阅读说明：本技术 一种多羧基螯合剂及其制备方法和应用 (Polycarboxyl chelating agent, and preparation method and application thereof ) 是由 郭丽媛 李小瑞 王晨 侯妍 杨晓武 李刚辉 于 2020-05-28 设计创作，主要内容包括：本发明公开了一种多羧基螯合剂及其制备方法和应用,制备方法包括：(1)将双季戊四醇和丙酰氯加入三口烧瓶中,得到粘稠液体中间体Ⅰ。(2)将步骤(1)中所得粘稠液体中间体Ⅰ加入四口烧瓶中,再将第一溶剂二甲基亚砜加入到四口烧瓶中,然后将氯乙酸钠加入含有二甲基亚砜等溶剂的溶液中,得到固体产物中间体Ⅱ。(3)将步骤(2)中的固体产物中间体Ⅱ加入第二溶剂二甲基甲酰胺中,在磁力搅拌下加入己二异氰酸酯(HDI),所得即为多羧基螯合剂。该一种多羧基螯合剂的制备方法,成功制备一种具有絮凝、螯合双功能的重金属螯合剂。(The invention discloses a polycarboxyl chelating agent and a preparation method and application thereof, wherein the preparation method comprises the following steps: (1) adding dipentaerythritol and propionyl chloride into a three-neck flask to obtain a viscous liquid intermediate I. (2) Adding the viscous liquid intermediate I obtained in the step (1) into a four-neck flask, adding dimethyl sulfoxide serving as a first solvent into the four-neck flask, and adding sodium chloroacetate into a solution containing solvents such as dimethyl sulfoxide to obtain a solid product intermediate II. (3) And (3) adding the solid product intermediate II obtained in the step (2) into a second solvent, namely dimethylformamide, and adding Hexamethylene Diisocyanate (HDI) under magnetic stirring to obtain the polycarboxyl chelating agent. The preparation method of the polycarboxyl chelating agent successfully prepares the heavy metal chelating agent with the double functions of flocculation and chelation.)

1. A polycarboxy chelating agent, wherein the polycarboxy chelating agent has a structural formula:

2. a preparation method of a polycarboxyl chelating agent is characterized by comprising the following steps:

1) mixing dipentaerythritol and propionyl chloride, stirring and reacting for 2-4 hours at 35-45 ℃, cooling to room temperature, neutralizing, washing with water, extracting, and distilling under reduced pressure to remove a solvent to obtain a viscous liquid intermediate I;

2) adding a first solvent into the viscous liquid intermediate I, adding powdery sodium hydroxide after the viscous liquid intermediate I is completely dissolved, stirring and reacting for 0.5-1 h at 35-45 ℃, then adding sodium chloroacetate into the solution, heating to 70-90 ℃, reacting for 5-7 h, and performing suction filtration to obtain a solid product intermediate II;

3) and adding the solid product intermediate II into a second solvent, adding hexamethylene diisocyanate while stirring, heating to 40-50 ℃, reacting for 3-4 h, performing suction filtration, and drying to obtain the polycarboxyl chelating agent.

3. The method for preparing polycarboxy chelating agent as claimed in claim 2, wherein the molar ratio of the dipentaerythritol to the propionyl chloride in the step 1) is 1 (3-3.1).

4. The method for preparing polycarboxy chelating agent as claimed in claim 2, wherein the concentration of the sodium hydroxide solution in step 1) is 3-6% by mass.

5. The method for preparing polycarboxy chelating agent as set forth in claim 2, wherein in the step 2), the ratio of the addition amount of the viscous liquid intermediate i to the first solvent is 0.025 mol: 100 mL.

6. The method of claim 2, wherein the first solvent is dimethyl sulfoxide.

7. The method for preparing polycarboxy chelating agent as set forth in claim 2, wherein the solid product intermediate ii, the second solvent and hexamethylene diisocyanate are added in a molar ratio of 2: 30: 1.

8. the method of claim 2, wherein the second solvent is dimethylformamide.

9. The method of claim 1The application of the polycarboxyl chelating agent is characterized in that the polycarboxyl chelating agent is used for adsorbing heavy metal ions in sewage; the heavy metal is Cu²⁺、Ni²⁺Or Pb²⁺。

10. The use of the polycarboxy chelating agent as claimed in claim 9, wherein in step 4), the polycarboxy chelating agent is added in an amount of 1-10mL/L based on the wastewater.

