Zinc and cobalt loaded coal gangue composite material as well as preparation method and application thereof

Abstract

The invention belongs to the technical field of catalytic materials, and particularly relates to a zinc and cobalt loaded coal gangue composite material as well as a preparation method and application thereof. The composite material comprises coal gangue as a carrier, and zinc and cobalt loaded on the coal gangue, the molar ratio of zinc to cobalt is 1: (1-3). The preparation method comprises the following steps: impregnating coal gangue powder in a solution containing zinc ions and cobalt ions, then carrying out solid-liquid separation, drying the obtained solid in a drying oven, and grinding to obtain the zinc and cobalt loaded doped coal gangue composite material. The catalyst can realize rapid degradation of floxacin antibiotics, and realizes efficient removal of antibiotics in a water environment through dual effects of adsorption and degradation.

Description

Technical Field

[0001] The invention belongs to the technical field of catalytic materials, and in particular relates to a zinc- and cobalt-loaded coal gangue composite material and a preparation method and application thereof. Background Art

[0002] Floxacin antibiotics are a class of broad-spectrum antimicrobial drugs, such as ciprofloxacin, levofloxacin and norfloxacin, which are widely used in the medical field to treat various bacterial infections. However, the degradation of these drugs in the environment may cause environmental pollution and ecological problems. The residues of floxacin antibiotics in water and soil may have a negative impact on aquatic organisms and soil microorganisms, and may even lead to the spread of drug resistance. Therefore, it is of great significance to develop an effective treatment technology and materials to solve this problem.

[0003] At present, there are biological technology, physical technology, and advanced oxidation technology for the degradation of oxazolidinone antibiotics. Although these technologies can remove oxazolidinone antibiotics to a certain extent, there are still many challenges. For example, the degradation rate of biological technology is slow and may produce drug-resistant bacteria; although physical technology is effective, it is costly and cannot fundamentally degrade organic matter. Chemical technology, especially advanced oxidation technology (AOPs), can generate reactive oxygen species (ROS) such as sulfate radicals (SO) by activating persulfates (permonosulfate (PMS) and peroxydisulfate (PDS)). 4 •−), hydroxyl radical (•OH), superoxide radical (O 2 •−) and singlet oxygen ( 1 O 2 ) to degrade xacin antibiotics. Among them, the persulfate technology has a low pollutant removal efficiency at room temperature due to the stable chemical properties of PMS. In order to quickly degrade pollutants, appropriate methods are often used to activate PMS to promote SO 4 •- production can improve the degradation effect.

[0004] Coal gangue is waste rock discharged during the coal mining process. It is a gray-black rock with a lower carbon content and harder than coal. It has a higher ash, volatile and sulfur content, so it cannot be directly used in industrial production and has become an environmental pollutant that is difficult to treat. The main components of coal gangue include Al 2 O 3 and SiO 2 , and varying amounts of Fe 2 O 3 , CaO, MgO, Na 2 O.K 2 O.P 2 O 5 、SO 3and trace rare elements. These components make coal gangue have a variety of potential utilization values. Therefore, if coal gangue can be used as a resource to prepare composite materials with specific functions, it can not only solve environmental problems, but also realize the resource utilization of the environment. Summary of the invention

[0005] The purpose of the present invention is to provide a zinc and cobalt loaded coal gangue composite material and a preparation method and application thereof, so as to solve the problem that the degradation effect of peroxymonosulfate is low when degrading floxacin antibiotics.

[0006] The present invention is achieved through the following technical solutions: The invention discloses a zinc- and cobalt-loaded coal gangue composite material, comprising coal gangue as a carrier, and zinc and cobalt loaded on the coal gangue; The molar ratio of zinc to cobalt is 1:1-3.

[0007] Furthermore, the total molar mass ratio of metallic zinc and cobalt to the mass of coal gangue is (2-4)M:(5-10)g.

[0008] The present invention also discloses a method for preparing the zinc and cobalt loaded coal gangue composite material, comprising the following steps: dissolving a zinc source and a cobalt source in deionized water to form a mixed solution; The ground gangue powder is immersed in the mixed solution, and after magnetic stirring, solid-liquid separation is performed, the solid matter is filtered and washed, and dried at 100-120° C. for 8-12 hours, and after grinding, a gangue composite material loaded with metal zinc and cobalt is obtained.

[0009] Further, magnetic stirring was performed for 8-12 h.

[0010] Further, the coal gangue is ground to 100-200 mesh.

[0011] Furthermore, the zinc source is zinc chloride, zinc nitrate or zinc sulfate.

[0012] Furthermore, the cobalt source is cobalt nitrate.

[0013] The present invention also discloses the use of the zinc and cobalt loaded coal gangue composite material as a catalyst in activating persulfate to degrade organic pollutants in polluted water. The zinc and cobalt loaded coal gangue composite material is mixed with polluted water containing organic pollutants for pre-adsorption. After the pre-adsorption, persulfate is added to the polluted water to catalyze the degradation of organic pollutants.

