Resourceful treatment method for reducing heavy metal content of coal gangue

Abstract

The invention discloses a resourceful treatment method for reducing the heavy metal content of coal gangue in the field of resourceful treatment of coal gangue. The ZIF-8 nano particles in the self-made Fe3O4 / ZIF-8 nano composite material have rhombic dodecahedron shapes, Fe3O4 particles are gathered to form approximately spherical clusters, and the ZIF-8 nano particles can be embedded into the porous structure of the Fe3O4 clusters, so that the specific surface area of the composite material is increased, the porous structure and the high specific surface area of the composite material provide a large number of physical adsorption sites, and the adsorption efficiency of the composite material is improved. The heavy metal ions can be adsorbed through Van der Waals' force and other physical adsorption effects, then through biological synergistic treatment with ryegrass, the heavy metal content in the coal gangue is reduced, the heavy metal content of the treated coal gangue is greatly reduced, the coal gangue can be used for preparation of biological organic soil and soil conditioners, and resourceful treatment is achieved.

Description

Technical Field

[0001] The invention belongs to the field of coal gangue resource processing, and in particular relates to a resource processing method for reducing the heavy metal content of coal gangue. Background Art

[0002] Gangue is a common solid waste, mainly produced during coal mining and washing. Gangue contains a certain amount of heavy metals, such as lead, mercury, cadmium, etc., which may cause harm to the human body and the environment. Therefore, it is necessary to find an effective method to reduce or remove heavy metals in gangue. Therefore, it is necessary to propose a resource treatment method for reducing the heavy metal content of gangue. Summary of the invention

[0003] In view of the above situation, in order to overcome the defects of the prior art, the present invention provides a resource treatment method for reducing the heavy metal content of coal gangue, by treating coal gangue with the biological synergy of homemade Fe3O4 / ZIF-8 nanocomposite material and ryegrass to reduce the heavy metal content in coal gangue.

[0004] In order to achieve the above object, the following technical scheme is adopted: The present invention provides a resource processing method for reducing the heavy metal content of coal gangue, and the method comprises the following steps:

[0005] (1) Na2SO3 and FeCl3·6H2O were added to deionized water at the same time, stirred for 1 h under nitrogen protection, and then 20 mol / L sodium hydroxide solution was added dropwise. After stirring for 5 min, the black product was collected with a magnet, and then washed with deionized water and ethanol for 3 times, and vacuum dried at 60°C for 12 h to obtain Fe3O4 nanoparticles;

[0006] (2) The Fe3O4 nanoparticles were dispersed in methanol at room temperature, followed by addition of polyvinyl pyrrolidone, stirring at 300 rpm for 20 min, and then adding 20 mg / mL of a methanol solution of Zn(NO3)2·6H2O and 60 mg / mL of a methanol solution of 2-methylimidazole, stirring for 24 h, collecting the black product with a magnet, and then washing with deionized water and ethanol for 3 times, and vacuum drying at 60°C for 12 h to obtain a Fe3O4 / ZIF-8 nanocomposite material;

[0007] (3) Sterilize part of the coal gangue for 48 hours to obtain sterilized coal gangue for use, mix the coal gangue, sterilized coal gangue, fungus residue, Fe3O4 / ZIF-8 nanocomposite material, straw, phosphogypsum and riverbed mud evenly, and lay them on a 100-mesh nylon cloth to obtain a matrix layer, and sow ryegrass seeds in the matrix layer.

[0008] Furthermore, in the step (1), the mass ratio of Na2SO3, FeCl3·6H2O, deionized water and sodium hydroxide solution is 1.5-2.5:16-25:200-300:1-5.

[0009] Furthermore, in the step (1), the mass ratio of Fe3O4 nanoparticles, methanol, polyvinyl pyrrolidone, methanol solution of Zn(NO3)2·6H2O, and methanol solution of 2-methylimidazole is 1-5:25-40:0.1-0.5:10-20:10-20.

[0010] Furthermore, the matrix layer includes the following components in parts by weight: 65-85 parts of coal gangue, 10-15 parts of sterilized coal gangue, 5-15 parts of fungus residue, 8-12 parts of Fe3O4 / ZIF-8 nanocomposite material, 10-15 parts of straw, 10-15 parts of phosphogypsum, and 15-20 parts of riverbed mud.

[0011] Furthermore, the thickness of the matrix layer is 12-15 cm.

[0012] Furthermore, the straw is a combination of one or more of corn straw, soybean straw, and sweet potato straw.

[0013] Furthermore, the sterilization process of the coal gangue is as follows: soaking in a solution containing 5-10% sodium formate and 10-12% alcohol for 30-60 minutes.

