Melamine polyamine polymer material, preparation method thereof and application thereof in thallium pollution treatment

Abstract

The application discloses a melamine polyamine high molecular material, a preparation method thereof and application of the melamine polyamine high molecular material in thallium pollution treatment. The melamine polyamine high molecular material has the following structural formula: the melamine polyamine high molecular material can resist high-temperature and acidic corrosion environment of smelting flue gas, has high trapping and adsorption capacity for thallium in the flue gas or wastewater, and can be widely applied to removal of thallium in various industrial flue gas and wastewater.

Description

TECHNICAL FIELD

[0001] The present application relates to a thallium adsorption material, in particular to a melamine polymer material and a preparation method thereof, and further relates to application of the melamine polymer material in flue gas and wastewater thallium removal, and belongs to the field of waste gas and wastewater treatment. BACKGROUND

[0002] Metallic thallium is a heavy metal that is extremely harmful to the ecological environment, and its toxicity even exceeds that of heavy metals mercury and lead, and it has the property of biological accumulation. Even if exposed to an environment containing only trace amounts of thallium, due to its accumulation property, it can cause great environmental harm after a long period of accumulation. Thallium is a mineral associated metal or a component of solid waste, such as lithium mica, spodumene, iron ore, lead-zinc ore, copper ore, fly ash, etc., especially in the process of high-temperature roasting, kiln or incineration, it enters the industrial flue gas, and further enters the water in the flue gas purification process. The treatment of metallic thallium in water is difficult, and the treatment requirements for thallium are relatively extremely strict, generally below a few ppb. At present, the treatment methods for metallic thallium in water include chemical precipitation, adsorption, biological preparation treatment, ion exchange, ultrafiltration and reverse osmosis, etc. Even if the treatment target requirements are met, the treatment cost is relatively high, which brings more and more economic pressure and environmental pressure to thallium-related production enterprises. The method of directly solidifying metallic thallium by gas phase adsorption is rarely used, and there is no report of industrial application. Therefore, it is of great practical significance to actively develop gas phase direct thallium removal, prevent a large amount of metallic thallium in the gas phase from mixing into water, and as much as possible avoid the high treatment cost of treating thallium-containing wastewater, for the environmental governance of metallic thallium and other heavy metals. SUMMARY

[0003] In view of the defects in the prior art, a first object of the present application is to provide a melamine polymer material, which has good thermal stability and good acid stability, and has high binding capacity for thallium, and can be used as a thallium adsorption material.

[0004] A second object of the present application is to provide a preparation method of the melamine polymer material, which is simple, has low raw material cost, and has mild process conditions, and is conducive to large-scale production.

[0005] A third object of the present application is to provide application of the melamine polymer material as a thallium adsorption material in flue gas or wastewater thallium removal. The melamine polymer material can withstand the high temperature, high dust and acidic corrosion environment of industrial flue gas, has a large specific surface area, and is rich in various types of amine groups, has high trapping and adsorption capacity for thallium in flue gas or wastewater, and the use method is simple, and can be widely applied to the removal of thallium in various smelting flue gas and industrial wastewater.

[0006] In order to realize the above technical purposes, the application provides a melamine polymer material with the following structural formula:

[0007]

[0008] wherein n=10-1000. Preferably, n=100-500.

[0009] The melamine polymer material contains a large number of primary amine, secondary amine and tertiary amine groups and triazacyclo groups with strong coordination ability, and the synergistic effect of the groups can produce coordination and chelation with thallium to form a stable thallium complex. The melamine polymer material is in the form of powder and has a high adsorption area, thereby showing high adsorption activity. Meanwhile, the melamine polymer material has stable chemical structure, good high-temperature resistance and acid corrosion resistance.

[0010] The application further provides a preparation method of the melamine polymer material. The method comprises adding ammonia water and dropwise adding a sodium hydroxide solution to perform a substitution reaction in a cyanuric chloride solution, and then adding p-phenylenediamine and dropwise adding a sodium hydroxide solution to perform a condensation reaction.

[0011] The application uses cyanuric chloride as a starting material, modifies the amino group on the triazine ring through a substitution reaction, and then further forms the melamine polymer material through condensation with p-phenylenediamine.

[0012] As a preferred scheme, the substitution reaction is performed at 30-70°C for 2-4 hours. In the preferred reaction condition, the amino group on the triazine ring is mainly monosubstituted.

[0013] As a preferred scheme, the condensation reaction is performed at 70-95°C for 2-4 hours.

[0014] The cyanuric chloride solution of the application is, for example, an acetone solution of cyanuric chloride.

[0015] As a preferred scheme, the molar ratio of cyanuric chloride to ammonia water is 1:1-1.05. If the ratio of ammonia water is too high, there is a multiple substitution side reaction of the amino group, and it is best to strictly react according to the stoichiometric ratio of 1:1.

