Iron-carbon micro-electrolysis filler for degrading nitroguanidine wastewater and preparation method thereof
By preparing a multi-level porous iron-carbon microelectrolysis material, the problem of poor treatment effect of nitroguanidine wastewater was solved, achieving efficient degradation and cost control. It is suitable for the treatment of high-concentration acidic wastewater in the production process of nitroguanidine.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- HUAIYIN INSTITUTE OF TECHNOLOGY
- Filing Date
- 2024-06-19
- Publication Date
- 2026-07-07
AI Technical Summary
Existing technologies are ineffective in treating the high-concentration acidic wastewater generated during the production of nitroguanidine. Conventional methods are not very effective, and the iron-carbon micro-electrolysis material prepared from red mud has limited contact between iron and carbon, which affects the formation of the galvanic cell and the degradation of wastewater.
Using red mud as the iron source, liquid waste oil as the carbon source, and potassium hydroxide as the pore-forming agent, multi-level porous iron-carbon microelectrolysis materials were prepared through steps such as heat treatment, pH adjustment with flocculant, and calcination to ensure good contact between iron and carbon materials and the formation of a porous structure.
It improves wastewater degradation efficiency, achieves efficient removal of organic pollutants from acidic wastewater, reduces preparation costs, and reduces environmental pollution.
Smart Images
Figure CN118702224B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to an iron-carbon micro-electrolysis filler for the degradation of nitroguanidine wastewater and its preparation method, particularly to an iron-carbon micro-electrolysis material prepared using red mud as the magnetic material source and waste oil as the carbon source and its preparation method, belonging to the technical field of iron-carbon micro-electrolysis material preparation. Background Technology
[0002] The production of energetic materials and explosives, such as nitroguanidine, generates large quantities of highly concentrated acidic wastewater containing significant amounts of organic matter. Due to its high acidity, conventional wastewater treatment methods are ineffective. The iron-carbon internal electrolysis method utilizes zero-valent iron and carbon from iron filings to form the positive and negative electrodes of a tiny galvanic cell. Using acidic wastewater as the electrolyte, a redox reaction occurs under acidic conditions to form the galvanic cell, effectively reducing COD in the wastewater. This method is an effective approach for wastewater treatment in related industries.
[0003] Red mud is a solid waste produced by aluminum plants. Its main chemical component is hematite (Fe2O3), which can be used as a source of magnetic materials and zero-valent iron. Therefore, red mud can be used as a cheap raw material for preparing iron-carbon materials. For example, red mud can be mixed with asphalt and coke, granulated, and then treated in the absence of air to prepare iron-carbon micro-electrolysis materials (CN113526620A); solid residue from potassium humate extraction from vegetable waste can be mixed with red mud and potassium carbonate and calcined to obtain iron-carbon composite materials (CN114768760A); iron powder, red mud, lignin, and clay can be mixed, granulated, and then calcined under a reducing atmosphere to prepare anti-caking granular ceramic iron-carbon composite materials (CN103253741A). In the above-mentioned iron-carbon composite materials prepared using red mud as raw material, the carbon material used is mainly solid particles, which have limited contact with the red mud. Furthermore, the silicon and aluminum components in the red mud are still present, which may affect the contact between iron and carbon in the product, thus affecting the formation of the galvanic cell and the degradation effect of wastewater. Summary of the Invention
[0004] Objective of the Invention: The first objective of this invention is to provide an iron-carbon microelectrolysis packing material for the degradation of nitroguanidine wastewater and its preparation method. The second objective of this invention is to provide a method for preparing the iron-carbon microelectrolysis packing material for the degradation of nitroguanidine wastewater.
[0005] Technical solution: An iron-carbon micro-electrolysis packing material for the degradation of nitroguanidine wastewater, comprising red mud as the iron source, liquid waste oil as the carbon source, and potassium hydroxide as the pore-forming agent.
[0006] The preparation method of the iron-carbon micro-electrolysis packing material for the degradation of nitroguanidine wastewater according to the present invention includes the following steps:
[0007] (1) Grind the red mud and add it to a strong acid solution, heat treat it, filter it, and obtain the leachate;
[0008] (2) Add the organic flocculant to the leachate, stir, adjust the pH of the solution, filter, dry, and obtain precipitate Fe(OH)3;
[0009] (3) Mix Fe(OH)3 with KOH, grind, add liquid waste oil, stir evenly to obtain a mixture;
[0010] (4) Calcine the mixture, cool it, add hot water, stir, filter it, and dry it to obtain a multi-level porous iron-carbon microelectrolysis material.
