WO2020103847A1 - Heavy metal removing preparation, synthesis method for same, and applications thereof - Google Patents

Abstract

The present invention relates to a heavy metal removing preparation, a synthesis method for same, and applications thereof. The synthesis method comprises the following specific steps: (1) with a dichloroalkane and ammonia serving as reaction raw materials, performing amination and oligomerization reactions in an alkaline condition; and, (2) adding carbon disulfide to the system produced in step (1) and reacting in an alkaline condition, thus completing the process; the method further comprises the removal of ammonia. The synthesis of the heavy metal removing preparation described in the present invention has the inexpensive dichloroalkane and ammonia serving as the raw materials, undergoes two reactions, is inexpensive, and has a high yield. The present invention overcomes the disadvantage and shortcoming of the prior art in which ethylenediamine is used as the raw material and significantly reduces production costs; the heavy metal removing preparation produced retains stable heavy metal removing performance even in extremely low pH conditions and provides very significant effects in the actual removal of heavy metals in industrial wastewater from plating and smelting.

Description

Heavy metal removal preparation and its synthesis method and application

cross reference

This application claims the priority of Chinese patent applications No. 201811422381.7 filed on November 23, 2018 and No. 201910739954.7 filed on August 12, 2019, the entire disclosure of which is incorporated herein by reference in its entirety.

Technical field

The invention relates to the technical field of heavy metal pollution control, in particular to a heavy metal removal preparation and its synthesis method and application.

Background technique

Heavy metal pollution has almost spread all over the world, and heavy metal pollution has been found in many regions of the world. The problem of heavy metal pollution in our country is more prominent. The bottom pollution of rivers, lakes and reservoirs is serious, and the pollution rate of heavy metals is extremely high. Various mine mining, metal smelting, electroplating industry, fertilizer industry, etc. produce a large amount of heavy metal-containing wastewater and discharge it into the environmental water body, resulting in a sharp increase in the content of heavy metal in the environmental water body, causing pollution of the watershed. The heavy metals that pollute the environment mainly include mercury, cadmium, chromium, lead, nickel, copper, antimony, arsenic, selenium, etc. Heavy metals not only cause acute and chronic poisoning of humans and animals, but also can cause various diseases through accumulation in the human body and bioaccumulation of the food chain, and eventually lead to life-long disability or death, which seriously threatens human and biological health.

So far, people have developed a variety of technical methods for removing heavy metals in water, including chemical coagulation precipitation method, membrane method, ion exchange method, adsorption method and zero-valent iron technology. The coagulation precipitation method is to add a precipitating agent under the condition of near neutral pH value, so that heavy metals are separated from the water body through precipitation and co-precipitation. Typical coagulation precipitation techniques include neutralization coagulation precipitation techniques, sulfide precipitation techniques, and coagulation-flocculation-precipitation methods based on iron and aluminum salts. Due to its advantages of obvious effect, simplicity, low cost and easy implementation, the coagulation precipitation method has been widely used in the treatment of heavy metal contaminated wastewater in countries all over the world. However, despite being widely used, the main problem of the traditional coagulation precipitation method is that slaked lime needs to be used to adjust the pH to perform coagulation precipitation under near-neutral conditions, so a large amount of low-density heavy metal-containing sludge is generated, and heavy metal sludge is not easy to recover The problem of post-disposal of hazardous solid waste is very difficult. For the electroplating wastewater containing cadmium, nickel and zinc, after conventional acid-base adjustment and sulfidation and other flocculation and sedimentation treatment, although some cadmium, nickel and zinc have been effectively removed, it is still difficult to achieve the standard discharge. Even multiplying the amount of precipitation chemicals is useless, which is a headache for the electroplating wastewater treatment industry and enterprises. The reason is that cadmium, nickel, and zinc-containing electroplating wastewater contains some cadmium, nickel, and zinc as chelated metal ions with tight chelation, which cannot be removed by conventional precipitation techniques. In recent years, heavy metal adsorbents using chelating resins as materials have been used more and more, but chelating resins are very expensive, the adsorption regeneration process is cumbersome and the post-treatment of the regeneration liquid is difficult, which is likely to cause secondary pollution.

In view of this, the present invention is specifically proposed.

Summary of the invention

The present invention proposes a novel synthesis method for heavy metal removal preparations (which may be referred to as heavy metal trapping agents), as well as heavy metal removal preparations prepared by this method and their applications.

As a first object of the present invention, a method for synthesizing a heavy metal removal preparation is provided. The method includes the following specific steps:

(1) Ammonia and oligomerization reactions are carried out under alkaline conditions with dichloroalkane and ammonia as raw materials;

(2) Add carbon disulfide to the system obtained in step (1) and carry out the reaction under alkaline conditions to obtain;

Wherein, the dichloroalkane is represented by the general formula I,

(CH ₂ ) _n Cl ₂ Formula I

Among them, n is 2-4;

Preferably, the dichloroalkane is dichloroethane or dichloropropane.

The method of the present invention further includes the removal of ammonia.

Specifically, the present invention proposes at least two parallel technical solutions based on the different timing of ammonia removal.

As one of the parallel technical solutions, the removal of the ammonia is performed after the reaction of step (2) is completed.

The above-mentioned ammonia can be removed by evaporation, and the evaporation can be performed at a temperature of 50-140 ° C, and a more suitable temperature range is 80-100 ° C.

Preferably, the alkaline condition is adjusted by adding an alkaline substance selected from at least one of sodium carbonate, ammonia, sodium hydroxide, potassium hydroxide, calcium hydroxide, and magnesium hydroxide; The molar ratio of the dichloroalkane to the alkaline substance is 1: 0.1-1: 5, preferably 1: 1-1: 3. Further, in order to reduce by-products and increase conversion efficiency to increase yield, it is more preferable that the alkaline substance is a weak base, such as sodium carbonate and / or ammonia.

As another parallel technical solution, the removal of the ammonia is performed after the completion of the amination and oligomerization reaction in step (1).

Preferably, after the ammoniation and oligomerization reaction, and before removing excess ammonia, the pH of the system is adjusted to be above 9.0; preferably 10.0 to 13.5.

The ammonia is removed by distillation, and the pH value of the distillation system is based on that the ammonia molecule (NH ₃ ) in the solution accounts for more than 99% of the total ammonia.

Preferably, the removal of ammonia is carried out at 60 to 160 ° C for 0.5 to 10 hours; preferably 1 to 4 hours; the distillation is faster at higher temperatures, and a small amount of ethylenediamine contained in the ammonia and the ammoniated product can all be distilled After the distillate is recovered, it can be reused as a reactant.

Preferably, the alkaline condition is adjusted by adding an alkaline substance selected from at least one of sodium carbonate, ammonia, sodium hydroxide, potassium hydroxide, calcium hydroxide, and magnesium hydroxide, conditions It is that the alkaline conditions in step (2) cannot be adjusted by adding ammonia to avoid the reaction of ammonia with carbon disulfide in step (2). Preferably, the molar ratio of the dichloroalkane to the alkaline substance is 1: 0.1-1: 5, preferably 1: 1: 1-1: 3.

Further preferably, the alkaline conditions in step (1) are adjusted by adding sodium carbonate and / or ammonia; the alkaline conditions in step (2) are adjusted by adding sodium carbonate.

In one embodiment of the two parallel technical solutions of the present invention, in the synthesis method of the present invention, the alkaline substance is added in the form of an aqueous solution, an alcohol solution, or an alcohol-water mixture, and the alcohol includes but Not limited to ethanol, propanol, methanol. Preferably, the alkaline substance can be added separately, or mixed with other raw materials (dichloroalkane, etc.), and can also be slowly added dropwise during the reaction.

Preferably, the ammonia is added in the form of an aqueous ammonia solution, an ammonia alcohol solution, or an ammonia alcohol-water mixture. Preferably, the alcohol is ethanol, propanol or methanol.

Preferably, the ammonia is an aqueous ammonia solution, and the concentration of the aqueous ammonia solution is not particularly limited, and it is preferably an aqueous ammonia solution having a mass concentration of 5 to 60% (more preferably 20 to 60%).

Preferably, when the alkaline condition in step (1) is adjusted by adding the above alkaline substance other than ammonia, that is, when the alkaline substance in step (1) is not ammonia, the dichloroalkane The molar ratio to ammonia is 1: 1.1 to 1: 5, preferably 1: 1: 1 to 1: 3.