[0016] As a preferred scheme, the mass percentage concentration of the sodium hydroxide solution is 15-25%, and the total amount is 3-4 equivalents.

[0017] As a preferred scheme, the molar ratio of p-phenylenediamine to cyanuric chloride is 1:1, and strictly reacting according to the stoichiometric ratio of 1:1 is beneficial to obtaining a polymer with high molecular weight.

[0018] The application also provides an application of the melamine polymer material, which is applied to flue gas or wastewater thallium removal as a thallium adsorption material.

[0019] As a preferred scheme, the adsorption material containing the melamine polymer material is sprayed into the flue gas pipeline to adsorb thallium in the flue gas. The adsorption material is previously gas fluidized.

[0020] As a preferred scheme, the adsorption material containing the melamine polymer material is directly added to the wastewater to adsorb thallium in the wastewater.

[0021] As a more preferred scheme, the adsorption material further contains auxiliary materials. For example, diatomite can increase the dispersion and absorption effect of the polymer material.

[0022] As a preferred scheme, the melamine polymer material is applied to the process of flue gas thallium removal as a thallium adsorption material, which involves the following simple flue gas thallium removal device and method. The flue gas thallium removal device mainly consists of a flue gas feeding device and a flue gas dust removal device. The feeding device can consist of a fan (1), a storage bin (2), a feeder (3), a mixer (4), a spraying pipe (5), and a flue (6), etc. The flue gas dust removal device can consist of a dust collector (7) and a discharge hopper (8), etc. The fan (1) is connected to the mixer (4) through a pipeline, the storage bin (2) is connected to the feeder (3) through a pipeline, the feeder (3) is connected to the mixer (4) through a pipeline, the mixer (4) is connected to the spraying pipe (5) through a pipeline, the spraying pipe (5) is connected to the flue (6), the flue (6) is connected to the dust collector (7), and the dust collector (7) is connected to the discharge hopper (8) through a pipeline. The adsorption material such as the melamine polymer material is previously stored in the storage bin (2), enters the mixer (4) through the feeder (3) and the connecting pipeline, the gas blown by the fan (1) enters the mixer (4), fluidizes the thallium removal powder material entering the mixer (4), and enters the flue gas pipeline (6) through the spraying pipe (5) together with the gas, mixes with the thallium-containing flue gas in the flue (6), efficiently adsorbs and chelates the thallium metal in the flue gas, forms stable chelates with the thallium metal, and is intercepted in the dust collector (7) to enter the discharge hopper (8). The excess adsorption material or the adsorption material not adsorbed to saturation can be discharged through the discharge hopper (8) and can be recycled to the storage bin (2) for reuse until the adsorption material is fully involved in the adsorption of thallium and other heavy metals and the adsorption approaches saturation. Finally, the adsorption material adsorbed to saturation is discharged from the discharge hopper (8) and is separately disposed. A small amount of adsorption material not completely intercepted by the dust collector can be treated through subsequent flue gas purification washing and filtering to achieve the goal of removing thallium and other metals from the flue gas.

[0023] The synthetic route of the melamine polymer material is specifically as follows:

[0024]

[0025] The special molecular structure of the melamine polymer material of the present application endows it with excellent physical and chemical properties such as high melting point and stability under acidic conditions, and it is in a powder state and has a high specific surface area, and has coordination chelation with thallium and other heavy metals in flue gas or wastewater, and shows strong trapping capacity.

[0026] The melamine polymer material of the present application can be used alone or in combination with other heavy metal adsorption materials.

[0027] Compared with the prior art, the technical scheme of the present application has the following technical effects:

[0028] 1) The melamine polymer material provided by the present application contains a large number of primary amine, secondary amine and tertiary amine groups and other electron-rich polar groups, and also contains a strong coordination ability of triazacyclic ring, and the synergistic effect between these groups can produce coordination and chelation with thallium and other heavy metals to form a stable thallium complex, and the melamine polymer material is in a powder state and has a high adsorption area, thereby showing high adsorption activity, and the chemical structure of the melamine polymer material is stable, has good high-temperature resistance and acid corrosion resistance, and is particularly suitable for trapping and removing thallium in flue gas or wastewater.

[0029] 2) The melamine polymer material can be used to directly and efficiently remove thallium in gas phase, so as to prevent thallium in flue gas from being transferred to wastewater in a large amount in the flue gas washing and purification process, thereby reducing the treatment difficulty and cost of thallium.

[0030] 3) The method for removing thallium in flue gas or wastewater by using the melamine polymer material has a simple process flow and simple equipment structure, and has good cost performance.

[0031] 4) The method for removing thallium in flue gas or wastewater by using the melamine polymer material does not produce new wastewater and exhaust gas, and does not cause secondary pollution.