Technical Field

The invention relates to the field of fine chemical water treatment, and particularly relates to a polycarboxyl chelating agent, and a preparation method and application thereof.

Background

Heavy metals seriously damage the natural environment, and the heavy metals in the water mainly come from mining, metal smelting, chemical production wastewater, pesticide and fertilizer use, household garbage and the like. Heavy metals are discharged into the environment and are difficult to remove by chemical or biological degradation, thus causing environmental pollution. While human beings are at the top of the food chain, these heavy metals are easily transported through the food chain and finally enriched in the human body. The existing treatment methods of heavy metals in wastewater comprise a sulfide precipitation method, a reduction method, a biological flocculation method, a plant restoration method and the like, each method has the advantages and limitations, and the methods are influenced by technical and economic problems. The chelating precipitation method becomes a research hotspot in recent years, can overcome the limitation of technical and economic problems, and the chelating agent is a water-soluble molecule, has heavy metal chelating groups which can form a coordination body with heavy metal ions, and can selectively generate a water-insoluble metal complex with the heavy metal ions, thereby removing the heavy metal ions in water.

The chelating agent with larger molecular weight has relatively poorer solubility in water, and the chelating agent with smaller molecular weight has high utilization rate of radicals, but the generated chelating precipitate has tiny floc and poor settling property, and the floc can be well settled only by adding a flocculating agent.

Disclosure of Invention

In order to solve the problem of poor solubility of a high molecular weight chelating agent in the prior art, the invention aims to provide a polycarboxyl chelating agent, a preparation method and application thereof.

The technical scheme adopted by the invention is as follows:

a polycarboxy chelating agent having the formula:

a method of preparing a polycarboxy chelating agent comprising the steps of:

1) mixing dipentaerythritol and propionyl chloride, stirring and reacting for 2-4 hours at 35-45 ℃, cooling to room temperature, neutralizing, washing with water, extracting, and distilling under reduced pressure to remove a solvent to obtain a viscous liquid intermediate I;

2) adding a first solvent into the viscous liquid intermediate I, adding powdery sodium hydroxide after the viscous liquid intermediate I is completely dissolved, stirring and reacting for 0.5-1 h at 35-45 ℃, then adding sodium chloroacetate into the solution, heating to 70-90 ℃, reacting for 5-7 h, and performing suction filtration to obtain a solid product intermediate II;

3) and adding the solid product intermediate II into a second solvent, adding hexamethylene diisocyanate while stirring, heating to 40-50 ℃, reacting for 3-4 h, performing suction filtration, and drying to obtain the polycarboxyl chelating agent.

As a further improvement of the invention, in the step 1), the molar ratio of the dipentaerythritol to the propionyl chloride is 1 (3-3.1).

As a further improvement of the invention, in the step 1), the mass concentration of the sodium hydroxide solution is 3-6%.

As a further improvement of the present invention, in step 2), the ratio of the addition amount of the viscous liquid intermediate i to the first solvent is 0.025 mol: 100 mL.

As a further improvement of the present invention, the first solvent is dimethyl sulfoxide.

As a further improvement of the present invention, in the step 3), the addition amount molar ratio of the solid product intermediate ii, the second solvent and the hexamethylene diisocyanate is 2: 30: 1.

as a further refinement of the invention, the second solvent is dimethylformamide.

The application of a polycarboxyl chelating agent is used for adsorbing heavy metal ions in sewage; the heavy metal is Cu²⁺、Ni²⁺Or Pb²⁺。

The ratio of the addition amount of the polycarboxyl chelating agent to the waste water is 1-10 mL/L.

Compared with the prior art, the invention has the following advantages:

the preparation method aims at the problems that the high molecular weight chelating agent has poor solubility, the low molecular weight chelating agent has high chelating group utilization rate, but the generated chelate precipitate floc is fine and has poor settling property, and the floc can be well settled only by adding the flocculating agent. The polycarboxyl chelating agent is a heavy metal chelating agent with double functions of flocculation and chelation.