When the alkaline conditions in step (1) are achieved by adding ammonia (especially ideal), that is, in step (1), the excess of ammonia is selected to be increased; that is, when ammonia is used as the reaction raw material and as an alkaline substance, the The molar ratio of dichloroalkane to ammonia is 1: 1.1 to 1: 5; preferably 1: 2-1: 4.

Preferably, the reaction temperature of the amination and oligomerization reaction is 40-200 ° C, preferably 80-160 ° C; the reaction time is 0.5-10h; preferably 1-4h. At higher temperatures, the reaction is faster and the reaction is more complete.

Preferably, in step (2), the molar ratio of carbon disulfide to dichloroalkane is 1: 1-3: 1; preferably the molar ratio is 1: 1-2: 1.

Preferably, the alkaline condition in step (2) is adjusted by adding an alkaline substance, and the amount of the alkaline substance is adjusted so that the pH of the initial raw material system of the reaction is 9-13; preferably 9-12 ; More preferably 9-11. At this pH, vulcanization is relatively complete and there are few by-products.

Preferably, the reaction temperature of the reaction is 10 to 100 ° C, preferably 30 to 80 ° C; the reaction time is 0.5 to 10h, preferably 1 to 4h. When the temperature is too low, the reaction is slow and incomplete; when the temperature is high, the reaction rate is fast and the reaction is relatively complete, but when the temperature is too high and under strong alkaline conditions, it is easy to produce Na ₂ CS _{3 as a} by-product.

According to the synthesis method of the present invention, after the reaction is completed, the insoluble part of the product (dithiocarbamic acid) is added with an appropriate amount of alkali to dissolve, and the remaining ammonia is distilled to obtain the heavy metal removal preparation mentioned in the present invention. . The optional alkaline substances here include sodium hydroxide, potassium hydroxide, calcium hydroxide, and sodium carbonate, and the remaining ammonia collected after evaporative cooling is recovered and used as a reactant.

As a specific embodiment of the present invention, a method for synthesizing a heavy metal removal preparation is provided. The method includes the following specific steps:

(1): Ammonia and oligomerization reactions are conducted with dichloroalkane and ammonia as reaction raw materials in the presence of alkaline substances, especially weak bases;

(2): Add carbon disulfide to the product system obtained in step (1), react in the presence of an alkaline substance, especially a weak base, and distill off the remaining ammonia in the product.

Wherein, the dichloroalkane is represented by the general formula I,

(CH ₂ ) _n Cl ₂ Formula I

Among them, n is 2-4;

Preferably, the dichloroalkane is dichloroethane or dichloropropane.

Preferably, the ammonia is provided in the form of an ammonia aqueous solution, an ammonia alcohol solution, or an ammonia alcohol-water mixture, and suitable alcohols such as ethanol, propanol, and methanol are provided.

More preferably, the ammonia is an aqueous ammonia solution of any concentration, especially an aqueous ammonia solution with a mass concentration of 20 to 60%.

Preferably, the alkaline substance may be a strong base or a weak base, and may specifically be selected from at least one of sodium carbonate, ammonia, sodium hydroxide, potassium hydroxide, and calcium hydroxide;

And, in order to reduce by-products and increase the yield, a more preferred alkaline substance is a weak base, such as sodium carbonate and / or ammonia.

In the method of the present invention, a weak base is added to the material system of step (1) to improve conversion efficiency. When ammonia is selected as the basic substance (especially ideal), it is sufficient to choose to increase the excess of ammonia in the synthesis scheme.

In the synthesis method described in the present invention, the alkaline substance may be added alone, or mixed with other raw materials (dichloroalkane, etc.), and may also be slowly added dropwise during the reaction.

Preferably, in step (1), the molar ratio of dichloroalkane to basic substance is 1: 0.1-1: 5, and a more suitable molar ratio is 1: 1-1: 3.

When adding excess ammonia as both a reactant and a preferred weak base to provide a weak base environment, step (1) is equivalent to: using dichloroalkane represented by the general formula (CH ₂ ) _n Cl ₂ and excess ammonia as reaction raw materials , Ammonia and oligomerization in the presence of weakly alkaline substances.

Preferably, the amount of the excess ammonia is subject to ensuring that there is free ammonia remaining in the reaction product of step (2) (a suitable amount such as the molar ratio of dichloroalkane and ammonia is 1: 2-1: 4), this The residual amount of free ammonia is such that the pH value of the product system (including the reaction product and residual ammonia) formed in step (2) is not less than 9.

In the above case, in addition to itself as the reaction raw material, an appropriate excess of ammonia as a weakly basic substance, its significant benefit is that it can maintain and stabilize the acidity and alkalinity required for the reaction. Ammonium chloride and ammonium ions (NH ₄ ⁺ ) as weak acids can greatly reduce and buffer the impact of the addition of strong bases such as sodium hydroxide in the second step reaction on the reaction system. The existing prior art directly uses ethylenediamine as a raw material and adds a strong base such as sodium hydroxide to obtain a dithiocarbamate with a certain degree of polymerization; in order to avoid a large amount of carbon disulfide under strong alkaline conditions Ineffective by-products such as Na ₂ CS ₃ , ethanol is generally added to the solvent system.

The existing methods all reduce the alkalinity of the solvent system by adding an organic solvent alcohol such as ethanol, which greatly increases the difficulty of synthesis and separation cost. The ammonium chloride generated in the first step reaction of the present invention acts as a weak acid to greatly buffer the strong base, so that the second step reaction is still in a weak base system even when the strong base is added, avoiding the subsequent second step reaction by adding carbon disulfide At that time, a large amount of by-product Na ₂ CS ₃ is produced in the strongly alkaline pure water system, so that the entire reaction system does not produce invalid by-products even if it is carried out in the pure water system. Therefore, the excess ammonia will not only negatively affect and interfere with the second-step reaction, but the greater benefit is that it provides extremely favorable reaction conditions for the second-step reaction. The two-step reactions are paved with each other to achieve perfect connection and beneficial coupling, thereby Break through the shortcomings and defects of the existing technology.

In the method of the present invention, the "alkaline substance, especially weak base" in step (2) may refer to the "alkaline substance, especially weak base" described in step (1), or it may mean additional addition The other basic substances depend on the amount of basic substances added in step (1), and the content of basic substances, especially weak bases, in step (2) is controlled to maintain the initial raw materials of the reaction in step (2) The pH value of the system is not less than 9, and the ideal pH value range is 9-13, preferably 9-12, more preferably 9-11.

More preferably, the weak base is provided in the form of an aqueous solution, an alcohol solution, or an alcohol-water mixture, and suitable alcohols such as ethanol, propanol, and methanol are preferably provided in the form of an aqueous solution.

Preferably, the above reaction uses pure water, ethanol or a water-alcohol mixture as the reaction solvent system.

Particularly preferably, the above reaction can use pure water as the reaction solvent system to further control the cost, and avoid the safety risks and subsequent separation difficulties caused by the use of the alcohol-containing solvent system.

In the reaction raw material, the molar ratio of dichloroalkane and ammonia (as the reaction raw material) is less than 1: 1, preferably 1: 1: 1 to 1: 5, more preferably the molar ratio is 1: 1.5 to 1: 3 or 1: 1.1 -1: 1.5 or 1: 1.5-1: 2.

The molar ratio of dichloroalkane to ammonia has a great influence on the degree of polymerization of dithiocarbamic acids and their mixed salts, as well as the reaction yield. Generally speaking, when the amount of ammonia added is large, the polymerization degree of the product is low, and it needs to be precipitated at a lower pH; when the amount of ammonia added is small, the product polymerization degree is high, which can be slightly acidic or even near neutral pH Precipitation precipitates, but excessively high degree of product polymerization can easily cause the product to fail to chelate nickel in electroplating wastewater.

In the synthesis method of the present invention, the molar ratio of carbon disulfide to dichloroalkane is 1: 1-3: 1, preferably the molar ratio is 1: 1-2: 1.

Preferably, the temperature range in step (1) is 40-200 ° C, and the more suitable temperature range is 80-160 ° C; when the temperature is higher, the reaction is faster and the reaction is more complete; the reaction time is 0.5-10h, a more suitable time It is 1-4h.

Preferably, 10-100 ° C in step (2), the more suitable temperature range is 30-80 ° C; the reaction is slow and incomplete when the temperature is too low; the reaction rate is fast and the reaction is relatively complete when the temperature is high, but the temperature is too high And under strong alkaline conditions, it is easy to produce Na ₂ CS _{3 as a} by-product; the reaction time is 0.5-10 h, and the more suitable time is 1-4 h.

