Dimeric polyethylene polyamine double-chelating group heavy metal chelating flocculant as well as preparation method and application of dimeric polyethylene polyamine double-chelating group heavy metal chelating flocculant

Abstract

The invention discloses a dimeric polyethylene polyamine double chelating group heavy metal chelating flocculant as well as a preparation method and application thereof. The preparation method comprises the following steps: copolymerizing polyethylene polyamine and epichlorohydrin under the auxiliary action of NaOH to generate a dimer, carrying out nucleophilic addition reaction on the dimer and carbon disulfide in the presence of alkali, and introducing-CSS <-> into a non-terminal position of a dimer polyethylene polyamine molecular chain; then carrying out electrophilic substitution reaction with halogenated sodium acetate under a strong alkaline condition to introduce acetic acid groups to two ends of a molecular chain, so as to form a structure in which N (CH2COO-) 2 groups are arranged at two ends of a relatively long molecular chain and a plurality of-CSS-groups are connected in the middle. Product molecules have excellent molecular chain length and chelating group distribution, the chelating binding capacity to heavy metal ions is improved, generated flocs are dense and thick, and the settling separation performance is good. The method is simple in process, mild in reaction condition, simple and convenient to operate and control and easy to realize industrial production.

Description

Technical Field

[0001] The invention relates to the field of heavy metal wastewater treatment and stabilization of heavy metals in incineration fly ash, and in particular to a di-polyethylene polyamine-based double chelate group heavy metal chelate flocculant and a preparation method and application thereof. Background Art

[0002] Heavy metals or metalloids such as Hg, Pb, Cu, Cd, Cr, Zn, Mn, Ni, Co, Ag, Fe, and As, except for a few essential trace elements such as Zn, Cu, Mo, Cr, Co, and Fe, are mostly non-essential elements for the human body. Even if they are essential trace elements, exceeding a certain amount will have serious toxic effects on the human body. Since heavy metals are non-biodegradable, can produce significant toxicity in trace amounts, and are cumulative, they can easily enter the human body through the food chain, not only destroying the ecological environment, but also posing a serious threat to human life and safety. With the rapid development of industries such as electroplating, metallurgy, mineral mining and selection, and battery manufacturing, wastewater containing a large amount of heavy metal ions or heavy metal compounds is discharged into the soil and water bodies, endangering the growth and reproduction of aquatic organisms and plants, seriously damaging the ecological environment, and posing a serious threat to human drinking water and water use. Therefore, the effective treatment of heavy metal wastewater has become a global problem that needs to be solved urgently in the current field of environmental protection.

[0003] Heavy metals are not biodegradable, and their pollution and hazards can only be eliminated by changing their existence mode and form. The treatment methods that have been developed include chemical precipitation, ion exchange, flotation, adsorption, electrochemical, chelating flocculation (precipitation) and biological methods. The ion exchange method uses ion exchange resin to replace heavy metal ions in the solution. It has low treatment efficiency and limited scope of application. It is easy to produce high-concentration elution wastewater that is difficult to treat and cause secondary pollution. In the flotation method, surfactants are used to bind heavy metal ions. Although the treatment capacity is large and the operation speed is fast, the salt content of the effluent is high and the scum is difficult to control. Although the adsorption method has a wide source of materials and more thorough removal of heavy metals, the adsorption capacity of natural adsorption materials is small, elution and regeneration are difficult, and a large amount of solid hazardous waste that is difficult to dispose of is easily generated; while synthetic adsorption materials have problems such as high manufacturing cost and difficulty in elution regeneration and post-treatment. The electrochemical method has problems such as selectivity for heavy metal ions, limited adaptability, high requirements for operation control, and high cost. Phytoremediation in biological methods is often used to control heavy metals in soil, but is not suitable for the enrichment and removal of heavy metals in water. Moreover, this method only transfers heavy metals, rather than removing them from the environment. Traditional chemical precipitation methods consume a large amount of chemical agents and easily produce a large amount of hazardous waste residues that are difficult to dispose of. Compared with the above methods, the chelating flocculation (precipitation) method can use chelating flocculants to bind heavy metal ions in the water body by chelation, and separate them from the water body through flocculation (precipitation), thereby achieving efficient removal of heavy metals in the water body, significantly reducing the amount of heavy metal-containing waste residues, and the waste residues produced are easy to further separate, recycle and transform. Therefore, it can be suitable for large-scale treatment of various heavy metal wastewaters.

[0004] The key to the chelating flocculation (precipitation) method lies in the performance of the chelating agent or chelating flocculant. Currently, the heavy metal treatment agents that have been developed and widely used mainly include two categories: organic sulfides and dithiocarbamates (DTC). The most representative product of organic sulfides is the heavy metal ion scavenger sodium trithiocarbamate (TMT); DTC chelating agents mainly include HMP-2000, sodium thiocarbamate, ethylthiocyanate, ethylenediamine-based heavy metal chelating agent (CN101857296B), N,N'-sodium dithiopiperazinecarboxylate and polymer heavy metal ion capture precipitant (DTCR). These products all have a single chelating group, such as the chelating group of TMT is -SH (Na), while the chelating groups of DTC are all single dithiocarbamate groups (—CSS －), therefore, the chelating and binding ability to some heavy metal ions is not strong. For example, DTC is not effective in treating wastewater containing heavy metals such as Cr, Zn and Ni. When treating complex or composite pollutants containing multiple heavy metal ions or heavy metals coexisting with organic and inorganic substances, the effect is poor, and it is difficult to achieve the purpose of effectively removing multiple heavy metal ions in one step. Ethylene diamine tetraacetic acid (Na) (EDTA) is a widely used strong chelating agent that can form stable chelates with most metal ions. The main reason is that 1—N(CH2COO － )2 Chelating groups can form two stable Therefore, the introduction of -N(CH2COO － )2 group is bound to enhance the chelating ability of heavy metal ions. － A considerable part of the chelates formed by )2 and metal ions are water-soluble and difficult to separate from water; while -CSS － The chelate formed by chelating with heavy metal ions is insoluble in water and can be easily separated from water in the form of precipitation. － and—N(CH2COO － )2 into the same chelating agent molecule, it can be synthesized by -N(CH2COO － )2 will be with —CSS － Heavy metal ions that are not chelated strongly are firmly bound and through the interaction with CSS － The insoluble dithiocarbamate chelate formed is precipitated and separated from the water. The two complement each other and synergistically improve the removal efficiency of heavy metals in wastewater, and achieve efficient removal of multiple heavy metal ions in one step. Research and practice have shown that appropriately increasing the molecular (molecular chain) size of the chelating agent, that is, a chelating agent molecule contains more chelating groups, can bind more heavy metal ions, so that under the action of the molecular chain, it is conducive to aggregation to form flocs, so that the flocs are relatively coarse and compact, which is conducive to sedimentation separation and floc dehydration, and is convenient for post-processing. However, when the molecular chain reaches a certain length, due to the steric hindrance of the chain, a considerable part of the chelating groups will be "suspended" due to spatial mismatch, resulting in the formation of micro-flocs with too much charge of the same kind (usually negative charge) and not conducive to the growth of flocs. Therefore, while considering the chelating group, the size of the molecule must also be taken into account. Summary of the invention

[0005] In view of the above technical problems, the present invention provides a di-polyethylene polyamine-based double chelate group heavy metal chelate flocculant and a preparation method and application thereof.