[0014] The beneficial effects of the present invention are as follows: the present invention provides a resource-based treatment method for reducing the heavy metal content of coal gangue. The invention uses a self-made Fe3O4 / ZIF-8 nanocomposite material in which ZIF-8 nanoparticles have a rhombic dodecahedral shape, and Fe3O4 particles aggregate to form approximately spherical clusters, while ZIF-8 nanoparticles can be embedded in the porous structure of the Fe3O4 clusters, thereby increasing the specific surface area of ​​the composite material. The porous structure and high specific surface area provide a large number of physical adsorption sites, so that heavy metal ions can be adsorbed through physical adsorption such as van der Waals forces, and then through biological synergistic treatment with ryegrass, the heavy metal content in the coal gangue is reduced. The heavy metal content of the treated coal gangue is greatly reduced, and the coal gangue can be used for the preparation of biological organic soil and soil conditioner, thereby realizing resource-based treatment. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 These are the test results of As, Pb, Zn and Ni contents in the soil 100 days after ryegrass seeds were planted in Examples 1-3 and Comparative Example 1.

[0016] The accompanying drawings are used to provide further understanding of the present invention and constitute a part of the specification. They are used to explain the present invention together with the embodiments of the present invention and do not constitute a limitation of the present invention. DETAILED DESCRIPTION

[0017] The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0018] Unless otherwise defined, all professional and scientific terms used herein have the same meanings as those familiar to those skilled in the art. In addition, any methods and materials similar or equivalent to those described herein may be applied to the present invention. The preferred implementation methods and materials described herein are for demonstration purposes only and are not intended to limit the content of this application.

[0019] The experimental methods in the following examples are conventional methods unless otherwise specified, and the experimental materials used in the following examples are purchased from commercial channels unless otherwise specified.

[0020] Example 1

[0021] A resource processing method for reducing heavy metal content in coal gangue

[0022] The method comprises the following steps:

[0023] (1) Na2SO3 and FeCl3·6H2O were added to deionized water at the same time, stirred for 1 h under nitrogen protection, and then 20 mol / L sodium hydroxide solution was added dropwise. After stirring for 5 min, the black product was collected with a magnet, and then washed with deionized water and ethanol for 3 times, and vacuum dried at 60°C for 12 h to obtain Fe3O4 nanoparticles;

[0024] (2) The Fe3O4 nanoparticles were dispersed in methanol at room temperature, followed by addition of polyvinyl pyrrolidone, stirring at 300 rpm for 20 min, and then adding 20 mg / mL of a methanol solution of Zn(NO3)2·6H2O and 60 mg / mL of a methanol solution of 2-methylimidazole, stirring for 24 h, collecting the black product with a magnet, and then washing with deionized water and ethanol for 3 times, and vacuum drying at 60°C for 12 h to obtain a Fe3O4 / ZIF-8 nanocomposite material;

[0025] (3) Sterilize part of the coal gangue for 48 hours to obtain sterilized coal gangue for use, mix the coal gangue, sterilized coal gangue, fungus residue, Fe3O4 / ZIF-8 nanocomposite material, straw, phosphogypsum and riverbed mud evenly, and lay them on a 100-mesh nylon cloth to obtain a matrix layer, and sow ryegrass seeds in the matrix layer.

[0026] In the step (1), the mass ratio of Na2SO3, FeCl3·6H2O, deionized water and sodium hydroxide solution is 1.5:16:200:1.

[0027] In the step (1), the mass ratio of Fe3O4 nanoparticles, methanol, polyvinyl pyrrolidone, methanol solution of Zn(NO3)2·6H2O, and methanol solution of 2-methylimidazole is 1:25:0.1:10:10.

[0028] The matrix layer comprises the following components in parts by weight: 65 parts of coal gangue, 10 parts of sterilized coal gangue, 5 parts of fungus residue, 8 parts of Fe3O4 / ZIF-8 nanocomposite material, 10 parts of straw, 10 parts of phosphogypsum and 15 parts of riverbed mud.

[0029] The thickness of the matrix layer is 12 cm.

[0030] The straw is corn straw.

[0031] The sterilization process of the coal gangue is as follows: soaking in a solution containing 5% sodium formate and 10% alcohol for 30 minutes.

[0032] Example 2

[0033] A resource processing method for reducing heavy metal content in coal gangue

[0034] The steps included in the method are the same as those in Example 1.

[0035] In the step (1), the mass ratio of Na2SO3, FeCl3·6H2O, deionized water and sodium hydroxide solution is 2.5:25:300:5.

[0036] In the step (1), the mass ratio of Fe3O4 nanoparticles, methanol, polyvinyl pyrrolidone, methanol solution of Zn(NO3)2·6H2O, and methanol solution of 2-methylimidazole is 5:40:0.5:20:20.

[0037] The matrix layer comprises the following components in parts by weight: 85 parts of coal gangue, 15 parts of sterilized coal gangue, 15 parts of fungus residue, 12 parts of Fe3O4 / ZIF-8 nanocomposite material, 15 parts of straw, 15 parts of phosphogypsum and 20 parts of riverbed mud.

[0038] The thickness of the matrix layer is 15 cm.

[0039] The straw is soybean straw.

[0040] The sterilization process of the coal gangue is as follows: soaking in a solution containing 10% sodium formate and 12% alcohol for 60 minutes.

[0041] Example 3

[0042] A resource processing method for reducing heavy metal content in coal gangue

[0043] The steps included in the method are the same as those in Example 1.

[0044] In the step (1), the mass ratio of Na2SO3, FeCl3·6H2O, deionized water and sodium hydroxide solution is 2:20:250:4.