According to the synthesis method of the present invention, after the reaction is completed, the insoluble part of the product (dithiocarbamic acid) is added with an appropriate amount of alkali to dissolve. . The optional alkaline substances here include sodium hydroxide, potassium hydroxide, calcium hydroxide, and sodium carbonate, and the remaining ammonia collected after evaporative cooling is recovered and used as a reactant.

The evaporation temperature of the remaining ammonia can be carried out at 50-140 ° C, and the more suitable temperature range is 80-100 ° C.

Preferably, the reaction device of the synthesis method may be a reaction kettle (especially a reaction kettle with a stirring device) or a tube reactor.

The heavy metal removal preparation of the present invention may be either a liquid system after the reaction system has distilled off ammonia, or a solid substance (such as a powder) obtained by further drying, which can be directly put into the treatment after being dissolved and diluted during use. Heavy metals are captured and treated in wastewater containing heavy metals.

As another preferred embodiment of the present invention, a method for synthesizing a heavy metal removal preparation is provided, and the method includes the following specific steps:

(1) Using dichloroalkane and ammonia as reaction raw materials, after performing ammoniation and oligomerization under alkaline conditions, excess ammonia is removed;

(2) Add carbon disulfide to the system obtained in step (1) to react;

Wherein, the dichloroalkane is represented by the general formula I,

(CH ₂ ) _n Cl ₂ Formula I

Among them, n is 2-4;

Preferably, the dichloroalkane is dichloroethane or dichloropropane.

In the synthesis method of the present invention, after the amination and oligomerization reaction, excess ammonia is distilled off, and carbon disulfide is added to the distillation residue; the distillate can be reused; the ammonia is an ammonia solution or an alcohol solution of ammonia Or ammonia in the form of an alcohol-water mixture. The alcohol includes but is not limited to ethanol, propanol, and methanol; the concentration of the ammonia solution is not particularly limited, and it is preferably an ammonia solution with a mass concentration of 5 to 60%.

Further, the amination and oligomerization reaction are carried out in the presence of an alkaline substance, especially a weak base, the alkaline substance is selected from sodium carbonate, ammonia, sodium hydroxide, potassium hydroxide, calcium hydroxide, hydrogen At least one of magnesium oxide, the molar ratio of the dichloroalkane to the alkaline substance is 1: 0.1 to 1: 5, preferably 1: 1 to 1: 3; wherein, the alkaline substance is an aqueous solution, Add in the form of alcohol solution or alcohol-water mixture, the alcohol includes but not limited to ethanol, propanol, methanol;

Further, in order to reduce by-products and increase yield, it is more preferable that the alkaline substance is a weak base, such as sodium carbonate and / or ammonia.

As a preferred solution of the present invention, when ammonia is selected as the alkaline substance (especially ideal), it is sufficient to increase the excess of ammonia in the synthesis scheme; preferably, when ammonia is used as the reaction raw material and used as the alkaline substance, The molar ratio of the dichloroalkane to ammonia is 1: 1.1 to 1: 5; more preferably the molar ratio of the dichloroalkane to ammonia is 1: 1.5 to 1: 3 or 1: 1.1 to 1: 1.5 or 1: 1.5 ~ 1: 2.

The molar ratio of dichloroalkane to ammonia has a great influence on the polymerization degree of the product and the reaction yield. Generally speaking, when the amount of ammonia added is large, the polymerization degree of the product is low, and it needs to be precipitated at a lower pH; when the amount of ammonia added is small, the product polymerization degree is high, which can be slightly acidic or even near neutral pH Precipitation precipitates, but excessively high degree of product polymerization can easily cause the product to fail to chelate nickel in electroplating wastewater.

In the synthesis method described in the present invention, the alkaline substance may be added alone, or may be added together with other raw materials (dichloroalkane, etc.), or it may be slowly added dropwise during the reaction.

Further, after the ammoniation and oligomerization reaction, and before removing excess ammonia, the pH value of the system is adjusted to 9.0 or more; preferably 10.0 to 13.5.

In the present invention, excess ammonia is removed by distillation. The pH value of the distillation system is based on that the ammonia molecule (NH ₃ ) in the solution accounts for more than 99% of the total ammonia.

Further, before adding carbon disulfide to the reaction system, the pH value of the system is adjusted to 9-13; preferably 9-12; more preferably 9-11.

Further, the molar ratio of carbon disulfide to dichloroalkane is 1: 1 to 3: 1; preferably 1: 1 to 2: 1.

Further, the temperature of the amination and oligomerization reaction is 40-200 ° C, and the time is 0.5-10h; preferably, the reaction temperature is 80-160 ° C, and the time is 1-4h; the reaction is faster and the reaction is more complete at higher temperatures ;

And / or, the step of removing excess ammonia is performed at 60 to 160 ° C for 0.5 to 10 hours; preferably 1 to 4 hours; at higher temperatures, the distillation is faster, and a small amount of ethylenediamine contained in the ammonia and the ammoniated product All can be distilled off; the distillate can be reused as a reactant after recovery;

And / or, after adding carbon disulfide to the reaction system, the reaction is carried out at 10 to 100 ° C for 0.5 to 10 hours; preferably at 30 to 80 ° C for 1 to 4 hours; when the temperature is higher, the reaction rate is fast and the reaction is relatively complete, but the temperature Too high and under strong alkaline conditions will easily produce by-product Na ₂ CS ₃ .

Further, the synthesis method of the present invention further includes the step of adding a base to the reaction product of the step (2); preferably the base is selected from sodium hydroxide, potassium hydroxide, calcium hydroxide, magnesium hydroxide, One or more of sodium carbonate.

In the synthesis method of the present invention, after the reaction is completed, it is cooled, and the insoluble part (thiocarbamic acid) in the product is dissolved with an appropriate amount of alkali to obtain the heavy metal removal preparation mentioned in the present invention.

Further, the reaction device of the synthesis method described in the present invention may be a reaction kettle (especially a reaction kettle with a stirring device) or a tube reactor.

The synthesis method described in the present invention uses pure water, ethanol, and water-alcohol mixture as the solvent system; preferably pure water is used as the solvent system to further control costs and avoid potential safety hazards caused by the use of alcohol-containing solvent systems And subsequent separation difficulty.

The product obtained by the direct amination reaction of dichloroalkane and ammonia water is extremely complex. The product consists of a oligomeric amine mixed system of 2 to 10 or more amino groups. For example, in the substitution products of ethylene dichloride and ammonia, the yield of ethylenediamine monomer is very low, and most of the ammoniation products are mixtures of linear, cyclic, and branched chain oligomeric amine compounds. body. Under the reaction conditions of the present invention, the composition of the amine oligomer obtained after the direct reaction of ethylene dichloride and ammonia water is relatively complex, and the mass spectrum peak of ethylene diamine is not significant. However, this application for the first time realized the possibility of directly using dichloroalkane, ammonia and carbon disulfide as reaction raw materials to prepare a heavy metal trapping agent, and further confirmed the outstanding removal effect of the prepared heavy metal trapping agent on heavy metals.

The invention also provides a heavy metal removal preparation prepared by the synthesis method. Among them, the heavy metal removal preparation prepared by the two-step reaction has obvious advantages in removing strong chelated nickel and copper in acid wastewater; the heavy metal removal preparation prepared by the one-step reaction is mainly used for removing copper in acid wastewater It has obvious advantages; but when the moles of dichloroalkane and ammonia are relatively large, the heavy metal removal preparation prepared by one-step reaction can be used directly as an adsorbent in a resin state.

The heavy metal removal preparation of the present invention may be either a liquid system after the reaction system has distilled off ammonia, or a solid substance (such as a powder) obtained by further drying, which can be directly put into the treatment after being dissolved and diluted during use. Heavy metals are captured and treated in wastewater containing heavy metals.

The invention also provides a heavy metal adsorbent, which is an insoluble polymer resin prepared by a heavy metal removal preparation and a polymerization agent prepared by the above synthesis method.

Preferably, the polymerization agent is selected from one or more of dichloroethane, dichloropropane, dichlorobutane, glyoxal, glutaraldehyde, epichlorohydrin, preferably dichloroethane and dichloromethane Chloropropane.

The invention also provides the heavy metal removal preparation prepared by the synthesis method and the application of the heavy metal adsorbent in the removal of heavy metals; preferably in the removal of strong complex heavy metals and the capture of heavy metals in acid wastewater.