[0014] Compared with the prior art, the present invention has the following beneficial technical effects: The invention discloses a zinc- and cobalt-loaded coal gangue composite material. The industrial waste coal gangue is used as a raw material to prepare the zinc- and cobalt-loaded coal gangue composite material, which greatly reduces the cost, realizes the resource utilization of waste, and also achieves the environmental protection goal of treating waste with waste. The coal gangue is used as a carrier, zinc and cobalt are loaded on the coal gangue, and the doping of metallic zinc and cobalt elements makes the ZnCo@CG catalytic material provided by the invention have a high specific surface area and rich functional groups. The coal gangue composite material has good stability and reusability, and is easy to separate from the treated water and reuse.

[0015] The present invention also discloses a method for preparing a zinc and cobalt loaded coal gangue composite material, wherein the composite material is chemically composited with zinc source, cobalt source and coal gangue as main raw materials. Coal gangue powder is impregnated in a solution containing zinc ions and cobalt ions, and then solid-liquid separation is performed. The obtained solid is dried and ground to obtain a zinc and cobalt loaded doped coal gangue composite material. The use of industrial waste coal gangue as a raw material to prepare a catalyst greatly reduces the cost, realizes the resource utilization of waste, and also achieves the environmental protection goal of treating waste with waste. The preparation process is simple, does not require high-end equipment, and is easy to promote and apply.

[0016] The application of the zinc and cobalt loaded coal gangue composite material prepared by the present invention as a catalyst in activating persulfate to degrade organic pollutants in polluted water bodies, using metal zinc and cobalt modified coal gangue as a catalyst, oxygen-containing functional groups on the surface of the coal gangue exist on the surface of the catalytic material, which is conducive to the adsorption and further reaction of pollutants and persulfate at its surface interface, can efficiently activate persulfate to generate sulfate radicals, and significantly improve the removal efficiency of difficult-to-degrade organic matter such as norfloxacin. No secondary pollution will be generated in the whole process, which meets the principle requirements of green chemistry. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 Infrared images of coal gangue and metal zinc-cobalt modified coal gangue composite materials; Figure 2 The adsorption of norfloxacin contaminated liquid by different catalyst materials changes with time; Figure 3 The degradation of norfloxacin contaminated liquid by different catalyst materials changes over time; Figure 4 This is a diagram of the degradation cycle experiment of the catalyst material in Example 2 on norfloxacin contaminated liquid. DETAILED DESCRIPTION

[0018] In order to make the purpose, technical solution and advantages of the present invention more clear, the following is further described in detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention, that is, the embodiments described are only part of the embodiments of the present invention, not all embodiments.

[0019] The detailed description of the embodiments of the present invention provided in the following drawings is not intended to limit the scope of the invention claimed for protection, but merely represents a selected embodiment of the present invention. Based on the drawings and embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present invention.

[0020] It should be noted that the terms "comprises", "includes" or any other variations are intended to cover non-exclusive inclusion, so that a process, element, method, article or equipment that includes a series of elements includes not only those elements, but also includes other elements not explicitly listed, or also includes elements inherent to the process, element, method, article or equipment.

[0021] The features and performances of the present invention are further described in detail below in conjunction with the embodiments.

[0022] Unless otherwise specified, the present invention has no special requirements on the sources of the raw materials used in the preparation, and commercially available products known to those skilled in the art can be used.

[0023] The metal zinc and cobalt loaded coal gangue composite material provided by the invention comprises coal gangue with rich pore structure and metal zinc and cobalt loaded on the surface and in the pores of the coal gangue.

[0024] The present invention also provides a method for preparing the composite material loaded with metal zinc and cobalt, comprising the following steps: The gangue powder is impregnated in a solution containing a zinc source and a cobalt source, and after drying, the gangue powder with zinc ions and cobalt ions attached thereto is obtained.

[0025] In some specific embodiments of the present invention, the coal gangue is selected from Datong Mine in Shanxi Province, and the composition table of the coal gangue is shown in Table 1.

[0026] Table 1 Composition of coal gangue

[0027] The features and performances of the present invention are further described in detail below in conjunction with the embodiments.

[0028] Embodiment 1: This example provides a method for preparing a zinc and cobalt loaded coal gangue catalytic material, comprising the following steps: (1) Prepare 50 mL of a mixed solution by mixing 0.6815 g (0.1 M) zinc chloride and 1.4551 g (0.1 M) cobalt nitrate hexahydrate; (2) Add 5 g of coal gangue powder to the mixed solution; (3) The mixed solution was placed under magnetic stirring at room temperature for 12 h, dried in an oven at 110 °C, and ground to obtain a zinc and cobalt loaded coal gangue catalytic material, denoted as ZnCo@CG.

[0029] Embodiment 2: This example provides a method for preparing a zinc and cobalt loaded coal gangue catalytic material, comprising the following steps: (1) Prepare 50 mL of a mixed solution of 0.9468 g (0.1 M) zinc nitrate and 2.9103 g (0.2 M) cobalt nitrate hexahydrate; (2) Add 5 g of coal gangue powder to the mixed solution; (3) The mixed solution was placed under magnetic stirring at room temperature for 8 h, dried in an oven at 120 °C, and ground to obtain a zinc and cobalt loaded coal gangue catalytic material, denoted as ZnCo@CG.

[0030] Embodiment 3: This example provides a method for preparing a zinc and cobalt loaded coal gangue catalytic material, comprising the following steps: (1) Prepare 50 mL of a mixed solution by mixing 0.6815 g (0.1 M) zinc chloride and 4.3654 g (0.3 M) cobalt nitrate hexahydrate; (2) Add 5 g of coal gangue powder to the mixed solution; (3) The mixed solution was placed under magnetic stirring at room temperature for 12 h, dried in an oven at 120 °C, and ground to obtain a zinc and cobalt loaded coal gangue catalytic material, denoted as ZnCo@CG.

[0031] Embodiment 4: This example provides a method for preparing a zinc and cobalt loaded coal gangue catalytic material, comprising the following steps: (1) Prepare 50 mL of a mixed solution by mixing 0.6815 g (0.1 M) zinc chloride and 2.9103 g (0.2 M) cobalt nitrate hexahydrate; (2) Add 10 g of coal gangue powder to the mixed solution; (3) The mixed solution was placed under magnetic stirring at room temperature for 10 h, dried in an oven at 120 °C, and ground to obtain a zinc and cobalt loaded coal gangue catalytic material, denoted as ZnCo@CG.

[0032] Embodiment 5: This example provides a method for preparing a zinc and cobalt loaded coal gangue catalytic material, comprising the following steps: (1) Prepare 50 mL of a mixed solution by mixing 0.6815 g (0.1 M) zinc chloride and 2.9103 g (0.2 M) cobalt nitrate hexahydrate; (2) Add 5 g of coal gangue powder to the mixed solution; (3) The mixed solution was placed under magnetic stirring at room temperature for 8 h, dried in an oven at 100 °C, and ground to obtain a zinc and cobalt loaded coal gangue catalytic material, denoted as ZnCo@CG.

[0033] Comparative Example 1: The difference from Example 1 is that the coal gangue is washed, ground and dried to obtain a pure coal gangue catalyst. The rest of the contents are consistent with Example 1.

[0034] Comparative Example 2: This example provides a method for preparing a zinc-loaded coal gangue catalytic material, comprising the following steps: (1) Prepare 50 mL of solution with 0.6815 g (0.1 M) zinc chloride; (2) Add 5 g of coal gangue powder to the solution; (3) The mixed solution was placed under magnetic stirring at room temperature for 12 h, and then dried in an oven at 120° C. to obtain a zinc-loaded coal gangue catalyst material.

[0035] Comparative Example 3: This example provides a method for preparing a cobalt-loaded coal gangue catalytic material, comprising the following steps: (1) Prepare 50 mL of solution by adding 2.9103 g (0.2 M) cobalt nitrate hexahydrate; (2) Add 5 g of coal gangue powder to the solution; (3) The mixed solution was placed under magnetic stirring and impregnated at room temperature for 12 h, and then dried in an oven at 120° C. to obtain a cobalt-loaded coal gangue catalyst material.

[0036] Application Example 1: The norfloxacin aqueous solution with a concentration of 20mg / L was prepared with deionized water, 100mL was taken in a conical flask, and 40mg of the coal gangue composite material of the load zinc and cobalt prepared in Examples 1-5 and the materials prepared in Comparative Examples 1-3 were added respectively to form multiple control groups to study the adsorption performance of the material to pollutants. The whole reaction was carried out in a constant temperature shaking incubator at room temperature at a speed of 180rpm / min. During the reaction, 4.0mL of the reaction solution sample was taken out at a predetermined time interval, and a 0.22μm water system microporous filter was used to inject it into a 4.0mL centrifuge tube containing the norfloxacin concentration for the determination. The experimental process was carried out in a light-proof environment.

[0037] The results are as follows Figure 2 As shown, compared with the single metal-doped gangue materials of Comparative Examples 1 and 2 and Comparative Example 3, the loaded bimetallic composite materials prepared in Examples 1-5 have better adsorption performance, indicating that the bimetallic loading improves the adsorption capacity of pollutants. And the adsorption equilibrium is basically reached within 30 minutes.