[0032] 5) The preparation method of the melamine polymer material is simple, low in cost, and conducive to large-scale production. BRIEF DESCRIPTION OF DRAWINGS

[0033] Figure 1 It is a structure schematic view of the flue gas thallium removal device of the present application;

[0034] Among them, 1, fan; 2, storage bin; 3, feeder; 4, mixer; 5, material spraying pipe; 6, flue; 7, dust collector; 8, discharge hopper;

[0035] Figure 2 Molecular structure diagram of melamine-based polymer material prepared in Example 1;

[0036] Figure 3 Infrared spectrum diagram of melamine-based polymer material prepared in Example 1.

[0037] Figure 4 Thermogravimetric diagram of melamine-based polymer material prepared in Example 1. DETAILED DESCRIPTION

[0038] The technical solutions of the present application will be described clearly and completely in combination with specific embodiments. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all the other embodiments obtained by those skilled in the art without creative labor fall within the protection scope of the present application.

[0039] Example 1

[0040] Synthesis method of melamine-based polymer material: under stirring, ammonia water (1N, industrial ammonia water) is added to a solution (acetone, 1 mol / L) of cyanuric chloride (1N) at a temperature of 5℃, then 20% sodium hydroxide solution (1N) is added dropwise and reacted at 50℃ for 3 hours; under stirring, p-phenylenediamine (1N) is added to the above reaction system, then 20% sodium hydroxide solution (2N) is added dropwise, and reacted at 90℃ for 3.5 hours, after cooling, filtration, washing and drying, the melamine-based polymer material is obtained as a white or light yellow powder, with a molecular weight of about 24000 and a melting point of >300℃.

[0041]

[0042] The structural schematic diagram of the smoke thallium removal device of the present application is as shown in Figure 1As shown: mainly by fan 1, storage bin 2, feeder 3, mixer 4, spray pipe 5, flue 6, dust collector 7, discharge hopper 8 etc. The fan 1 is connected with the mixer 4 through the pipeline, the storage bin 2 is connected with the feeder 3 through the pipeline, the feeder 3 is connected with the mixer 4 through the pipeline, the mixer 4 is connected with the spray pipe 5 through the pipeline, the spray pipe 5 is connected with the flue 6, the flue 6 is connected with the dust collector 7, and the dust collector 7 is connected with the discharge hopper 8 through the pipeline. The thallium-removing powder material is stored in the storage bin 2 in advance, enters the mixer 4 through the feeder 3 and the connecting pipeline, the air blown by the fan 1 enters the mixer 4, the thallium-removing powder material entering the mixer 4 is fluidized, and enters the flue 6 through the spray pipe 5 together with the air, mixes with the thallium-containing flue gas in the flue 6, the thallium-removing powder material efficiently absorbs thallium metal in the flue gas, and forms a stable chelate complex with the thallium metal, and is intercepted in the dust collector 7, enters the discharge hopper 8, and the excess thallium-removing powder material and the unsaturated thallium-removing powder material are discharged through the discharge hopper 8, can be returned to the storage bin 2 for recycling, until the thallium-removing powder material participates in the absorption of thallium metal as much as possible and is nearly saturated, and finally is discharged by the discharge hopper 8, and the powder material containing thallium metal and other heavy metals is disposed separately.

[0043] The specific operation process of the present application is as follows:

[0044] The thallium-removing powder material is stored in the storage bin 2 in advance, enters the mixer 4 through the feeder 3 and the connecting pipeline, the air blown by the fan 1 enters the mixer 4, the thallium-removing powder material entering the mixer 4 is fluidized, and enters the flue 6 through the spray pipe 5 together with the air, mixes with the thallium-containing flue gas in the flue 6, the thallium-removing powder material efficiently absorbs thallium metal in the flue gas, and forms a stable chelate complex with the thallium metal, and is intercepted in the dust collector 7, enters the discharge hopper 8, and the excess thallium-removing powder material and the unsaturated thallium-removing powder material are discharged through the discharge hopper 8, can be returned to the storage bin 2 for recycling, until the thallium-removing powder material participates in the absorption of thallium metal as much as possible and is nearly saturated, and finally is discharged by the discharge hopper 8, and the powder material containing thallium metal and other heavy metals is disposed separately.

[0045] Example 2

[0046] The device and method for flue gas thallium removal in this embodiment specifically include the following steps:

[0047] (1) The thallium-removing powder material (the melamine-based polymer powder prepared in Example 1) is stored in the storage bin in advance.

[0048] (2) Open the feeder, and the thallium-removing powder material enters the mixer through the connecting pipeline.