The heavy metals mentioned in the present invention include but are not limited to nickel, copper, zinc, lead, cadmium, chromium, arsenic, antimony, mercury; preferably nickel and / or copper. The heavy metal removal preparation described in the present invention can be further used in conjunction with other flocculation and coagulant co-precipitation, centrifugal separation, sand filtration, pressure filtration, membrane separation and other water and wastewater treatment technologies to purify the water body. The present invention is not particularly limited.

The object of the application may be a solid or a liquid. The solid refers to solid wastes containing heavy metals, including but not limited to heavy metals from industrial waste residues; the liquid refers to liquids contaminated by heavy metals, such as Heavy metal contaminated wastewater, especially heavy metal-containing wastewater from the electroplating and smelting industries; it is particularly noteworthy that the heavy metal removal preparation is used in an environment with a pH of 1-10; preferably the pH is 1-4. The strong acid heavy metal wastewater can be used directly without pH adjustment to neutrality. Therefore, the heavy metal removal preparation of the present invention is particularly suitable for low pH acidic heavy metal polluted wastewater.

Further, the specific use method of the heavy metal removal preparation is:

When the object to be treated is hazardous solid waste containing heavy metals, the treatment method can be as follows:

Take hazardous solid waste containing heavy metals, after leaching with acid or alkali solution, add the heavy metal removal preparation prepared by the present invention to the leaching solution, stir, or further add coagulant, and obtain heavy metal high after stirring precipitation or filtration Concentrated organic solid materials; and the filtrate (the leaching solution after heavy metals are effectively removed) can be discharged directly after acid and alkali neutralization.

When the object to be treated is heavy metal contaminated wastewater, the treatment method can be as follows:

Take heavy metal contaminated wastewater, add the heavy metal removal preparation to it, stir and adjust the pH value, then add flocculant and coagulant in sequence, and obtain purified effluent after stirring and precipitation;

Or after adding the heavy metal removal preparation, stirring and adjusting the appropriate pH for several minutes, the suspended turbid liquid is directly filtered with a membrane to obtain purified water quality.

When the heavy metal polluted wastewater is acidic, the treatment method may be as follows:

Take acidic heavy metal contaminated wastewater, add the heavy metal removal preparation to it, stir, or further add coagulant, after stirring to precipitate or filter to obtain acidic wastewater with heavy metals effectively removed, then add alkaline substances such as slaked lime, hydrogen Sodium oxide, potassium hydroxide and sodium carbonate are neutralized to obtain the final purified effluent (the sludge generated after adding hydrated lime is effectively removed in advance due to heavy metals and can be directly landfilled).

The invention directly uses dichloroalkane, ammonia and carbon disulfide as initial raw materials, and prepares a mixture of dithiocarbamic acids and their salts in a pure water system, ethanol or water-alcohol mixed system under alkaline conditions as a removal and Capturing the active ingredients of heavy metals. The invention adopts a one-pot method to prepare the heavy metal removal preparation, boldly tries and breaks through the routine, completely avoids and omits the very complicated and difficult separation and purification of reactants (ammonia) and intermediate products (amine polymers). The mixed salt obtained after the two-step reaction is non-volatile, so after the remaining ammonia is simply distilled off, the heavy metal removal preparation can be obtained, so that the content of active ingredients in the preparation can be increased instead. The synthesis of the heavy metal preparation uses inexpensive dichloroalkane and ammonia as raw materials, and adopts a one-pot process to undergo two or one-step reactions. The cost is low and the yield is high. After evaporating the remaining ammonia, dithiocarbamic acid substances and The mixture of salts is used as an active ingredient for removing heavy metals. Excess ammonia is recovered for use as a reactant, and almost no “three wastes” are produced during the entire synthesis process, which is green and pollution-free.

The invention significantly reduces the production cost. Based on the output of 1 ton, the method described in the invention can reduce the raw material cost from as high as 12,000 to 15,000 yuan per ton (industrial ethylenediamine price) to 2 -3 thousand yuan (the price of industrial ammonia and dichloroethane is only 2-3 thousand yuan per ton) yuan, with extremely high economic value and practical benefits.

In addition, the heavy metal removal preparation prepared by the present invention also has obvious advantages over similar products in terms of application effect, and can maintain stable heavy metal removal performance in a wider range of pH conditions, especially in strong acid wastewater. It can play a very significant effect in the removal of heavy metals in industrial wastewater such as electroplating and smelting.

BRIEF DESCRIPTION

FIG. 1 A is a high-resolution mass spectrum of the product after the first round of the first step of Example 1; B is a high-resolution mass spectrum of the product after the first round of the first step of Example 3. FIG.

In Figure 2, A is the infrared spectrum of the third round of heavy metal removal preparation of Example 1; B, Example 3 is the infrared spectrum of the third round of heavy metal removal preparation.

In FIG. 3, A is the mass spectrum of the third round of heavy metal removal preparation of Example 1; B, Example 3 is the mass spectrum of the third round of heavy metal removal preparation.

4 is a Fourier transform-infrared spectrum (FT-IR) diagram of the heavy metal removal preparation prepared in Examples 9-10;

5 is a mass spectrum (TOF-MS) of the heavy metal removal preparation prepared in Examples 9-10.

detailed description

Exemplary embodiments of the present invention are provided in the following examples. The following embodiments are given by way of example only, and are used to help ordinary technicians use the present invention. The described embodiments do not limit the scope of the invention in any way.

Example 1

The invention provides a heavy metal removal preparation, the preparation method of which includes the following steps:

To a 100ml reactor, add 6.19g of 1,2-dichloroethane, 8.50g of a 25-28% ammonia aqueous solution (dichloroethane / ammonia molar ratio is about 1: 2), 28ml of pure water, sealed At 140 ℃ magnetic stirring reaction for 4h (, the maximum pressure during the reaction is about 1.1MPa. The first step of the reaction is completed and cooled, the pipette sucks a small amount of 1,2-dichloroethane that has not completely reacted at the bottom. Use concentrated hydroxide The potassium solution adjusted the pH to 13.2, the total volume was 55ml, distilled under magnetic stirring at 120 ° C and received the distillate with 15ml of pure water. After distillation for 3 hours, the final volume of the distillate was 36ml, and the volume of the remaining distillation liquid was 34ml. Add 1 : 1 hydrochloric acid to adjust the pH of the distillation residue to 11.0, then add 6.30g carbon disulfide (dichloroethane / carbon disulfide molar ratio is about 1: 1.33), seal, and react under magnetic stirring at 50 ℃ for 8h. Cool down after the above process , The insoluble part of the product is dissolved by adding alkali to obtain heavy metal removal preparation.

Using the distillate from the previous round as the raw material for the first step of the subsequent round, add a certain amount of 25-28% aqueous ammonia solution to maintain a dichloroethane / ammonia molar ratio of about 1: 2 and a reaction volume of 42ml , Sealed at 140 ℃ for 4h. After the first step of the reaction, the pH is adjusted to alkaline (see Table 1), distillation at 120 ℃, the distillation residue is under alkaline conditions (see Table 1; the fourth and fifth rounds do not adjust the pH of the distillation residue) to continue React with carbon disulfide at 50 ℃ for 8h. This was repeated for five rounds to obtain the heavy metal removal preparation mentioned in the present invention in sequence.

Example 1 The high-resolution mass spectrum of the product after the first step of the first round of reaction is shown in FIG. 1A. The product is mainly an oligomeric amine compound with a molecular weight range of 100-800 and an ethylenediamine with a characteristic molecular weight of 60. The mass spectrum peak is not significant.

The infrared spectrum of the obtained third heavy metal removal preparation is shown in FIG. 2A, and the mass spectrum is shown in FIG. 3A. The product is composed of a complex oligomer mixed system with a molecular weight range of 100-1000.

It can be seen from Table 1 that in five rounds (among which ammonia is recycled and reused 4 times), the conversion rate of ethylene dichloride is as high as 94-98%; the vulcanization efficiency is kept between 50-56%.

Table 1 Key parameters of five synthetic reincarnations in Example 1

A	first round	second round	Third round	Fourth round	Round five
Conversion rate of dichloroethane%	96	98	94	94	96
Distillation initial pH	13.2	13.0	12.5	12.0	12.5
NH 3 steaming efficiency%	98	98	97	97	97
Initial pH of sulfurization reaction	11.0	10.5	11.0	12.0	12.5
Curing efficiency%	52	50	55	55	56

Example 2

In this example, the heavy metal removal preparation prepared in five consecutive rounds of Example 1 is used to remove heavy metals. The specific scheme is as follows:

The actual nickel-containing electroplating wastewater (taken from a company in Jiangsu) and copper-containing smelting wastewater (taken from a company in Jiangxi) were taken in multiple portions of 500ml each, as shown in Table 2, and the above examples were added to the above samples for five rounds. The heavy metal scavenger obtained from the secondary synthesis using thiocarbamic acid mixed salt as the active ingredient, adjust the pH 1-4, and it will be cloudy after stirring for 10 minutes, the precipitation will be good within 5 minutes, take the clarified water, measure the raw water and the treated water For nickel concentration, calculate the removal rate.

