Molybdenum-modified tricarbon dioxide polymer and application thereof in treating underground water composite pollutants in mining area

Abstract

The invention relates to a molybdenum-modified three-carbon dioxide polymer and application thereof in treatment of underground water composite pollutants in mining areas, and belongs to the technical field of new materials and application thereof. The molybdenum modified three-carbon dioxide polymer is prepared by the following steps: (1) adding malonic acid, acetic anhydride and ammonium molybdate into a reaction container, heating to dissolve, then continuously heating to 135-145 DEG C, and keeping for 0.5-6 hours; (2) after the reaction is finished, dropwise adding diethyl ether to precipitate a product, carrying out suction filtration, washing with diethyl ether, and collecting the precipitated product; (3) performing vacuum drying on the precipitation product to obtain a solid product; and (4) heating the solid product to 300 DEG C in a nitrogen atmosphere, carrying out heat treatment for 0.5-2 hours at the temperature, and cooling to room temperature to obtain a dark red solid material, namely the molybdenum-modified tricarcarbon dioxide polymer, the polymer is mild in synthesis process, the polymer is used for treating heavy metal-containing sewage, a precipitator or a chemical reactant does not need to be additionally added, the heavy metal removal rate can reach 75%, and the method is suitable for industrial production. The method is economical and environment-friendly.

Description

Technical Field

[0001] The invention relates to new materials and applications thereof, and in particular to a molybdenum-modified carbon dioxide polymer and applications thereof in treating composite pollutants in underground water of mining areas. Background Art

[0003] Traditional groundwater treatment technologies mainly include physical, chemical and biological methods. Physical methods such as filtration, sedimentation and membrane separation are mainly used to remove suspended particles and some precipitated substances in water, but it is difficult to effectively remove dissolved heavy metal ions and organic pollutants. The chemical method is to add additional chemical reagents to induce precipitation, oxidation-reduction and other reactions of pollutants. Although it has a significant removal effect, it is easy to cause secondary pollution and has a high treatment cost. The biological method uses the metabolism of microorganisms to decompose organic pollutants, but the treatment cycle is long and the removal effect of heavy metal ions is not good.

[0004] Therefore, it is urgent to develop new efficient and environmentally friendly materials, which has important practical significance and application value in solving the problem of treating complex pollutants in groundwater in mining areas. Summary of the invention

[0005] In view of the needs and existing problems in the above-mentioned fields, the present invention has conducted research and development on the treatment of composite pollutants in groundwater by carbon dioxide polymers. Based on the research results, the present invention is proposed, which is as follows: The first aspect of the present invention provides a method for preparing a molybdenum-modified carbon dioxide polymer, characterized in that it comprises the following steps: (1) Add malonic acid, acetic anhydride and ammonium molybdate into a reaction vessel, heat to dissolve, and then continue to raise the temperature to 135-145°C and maintain for 0.5-6 hours; (2) After the reaction is completed, add ether dropwise to precipitate the product, filter it with suction, then wash it with ether and collect the precipitated product; (3) The precipitated product is vacuum dried to obtain a solid product; (4) The solid product is heated to 300°C in a nitrogen atmosphere, heat treated at this temperature for 0.5 to 2 hours, and cooled to room temperature to obtain a dark red solid material, namely, molybdenum-modified carbon dioxide polymer.

[0006] Preferably, the preparation method is characterized in that: in step (1), the molar ratio of malonic acid to acetic anhydride is 1:2, the amount of ammonium molybdate added is such that the mass fraction of molybdenum in the reaction mixture is 2.5%; the heating temperature for dissolving is 90°C, and the heating time is 10 to 20 minutes.

[0007] Preferably, the preparation method is characterized in that: the vacuum drying temperature in step (3) is 85-95°C; in step (4), the heating rate in the nitrogen atmosphere is 5°C·min -1 .

[0008] Preferably, the preparation method is characterized in that: in step (4), it also includes grinding the dark red solid material to 150-250 mesh after the heat treatment.

[0009] The second aspect of the present invention seeks to protect a molybdenum-modified tricarbon dioxide polymer prepared by any of the above methods.

[0010] The third aspect of the present invention is to protect the use of the molybdenum-modified carbon dioxide polymer in the treatment of complex pollutants in groundwater in mining areas, which is characterized in that the ground and pulverized molybdenum-modified carbon dioxide polymer is added to the groundwater complex pollutants to be treated for reaction, and the groundwater complex pollutants refer to wastewater heavily contaminated by heavy metal complexes in mining areas.

[0011] Preferably, the application comprises filtering and removing the precipitate including the molybdenum-modified carbon trioxide polymer after the reaction is completed to obtain purified water.