[0045] In the step (1), the mass ratio of Fe3O4 nanoparticles, methanol, polyvinyl pyrrolidone, methanol solution of Zn(NO3)2·6H2O, and methanol solution of 2-methylimidazole is 2:30:0.4:15:15.

[0046] The matrix layer comprises the following components in parts by weight: 70 parts of coal gangue, 12 parts of sterilized coal gangue, 10 parts of fungus residue, 10 parts of Fe3O4 / ZIF-8 nanocomposite material, 12 parts of straw, 12 parts of phosphogypsum and 18 parts of riverbed mud.

[0047] The thickness of the matrix layer is 13 cm.

[0048] The straw is a combination of corn straw, soybean straw and sweet potato straw in a mass ratio of 2:1:1.

[0049] The sterilization process of the coal gangue is as follows: soaking in a solution containing 8% sodium formate and 44% alcohol for 50 minutes.

[0050] Comparative Example 1

[0051] The difference between this comparative example and Example 1 is that the matrix layer does not contain the Fe3O4 / ZIF-8 nanocomposite material, and the remaining components and component contents are the same as those in Example 1.

[0052] Results Analysis

[0053] Inductively coupled plasma mass spectrometry was used to detect As, Pb, Zn and Ni in the soil of Examples 1-3 and Comparative Example 1 100 days after ryegrass seeds were planted. The results are shown in Figure 1 .

[0054] pass Figure 1 It can be seen that the treatment method of the present invention can effectively reduce the contents of As, Pb, Zn and Ni in the soil, proving that the treatment effect of the Fe3O4 / ZIF-8 nanocomposite material is effective.

[0055] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

[0056] The present invention and its implementation methods are described above, which is not restrictive. The drawings are only one of the implementation methods of the present invention, and the actual application is not limited thereto. In short, if ordinary technicians in the field are inspired by it and design methods and embodiments similar to the technical solution without creativity without departing from the purpose of the invention, they should all fall within the protection scope of the present invention.

Claims

1. A resource treatment method for reducing the heavy metal content of coal gangue, characterized in that: The method comprises the following steps: (1) Na2SO3 and FeCl3·6H2O were added to deionized water at the same time, stirred for 1 h under nitrogen protection, and then 20 mol / L sodium hydroxide solution was added dropwise. After stirring for 5 min, the black product was collected with a magnet, and then washed with deionized water and ethanol for 3 times, and vacuum dried at 60°C for 12 h to obtain Fe3O4 nanoparticles; (2) The Fe3O4 nanoparticles were dispersed in methanol at room temperature, followed by addition of polyvinyl pyrrolidone, stirring at 300 rpm for 20 min, and then adding 20 mg / mL of a methanol solution of Zn(NO3)2·6H2O and 60 mg / mL of a methanol solution of 2-methylimidazole, stirring for 24 h, collecting the black product with a magnet, and then washing with deionized water and ethanol for 3 times, and vacuum drying at 60°C for 12 h to obtain a Fe3O4 / ZIF-8 nanocomposite material; (3) Sterilize part of the coal gangue for 48 hours to obtain sterilized coal gangue for use, mix the coal gangue, sterilized coal gangue, fungus residue, Fe3O4 / ZIF-8 nanocomposite material, straw, phosphogypsum and riverbed mud evenly, and lay them on a 100-mesh nylon cloth to obtain a matrix layer, and sow ryegrass seeds in the matrix layer.

2. The resource processing method for reducing the heavy metal content of coal gangue according to claim 1 is characterized in that: In the step (1), the mass ratio of sodium sulfite, ferric chloride hexahydrate, deionized water and sodium hydroxide solution is 1.5-2.5:16-25:200-300:1-5.

3. A resource processing method for reducing the heavy metal content of coal gangue according to claim 2, characterized in that: In the step (1), the mass ratio of Fe3O4 nanoparticles, methanol, polyvinyl pyrrolidone, methanol solution of Zn(NO3)2·6H2O, and methanol solution of 2-methylimidazole is 1-5:25-40:0.1-0.5:10-20:10-20.

4. The resource processing method for reducing the heavy metal content of coal gangue according to claim 3 is characterized in that: The matrix layer comprises the following components in parts by weight: 65-85 parts of coal gangue, 10-15 parts of sterilized coal gangue, 5-15 parts of fungus residue, 8-12 parts of Fe3O4 / ZIF-8 nanocomposite material, 10-15 parts of straw, 10-15 parts of phosphogypsum and 15-20 parts of riverbed mud.

5. A resource processing method for reducing the heavy metal content of coal gangue according to claim 4, characterized in that: The thickness of the matrix layer is 12-15 cm.

6. A resource processing method for reducing the heavy metal content of coal gangue according to claim 5, characterized in that: The straw is a combination of one or more of corn straw, soybean straw and sweet potato straw.

7. A resource processing method for reducing the heavy metal content of coal gangue according to claim 6, characterized in that: The sterilization process of the coal gangue is as follows: soaking in a solution containing 5-10% sodium formate and 10-12% alcohol for 30-60 minutes.

Images