At the same time, the control 1 is set, without adding the heavy metal removal formulation of the present invention, only the removal effect of the conventional flocculant ferric chloride (100 mg / L) and the coagulant polyacrylamide (5 mg / L) is added.

The results are shown in Table 2. Without the preparation of the present invention, the removal efficiency of nickel was only 6.8% under the condition that only the ferric chloride flocculant and polyacrylamide coagulant were added. After applying the heavy metal removal preparation obtained according to plan A in the five rounds of the above example, the actual removal of nickel in electroplating wastewater is as high as 95.2-96.8%, and the nickel concentration in the effluent is 0.08-0.12mg / L, which can meet the standard discharge; The copper removal rate of copper smelting wastewater is as high as 99.8-99.9%.

Table 2 The effect of heavy metal removal preparations on the removal of nickel and copper in actual wastewater

Example 3

The invention provides a heavy metal removal preparation, the preparation method of which includes the following steps:

To a 100ml reactor, add 6.19g 1,2-dichloroethane, 8.50g (concentration of 25-28% ammonia solution, 30ml 20% sodium carbonate solution (dichloroethane / ammonia / sodium carbonate molar ratio About 1: 2: 0.9), sealed, and reacted under magnetic stirring at 140 ℃ for 4h, the highest pressure during the reaction is about 1.2MPa. The first step of the reaction is completed and cooled, the straw sucks a small amount of unreacted 1,2- at the bottom Dichloroethane. Adjust the pH to 13.2 with concentrated sodium hydroxide solution, the total volume is 51ml, distill with magnetic stirring at 120 ° C and receive the distillate with 20ml of pure water. After 3 hours of distillation, the final volume of the distillate is 32ml, The volume of the remaining distillation liquid is 39ml. Add 1: 1 hydrochloric acid to adjust the pH of the remaining distillation liquid to 9.0, then add 6.30g of carbon disulfide (dichloroethane / carbon disulfide molar ratio is about 1: 1.33), sealed, magnetic stirring at 50 ℃ The reaction is carried out for 8 hours. After the above process is completed, it is cooled, and the insoluble part of the product is further dissolved with alkali to obtain a heavy metal removal preparation.

Using the distillate from the previous reaction as the raw material for the subsequent reaction, add 6.0 g of Na ₂ CO ₃ and add a certain amount of 25-28% aqueous ammonia solution to maintain the mole of dichloroethane / ammonia / sodium carbonate The ratio is about 1: 2: 0.9, sealed, and reacted at 140 ° C for 4h. After the first step of the reaction, the pH is adjusted to alkaline (see Table 3), distillation at 120 ℃, the distillation residue is under alkaline conditions (see Table 3; the fourth and fifth rounds do not adjust the pH of the distillation residue) to continue React with carbon disulfide at 50 ℃ for 8h. This was repeated for five rounds to obtain the heavy metal removal preparation mentioned in the present invention in sequence.

Example 3 The high-resolution mass spectrum of the product after the first step of the first round of reaction is shown in FIG. 1B. The product is mainly an oligomeric amine compound with a molecular weight range of 100-800 and a characteristic molecular weight of 60 ethylenediamine. The mass spectrum peak is not significant.

The infrared spectrum of the obtained third heavy metal removal preparation is shown in FIG. 2B, and the mass spectrum is shown in FIG. 3B. The product is composed of a complex oligomer mixed system with a molecular weight range of 100-1200.

From Table 3, it can be seen that in five rounds (ammonium recycling and reuse 4 times), the conversion rate of ethylene dichloride is as high as 94-96%; the vulcanization efficiency is maintained between 42-60%.

Table 3 Example 3 Key Parameters of Amination-Ammonia Distillation-Vulcanization in Five Synthesis Cycles

A	first round	second round	Third round	Fourth round	Round five
Conversion rate of dichloroethane%	94	96	95	95	96
Distillation initial pH	13.2	13.2	12.0	12.0	12.5

NH 3 steaming efficiency%	98	97	96	95	96
Initial pH of sulfurization reaction	9.0	10.0	11.0	11.7	12.3
Curing efficiency%	42	58	56	58	60

Example 4

In this example, the heavy metal removal preparation prepared in Example 3 for five consecutive rounds is used to remove heavy metals. The specific scheme is the same as in Example 2.

The results are shown in Table 4. After applying the heavy metal removal preparations obtained in the five rounds of the above example, the actual nickel removal in the electroplating wastewater is as high as 95.6-97.6%, and the nickel concentration in the effluent is 0.06-0.13mg / L, which can meet the standard discharge ; The removal rate of copper in high concentration copper-containing smelting wastewater is as high as 99.8-99.9%.

Table 4 The effect of heavy metal removal preparations on the removal of nickel and copper in actual wastewater

Example 5

The invention provides a heavy metal removal preparation, the preparation method of which includes the following steps:

Add 6.19g of 1,2-dichloroethane and 17.0g of ammonia solution with a concentration of 25-28% (dichloroethane / ammonia molar ratio of about 1: 4) to a 100ml reactor, seal, and magnetic force at 100 ℃ The reaction was stirred for 4h. In the first step, the reaction is completed and cooled, and a small amount of 1,2-dichloroethane which has not completely reacted at the bottom is sucked away by a pipette. The pH was adjusted to 11.5 with sodium carbonate, the total volume was 50 ml, distilled under magnetic stirring at 120 ° C and 15 ml of pure water was used to receive the distillate. After 3 hours of distillation, the volume of the remaining distillation liquid was 35 ml. Then, 6.30 g of carbon disulfide (the molar ratio of ethylene dichloride / carbon disulfide is about 1: 1.33) was added, sealed, and reacted under magnetic stirring at 50 ° C for 6 hours. After the above process is finished, it is cooled, and the insoluble part of the product is further dissolved with alkali to obtain the heavy metal removal preparation mentioned in the present invention. The conversion rate of dichloroethane is 87%; the vulcanization efficiency is 65%.

Example 6

The invention provides a heavy metal removal preparation, the preparation method of which includes the following steps:

To a 100ml reactor, add 6.19g of 1,2-dichloroethane, 6.4g of 25-28% ammonia solution, 30ml of 30% sodium carbonate solution (dichloroethane / ammonia / sodium carbonate molar ratio is about It is 1: 1.5: 1.3), sealed, and reacted under magnetic stirring at 160 ° C for 4h. In the first step, the reaction is completed and cooled, and a small amount of 1,2-dichloroethane which has not completely reacted at the bottom is sucked away by a pipette. The pH was adjusted to 12.0, the total volume was 50ml, distilled under magnetic stirring at 120 ° C and 15ml of pure water was used to receive the distillate. After distillation for 3 hours, the volume of the remaining distillation liquid was 38 ml. Then, 9.50 g of carbon disulfide (the molar ratio of ethylene dichloride / carbon disulfide is about 1: 2) was added, sealed, and reacted under magnetic stirring at 60 ° C. for 4 hours. After the above process is finished, it is cooled, and the insoluble part of the product is further dissolved with alkali to obtain the heavy metal removal preparation mentioned in the present invention. The conversion rate of dichloroethane is 85%; the vulcanization efficiency is 45%.

Example 7

The invention provides a heavy metal removal preparation, the preparation method of which includes the following steps:

To a 100ml reactor, add 7.08g of 1,2-dichloropropane, 8.50g of ammonia solution with a concentration of 25-28%, and 20ml of 30% sodium carbonate solution for sealing (the molar ratio of dichloropropane / ammonia / sodium carbonate is about 1: 2: 0.9), react under magnetic stirring at 120 ℃ for 4h. In the first step, the reaction is completed and cooled, and a small amount of 1,2-dichloropropane at the bottom which has not been completely reacted is sucked away by a pipette. The pH was adjusted to 12.0 with sodium hydroxide, the total volume was 50 ml, distilled under magnetic stirring at 120 ° C and 15 ml of pure water was used to receive the distillate. After 3 hours of distillation, the volume of the remaining distillation liquid was 36 ml. Then add 9.50g of carbon disulfide (the molar ratio of ethylene dichloride / carbon disulfide is about 1: 2), seal, and react under magnetic stirring at 40 ° C for 8 hours. After the above process is finished, it is cooled, and the insoluble part of the product is further dissolved with alkali to obtain the heavy metal removal preparation mentioned in the present invention. The conversion rate of dichloropropane is 85%; the vulcanization efficiency is 40%.