According to the preparation method, the metal complex containing a plurality of carboxyl chelating groups and heavy metal has large floc, so that the heavy metal chelating agent can be well settled without using a flocculating agent, the use of chemicals in the chelating and precipitating process is reduced, and the heavy metal chelating agent with the double functions of flocculation and chelation is successfully prepared.

According to the application of the invention, the concentration of the heavy metal is reduced along with the increase of the chelating agent of the metal complex generated by the polycarboxyl chelating agent and the heavy metal, the heavy metal can be well settled without using a flocculating agent, and the use of chemicals in the chelating and precipitating process is reduced.

Description of the drawings:

FIG. 1 Synthesis of polycarboxy chelating agent obtained in example 1;

FIG. 2 nuclear magnetic hydrogen spectra of a polycarboxy chelating agent obtained in example 1;

FIG. 3 is a graph showing the relationship between the amount of chelating agent added and the residual concentration of heavy metals in example 1.

Detailed Description

The technical solution in the embodiments of the present invention will be clearly and completely described below. It is to be understood that the described embodiments are merely exemplary of the invention, and not restrictive of the full scope of the invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

The invention relates to a polycarboxyl chelating agent, which has the following structural formula:

the principle is as follows: the chelating agent has heavy metal chelating groups which can form a coordination compound with heavy metal ions and can selectively generate a water-insoluble metal complex with the heavy metal ions, thereby removing the heavy metal ions in the water. Compared with a high-molecular-weight chelating agent, the multi-carboxyl chelating agent prepared by the invention has more excellent solubility, and because the metal complex generated by a plurality of carboxyl chelating groups and heavy metal has large floc, the metal complex can be well settled without using a flocculating agent, the use of chemicals in the chelating and precipitating process is reduced, and the heavy metal chelating agent with the double functions of flocculation and chelation is successfully prepared.

Specifically, the preparation method of the polycarboxyl chelating agent comprises the following steps:

(1) adding dipentaerythritol and propionyl chloride into a three-neck flask, wherein the molar ratio of the dipentaerythritol to the propionyl chloride is 1 (3-3.1). After the addition, stirring and reacting for 2-4 h at 35-45 ℃, and cooling to room temperature. And (3) neutralizing with a sodium hydroxide solution, wherein the concentration of the sodium hydroxide solution is 3-6% (mass fraction). Washing with water, extracting with organic solvent, and distilling under reduced pressure to remove solvent to obtain viscous liquid intermediate I.

(2) Adding the viscous liquid intermediate I obtained in the step (1) into a four-neck flask, wherein the addition amount of the viscous liquid intermediate I is 0.025 mol. Then, dimethyl sulfoxide (DMSO), a first solvent, was added to the four-necked flask in an amount of 100 mL. After the sodium hydroxide is completely dissolved, adding powdery sodium hydroxide, stirring and reacting for 0.5-1 h at 35-45 ℃, wherein the addition amount of the powdery sodium hydroxide is 4 g. Then, sodium chloroacetate was added to a solution containing a solvent such as dimethyl sulfoxide in an amount of 0.05 mol. And heating to 70-90 ℃, reacting for 5-7 h, and performing suction filtration on the solution to obtain a solid product intermediate II.

(3) And (3) adding the solid product intermediate II in the step (2) into a second solvent, wherein the addition amount of the solid product intermediate II is 0.02mol, the second solvent is Dimethylformamide (DMF), and the addition amount is 21.93 g. Hexamethylene Diisocyanate (HDI) was added with magnetic stirring in an amount of 0.01 mol. And heating to 40-50 ℃, reacting for 3-4 h, and performing suction filtration and drying to obtain the polycarboxyl chelating agent.

4) Adding the polycarboxyl chelating agent obtained in the step (3) into heavy metal-containing wastewater, wherein the addition amount of the polycarboxyl chelating agent is 1-10mL, and the heavy metal-containing wastewater contains Cu²⁺、Ni²⁺、Pb²⁺The heavy metal content was 100mg/L, 65mg/L, and 78mg/L, respectively. Stirring with a magnetic stirrer for 0.5h, centrifuging, collecting supernatant, and analyzing heavy metal ion concentration.

The invention is further illustrated by the following specific examples and figures: