, and is preferably a rotary evaporator.

In step S3, the distillation temperature is 58-65 ℃; specifically, the distillation temperature may be 58 ℃, 59 ℃, 60 ℃, 61 ℃, 62 ℃, 63 ℃, 64 ℃ or 65 ℃; preferably, the distillation temperature is 60 ℃.

After the sodium polyacrylate is prepared, the sodium polyacrylate and Mg (NO) are mixed₃)₂·6H₂O and Al (NO)₃)₃·9H₂And adding the O mixed solution and the NaOH solution into the sodium polyacrylate solution for reaction to prepare the sodium polyacrylate intercalated hydrotalcite composite material. In this process, Mg (NO)₃)₂·6H₂O and Al (NO)₃)₃·9H₂Adding the O mixed solution and NaOH solution separately when Mg (NO)₃)₂·6H₂O and Al (NO)₃)₃·9H₂And after the O mixed solution is added, the addition of the NaOH solution is stopped.

In the method of the present invention, in step S4, the concentration of the sodium polyacrylate solution after being dissolved with water is 0.45-0.55 g/mL; specifically, the concentration of the sodium polyacrylate solution after dissolution with water may be 0.45g/mL, 0.47g/mL, 0.49g/mL, 0.51g/mL, 0.53g/mL, or 0.55 g/mL; preferably, the concentration of the sodium polyacrylate solution after dissolution in water is 0.49 g/mL.

In the method of the present invention, in step S4, Mg (NO) is added₃)₂·6H₂O and Al (NO)₃)₃·9H₂O mixed solution of said Mg (NO)₃)₂·6H₂The concentration of O solution is 0.09-0.1g/mL, specifically, the Mg (NO)₃)₂·6H₂The concentration of the O solution may be 0.09g/mL, 0.092g/mL, 0.094g/mL, 0.096g/mL, 0.098g/mL, or 0.1g/mL, preferably the Mg (NO) is used₃)₂·6H₂The concentration of the O solution is 0.097 g/mL; the Al (NO)₃)₃·9H₂The concentration of O solution is 0.071-0.075g/mL, specifically, the Al (NO)₃)₃·9H₂The concentration of the O solution can be 0.071g/mL, 0.072g/mL, 0.073g/mL, 0.074g/mL or 0.075g/mL, preferably the Al (NO)₃)₃·9H₂The concentration of the O solution was 0.073 g/mL.

In the method of the invention, in step S4, the concentration of the NaOH solution is 0.03-0.035 g/mL; specifically, the concentration of the NaOH solution can be 0.03g/mL, 0.031g/mL, 0.032g/mL, 0.033g/mL, 0.034g/mL, or 0.035 g/mL; preferably, the concentration of the NaOH solution is 0.032 g/mL.

In the method of the present invention, in step S4, sodium polyacrylate solution and Mg (NO) are added to a five-necked flask₃)₂·6H₂O and Al (NO)₃)₃·9H₂The volume ratio of the O mixed solution is 1: 4.5-5.5; specifically, sodium polyacrylate solution and Mg (NO) are added into a five-neck flask₃)₂·6H₂O and Al (NO)₃)₃·9H₂The volume ratio of the O mixed solution can be 1:4.5, 1:4.7, 1:4.9, 1:5.1, 1:5.3 or 1: 5.5; preferably, the sodium polyacrylate solution and Mg (NO) are added into a five-neck flask₃)₂·6H₂O and Al (NO)₃)₃·9H₂The volume ratio of the O mixed solution may be 1:5.

In the method of the present invention, in step S4, the pH of the mixed solution in the five-necked flask was controlled to be within a suitable range by dropwise addition of a NaOH solution. In step S4, the reaction pH value is controlled to be 9-10 by dripping NaOH solution; specifically, the reaction pH can be controlled at 9, 9.2, 9.4, 9.6, 9.8 or 10 by dropwise adding NaOH solution; preferably, the reaction pH is controlled at 9.5 by dropwise addition of NaOH solution.