[0006] The dimerized polyethylene polyamine-based double chelate group heavy metal chelate flocculant provided by the present invention is characterized in that the molecule has both -CSS － and—N(CH2COO－ )2 Two strong chelating groups can complement each other and have strong chelating binding ability for most heavy metal ions in water; and have a longer molecular chain, and contain more strong chelating groups in the molecule, which can aggregate the formed chelates through the connection of the molecular chain to form micro-flocculation, thereby promoting the formation and growth of floccules. Therefore, it has both strong chelating binding ability for most heavy metals and good flocculation and sedimentation performance, and can achieve efficient removal of multiple heavy metal ions in one step, thereby broadening its scope of application; the structure of its main component is shown in formula (Ⅰ):

[0007]

[0008] In formula (I), 2≤x≤4, 1≤y≤x, and x and y are both integers; when y<x, x-y N atoms are connected to H atoms. － and—N(CH2COO － )2 Two strong chelating groups; auxiliary ingredients are xanthogenic acid and NaOH; the appearance is reddish brown or brownish red viscous liquid.

[0009] The preparation method of the above-mentioned diethylene glycol polyamine-based double chelate group heavy metal chelate flocculant comprises the following steps:

[0010] (1) Add polyethylene polyamine to a reactor at a molar ratio of 2:1 to 1.05, slowly dropwise add epichlorohydrin at room temperature for 1 to 1.5 hours; then dropwise add an alkali or alkaline salt solution in an amount equal to that of epichlorohydrin, and continue to react for 1 to 2 hours;

[0011] (2) distilled water 5 to 6 times the volume of the reaction mixture in step (1) was added to dilute the mixture, and then NaOH was added at a ratio of (n-1) times the amount of polyethylene polyamine to the amount of NaOH of 1:0.55 to 1.2, wherein n represents the number of N atoms in the polyethylene polyamine molecule, and stirred at room temperature for 0.5 to 1 hour;

[0012] (3) Add carbon disulfide at a ratio of (n-1) times the amount of polyethylene polyamine to the amount of carbon disulfide of 1:0.25-1.05, wherein n represents the number of nitrogen atoms in the polyethylene polyamine molecule, and stir the mixture at room temperature for 3.5-5 hours until the bottom oil droplets disappear, then heat the mixture to 50-60°C for 1-1.5 hours, and then cool the mixture to room temperature to obtain solution A;

[0013] (4) weighing sodium halogenated acetate and adding it to a reactor at a molar ratio of sodium halogenated acetate to polyethylene polyamine of 2.05 to 2.1:1, and adding distilled water to prepare a solution with a mass fraction of 30% to 35%, thereby obtaining solution B;

[0014] (5) adding the solution A obtained in step (3) to the solution B obtained in step (4) and mixing them thoroughly; then weighing the alkali or alkaline salt according to the molar ratio of the alkali or alkaline salt to the polyethylene polyamine of 2 to 2.1:1, adding distilled water to prepare a solution with a mass fraction of 20% to 30%, and slowly adding the solution in three batches, each batch being added until the pH value of the solution drops to 9 to 11 before adding the next batch, and continuing to react at room temperature for 4 to 6 hours after the addition is completed, and then heating to 50 to 60° C. and continuing to react for 1 to 1.5 hours, and cooling to room temperature to obtain a di-polyethylene polyamine-based double chelate group heavy metal chelating flocculant.

[0015] Furthermore, in step (1), the polyethylene polyamine is any one of diethylene triamine, triethylene tetraamine or tetraethylene pentamine, preferably triethylene tetraamine.

[0016] Furthermore, in steps (1) and (5), the base or alkaline salt is any one of NaOH and Na2CO3, preferably NaOH.

[0017] Furthermore, in step (3), the halogenated acetate is any one of sodium chloroacetate or sodium bromoacetate, preferably sodium chloroacetate.

[0018] Furthermore, the slow addition rate of the epichlorohydrin in step (1) is 1 to 2 drops / min; and in step (5), the slow addition time of the alkali or alkaline salt is 40 to 60 minutes.

[0019] Furthermore, the polyethylene polyamine, epichlorohydrin, alkali or alkaline salt, carbon disulfide and sodium haloacetate are all products with purity above industrial grade and are used without further purification.

[0020] Furthermore, in steps (1) and (4), the reactor is equipped with a mechanical stirrer, a dropping funnel and a reflux condenser.

[0021] The above-mentioned chelating flocculant is applied to the treatment of various heavy metal wastewaters or heavy metals in incineration fly ash, and has excellent treatment effect.

[0022] The present invention relates to a method for preparing a di-polyethylene polyamine-based double chelate heavy metal chelate flocculant. The method firstly copolymerizes polyethylene polyamine with epichlorohydrin under the auxiliary action of NaOH to generate a dimer, thereby doubling the molecular chain; then reacts with carbon disulfide in the presence of an alkali to preferentially convert CSS － The acetic acid group (—CH2COO － ) are introduced to both ends of the molecular chain to form two groups of strong chelating groups—N(CH2COO －)2, forming a longer molecular chain with -N(CH2COO － )2 groups, multiple CSS connected in the middle of the molecular chain － The present invention overcomes the shortcomings of common chelating agents with a single group and poor chelating and binding ability to some heavy metals, and enables the product molecules to have a better molecular chain length and chelating group distribution, significantly improving the chelating and binding ability to most heavy metal ions, which is conducive to promoting the formation and growth of micro-flocculation, making the flocs dense and coarse, improving the sedimentation and separation performance, and facilitating the post-treatment and recycling of sediment.

[0023] Compared with the prior art, the present invention has the following beneficial effects:

[0024] (1) The present invention prolongs the molecular chain to 2 times by copolymerizing polyethylene polyamine with epichlorohydrin, giving the product molecule a better molecular chain length, overcoming the disadvantage that the chelating agent is difficult to chelate multiple heavy metal ions through the same molecular chain due to its short molecular chain and few chelating groups and forming a larger micro-flocculation through the connection of its molecular chain, or overcomes the disadvantage that the molecular chain is difficult to stretch in the aqueous solution, so that some chelating groups are difficult to chelate and bind heavy metal ions, so that the chelating groups in the chelating agent are fully utilized, and the excessive negative charge of the formed micro-flocculation due to the failure to chelate heavy metal ions is reduced, thereby facilitating the further growth of the micro-flocculation; the nucleophilic addition reaction is preferentially carried out at the secondary amine position of the polyamine to form a large micro-flocculation. － The group is introduced into the secondary amine position of the polyamine to ensure the introduction of -CH2COO － It can only enter the end position of the dimerized polyethylene polyamine molecular chain, thereby achieving effective regulation and optimization of the molecular structure.