Example 8

In this example, the heavy metal removal preparations prepared in Examples 5, 6, and 7 are used to remove heavy metals, and the specific scheme is the same as in Example 2.

The results are shown in Table 5. After applying the heavy metal removal preparations prepared in Examples 5, 6, and 7, the actual nickel removal in electroplating wastewater was as high as 95.2-97.2%, and the nickel concentration in the effluent was 0.07-0.12 mg / L. Discharge can be achieved; the copper removal rate of high concentration copper-containing smelting wastewater is as high as 99.8-99.9%.

Table 5 The effect of heavy metal removal preparations on the removal of nickel and copper in actual wastewater

Example 9:

Add 6.20g of 1,2-dichloroethane and 8.50g of 25-28% ammonia aqueous solution (dichloroethane / ammonia molar ratio is about 1: 2) to a 100ml reactor, seal, and magnetic force at 100 ℃ React for 4h with stirring;

Then slowly add 5ml of 40% sodium hydroxide aqueous solution to the reactor to adjust the pH to 9.6, then add 9.50g of carbon disulfide (dichloroethane / NaOH / carbon disulfide molar ratio is about 1: 0.8: 2), sealed, 50 The reaction was carried out under magnetic stirring at ℃ for 4h.

After the above process is completed, it is cooled, and the insoluble part (dithiocarbamic acid) in the product is further dissolved with alkali, and the remaining ammonia is evaporated to obtain the heavy metal removal preparation mentioned in the present invention. Conversion rate) was 86%. The infrared spectroscopy (FT-IR) and high-resolution mass spectrometry (TOF-MS) of the resulting preparation are shown as A in FIGS. 4 and 5.

Example 10:

To a 100ml reactor, add 6.20g of 1,2-dichloroethane, 8.50g of 25-28% aqueous ammonia solution, 15ml of 40% sodium carbonate aqueous solution (dichloroethane / ammonia / sodium carbonate molar Ratio is about 1: 2: 0.9), sealed, and reacted at 100 ℃ for 4h;

Then, 9.50 g of carbon disulfide (the molar ratio of dichloroethane / carbon disulfide is about 1: 2) was added to the reactor, sealed, and reacted under magnetic stirring at 60 ° C. for 4 h.

After the above process is finished, it is cooled, and the insoluble part (dithiocarbamic acid) in the product is further dissolved with alkali. After the remaining ammonia is evaporated, the heavy metal removal preparation mentioned in the present invention is obtained with a yield of 83.7%. The infrared spectroscopy (FT-IR) and high-resolution mass spectrometry (TOF-MS) of the resulting preparation are shown as B in FIGS. 4 and 5.

Example 11:

Add 6.20g of 1,2-dichloroethane and 8.50g of 25-28% ammonia aqueous solution (dichloroethane / ammonia molar ratio is about 1: 2) to a 100ml reactor, seal, and magnetic force at 140 ℃ The reaction was stirred for 4h. Then slowly add 5ml of 40% sodium hydroxide aqueous solution to the reactor to adjust the pH to 9.3, add 9.50g of carbon disulfide (dichloroethane / NaOH / carbon disulfide molar ratio is about 1: 0.8: 2), seal, magnetic force at 50 ℃ The reaction was stirred for 4h. After the above process is completed, it is cooled, and the insoluble part (dithiocarbamic acid) in the product is further dissolved with alkali. After the remaining ammonia is evaporated, the heavy metal removal preparation mentioned in the present invention is obtained with a yield of 90.3%.

Example 12

To a 100ml reactor, add 6.20g of 1,2-dichloroethane, 8.50g of 25-28% aqueous ammonia solution, 15ml of 40% sodium carbonate aqueous solution (dichloroethane / ammonia / sodium carbonate molar ratio is about It is 1: 2: 0.9), sealed, and reacted under magnetic stirring at 140 ℃ for 4h. Then add 9.50g of carbon disulfide (the molar ratio of ethylene dichloride / carbon disulfide is about 1: 2), seal, and react under magnetic stirring at 50 ° C for 4 hours. After the above process is finished, it is cooled, and the insoluble part (dithiocarbamic acid) in the product is further dissolved with alkali. After the remaining ammonia is evaporated, the heavy metal removal preparation mentioned in the present invention is obtained with a yield of 90.6%.

Example 13

To a 100ml reactor, add 7.08g of 1,2-dichloropropane, 8.50g of 25-28% aqueous ammonia solution, 15ml of 40% sodium carbonate solution (dichloropropane / ammonia / sodium carbonate molar ratio is about 1: 2: 0.9), react with magnetic stirring at 140 ℃ for 4h. Then add 9.50g of carbon disulfide to the reactor, seal, and react under magnetic stirring at 50 ° C for 4h. After the above process is completed, it is cooled, and the insoluble part (dithiocarbamic acid) in the product is further dissolved with alkali. After the remaining ammonia is evaporated, the heavy metal removal preparation mentioned in the present invention is obtained with a yield of 92.8%.

Example 14 (Heavy metal adsorbent)

Take 1.00 g of the heavy metal removal preparation obtained in the above Example 11 in a reaction kettle, add 2.00 g of 1,2-dichloroethane and 10 ml of a 20% sodium carbonate aqueous solution, raise the temperature to 80 ° C, and react for 4 hours. After the reaction, it was cooled to obtain a yellow-white insoluble polymer resin with a yield of 91.4%.

In order to verify the application effect of the heavy metal adsorbent obtained in this example, the following experiments are also provided:

Take 0.2g of the resin prepared above, put in 100ml of copper-containing acidic mine wastewater (from a company in Jiangxi, Cu ²⁺ = 5.7mg / L; pH = 2.0), shake for 60 minutes, take the supernatant, and determine the copper The concentration dropped to 0.05mg / L.

It should be mentioned that, according to the reaction principle, the heavy metal removal preparations obtained in 9-13 in the above examples can be used to prepare insoluble polymer resins and used as an adsorbent for removing heavy metals. In addition to 1,2-dichloroethane, optional polymerization reagents include: dichloropropane, dichlorobutane, glyoxal, glutaraldehyde, epichlorohydrin, or mixtures thereof. In addition to sodium carbonate, the alkaline substance optionally includes sodium hydroxide, potassium hydroxide, and calcium hydroxide. The reaction temperature range is 20-200 ° C, and the more suitable temperature range is 50-150 ° C. The reaction time is 0.5-10h, and the more suitable time is 1-4hr.

After adsorption and saturation, the above resin is placed in acid, alkali, or metal chelating agent such as EDTA, NTA solution for regeneration and reuse.

Example 15

To a 100ml reactor, add 6.20g of 1,2-dichloroethane, 4.68g of ammonia solution with a concentration of 25-28%, 15ml of 40% sodium carbonate aqueous solution (dichloroethane / ammonia / sodium carbonate molar ratio is about It is 1: 1.1: 0.9), sealed, and reacted under magnetic stirring at 140 ℃ for 4h. Then add 9.50g of carbon disulfide (the molar ratio of ethylene dichloride / carbon disulfide is about 1: 2), seal, and react under magnetic stirring at 50 ° C for 4 hours. After the remaining ammonia is evaporated, the heavy metal removal preparation mentioned in the present invention is obtained with a yield of 62.3%.

Example 16

To a 100ml reactor, add 6.20g of 1,2-dichloroethane, 6.38g of 25-28% aqueous ammonia solution, 15ml of 40% sodium carbonate aqueous solution (dichloroethane / ammonia / sodium carbonate molar ratio is about It is 1: 1.5: 0.9), sealed, and reacted under magnetic stirring at 140 ℃ for 4h. Then add 9.50g of carbon disulfide (the molar ratio of ethylene dichloride / carbon disulfide is about 1: 2), seal, and react under magnetic stirring at 50 ° C for 4 hours. After the remaining ammonia is evaporated, the heavy metal removal preparation mentioned in the present invention is obtained, and the obtained yield is 84.2%.