[0038] Application Example 2: A 20 mg / L norfloxacin aqueous solution was prepared with deionized water, 100 mL was taken in a conical flask, and 40 mg of the zinc and cobalt-loaded gangue composite materials prepared in Examples 1-5 and the materials prepared in Comparative Examples 1-3 were added to form multiple control groups. After 30 min of adsorption equilibrium, 2 mM PMS was added to the conical flask to initiate the degradation stage. The adsorption and degradation properties of the material for pollutants were studied. The entire reaction was carried out in a constant temperature shaking incubator at room temperature at a speed of 180 rpm / min. During the reaction, 4.0 mL of the reaction solution sample was taken out at predetermined time intervals and injected into a 4.0 mL centrifuge tube containing a 0.22 μm water system microporous filter for the determination of norfloxacin concentration. The experimental process was carried out in a light-proof environment.

[0039] The results are as follows Figure 3 As shown, compared with the pure coal gangue material of Comparative Example 1, the metal-doped coal gangue composite catalytic materials prepared in Examples 1-5 and Comparative Examples 2-3 have significantly increased degradation efficiency for norfloxacin, indicating that metal loading improves the ability to degrade pollutants, especially the bimetal loading is better than the single metal loading.

[0040] from Figure 3 It can also be seen that, compared with Examples 1-3, the ratio of metal zinc and cobalt in Example 2 has the best degradation effect. Comparing Example 1 with Example 5, it can be seen that there is no significant difference in the drying temperature within 100-120°C. The catalytic degradation system after pre-adsorption for 30 minutes in the best embodiment 2 has the best norfloxacin removal ability, and the removal efficiency is further improved. The material can adsorb norfloxacin on the surface of the material through the electrostatic effect, effectively activate PMS to produce more active species, and greatly improve the efficiency of removing norfloxacin.

[0041] The reusability and stability of the ZnCo@CG of Example 2 were evaluated. Figure 4 As shown in Figure 2, during the first use, the removal of norfloxacin by ZnCo@CG reached 92.9%. As the number of cycles increased, the removal of norfloxacin gradually decreased. However, after 3 cycles, the removal of norfloxacin by ZnCo@CG remained at 68%. These results confirm that the coal gangue catalyst composite has good stability and reusability.

[0042] The gangue composite material loaded with metal zinc and cobalt and the pure gangue material prepared in Example 1 of the present invention were characterized by infrared spectroscopy. The results are as follows: Figure 1 As shown. Figure 1 It can be seen that after the introduction of metal zinc and cobalt, 3600cm -1 The water-absorbing hydroxyl peaks on the left and right disappeared, indicating that metallic zinc and cobalt have been successfully loaded on the coal gangue.

[0043] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the above embodiments, ordinary technicians in the relevant field should understand that the specific implementation methods of the present invention can still be modified or replaced by equivalents. Any modification or equivalent replacement that does not depart from the spirit and scope of the present invention should be covered within the scope of protection of the claims of the present invention.

Claims

1. A zinc and cobalt loaded coal gangue composite material, characterized in that: Comprising coal gangue as a carrier, and zinc and cobalt loaded on the coal gangue; The molar ratio of zinc to cobalt is 1:1-3.

2. The zinc and cobalt loaded coal gangue composite material according to claim 1, characterized in that: The total molar mass ratio of metallic zinc and cobalt to the mass of coal gangue is (2-4)M:(5-10)g.

3. The method for preparing a zinc and cobalt loaded coal gangue composite material according to claim 1 or 2, characterized in that: The following steps are involved: dissolving a zinc source and a cobalt source in deionized water to form a mixed solution; The ground gangue powder is immersed in the mixed solution, and after magnetic stirring, solid-liquid separation is performed, the solid matter is filtered and washed, and dried at 100-120° C. for 8-12 hours, and after grinding, a gangue composite material loaded with metal zinc and cobalt is obtained.

4. The method for preparing a zinc and cobalt loaded coal gangue composite material according to claim 3, characterized in that: Magnetic stirring for 8-12h.

5. The method for preparing a zinc and cobalt loaded coal gangue composite material according to claim 3, characterized in that: Grind the coal gangue to 100-200 mesh.

6. The method for preparing a zinc and cobalt loaded coal gangue composite material according to claim 3, characterized in that: The zinc source is zinc chloride, zinc nitrate or zinc sulfate.

7. The method for preparing a zinc and cobalt loaded coal gangue composite material according to claim 3, characterized in that: The cobalt source is cobalt nitrate.

8. The use of the zinc and cobalt loaded coal gangue composite material according to claim 1 or 2 as a catalyst for activating persulfate to degrade organic pollutants in polluted water, characterized in that: The zinc- and cobalt-loaded coal gangue composite material is mixed with polluted water containing organic pollutants for pre-adsorption; After the pre-adsorption, persulfate is added to the polluted water to catalyze the degradation of organic pollutants.

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