[0025] (2) The product of the present invention has both a more suitable molecular chain length and the properties of -CSS － and—N(CH2COO － )2 Two strong chelating groups, with more chelating functional groups and optimized group distribution, overcome the defects of common chelating agents with single functional groups and weak chelating and binding ability to some heavy metal ions; among them - CSS － and—N(CH2COO － )2 can complement each other and synergistically improve the chelating and binding ability of most heavy metal ions, and effectively promote the formation and growth of micro-flocculation through the connection of molecular chains, effectively improve its flocculation and sedimentation performance, and achieve efficient removal of multiple heavy metal ions in water in one step. Therefore, the scope of application of the product is effectively broadened.

[0026] (3) The product of the present invention can react rapidly with most heavy metal ions in wastewater at room temperature to form stable water-insoluble chelates. －)2 group can capture heavy metal ions from most heavy metal chelates that are slightly weaker than it, so that the product of the present invention can effectively treat not only free heavy metal wastewater, but also most complex heavy metal wastewater. Since the product of the present invention can form stable chelates with most heavy metal ions in water, it can achieve efficient removal of multiple heavy metal ions in one step, especially for complex wastewater containing multiple heavy metal ions and composite heavy metal wastewater composed of heavy metals and organic pollutants or multiple inorganic ions. It also has excellent treatment effect.

[0027] (4) The product of the present invention is used for actual wastewater treatment. It only needs to add a certain amount of the product of the present invention to the heavy metal wastewater and stir it sufficiently to quickly produce insoluble flocs, which can be separated by sedimentation and filtered. No complicated equipment and procedures are required. Therefore, the treatment process is simple and is conducive to promotion and application.

[0028] (5) The preparation method of the present invention has simple process, mild reaction conditions, easy operation and control, no "three wastes" are generated, the required equipment is conventional equipment, it is easy to realize industrial production, and has broad application prospects.

[0029] The invention is suitable for treating various heavy metal wastewaters and fixing heavy metals in incineration fly ash, and has an excellent treatment effect on complex wastewater containing multiple heavy metal ions and composite heavy metal wastewater composed of heavy metals and organic pollutants or multiple inorganic ions. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 The figure is a process flow chart of the preparation method of the present invention.

[0031] Figure 2 This is the infrared spectrum of the product of the present invention, the di-polyethylene polyamine-based double chelate group heavy metal chelate flocculant (the sample of Example 5).

[0032] Figure 3 This is a diagram showing the chelating flocculation mechanism of the product of the present invention. DETAILED DESCRIPTION

[0033] The present invention is further described in detail below in conjunction with the accompanying drawings and specific embodiments, but the present invention is not limited thereto.

[0034] Examples 1 to 12 are preparation methods of the product of the present invention, the di-polyethylene polyamine-based double chelate group heavy metal chelate flocculant, and Examples 13 to 17 are application examples of the product of the present invention.

[0035] Example 1

[0036] (1) 13.1 mL of 99.00% diethylenetriamine was added to a 250 mL three-necked flask equipped with a mechanical stirrer, a dropping funnel and a reflux condenser, and 4.8 mL of 98.00% epichlorohydrin was slowly added dropwise at a rate of 2 drops / min at room temperature. After the addition was complete, the mixture was reacted for 1.5 h; then 6.0 mL of 30.00% NaOH solution was added dropwise and the reaction was continued for 2 h;

[0037] (2) Add 120 mL of distilled water to dilute, then add 6.3 g of solid NaOH with a mass fraction of 96.00%, and stir at room temperature for 1 h;

[0038] (3) 7.8 mL of 99.00% carbon disulfide was slowly added dropwise to the solution in step (2), and the mixture was stirred at room temperature for 3.5 h until the bottom oil droplets disappeared, and then the temperature was raised to 60° C. for 1 h, and then the temperature was lowered to room temperature;

[0039] (4) 29.24 g of 98% sodium chloroacetate was added to a 500 mL three-necked flask equipped with a mechanical stirrer, a dropping funnel, and a reflux condenser, and 66.3 mL of distilled water was added to prepare a solution with a mass fraction of 30.00%;

[0040] (5) adding the solution obtained in step (3) to the solution obtained in step (4) and mixing thoroughly; weighing 10.00 g of solid NaOH with a mass fraction of 96%, adding 22.0 mL of distilled water to dissolve it into a solution with a mass fraction of 30.00%, transferring it to a dropping funnel and adding it in three batches, each adding time is 40 min, and adding the next batch after the pH value of the reaction liquid drops to about 10. After the addition is completed, continue to react at room temperature for 4 h, then heat it to 60 ° C and continue to react for 1 h, cool it to room temperature, and obtain 247.4 mL of reddish brown liquid, i.e., dimerized polyethylene polyamine double chelate group heavy metal chelate flocculant.

[0041] Example 2

[0042] (1) 13.1 mL of 99.00% diethylenetriamine was added to a 250 mL three-necked flask equipped with a mechanical stirrer, a dropping funnel and a reflux condenser, and 5.1 mL of 98.00% epichlorohydrin was slowly added dropwise at a rate of 1 drop / min at room temperature. After the addition was complete, the mixture was reacted for 1 hour. Then, 7.5 mL of 26.00% NaOH solution was added dropwise and the reaction was continued for 1.5 hours.

[0043] (2) Add 124 mL of distilled water to dilute, then add 11.00 g of solid NaOH with a mass fraction of 96.00%, and stir at room temperature for 1 h;

[0044] (3) 15.6 mL of 99.00% carbon disulfide was slowly added dropwise to the solution in step (2), and the mixture was stirred at room temperature for 5.5 h until the bottom oil droplets disappeared, and then the mixture was heated to 50° C. for 1.5 h, and then cooled to room temperature;

[0045] (4) 29.95 g of 98.00% sodium chloroacetate was added to a 500 mL three-necked flask equipped with a mechanical stirrer, a dropping funnel, and a reflux condenser, and 61.8 mL of distilled water was added to prepare a 32.00% solution;

[0046] (5) adding the solution obtained in step (3) to the solution obtained in step (4) and mixing thoroughly; weighing 10.50 g of solid NaOH with a mass fraction of 96.00%, adding 28.3 mL of distilled water to dissolve it into a solution with a mass fraction of 26.00%, transferring it to a dropping funnel and adding it in three batches, each adding time is 50 min, and adding the next batch after the pH value of the reaction liquid drops to about 10. After the addition is completed, continue to react at room temperature for 5 h, then heat it to 55 ° C and continue to react for 0.75 h, cool it to room temperature, and obtain 270.0 mL of reddish brown liquid, i.e., dimerized polyethylene polyamine double chelate group heavy metal chelate flocculant.