Example 17

Add 6.20g of 1,2-dichloroethane and 12.75g of a 25-28% ammonia aqueous solution (dichloroethane / ammonia molar ratio of about 1: 3) to a 100ml reactor, seal, and magnetic force at 100 ℃ The reaction was carried out with stirring for 4h; then 9.50g of carbon disulfide (the molar ratio of ethylene dichloride / carbon disulfide was about 1: 2) was added, sealed, and reacted under magnetic stirring at 50 ° C for 4h. After the remaining ammonia is evaporated, the heavy metal removal preparation mentioned in the present invention is obtained with a yield of 91.6%.

Example 18

Add 6.20g of 1,2-dichloroethane and 21.25g of a 25-28% ammonia aqueous solution (dichloroethane / ammonia molar ratio is about 1: 5) to a 100ml reactor, seal, and magnetic force at 100 ℃ The reaction was carried out with stirring for 4h; then 9.50g of carbon disulfide (the molar ratio of ethylene dichloride / carbon disulfide was about 1: 2) was added, sealed, and reacted under magnetic stirring at 50 ° C for 4h. After the remaining ammonia is evaporated, the heavy metal removal preparation mentioned in the present invention is obtained with a yield of 92%.

Comparative example 1

Add 6.20g of 1,2-dichloroethane and 4.25g of a 25-28% ammonia aqueous solution (dichloroethane / ammonia molar ratio is about 1: 1) to a 100ml reactor, seal, and magnetic force at 100 ℃ The reaction was stirred for 4h; then 5ml of 40% aqueous sodium hydroxide solution was slowly added to the reactor to adjust the pH to 9.6, then 9.50g of carbon disulfide was added, sealed, and reacted under magnetic stirring at 50 ° C for 4h. After the above process is finished, it is cooled, and the insoluble part (dithiocarbamic acid) in the product is further dissolved with alkali. After the remaining ammonia is evaporated, the heavy metal removal preparation mentioned in the present invention is obtained, and the yield is only 19%.

Comparative example 2

To a 100ml reactor, add 6.20g 1,2-dichloroethane, 4.25g ammonia solution with a concentration of 25-28%, 16.6ml 40% sodium carbonate solution (dichloroethane / ammonia / sodium carbonate molar ratio) About 1: 1: 1), sealed, and reacted under magnetic stirring at 100 ° C for 4h; then added 9.50g of carbon disulfide, sealed, and reacted under magnetic stirring at 50 ° C for 4h. After the above process is finished, it is cooled, and the insoluble part (dithiocarbamic acid) in the product is further dissolved with alkali. After the remaining ammonia is evaporated, the heavy metal removal preparation mentioned in the present invention is obtained. The obtained yield is compared with Comparative Example 2. Significantly increased to 58%, but still lower than the 86% yield in Example 9 when ammonia was added in excess.

Comparative Example 3

Add 7.08g of 1,2-dichloropropane and 8.50g of 25-28% ammonia aqueous solution (dichloropropane / ammonia molar ratio is about 1: 2) to the 100ml reaction kettle, and react under magnetic stirring at 100 ℃ for 4h . After the first step reaction, it was observed that most of the insoluble dichloropropane was not converted into water-soluble amine compounds, and the conversion efficiency was very low. It was confirmed that for dichloropropane, compared with dichloroethane Alkanes, for their effective amination and oligomerization, require a more stable weak alkaline environment.

Comparative Example 4

To a 100ml reactor, add 6.20g of 1,2-dichloroethane, 8.50g of 25-28% aqueous ammonia solution and 6.3ml of 40% sodium hydroxide aqueous solution (dichloroethane / ammonia / hydroxide) The molar ratio of sodium is about 1: 2: 1), sealed, and reacted under magnetic stirring at 100 ° C for 4h; then 9.50g of carbon disulfide is added to the reactor, sealed, and reacted under magnetic stirring at 60 ° C for 4h. The final yield was 42.8%. That is, the weakly alkaline environment is significantly superior to the strongly alkaline environment in the two-step embodiment.

In order to verify the application effect of the heavy metal adsorbent obtained in this example, the following test examples are provided:

Test Example 1:

This experimental example provides a specific application of the heavy metal removal preparation prepared in the above example for removing heavy metals. The specific scheme is as follows:

Separately take multiple parts of actual nickel-containing electroplating wastewater (from an enterprise in Jiangsu) and copper-containing smelting wastewater (from an enterprise in Jiangxi), each 500ml, as shown in Table 6, add the above example 9- 15 Synthesized heavy metal scavenger with dithiocarbamic acid mixed salt as active ingredient, adjust the pH 1-4, stir after 10 minutes and see turbidity, precipitate well within 5 minutes, take clear water, measure raw water and treated water For the nickel concentration, calculate the removal rate.

At the same time, the control 1 is set, without adding the heavy metal removal preparation of the present invention, only the removal effect of the conventional flocculant ferric chloride and the coagulant polyacrylamide is added.

The results are shown in Table 6. Without the preparation of the present invention, the removal efficiency of nickel was only 6.8% under the condition that only the ferric chloride flocculant and polyacrylamide coagulant were added. After applying the heavy metal removal preparations obtained in Example 9, Example 10, Example 11, Example 12, and Example 13, the actual nickel removal in the electroplating wastewater was as high as 96.0-96.8%, and the nickel concentration in the effluent was 0.08-0.1mg / L, can reach the standard discharge; the removal rate of copper in high concentration copper-containing smelting wastewater is as high as 99.8%.

Although the heavy metal preparation obtained with dichloropropane as the initial raw material has a significant removal effect on the chelated nickel in electroplating wastewater, the actual nickel removal rate in electroplating wastewater is 72.0%, and its performance is weaker than that obtained with dichloroethane as the initial raw material Of the preparation.

The resin obtained in Example 14 has a high adsorption and removal rate of copper of high-concentration copper-containing smelting wastewater, but it has no obvious effect on the removal of nickel in the electroplating wastewater.

The nickel removal agent J-301 purchased from the market under the same experimental conditions has a nickel removal rate of only 76.0%.

Table 6 The removal effect of heavy metal removal preparations on nickel and copper in actual wastewater

Test Example 2:

Take 500ml of copper-containing acid mine wastewater (from an enterprise in Jiangxi, Cu ²⁺ = 5.7mg / L; pH = 2.0), and directly add the heavy metal removal preparation with a final concentration of 100mg / L prepared from the present invention (from Example 9- 15), stir for 10 minutes, take the supernatant after precipitation, and the copper concentration drops to 0.06-0.14mg / L after measurement; add slaked lime to neutralize and filter, to obtain the final purified effluent.

Table 7 The removal effect of heavy metal removal preparations on copper in actual copper-containing acid mine wastewater

Industrial applicability

The invention provides a heavy metal removal preparation. The heavy metal removal preparation of the present invention is prepared by the following method: (1) Dichloroalkane and ammonia are used as reaction raw materials to perform amination and oligomerization under alkaline conditions; (2) To the system obtained in step (1) Carbon disulfide is added, and the reaction is carried out under alkaline conditions, that is, the method further includes the removal of ammonia. The synthesis of the heavy metal removal preparation of the present invention uses inexpensive dichloroalkane and ammonia as raw materials, and undergoes a two-step reaction with low cost and high yield. The invention breaks through the disadvantages and defects of using ethylenediamine as a raw material in the prior art, and significantly reduces the production cost. The heavy metal removal preparation prepared by the invention maintains stable heavy metal removal performance under extremely low pH conditions, and can be used in actual plating and smelting. It has a very significant effect in the removal of heavy metals in industrial wastewater, etc., and has good economic value and application prospects.