In the method of the present invention, in step S4, the reaction temperature of the reaction is 38 to 45 ℃; specifically, the reaction temperature of the reaction may be 38 ℃, 39 ℃, 40 ℃, 41 ℃, 42 ℃, 43 ℃, 44 ℃ or 45 ℃; preferably, the reaction temperature of the reaction is 40 ℃.

In the method of the present invention, in step S4, Mg (NO)₃)₂·6H₂O and Al (NO)₃)₃·9H₂After the titration of the O mixed solution and the NaOH solution is stopped, the reaction time of the continuous condensation reflux reaction is 2.8 to 4 hours; specifically, the reaction time for continuing the condensation reflux reaction may be 2.8 hours, 3 hours, 3.2 hours, 3.4 hours, 3.6 hours, 3.8 hours, or 4 hours; preferably, the reaction time for continuing the condensation reflux reaction is 3 hours.

In the method of the present invention, after the reaction in step S4 is completed, the obtained product needs to be hydrothermally treated in a water bath, so that the crystal form of the obtained intercalated hydrotalcite is more stable. Preferably, the resulting product is transferred to a reaction kettle for hydrothermal treatment in a water bath.

In step S5, the hydrothermal temperature is 85-95 ℃; specifically, the hydrothermal temperature may be 85 ℃, 87 ℃, 89 ℃, 91 ℃, 93 ℃ or 95 ℃; preferably, the hydrothermal temperature is 90 ℃.

In step S5, the hydrothermal time is 3.8 to 5 hours; specifically, the hydrothermal time may be 3.8 hours, 4 hours, 4.2 hours, 4.4 hours, 4.6 hours, 4.8 hours, or 5 hours; preferably, the hydrothermal time is 4 hours.

In step S5, after the hydrothermal reaction, the product is centrifuged to separate the target product from other components. The centrifugation rate of each centrifugation is 3800-; the centrifugation time of each centrifugation is 8-15min, specifically, the centrifugation time of each centrifugation can be 8min, 9min, 10min, 11min, 12min, 13min, 14min or 15min, and preferably, the centrifugation time of each centrifugation is 10 min.

In step S5, multiple centrifugations are required to completely separate the target product from other components. Repeating the centrifugation operation until the pH value of the supernatant is 7-8, and stopping the centrifugation; specifically, the centrifugation operation may be repeated until the pH of the supernatant is 7, 7.2, 7.4, 7.6, 7.8, or 8; preferably, the centrifugation is repeated until the pH of the supernatant is 7.5.

In the method of the present invention, in step S6, the drying temperature is 78-85 ℃, specifically, the drying temperature may be 78 ℃, 79 ℃, 80 ℃, 81 ℃, 82 ℃, 83 ℃, 84 ℃ or 85 ℃, and preferably, the drying temperature is 80 ℃; the drying time is 20 to 30 hours, specifically, the drying time may be 20 hours, 22 hours, 24 hours, 26 hours, 28 hours or 30 hours, and preferably, the drying time may be 24 hours.

In a second aspect, the present invention provides a sodium polyacrylate intercalated hydrotalcite composite material prepared by the method described above, the composite material comprising sodium polyacrylate and hydrotalcite, and the sodium polyacrylate is attached between the layered plate structures of the hydrotalcite.

The third aspect of the invention provides the application of the sodium polyacrylate intercalated hydrotalcite composite material in the adsorption of lead ions in water.

According to the invention, the raw water talc is modified, and the sodium polyacrylate is inserted between the laminated plate structures of the raw water talc to obtain the sodium polyacrylate intercalated hydrotalcite composite material, so that the adsorption effect of the composite material on lead ions in water is greatly improved compared with that of the raw water talc.

The present invention will be described in detail by way of examples, but the scope of the present invention is not limited thereto.