[0047] Example 3

[0048] (1) 13.1 mL of 99.00% diethylenetriamine was added to a 250 mL three-necked flask equipped with a mechanical stirrer, a dropping funnel and a reflux condenser, and 4.9 mL of 98.00% epichlorohydrin was slowly added dropwise at a rate of 1 drop / min at room temperature. After the addition was completed, the mixture was reacted for 1.25 h; then 10.1 mL of 20.00% NaOH solution was added dropwise and the reaction was continued for 1.5 h;

[0049] (2) Add 130.0 mL of distilled water to dilute, then add 8.25 g of solid NaOH with a mass fraction of 96.00%, and stir at room temperature for 1 h;

[0050] (3) 11.7 mL of 99.00% carbon disulfide was slowly added dropwise to the solution in step (2), and the mixture was stirred at room temperature for 4 h until the bottom oil droplets disappeared, and then the mixture was heated to 52° C. for 1.25 h, and then cooled to room temperature;

[0051] (4) 29.24 g of sodium chloroacetate with a mass fraction of 98.00% was added to a 500 mL three-necked flask equipped with a mechanical stirrer, a dropping funnel and a reflux condenser, and 52.6 mL of distilled water was added to prepare a solution with a mass fraction of 32.00%;

[0052] (5) adding the solution obtained in step (3) to the solution obtained in step (4) and mixing thoroughly; weighing 10.25 g of solid NaOH with a mass fraction of 96.00%, adding 39.0 mL of distilled water to dissolve it into a solution with a mass fraction of 20.00%, transferring it to a dropping funnel and adding it in three batches, each adding time is 60 min, and adding the next batch after the pH value of the reaction liquid drops to about 10. After the addition is completed, continue to react at room temperature for 6 h, then heat it to 50 ° C and continue to react for 1.5 h, cool it to room temperature, and obtain 278.4 mL of reddish brown liquid, i.e., dimerized polyethylene polyamine double chelate group heavy metal chelate flocculant.

[0053] Example 4

[0054] (1) 18.8 mL of 95.00% triethylenetetramine was added to a 250 mL three-necked flask equipped with a mechanical stirrer, a dropping funnel and a reflux condenser, and 4.8 mL of 98.00% epichlorohydrin was slowly added dropwise at a rate of 1 drop / min at room temperature. After the addition was completed, the mixture was reacted for 1 hour. Then, 6.0 mL of 30.00% NaOH solution was added dropwise and the reaction was continued for 1 hour.

[0055] (2) Add 120.0 mL of distilled water to dilute, then add 5.78 g of solid NaOH with a mass fraction of 96.00%, and stir at room temperature for 0.5 h;

[0056] (3) 11.7 mL of 99.00% carbon disulfide was slowly added dropwise to the solution in step (2), and the mixture was stirred at room temperature for 4 h until the bottom oil droplets disappeared, and then the mixture was heated to 52° C. for 1.25 h, and then cooled to room temperature;

[0057] (4) 29.24 g of 98.00% sodium chloroacetate was added to a 500 mL three-necked flask equipped with a mechanical stirrer, a dropping funnel and a reflux condenser, and 64.3 mL of distilled water was added to prepare a 30.00% solution;

[0058] (5) Add the solution obtained in step (3) to the solution obtained in step (4) and mix thoroughly; weigh 10.30 g of solid NaOH with a mass fraction of 96.00%, add 29.3 mL of distilled water to dissolve it into a solution with a mass fraction of 25.00%, transfer it to a dropping funnel and add it in 3 batches, each adding time is 40 min, and add the next batch when the pH value of the reaction liquid drops to about 10. After the addition is completed, continue to react at room temperature for 4 h, then heat it to 50 ° C and continue to react for 1.5 h, cool it to room temperature, and obtain 263.2 mL of reddish brown liquid, i.e., dimerized polyethylene polyamine double chelate group heavy metal chelate flocculant.

[0059] Example 5

[0060] (1) 18.8 mL of 95.00% triethylenetetramine was added to a 250 mL three-necked flask equipped with a mechanical stirrer, a dropping funnel and a reflux condenser, and 4.9 mL of 98.00% epichlorohydrin was slowly added dropwise at a rate of 2 drops / min at room temperature. After the addition was completed, the mixture was reacted for 1.25 h; then 10.0 mL of 20.00% NaOH solution was added dropwise and the reaction was continued for 1 h;

[0061] (2) Add 125.0 mL of distilled water to dilute, then add 11.00 g of solid NaOH with a mass fraction of 96.00%, and stir at room temperature for 1 h;

[0062] (3) 15.6 mL of 99.00% carbon disulfide was slowly added dropwise to the solution in step (2), and the mixture was stirred at room temperature for 3.5 h until the bottom oil droplets disappeared, and then the temperature was raised to 55° C. for 1 h, and then the temperature was lowered to room temperature;

[0063] (4) 30.04 g of 98.00% sodium chloroacetate was added to a 500 mL three-necked flask equipped with a mechanical stirrer, a dropping funnel and a reflux condenser, and 62.0 mL of distilled water was added to prepare a 32.00% solution;

[0064] (5) Add the solution obtained in step (3) to the solution obtained in step (4) and mix thoroughly; weigh 10.50 g of solid NaOH with a mass fraction of 96.00%, add 23.1 mL of distilled water to dissolve it into a solution with a mass fraction of 30.00%, transfer it to a dropping funnel and add it in 3 batches, each adding time is 50 min, and the next batch is added when the pH value of the reaction liquid drops to about 10. After the addition is completed, continue to react at room temperature for 4 hours, then heat to 55°C and continue to react for 1.25 hours, cool to room temperature, and obtain 277.6 mL of reddish-brown liquid, i.e., dimerized polyethylene polyamine-based double chelate group heavy metal chelating flocculant, recorded as IDA-DTETA-DTC.

[0065] Using triethylenetetramine (TETA) as a raw material, a triethylenetetramine dimer grafted dithiocarboxylic acid chelating flocculant was prepared according to the ratios and conditions of steps (1) to (3) of this embodiment, and was denoted as DTETA-DTC.

[0066] Example 6

[0067] (1) 18.8 mL of 95.00% triethylenetetramine was added to a 250 mL three-necked flask equipped with a mechanical stirrer, a dropping funnel and a reflux condenser, and 5.1 mL of 98.00% epichlorohydrin was slowly added dropwise at a rate of 1 drop / min at room temperature. After the addition was completed, the mixture was reacted for 1.5 h; then 7.6 mL of 26.00% NaOH solution was added dropwise and the reaction was continued for 1 h;

[0068] (2) Add 126.0 mL of distilled water to dilute, then add 16.50 g of solid NaOH with a mass fraction of 96.00%, and stir at room temperature for 0.75 h;

[0069] (3) 23.4 mL of 99.00% carbon disulfide was slowly added dropwise to the solution in step (2), and the mixture was stirred at room temperature for 5 h until the bottom oil droplets disappeared, and then the mixture was heated to 60° C. for 1.5 h, and then cooled to room temperature;

[0070] (4) 29.76 g of 98.00% sodium chloroacetate was added to a 500 mL three-necked flask equipped with a mechanical stirrer, a dropping funnel, and a reflux condenser, and 53.6 mL of distilled water was added to prepare a solution with a mass fraction of 32.00%;

[0071] (5) adding the solution obtained in step (3) to the solution obtained in step (4) and mixing thoroughly; weighing 10.25 g of solid NaOH with a mass fraction of 96.00%, adding 22.6 mL of distilled water to dissolve it into a solution with a mass fraction of 30.00%, transferring it to a dropping funnel and adding it in three batches, each adding time is 60 min, and adding the next batch after the pH value of the reaction liquid drops to about 10. After the addition is completed, continue to react at room temperature for 6 h, then heat it to 60 ° C and continue to react for 1.5 h, cool it to room temperature, and obtain 272.9 mL of reddish brown liquid, i.e., dimerized polyethylene polyamine double chelate group heavy metal chelate flocculant.