Claims (13)

1. A method for synthesizing heavy metal removal preparations, characterized in that the method includes the following specific steps:

   (1) Ammonia and oligomerization reactions are carried out under alkaline conditions with dichloroalkane and ammonia as raw materials;

   (2) Add carbon disulfide to the system obtained in step (1) and carry out the reaction under alkaline conditions;

   Wherein, the dichloroalkane is represented by the general formula I,

   (CH ₂ ) _n Cl ₂ Formula I

   Among them, n is 2-4;

   Preferably, the dichloroalkane is dichloroethane or dichloropropane;

   Wherein, the method further includes the removal of ammonia.
2. The synthesis method according to claim 1, wherein the removal of the ammonia is performed after the reaction of step (2) is completed;

   Preferably, the ammonia is removed by evaporation, and the evaporation is performed at a temperature of 50-140 ° C;

   Preferably, the alkaline condition is adjusted by adding an alkaline substance selected from at least one of sodium carbonate, ammonia, sodium hydroxide, potassium hydroxide, calcium hydroxide, and magnesium hydroxide, preferably It is sodium carbonate and / or ammonia; preferably, the molar ratio of the dichloroalkane to the alkaline substance is 1: 0.1 to 1: 5, preferably 1: 1 to 1: 3.
3. The synthesis method according to claim 1, characterized in that the removal of the ammonia is performed after the completion of the amination and oligomerization reaction of step (1);

   Preferably, after the ammoniation and oligomerization reaction and before removing excess ammonia, the pH of the system is adjusted to be above 9.0; preferably 10.0 to 13.5; the removal of ammonia is performed at 60 to 160 ° C for 0.5 to 10h;

   Preferably, the alkaline condition is adjusted by adding an alkaline substance selected from at least one of sodium carbonate, ammonia, sodium hydroxide, potassium hydroxide, calcium hydroxide, and magnesium hydroxide, conditions It is that the alkaline conditions in step (2) cannot be adjusted by adding ammonia; preferably, the molar ratio of the dichloroalkane to the alkaline substance is 1: 0.1 to 1: 5, preferably 1: 1 ~ 1: 3;

   Preferably, the alkaline conditions in step (1) are adjusted by adding sodium carbonate and / or ammonia; the alkaline conditions in step (2) are adjusted by adding sodium carbonate.
4. The synthesis method according to any one of claims 1 to 3, characterized in that the ammonia is added in the form of an aqueous ammonia solution, an ammonia alcohol solution, or an ammonia alcohol-water mixture; preferably the alcohol is ethanol, Propyl alcohol or methanol; more preferably, the ammonia is an aqueous ammonia solution, further preferably an aqueous ammonia solution with a mass concentration of 5-60%.
5. The synthesis method according to any one of claims 2-3, characterized in that when the alkaline conditions in step (1) are adjusted by adding the alkaline substance other than ammonia, the The molar ratio of dichloroalkane and ammonia is 1: 0.1-1: 5, preferably 1: 1: 1-1: 3; when the alkaline conditions in step (1) are adjusted by adding ammonia, the reaction raw materials The molar ratio of dichloroalkane to ammonia is 1: 1.1 to 1: 5; preferably 1: 2-1: 4;

   In step (2), the molar ratio of carbon disulfide to dichloroalkane is 1: 1-3: 1; preferably the molar ratio is 1: 1-2: 1.
6. The synthesis method according to any one of claims 1-3, characterized in that, in step (2), the pH of the alkaline condition is 9-13; preferably 9-12.
7. The synthesis method according to any one of claims 1 to 3, characterized in that in step (1), the reaction temperature of the amination and oligomerization reaction is 40 to 200 ° C, preferably 80 to 160 ° C; The reaction time is 0.5 to 10h; preferably 1 to 4h;

   In step (2), the reaction temperature of the reaction is 10 to 100 ° C, preferably 30 to 80 ° C; the reaction time is 0.5 to 10h, preferably 1 to 4h.
8. The synthesis method according to claim 1, wherein the method comprises the following specific steps:

   (1) Ammonia and oligomerization reactions are carried out under alkaline conditions with dichloroalkane and ammonia as raw materials;

   (2) Add carbon disulfide to the system obtained in step (1), perform the reaction under alkaline conditions, and distill off the remaining ammonia in the product;

   Wherein, the dichloroalkane is represented by the general formula I,

   (CH ₂ ) _n Cl ₂ Formula I

   Among them, n is 2-4;

   Preferably, the dichloroalkane is dichloroethane or dichloropropane;

   The ammonia is added in the form of an aqueous ammonia solution, an ammonia alcohol solution, or an ammonia alcohol-water mixture; preferably the alcohol is ethanol, propanol, or methanol; more preferably, the ammonia is an aqueous ammonia solution, and further preferably the mass concentration is 20-60% ammonia solution;

   The alkaline condition is adjusted by adding an alkaline substance selected from at least one of sodium carbonate, ammonia, sodium hydroxide, potassium hydroxide, calcium hydroxide, and magnesium hydroxide, preferably sodium carbonate And / or ammonia; the molar ratio of the dichloroalkane to the alkaline substance is 1: 0.1-1: 5, preferably 1: 1-1: 3;

   In step (1), the molar ratio of the dichloroalkane to ammonia is 1: 1.1 to 1: 5, preferably 1: 1.5 to 1: 3; the reaction temperature of the amination and oligomerization reaction is 40 to 200 ℃, preferably 80 ~ 160 ℃; reaction time is 0.5 ~ 10h; preferably 1 ~ 4h;

   In step (2), the molar ratio of carbon disulfide to dichloroalkane is 1: 1-3: 1; preferably the molar ratio is 1: 1-2: 1; the pH of the alkaline conditions is 9-13; preferably It is 9-12; the reaction temperature of the reaction is 10-100 ° C, preferably 30-80 ° C; the reaction time is 0.5-10h, preferably 1-4h.
9. The synthesis method according to claim 1, wherein the method comprises the following specific steps:

   (1) Using dichloroalkane and ammonia as reaction raw materials, after performing ammoniation and oligomerization under alkaline conditions, excess ammonia is removed;

   (2) Add carbon disulfide to the system obtained in step (1) and carry out the reaction under alkaline conditions;

   Wherein, the dichloroalkane is represented by the general formula I,

   (CH ₂ ) _n Cl ₂ Formula I

   Among them, n is 2-4;

   Preferably, the dichloroalkane is dichloroethane or dichloropropane;

   The ammonia is added in the form of an aqueous ammonia solution, an ammonia alcohol solution, or an ammonia alcohol-water mixture; preferably the alcohol is ethanol, propanol, or methanol; more preferably, the ammonia is an aqueous ammonia solution, and further preferably the mass concentration is 20-60% ammonia solution;

   After the ammoniation and oligomerization reaction, and before removing excess ammonia, the pH of the system is adjusted to be above 9.0; preferably 10.0 to 13.5; the removal of ammonia is performed at 60 to 160 ° C for 0.5 to 10 hours;

   The alkaline condition is adjusted by adding an alkaline substance, the alkaline substance is selected from at least one of sodium carbonate, ammonia, sodium hydroxide, potassium hydroxide, calcium hydroxide, magnesium hydroxide, the condition is the step ( The alkaline conditions in 2) cannot be adjusted by adding ammonia; preferably, the alkaline conditions in step (1) are adjusted by adding sodium carbonate and / or ammonia; the alkali in step (2) The sexual conditions are adjusted by adding sodium carbonate; the molar ratio of the dichloroalkane to the alkaline substance is 1: 0.1 to 1: 5, preferably 1: 1 to 1: 3

   In step (1), the molar ratio of the dichloroalkane to ammonia is 1: 1.1 to 1: 5, preferably 1: 1.5 to 1: 3 or 1: 1.1 to 1: 1.5 or 1: 1.5 to 1: 2 ; The reaction temperature of the amination and oligomerization reaction is 40 ~ 200 ℃, preferably 80 ~ 160 ℃; the reaction time is 0.5 ~ 10h; preferably 1 ~ 4h;

   In step (2), the molar ratio of carbon disulfide to dichloroalkane is 1: 1-3: 1; preferably the molar ratio is 1: 1-2: 1; the pH of the alkaline conditions is 9-13; preferably It is 9-12; the reaction temperature of the reaction is 10-100 ° C, preferably 30-80 ° C; the reaction time is 0.5-10h, preferably 1-4h.
10. A heavy metal removal preparation characterized by being prepared by the synthesis method according to any one of claims 1-6.
11. A heavy metal adsorbent, characterized in that the heavy metal adsorbent is an insoluble polymer resin prepared by a heavy metal removal preparation and a polymerization agent prepared by the synthesis method of any one of claims 1-9; preferably The polymerization agent is selected from one or more of dichloroethane, dichloropropane, dichlorobutane, glyoxal, glutaraldehyde, and epichlorohydrin.
12. Use of the heavy metal removal preparation prepared by the synthesis method according to any one of claims 1-9, the heavy metal removal preparation according to claim 10, or the heavy metal adsorbent according to claim 11 in removing heavy metals; Application of complexing heavy metals and capturing heavy metals in acid wastewater;

    Preferably, the heavy metal is one or more of nickel, copper, zinc, lead, cadmium, chromium, arsenic, antimony, mercury; most preferably nickel and / or copper.
13. The use according to claim 12, characterized in that the heavy metal removal preparation is used in an environment with a pH of 1-10; preferably the pH is 1-4.

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