[0012] Preferably, the application is characterized in that the heavy metal includes one or more of Mn, Cr, Cu, Zn, As, Cd, Sb, and Pb, and the particle size of the ground molybdenum-modified tricarbon dioxide polymer is between 150 and 250 meshes.

[0013] Preferably, the application is characterized in that the dosage of the molybdenum-modified carbon dioxide polymer is 0.1-0.5 g per liter of composite pollutants in groundwater to be treated.

[0014] Preferably, the application is characterized in that the dosage of the molybdenum-modified tricarbon dioxide polymer is 0.2 g per liter of composite pollutants in groundwater to be treated.

[0015] Preferably, the application is characterized in that, while adding the molybdenum-modified carbon dioxide polymer, persulfate is added at a final concentration of 1 to 5 mM.

[0016] Groundwater treatment requires long-term operation, which is an important consideration in the selection of treatment materials; carbon dioxide polymer p(C 3 O 2 )x) is composed of carbon monoxide (C 3 O 2) is a highly conjugated material formed by spontaneous polymerization at low temperatures. Its oxygen-rich framework makes it have good acid resistance and good structural stability. In addition, its synthesis conditions are relatively mild and it is soluble in solvents. The inventors speculate that the above characteristics of the carbon dioxide polymer make it an excellent candidate material. Its oxygen-rich carbon framework may provide abundant adsorption or reaction sites, which is easy to prepare on a large scale and can be coated on a carrier for water treatment. Based on the above speculation, the inventors developed a molybdenum-modified carbon dioxide polymer (Mo-p(C 3 O 2 ) x -300) and studied its application in groundwater treatment.

[0017] In the molybdenum-modified tricarbon dioxide polymer provided by the present invention, molybdenum has the effect of adsorbing or catalyzing the conversion of heavy metal ions and organic pollutants, and its oxygen-rich carbon framework is used to provide additional adsorption or reaction sites, thereby improving the removal efficiency of groundwater heavy metal composite pollutants; because molybdenum can be converted into MoO under specific conditions 4 2- , it reacts with the heavy metal ions in the wastewater to be treated to form insoluble heavy metal molybdate precipitates, thereby effectively removing the heavy metal ions. This process can achieve the purpose of removing heavy metal ions without the need to introduce additional chemical precipitants, significantly reducing the cost of wastewater treatment.

[0018] The data of the exemplary embodiment show that the molybdenum-modified tricarbon dioxide polymer provided by the present invention can achieve a heavy metal removal rate of up to 75% in water after five hours of treatment, proving that the molybdenum-modified tricarbon dioxide polymer is an excellent candidate material for underground wastewater treatment in mining areas. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 The Mo-p(C 3 O 2 ) x SEM and corresponding mapping diagram.

[0020] Figure 2 The Mo-p(C 3 O 2 ) x -300 SEM and corresponding mapping diagram.

[0021] Figure 3 The performance test results of the molybdenum-modified carbon dioxide polymer provided by the present invention are as follows: The ordinate C / C0 represents the removal ratio of Pb-EDTA; the abscissa represents the treatment time; the legend 0.1-5, 0.1-2.5, 0.1-1, 0.1-0 respectively represent the addition of 0.1 g / L Mo-p(C0) to Pb-EDTA solutions containing 5 mM, 2.5 mM, 1 mM and 0 mM disulfate. 3 O 2 ) x -300.

[0022] Figure 4 In order to test the performance of the molybdenum-modified tricarbon dioxide polymer provided by the present invention, 0.2 g / L Mo-p(C 3 O 2 ) x -300, Pb removal efficiency diagram, The vertical axis C / C0 represents the Pb-EDTA removal ratio; the horizontal axis represents the treatment time; the legend 0.2-5, 0.2-2.5, 0.2-1, 0.2-0 respectively represent the addition of 0.2 g / L Mo-p(C0) to Pb-EDTA solutions containing 5 mM, 2.5 mM, 1 mM and 0 mM disulfate. 3 O 2 ) x -300.

[0023] Figure 5 The molybdenum-modified carbon dioxide polymer Mo-p (C 3 O 2 ) x -300 treated groundwater test results, where the ordinate represents the lead concentration in groundwater; the abscissa represents the treatment time. DETAILED DESCRIPTION

[0024] The present invention will be further described below in conjunction with embodiments, but the present invention is not limited thereto.