[0072] Example 7

[0073] (1) 18.8 mL of 95.00% triethylenetetramine was added to a 250 mL three-necked flask equipped with a mechanical stirrer, a dropping funnel and a reflux condenser, and 5.0 mL of 98.00% epichlorohydrin was slowly added dropwise at a rate of 1 drop / min at room temperature. After the addition was complete, the mixture was reacted for 1.5 h; then 27.0 mL of 20.00% Na2CO3 solution was added dropwise and the reaction was continued for 2 h;

[0074] (2) Add 130.0 mL of distilled water to dilute, then add 12.00 g of solid NaOH with a mass fraction of 96.00%, and stir at room temperature for 1 h;

[0075] (3) 15.6 mL of 99.000% carbon disulfide was slowly added dropwise to the solution in step (2), and the mixture was stirred at room temperature for 5 h until the bottom oil droplets disappeared, and then the mixture was heated to 60° C. for 1 h, and then cooled to room temperature;

[0076] (4) 40.40 g of sodium bromoacetate with a mass fraction of 98.00% was added to a 500 mL three-necked flask equipped with a mechanical stirrer, a dropping funnel and a reflux condenser, and 91.6 mL of distilled water was added to prepare a solution with a mass fraction of 30.00%;

[0077] (5) Add the solution obtained in step (3) to the solution obtained in step (4) and mix thoroughly; weigh 25.69 g of solid Na2CO3 with a mass fraction of 99.00%, add 101.5 mL of distilled water to dissolve it into a solution with a mass fraction of 20.00%, transfer it to a dropping funnel and add it in 3 batches, each adding time is 60 min, and add the next batch when the pH value of the reaction liquid drops to about 10. After the addition is completed, continue to react at room temperature for 6 h, then heat it to 60°C and continue to react for 1.5 h, cool it to room temperature, and obtain 401.4 mL of orange-red liquid, i.e., dimerized polyethylene polyamine double chelate group heavy metal chelate flocculant.

[0078] Example 8

[0079] (1) 18.8 mL of 95.00% triethylenetetramine was added to a 250 mL three-necked flask equipped with a mechanical stirrer, a dropping funnel and a reflux condenser, and 4.8 mL of 98.00% epichlorohydrin was slowly added dropwise at a rate of 1 drop / min at room temperature. After the addition was complete, the mixture was reacted for 1.5 h; then 6.1 mL of 30.00% NaOH solution was added dropwise and the reaction was continued for 2 h;

[0080] (2) Add 120.0 mL of distilled water to dilute, then add 11.00 g of solid NaOH with a mass fraction of 96.00%, and stir at room temperature for 1 h;

[0081] (3) 15.6 mL of 99.00% carbon disulfide was slowly added dropwise to the solution in step (2), and the mixture was stirred at room temperature for 5 h until the bottom oil droplets disappeared, and then the temperature was raised to 55° C. for 1.5 h, and then the temperature was lowered to room temperature;

[0082] (4) 41.38 g of sodium bromoacetate with a mass fraction of 98.00% was added to a 500 mL three-necked flask equipped with a mechanical stirrer, a dropping funnel and a reflux condenser, and 74.5 mL of distilled water was added to prepare a solution with a mass fraction of 35.00%;

[0083] (5) Add the solution obtained in step (3) to the solution obtained in step (4) and mix thoroughly; weigh 10.50 g of solid NaOH with a mass fraction of 96.00%, add 23.1 mL of distilled water to dissolve it into a solution with a mass fraction of 30.00%, transfer it to a dropping funnel and add it in 3 batches, each adding time is 60 min, and add the next batch when the pH value of the reaction liquid drops to about 10. After the addition is completed, continue to react at room temperature for 6 h, then heat it to 60 ° C and continue to react for 1 h, cool it to room temperature, and obtain 276.8 mL of reddish brown liquid, i.e., dimerized polyethylene polyamine double chelate group heavy metal chelate flocculant.

[0084] Example 9

[0085] (1) 24.0 mL of 95.00% tetraethylene pentamine was added to a 250 mL three-necked flask equipped with a mechanical stirrer, a dropping funnel and a reflux condenser, and 4.8 mL of 98.00% epichlorohydrin was slowly added dropwise at a rate of 2 drops / min at room temperature. After the addition was completed, the mixture was reacted for 1 hour; then 9.9 mL of 20.00% NaOH solution was added dropwise and the reaction was continued for 1 hour;

[0086] (2) Add 124.0 mL of distilled water to dilute, then add 5.78 g of solid NaOH with a mass fraction of 96.00%, and stir at room temperature for 0.5 h;

[0087] (3) 7.7 mL of 99.00% carbon disulfide was slowly added dropwise to the solution in step (2), and the mixture was stirred at room temperature for 3.5 h until the bottom oil droplets disappeared, and then the mixture was heated to 50° C. for 1.25 h, and then cooled to room temperature;

[0088] (4) 29.24 g of sodium chloroacetate with a mass fraction of 98.00% was added to a 500 mL three-necked flask equipped with a mechanical stirrer, a dropping funnel and a reflux condenser, and 66.3 mL of distilled water was added to prepare a solution with a mass fraction of 30.00%;

[0089] (5) adding the solution obtained in step (3) to the solution obtained in step (4) and mixing thoroughly; weighing 10.50 g of solid NaOH with a mass fraction of 96.00%, adding 29.8 mL of distilled water to dissolve it into a solution with a mass fraction of 25.00%, transferring it to a dropping funnel and adding it in three batches, each adding time is 60 min, and adding the next batch after the pH value of the reaction liquid drops to about 10. After the addition is complete, continue to react at room temperature for 4.5 h, then heat it to 60 ° C and continue to react for 1 h, cool it to room temperature, and obtain 278.0 mL of reddish brown liquid, i.e., dimerized polyethylene polyamine double chelate group heavy metal chelate flocculant.

[0090] Example 10

[0091] (1) 24.0 mL of 95.00% tetraethylene pentamine was added to a 250 mL three-necked flask equipped with a mechanical stirrer, a dropping funnel and a reflux condenser, and 5.0 mL of 98.00% epichlorohydrin was slowly added dropwise at a rate of 1 drop / min at room temperature. After the addition was completed, the mixture was reacted for 1.25 h; then 7.4 mL of 26.00% NaOH solution was added dropwise and the reaction was continued for 1.5 h;

[0092] (2) Add 122.0 mL of distilled water to dilute, then add 10.50 g of solid NaOH with a mass fraction of 96.00%, and stir at room temperature for 0.75 h;

[0093] (3) 15.6 mL of 99.00% carbon disulfide was slowly added dropwise to the solution in step (2), and the mixture was stirred at room temperature for 4.5 h until the bottom oil droplets disappeared, and then the temperature was raised to 55° C. for 1.25 h, and then the temperature was lowered to room temperature;

[0094] (4) 29.52 g of sodium chloroacetate with a mass fraction of 98.00% was added to a 500 mL three-necked flask equipped with a mechanical stirrer, a dropping funnel and a reflux condenser, and 60.9 mL of distilled water was added to prepare a solution with a mass fraction of 32.00%;

[0095] (5) Add the solution obtained in step (3) to the solution obtained in step (4) and mix thoroughly; weigh 10.35 g of solid NaOH with a mass fraction of 96.00%, add 25.1 mL of distilled water to dissolve it into a solution with a mass fraction of 28.00%, transfer it to a dropping funnel and add it in 3 batches, each adding time is 50 min, and add the next batch when the pH value of the reaction solution drops to about 10. After the addition is completed, continue to react at room temperature for 5 h, then heat it to 60°C and continue to react for 1.25 h, cool it to room temperature, and obtain 275.8 mL of reddish brown liquid, i.e., dimerized polyethylene polyamine double chelate group heavy metal chelate flocculant.

[0096] Embodiment 11

[0097] (1) 24.0 mL of 95.00% tetraethylene pentamine was added to a 250 mL three-necked flask equipped with a mechanical stirrer, a dropping funnel and a reflux condenser, and 5.1 mL of 98.00% epichlorohydrin was slowly added dropwise at a rate of 1 drop / min at room temperature. After the addition was completed, the mixture was reacted for 1.5 h; then 6.3 mL of 30.00% NaOH solution was added dropwise and the reaction was continued for 1.5 h;

[0098] (2) Add 120.0 mL of distilled water to dilute, then add 16.50 g of solid NaOH with a mass fraction of 96.00%, and stir at room temperature for 1 h;

[0099] (3) 23.4 mL of 99.00% carbon disulfide was slowly added dropwise to the solution in step (2), and the mixture was stirred at room temperature for 5 h until the bottom oil droplets disappeared, and then the mixture was heated to 60° C. for 1 h, and then cooled to room temperature;

[0100] (4) 29.33 g of sodium chloroacetate with a mass fraction of 98.00% was added to a 500 mL three-necked flask equipped with a mechanical stirrer, a dropping funnel and a reflux condenser, and 52.8 mL of distilled water was added to prepare a solution with a mass fraction of 35.00%;

[0101] (5) Add the solution obtained in step (3) to the solution obtained in step (4) and mix thoroughly; weigh 10.50 g of solid NaOH with a mass fraction of 96.00%, add 23.1 mL of distilled water to dissolve it into a solution with a mass fraction of 30.00%, transfer it to a dropping funnel and add it in three batches, each adding time is 60 min, and add the next batch when the pH value of the reaction liquid drops to about 10. After the addition is completed, continue to react at room temperature for 6 h, then heat it to 60 ° C and continue to react for 1.5 h, cool it to room temperature, and obtain 275.6 mL of reddish brown liquid, i.e., dimerized polyethylene polyamine double chelate group heavy metal chelate flocculant.

[0102] Example 12

[0103] (1) 24.0 mL of 95.00% tetraethylene pentamine was added to a 250 mL three-necked flask equipped with a mechanical stirrer, a dropping funnel and a reflux condenser, and 4.9 mL of 98.00% epichlorohydrin was slowly added dropwise at a rate of 1 drop / min at room temperature. After the addition was completed, the mixture was reacted for 1.5 h; then 10.0 mL of 20.00% NaOH solution was added dropwise and the reaction was continued for 1.5 h;

[0104] (2) Add 125.0 mL of distilled water to dilute, then add 22.00 g of solid NaOH with a mass fraction of 96.00%, and stir at room temperature for 1 h;

[0105] (3) 31.1 mL of 99.00% carbon disulfide was slowly added dropwise to the solution in step (2), and the mixture was stirred at room temperature for 5 h until the bottom oil droplets disappeared, and then the mixture was heated to 60° C. for 1.5 h, and then cooled to room temperature;

[0106] (4) 30.04 g of 98.00% sodium chloroacetate was added to a 500 mL three-necked flask equipped with a mechanical stirrer, a dropping funnel, and a reflux condenser, and 38.1 mL of distilled water was added to prepare a 30.00% solution;

[0107] (5) Add the solution obtained in step (3) to the solution obtained in step (4) and mix thoroughly; weigh 10.50 g of solid NaOH with a mass fraction of 96.00%, add 29.8 mL of distilled water to dissolve it into a solution with a mass fraction of 25.00%, transfer it to a dropping funnel and add it in three batches, each adding time is 60 min, and the next batch is added when the pH value of the reaction liquid drops to about 10. After the addition is completed, continue to react at room temperature for 6 h, then heat it to 60 ° C and continue to react for 1.5 h, cool it to room temperature, and obtain 310.2 mL of reddish brown liquid, i.e., dimerized polyethylene polyamine double chelate group heavy metal chelate flocculant.

[0108] The infrared spectroscopy analysis of the di-polyethylene polyamine-based double chelate group heavy metal chelate flocculants obtained in Examples 1 to 12 showed basically the same results. The infrared spectroscopy analysis results of the di-polyethylene tetraamine-based double chelate group heavy metal chelate flocculant (IDA-DTETA-DTC) obtained in Example 5 are as follows: Figure 2 shown. Figure 2 The absorption peaks in the infrared spectrum can be attributed as follows: 3277.73cm -1 The stretching vibration peaks of -OH in the sample and OH in water, as well as the stretching vibration peaks of -NH; at 2905.58, 2815.26 cm -1 The asymmetric and symmetric stretching vibration peaks of -CH2- appear at 1356.16 cm -1 The bending vibration peak appears at 1676.88cm -1 The strong peak and 1414.46m -1 The slightly weaker peaks are the asymmetric stretching and symmetric stretching vibration peaks of carboxylate groups; 1620.46cm -1 The bending vibration peak of the combined water molecule and -OH; 1465.27cm -1 N-CSS - ) stretching vibration peaks of CN; 1304.39, 1206.08, 1156.30 and 1117.19 cm -1 The stretching vibration peaks of CO and CN in the molecule; 1052.87 and 925.60 cm -1 for-css - Stretching vibration peak of C=S and CS; 811.67cm -1 Attributable to — CSS － The element analysis of the above samples showed that the S content was 24.03% and the O content was 13.41%, which is equivalent to -CSS － and—CH2COO － Each chelating flocculant molecule contains 3.98 CSS － and 3.56—CH2COO－ The above results showed that IDA-DTETA-DTC had been successfully synthesized.

[0109] Embodiment 13

[0110] IDA-DTETA-DTC (—CSS prepared in Example 5 — The content of -N(CH2COOH)2 is 3.747mmol / g, and -N(CH2COOH)2 is 1.676mmol / g) and DTETA-DTC (-CSS — The content of Zn is 5.172mmol / g) as a chelating agent, and 100mg / L of Zn 2+ Cr 3 +、Mn 2+ 、Ni 2+ , Pb 2+ and Cu 2+ Simulated heavy metal water samples. Flocculation test conditions: Take 500mL simulated heavy metal water samples respectively, adjust the pH value to about 6, add reagents on the MY3000-6G intelligent color screen coagulation test stirring instrument (Wuhan Meiyu Instrument Co., Ltd.), stir quickly at 220r / min for 5min, stir at 100r / min for 10min, and then stir slowly at 60r / min for 7min, let it stand for 20min, take the clear liquid 2cm below the liquid surface and measure it on the AA-7000 atomic absorption spectrophotometer (Japan, Shimadzu Corporation), and the treatment effect is shown in Table 1.

[0111] Table 1 Removal effect of the product of the present invention on free heavy metal ions

[0112]

[0113] It can be seen from Table 1 that under the optimal conditions, the product IDA-DTETA-DTC of the present invention has a higher free Zn than the comparative sample DTETA-DTC. 2+ Cr 3 +、Mn 2+ 、Ni 2+ , Pb 2+ and Cu 2+ The plasma removal effect is good, and the residual ion concentration is far lower than the first-level standard of the "Comprehensive Wastewater Discharge Standard" (GB8978-1996), and even Pb 2+ and Cu 2+ Completely remove.

[0114] Embodiment 14

[0115] This example shows the sedimentation rate of flocs produced by heavy metal chelation in wastewater treated with the product IDA-DTETA-DTC of the present invention.

[0116] The sample IDA-DTETA-DTC obtained in Example 5 was used as a chelating agent, and DTETA-DTC was used as a comparative sample. 2+ The simulated wastewater was used as the test object. The test was first conducted according to the dosage of the reagent and the flocculation conditions of Example 13. After the stirring was stopped, the test solution was quickly transferred into a 500 mL graduated cylinder, the timing was started, and the descending height of the clear and turbid interface at different times was recorded. The results are shown in Table 2.

[0117] Table 2 IDA-DTETA-DTC chelated Pb 2+ The sedimentation rate of the generated flocs

[0118]

[0119] From the results in Table 2, it can be seen that the product IDA-DTETA-DTC of the present invention can treat Pb-containing 2+ The flocs generated by wastewater settle significantly faster than those generated by DTETA-DTC, and the height of the clear liquid after standing for 30 minutes is greater than that of the clear liquid treated with DTETA-DTC. During the experiment, it can be observed that the flocs generated by IDA-DTETA-DTC are coarser and denser than those generated by DTETA-DTC, and the clear liquid has lower turbidity and is clearer. Therefore, the flocs generated by IDA-DTETA-DTC have better flocculation and sedimentation performance.

[0120] Embodiment 15

[0121] Thiourea-Cu with a molar ratio of 1:1 and a concentration of 50 mg / L were prepared with deionized water. 2+ , Cu-citrate 2+ , Thiourea-Pb 2+ and citrate-Pb 2+ To simulate the complexed heavy metal wastewater sample, the IDA-DTETA-DTC obtained in Example 5, commercially available DTCR and sodium thiamethoxam were used as chelating agents, respectively. On the MY3000-6G intelligent color screen coagulation test stirring instrument (Wuhan Meiyu Instrument Co., Ltd.), the reagent was added, and the mixture was stirred quickly at 220 r / min for 5 min, stirred at 100 r / min for 10 min, polyacrylamide (PAM) was added, and then stirring was continued for 10 min, and then slowly stirred at 60 r / min for 25 min, and allowed to stand for 30 min. The clear liquid 2 cm below the liquid surface was measured on an AA-7000 atomic absorption spectrophotometer (Japan, Shimadzu Corporation), and the turbidity was measured on a WZS-185 high turbidity meter (Shanghai Precision Scientific Instrument Co., Ltd.). The results are shown in Table 3.

[0122] Table 3 Removal effect of the product of the present invention on complexed heavy metal ions

[0123]

[0124] Note: The dosage is in the medicine - CSS － The molar ratio of the ion, the concentration unit is mg / L, and the turbidity unit is NTU.

[0125] As can be seen from Table 3, the product of the present invention has a good effect on the complexation of Cu 2+ 、Ni 2+ The removal effect is significantly better than that of commercially available sodium thiamethoxam and DTCR.

[0126] Example 16

[0127] The IDA-DTETA-DTC obtained in Example 5 was used as a chelating agent, and the comprehensive wastewater of a copper foil production plant was used as the treatment object. The pollutant indicators of the comprehensive wastewater are shown in Table 4. It contains pyrophosphate and is yellow-green turbid. The product IDA-DTETA-DTC obtained in Example 5, the commercially available heavy metal scavenger sodium forme and TMT-18 were used as reagents respectively. Take 200 mL of the wastewater sample, adjust the pH to about 6 with lime milk, and then place it on the MY3000-6G intelligent color screen coagulation test stirring instrument (Wuhan Meiyu Instrument Co., Ltd.), and add a certain amount of IDA-DTETA-DTC, sodium forme and TMT-18 chelating agents respectively. The stoichiometric ratio of IDA-DTETA-DTC and sodium forme (CSS in IDA-DTETA-DTC or sodium forme) is as follows: － The molar ratio of TMT-18 to heavy metal ions) was 1.5:1 and 2.3:1 respectively, and the stoichiometric ratio of TMT-18 was 1:1.5. The chelating agent was added under stirring at 220 r / min and stirred for 5 min; then stirred at 100 r / min for 20 min (when stirring for 10 min, add appropriate amount of polyacrylamide PAM), and then stirred at 60 r / min for 20 min, and allowed to stand for 20 min, and samples were taken for analysis to determine the concentration of heavy metal ions and COD in the treated water. The results are listed in Table 4.

[0128] Table 4 Removal effect of the product of the present invention on the comprehensive wastewater of the copper foil production plant

[0129]

[0130]

[0131] The results in Table 4 show that the treatment effect of the product IDA-DTETA-DTC on the comprehensive copper foil production wastewater is significantly better than that of the commonly used heavy metal scavengers sodium fumei and TMT-18 on the market. 2+ 、Zn 2+ 、Co 2+ , Fe3+ The four ions are completely removed, and Cr 3+ The removal rate is also very high, and the pollutant indicators are all lower than the limit values ​​specified in the "Electroplating Pollutant Emission Standard" (GB21900-2008); in particular, IDA-DTETA-DTC also has a high removal rate for Ca 2+ and Mg 2+ The COD in the treated water is also significantly removed, and the turbidity of the treated water is low.

[0132] Embodiment 17

[0133] The product IDA-DTETA-DTC obtained in Example 5, the commercial heavy metal scavenger sodium fumei and TMT-18 were used as heavy metal stabilizers for incineration fly ash, and all were prepared into solutions with a mass fraction of 5.00%. During the test, 250.00g of fly ash from a waste incineration plant was added to a reaction kneader, and then stabilizer and water were added according to the mass ratio of fly ash: stabilizer: water = 100: 1-3: 20, and the reaction was stirred and kneaded for 20 minutes, and then the reaction was continued for 2 hours, and then the sample was taken for leaching experiment according to the method specified in HJ / T300-2007, and the pollutant concentration in the leaching solution was determined. The results are shown in Table 5.

[0134] Table 5 Effects of the products of the present invention and commercially available stabilizers on incineration fly ash treatment

[0135]

[0136]

[0137] As can be seen from Table 5, the dosage of the product IDA-DTETA-DTC of the present invention is less than that of sodium thiamethoxam and TMT-18, and the stabilization effect on metal ions in fly ash is stronger. The concentration of metal elements in the leachate of the stabilized fly ash is lower than the limit value specified in GB16889-2008, and the fly ash can be safely landfilled in the landfill.

[0138] The results of Examples 13 to 17 show that the product IDA-DTETA-DTC of the present invention has better removal efficiency for heavy metal ions in free heavy metal wastewater, complex heavy metal wastewater and complex actual heavy metal wastewater than the comparative samples, and the generated flocs settle faster and can effectively fix metal ions in incineration fly ash. This is because IDA-DTETA-DTC contains two types of strong chelating groups - CSS - and -N(CH2COOH)2, which occur as attached Figure 3 The chelation effect shown in the figure. Among them, -CSS- can form a water-insoluble disulfide coordinated four-membered ring structure with most heavy metal ions, and the -N(CH2COOH)2 group can react with most metal ions, including Ca 2+ and Mg 2+The metal ions that are difficult to coordinate can form two stable five-membered rings to bind them to the chelating agent molecules; and through the two —CSS— groups from different IDA-DTETA-DTC molecules chelating with the same heavy metal ion, the chelates formed by different molecules are connected and gradually grow to form larger flocs or chelate molecular aggregates, thereby improving the performance of chelating and binding metal ions, improving the sedimentation performance of flocs and the stability of chelates. Through the synergistic effect of two types of strong chelating groups, the chelating removal efficiency of metal ions in wastewater or the stabilization efficiency of metal ions in fly ash is significantly improved.

[0139] The above are merely preferred embodiments of the present invention. Based on the above concept of the present invention, those skilled in the art can also make various modifications and changes thereto. For example, within the range of the ratios and process conditions given in the present invention, the ratios and process conditions can be combined and changed. Similar changes and modifications belong to the essence of the present invention.

Claims

1. A di-polyethylene polyamine-based double chelate group heavy metal chelate flocculant, characterized in that: The structure of its main component is shown in formula (I): In formula (I), 2≤x≤4, 1≤y≤x, and x and y are both integers; when y<x, x-y N atoms are connected to H atoms.

2. The diethylene glycol polyamine-based double chelate group heavy metal chelate flocculant according to claim 1, characterized in that: The auxiliary components of the chelating flocculant are xanthogenic acid and NaOH; the appearance of the chelating flocculant is reddish brown or brownish red viscous liquid.

3. The method for preparing the di-polyethylene polyamine-based double chelate group heavy metal chelate flocculant according to claim 1 or 2, characterized in that: The following steps are involved: (1) Add polyethylene polyamine to a reactor at a molar ratio of 2:1 to 1.05, slowly dropwise add epichlorohydrin at room temperature for 1 to 1.5 hours; then dropwise add an alkali or alkaline salt solution in an amount equal to that of epichlorohydrin, and continue to react for 1 to 2 hours; (2) distilled water 5 to 6 times the volume of the reaction mixture in step (1) was added to dilute the mixture, and then NaOH was added at a ratio of (n-1) times the amount of polyethylene polyamine to the amount of NaOH of 1:0.55 to 1.2, wherein n represents the number of N atoms in the polyethylene polyamine molecule, and stirred at room temperature for 0.5 to 1 hour; (3) adding carbon disulfide at a ratio of (n-1) times the amount of polyethylene polyamine to the amount of carbon disulfide of 1:0.25-1.05, wherein n represents the number of nitrogen atoms in the polyethylene polyamine molecule, stirring and reacting at room temperature for 3.5-5 hours until the bottom oil droplets disappear, then heating to 50-60°C for reaction for 1-1.5 hours, and then cooling to room temperature to obtain solution A; (4) weighing sodium halogenated acetate and adding it to a reactor at a molar ratio of sodium halogenated acetate to polyethylene polyamine of 2.05 to 2.1:1, and adding distilled water to prepare a solution with a mass fraction of 30% to 35%, thereby obtaining solution B; (5) adding the solution A obtained in step (3) to the solution B obtained in step (4) and mixing them thoroughly; then weighing the alkali or alkaline salt according to the molar ratio of the alkali or alkaline salt to the polyethylene polyamine of 2 to 2.1:1, adding distilled water to prepare a solution with a mass fraction of 20% to 30%, and slowly adding the solution in three batches, each batch being added until the pH value of the solution drops to 9 to 11 before adding the next batch, and continuing to react at room temperature for 4 to 6 hours after the addition is completed, and then heating to 50 to 60° C. and continuing to react for 1 to 1.5 hours, and cooling to room temperature to obtain a di-polyethylene polyamine-based double chelate group heavy metal chelating flocculant.

4. The method for preparing the di-polyethylene polyamine-based double chelate group heavy metal chelate flocculant according to claim 3, characterized in that: In step (1), the polyethylene polyamine is any one of diethylenetriamine, triethylenetetramine or tetraethylenepentamine.

5. The method for preparing the di-polyethylene polyamine-based double chelate group heavy metal chelate flocculant according to claim 3, characterized in that: In steps (1) and (5), the base or basic salt is either NaOH or Na2CO3.

6. The method for preparing the di-polyethylene polyamine-based double chelate group heavy metal chelate flocculant according to claim 3, characterized in that: In step (3), the halogenated acetate is any one of sodium chloroacetate or sodium bromoacetate.

7. The method for preparing the di-polyethylene polyamine-based double chelate group heavy metal chelate flocculant according to claim 3, characterized in that: In step (1), the epichlorohydrin is slowly added at a rate of 1 to 2 drops / min; in step (5), the base or alkaline salt is slowly added for 40 to 60 minutes.

8. The method for preparing the di-polyethylene polyamine-based double chelate group heavy metal chelate flocculant according to claim 3, characterized in that: The polyethylene polyamine, epichlorohydrin, alkali or alkaline salt, carbon disulfide and sodium haloacetate are all products with purity above industrial grade and are used without further purification.

9. The method for preparing the di-polyethylene polyamine-based double chelate group heavy metal chelate flocculant according to claim 3, characterized in that: In steps (1) and (4), the reactors are equipped with mechanical stirring, a dropping funnel and a reflux condenser.

10. Use of the diethylene glycol polyamine-based double chelate group heavy metal chelate flocculant obtained by the preparation method according to any one of claims 1 to 2 or any one of claims 3 to 9 in the treatment of heavy metals in heavy metal wastewater or incineration fly ash.

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