[0049] (3) Start the air blower to blow air into the mixer, fluidize the thallium removal powder material entering the mixer, and pass it into the flue through the injection pipe together with the air (the injection amount of the material is 50 mg / Nm 3 ), mix with the lead smelting flue gas containing 1.0 mg / Nm 3 of thallium and having a temperature of about 293°C, and the thallium removal powder material efficiently absorbs the thallium metal in the flue gas and forms a stable chelate complex with it, which is intercepted in the dust collector.

[0050] (4) The thallium content in the flue gas after the gas phase thallium removal treatment is reduced to 0.040 mg / Nm 3 , and the removal efficiency reaches 96.0%.

[0051] (5) The powder thallium removal material adsorbing thallium in the dust collector is collected into the discharge hopper, and excess thallium removal powder material and unsaturated thallium removal powder material not adsorbed are discharged through the discharge hopper.

[0052] (6) The powder material discharged from the discharge hopper can be returned to the storage bin for recycling until the thallium removal powder material is fully involved in the adsorption of thallium heavy metal and is close to saturation, and then is finally discharged from the discharge hopper. The powder material containing thallium metal is disposed separately.

[0053] Example 3

[0054] This example adopts a device and method for flue gas thallium removal, which specifically includes the following steps:

[0055] (1) The thallium removal powder material (60% of the melamine polymer powder prepared in Example 1 + 40% of the DBA powder (existing heavy metal removal polymer material)) is pre-stored in the storage bin.

[0056] (2) Start the feeder to pass the thallium removal powder material into the mixer through the connecting pipeline.

[0057] (3) Start the air blower to blow air into the mixer, fluidize the thallium removal powder material entering the mixer, and pass it into the flue through the injection pipe together with the air (the injection amount of the material is 35 mg / Nm 3 ), mix with the lithium mica sintering flue gas containing 0.269 mg / Nm 3 of thallium and having a temperature of about 350°C, and the thallium removal powder material efficiently absorbs the thallium metal in the flue gas and forms a stable chelate complex with it, which is intercepted in the dust collector.

[0058] (4) The thallium content in the flue gas after the gas phase thallium removal treatment is reduced to 0.007 mg / Nm 3 , and the removal efficiency reaches 97.4%.

[0059] (5) The powder of the dust collector adsorbed with thallium is collected into the discharge hopper, and the excess of the thallium-removing powder and the unsaturated thallium-removing powder are discharged through the discharge hopper.

[0060] (6) When the powder discharged from the discharge hopper can be returned to the storage bin for recycling, the thallium-removing powder is used until it is saturated, and then the powder containing thallium is disposed of separately.

[0061] Example 4

[0062] The embodiment adopts a method for removing thallium from wastewater, which specifically comprises the following steps:

[0063] (1) The thallium-removing powder is stored in the storage bin in advance.

[0064] (2) The discharger is opened, and the thallium-removing powder (1.0 g / l) prepared in Example 1 is added to the steel smelting sintering wastewater containing thallium (thallium content: 0.3 mg / l) for desulfurization. The thallium-removing powder efficiently adsorbs the thallium metal in the wastewater and forms a stable chelate complex with the thallium metal, which is intercepted in the dust collector.

[0065] (3) The thallium content in the wastewater after the thallium removal treatment is reduced to less than 5 μg / l, and the removal efficiency reaches 98.3%.

[0066] The above is only the preferred embodiment of the present application, and does not limit the patent scope of the present application. Any equivalent structure, pipeline and process transformation made according to the content of the present application, or direct / indirect application in other related technical fields within the concept of the present application are included in the patent protection scope of the present application.

Claims

1. Use of melamine-based polymeric material, characterized in that: Melamine polymer material is applied to flue gas or wastewater thallium removal as thallium adsorption material; The melamine polymer material has the following structural formula: ； Wherein, n=10~1000.

2. Use of melamine-based polymer material according to claim 1, characterized in that: The melamine polymer material is prepared by the following method: in cyanuric chloride solution, first add ammonia water and drop sodium hydroxide solution to carry out substitution reaction, then add p-phenylenediamine and drop sodium hydroxide solution to carry out condensation reaction.

3. Use of melamine-based polymer material according to claim 2, characterized in that: The substitution reaction conditions are: reaction at 30~70℃ for 1~4 hours.

4. The use of melamine-based polymer material according to claim 2, characterized in that: The condensation reaction conditions are: reaction at 70~95℃ for 1~4 hours.

5. The use of a melamine-based polymer material according to claim 1, characterized in that: The adsorption material containing melamine polymer material is sprayed into the flue gas pipeline to adsorb thallium in the flue gas.

6. The use of a melamine-based polymer material according to claim 1, characterized in that: The adsorption material containing melamine polymer material is directly added to wastewater to adsorb thallium in the wastewater.

7. The use of melamine-based polymer material according to claim 1, characterized in that: The adsorption material further contains auxiliary materials.

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