[0025] Example 1 Preparation of Molybdenum-Modified Carbon Dioxide Polymer The preparation of the Mo-modified carbon dioxide polymer of the present invention is carried out according to the following steps: 1. Mix malonic acid and acetic anhydride in a round-bottom flask at a molar ratio of 1:2, add ammonium molybdate so that the mass fraction of molybdenum in the mixture is 2.5%, and heat the mixture to 90°C for 15 minutes; 2. Then, the temperature was raised to 140°C and maintained for 5 hours. Then, 40 mL of ether was slowly dripped into the flask to precipitate the product. The product was filtered and washed three times with ether to collect the solid product. 3. The product was placed in a vacuum drying oven and dried overnight to obtain a solid product, which was expressed as Mo-p (C3 O 2 ) x .

[0026] 4. 1g of Mo-p(C 3 O 2 ) x The mixture was transferred to a porcelain boat, heated at a heating rate of 5°C / min in a nitrogen atmosphere and heat treated at 300°C for 1 hour. After cooling to room temperature, the solid product was collected and expressed as: Mo-p(C 3 O 2 ) x -300. Grind the solid product until it passes through a 200-mesh screen for later use.

[0027] 5. Detection and characterization of the product: The solid product Mo-p (C 3 O 2 ) x and Mo-p(C 3 O 2 ) x -300 was inspected using scanning electron microscopy (SEM) and elemental mapping.

[0028] The results are as follows Figure 1 and Figure 2 As shown, the element distribution mapping results prove that the solid product Mo-p (C 3 O 2 ) x and Mo-p(C 3 O 2 ) x -300 is composed of three elements: Mo, C, and O. At the same time, scanning electron microscopy shows that ( Figure 1 Upper left and Figure 2 Upper left) Mo-p(C 3 O 2 ) x and Mo-p(C 3 O 2 ) x -300 There are significant differences in appearance between the two.

[0029] Example 2 The molybdenum-modified carbon dioxide polymer Mo-p (C 3 O 2 ) x -300 for performance testing Take the Mo-p (C 3 O 2 ) x-300 was added to Pb-EDTA solutions containing different concentrations of disulfate (PDS) at dosages of 0.1 g / L and 0.2 g / L for performance testing.

[0030] 1. Experimental drugs: 0.1 mM Pb-EDTA solution, 250 mM PDS solution and Mo-p(C 3 O 2 ) x -300 Catalyst 2. Experimental steps: Mo-p(C 3 O 2 ) x -300 was added to 50 mL of 0.1 mM Pb-EDTA solution at net contents of 0.1 g / L and 0.2 g / L, respectively, for reaction, wherein the PDS concentrations were 0, 1, 2.5, and 5 mM, respectively. The supernatant was taken out by syringe at regular intervals and filtered through a microporous filter membrane, and the residual Pb-EDTA content in the sample was determined by liquid chromatography.

[0031] Mo-p(C 3 O 2 ) x The removal effect of -300 on Pb-EDTA (i.e. the ratio of Pb-EDTA concentration after treatment to that before treatment) is as follows Figure 3 and 4 As shown, the vertical axis is C / C 0 represents the removal rate (%), and the abscissa t / min represents the time.

[0032] Mo-p(C 3 O 2 ) x -300, when the dosage is 0.1g / L, the removal rate can reach 25~40%; when the dosage is 0.2g / L, the removal rate can reach 60~70%; When PDS was added, that is, the concentration of PDS was between 1 and 5 mM, the removal effect of Pb-EDTA was much higher than that without adding PDS, that is, PDS 0 mM. Example 3 Comparison of the final product Mo-p (C 3 O 2 ) x -300 and the intermediate product Mo-p(C 3 O 2 ) x 1. Experimental drugs: 0.1 mM Pb-EDTA solution, 250 mM H 2 O 2 Solution and Mo-p(C 3 O 2 )x -300 Catalyst 2. Experimental steps: Mo-p(C 3 O 2 ) x -300 was added to 50 mL of Pb-EDTA solution containing 1 mM disulfate (PDS) at a net content of 0.2 g / L for reaction; at the same time, Mo-p (C 3 O 2 ) x For control.

[0033] At the beginning of the reaction and after 5 hours of reaction, the supernatant was taken by syringe, filtered through a microporous filter membrane, and the concentration of Mo dissolved in the filtrate and the content of residual Pb-EDTA were determined. The results are shown in Table 1 Table 1

[0034] The results showed that adding the final product Mo-p(C 3 O 2 ) x -300 treatment, the Pb-EDTA concentration (residual amount) in the filtrate was lower than that of the intermediate product Mo-p(C 3 O 2 ) x processing.

[0035] And Mo-p(C 3 O 2 ) x In the process of treating sewage, a large amount of catalyst molybdenum was dissolved (4.78 mg / L). The catalyst dissolution concentration was the concentration of the final product Mo-p (C 3 O 2 ) x -300 treatment is more than four times. The Mo-p (C 3 O 2 ) x -300 will not dissolve in water in large quantities, which is conducive to recovery and reuse through filtration after treatment.

[0036] Example 4: Application of Actual Mine Underground Wastewater Step 1 Pretreatment of waste to be treated 1. Wastewater sample collection and analysis: Wastewater samples were collected from groundwater in a mining area to determine basic parameters such as heavy metal content, COD value, pH value, etc.

[0037]

[0038] 2. Wastewater pretreatment: Filter the collected wastewater samples to remove suspended particles to ensure the accuracy of subsequent experiments; Step 2: Add materials 1. Material preparation: Prepare the Mo-p (C 3 O 2 ) x -300 and peroxydisulfate (PDS).

[0039] 2. Adding materials: Add 0.2 g / L Mo-p(C 3 O 2 ) x -300, and at the same time 5 mM peroxydisulfate (PDS) was added.

[0040] Step 3 Reaction process 1. Oscillating reaction: Use a shaker to fully mix and oscillate the material and wastewater. The reaction time is 5 hours.

[0041] Sampling was conducted once at regular intervals, with 1 mL sampled each time. After filtering through a microporous filter membrane, the concentrations of heavy metal ions and organic pollutants in the samples were determined.

[0042] 2. Record data: record the concentration changes of heavy metal ions at each time point; The concentration of heavy metal ions was determined using an atomic absorption spectrometer, where the detection data of heavy metals (Pb) are as follows: Figure 5 As shown in the figure, after 5 hours of treatment, the concentration of heavy metal ions in the wastewater dropped to about 3.5 mg / L, and the removal rate reached 72.5%.

[0043] The above exemplary embodiment results show that the new material Mo-p (C 3 O 2 )x-300 can be used as a candidate material for underground wastewater treatment in mining areas.

Claims

1. A method for preparing a molybdenum-modified carbon dioxide polymer, characterized in that: The following steps are involved: (1) Add malonic acid, acetic anhydride and ammonium molybdate into a reaction vessel, heat to dissolve, and then continue to raise the temperature to 135-145°C and maintain for 0.5-6 hours; (2) After the reaction is completed, add ether dropwise to precipitate the product, filter it with suction, then wash it with ether and collect the precipitated product; (3) The precipitated product is vacuum dried to obtain a solid product; (4) The solid product is heated to 300°C in a nitrogen atmosphere, heat treated at this temperature for 0.5 to 2 hours, and cooled to room temperature to obtain a dark red solid material, namely, molybdenum-modified carbon dioxide polymer.

2. The preparation method according to claim 1, characterized in that: In step (1), the molar ratio of malonic acid to acetic anhydride is 1:2, and the amount of ammonium molybdate added is such that the mass fraction of molybdenum in the reaction mixture is 2.5%; the temperature for heating and dissolving is 90° C., and the heating time is 10 to 20 minutes.

3. The preparation method according to claim 1, characterized in that: The vacuum drying temperature in step (3) is 85-95°C; in step (4), the heating rate in the nitrogen atmosphere is 5°C min -1 .

4. The preparation method according to claim 1, characterized in that: Step (4) further includes grinding the dark red solid material to 150-250 mesh after the heat treatment.

5. A molybdenum-modified carbon dioxide polymer prepared by the method described in any one of claims 1 to 4.

6. The use of the molybdenum-modified carbon dioxide polymer according to claim 1 in treating composite pollutants in groundwater in mining areas, characterized in that: The molybdenum-modified carbon trioxide polymer that has been ground and crushed is added to the groundwater composite pollutants to be treated for reaction. The groundwater composite pollutants refer to wastewater that is heavily contaminated by heavy metal complexes in mining areas.

7. The use according to claim 6, characterized in that: The method includes filtering and removing the precipitate including the molybdenum-modified tricarbon dioxide polymer after the reaction is completed.

8. The use according to claim 6, characterized in that: The heavy metals include one or more of Mn, Cr, Cu, Zn, As, Cd, Sb, and Pb, and the particle size of the ground and crushed molybdenum-modified tricarbon dioxide polymer is between 150 and 250 meshes.

9. The use according to claim 6, characterized in that: The dosage of the molybdenum-modified tricarbon dioxide polymer is 0.1-0.5 g per liter of composite pollutants in groundwater to be treated.

10. The use according to any one of claims 6 to 9, characterized in that: While adding the molybdenum-modified tricarbon dioxide polymer, persulfate is added at a final concentration of 1-5 mM.

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