[0011] Further, in step (1), the strong acid is sulfuric acid or hydrochloric acid.
[0012] Furthermore, in step (1), the concentration of the strong acid is 3 to 5 mol / L.
[0013] Further, in step (1), the mass-to-volume ratio of the red mud to the strong acid solution is 20-30:100g / mL.
[0014] Furthermore, in step (1), the temperature of the heat treatment is 150-180°C, and the heat treatment time is 10-18h.
[0015] Further, in step (2), the organic flocculant is polyacrylamide, sodium hydroxymethyl cellulose, or sodium polyacrylate.
[0016] Furthermore, in step (2), the mass of the organic flocculant added to the leachate is 0.05–0.2 wt%.
[0017] Furthermore, in step (2), the pH of the solution is adjusted to 4 until a precipitate appears.
[0018] Furthermore, in step (2), the drying temperature is 100-120°C and the drying time is 8-10 hours.
[0019] Furthermore, in step (3), the liquid waste oil is one or more of waste lubricating oil, waste catering waste oil, or waste decolorized white oil.
[0020] Further, in step (3), the mass ratio of Fe(OH)3 precipitate, KOH and liquid waste oil is 1:0.2-0.5:0.5-1.5.
[0021] Furthermore, in step (3), the grinding time is 30 to 60 minutes.
[0022] Furthermore, in step (4), the calcination temperature is 650-800℃ and the calcination time is 1-2 hours.
[0023] Furthermore, in step (4), the solid-liquid ratio of the calcined mixture to the hot water is 1:3 to 5.
[0024] Furthermore, in step (4), the stirring time is more than 30 minutes.
[0025] Mechanism: In the first heat treatment stage of this invention, a strong acid reacts with iron oxide in the red mud, transferring iron ions to the leachate and separating them from the silicon components of the red mud. A flocculant is then added to the leachate, followed by the addition of alkali to adjust the pH to 4, resulting in Fe(OH)3 precipitate, which is then separated from aluminum ions in the solution (the pH range for Al(OH)3 precipitation is 6–10). The flocculant promotes the agglomeration and separation of the precipitate and also provides a carbon source for subsequent carbonization. In the third high-temperature treatment stage (calcination), the solid Fe(OH)3 decomposes into Fe2O3. Waste oil and flocculant are carbonized in a sealed environment, forming carbon materials on the surface and within the pores of Fe2O3. At the same time, KOH can react with carbon inside the carbon materials to generate CO, forming channels. At this time, CO and carbon materials can undergo a carbothermic reduction reaction with Fe2O3, and are successively reduced to Fe3O4 and zero-valent iron. After washing away soluble impurities with water, more channels are obtained. This invention utilizes red mud and waste oil to develop iron-carbon micro-electrolysis materials and applies them to wastewater treatment, reducing the pollution of both materials to the environment and achieving the beneficial effect of treating waste with waste.
[0026] Beneficial effects: Compared with the prior art, the present invention has the following significant advantages:
[0027] (1) This invention uses strong acid to etch red mud to extract iron from it. By adjusting the pH value of the leachate, high-purity Fe(OH)3 can be obtained, which is then decomposed into Fe2O3 at high temperature and then carbothermally reduced to zero-valent iron. This avoids the zero-valent iron being coated by silicon and aluminum in the red mud, which would affect the micro-electrolysis effect. The formed zero-valent iron has good contact with carbon materials and can effectively form a galvanic cell.
[0028] (2) This invention uses liquid waste oil and organic flocculant as the source of carbon materials and reducing agents, which increases the contact between carbon materials and iron oxide and improves the reduction efficiency. KOH etches the carbon materials to form channels, thus preparing porous composite materials and improving the adsorption and enrichment of pollutants by the materials.
[0029] (3) Compared with the existing red mud preparation of iron-carbon micro-electrolysis materials, the present invention uses waste oil and red mud as raw materials, the operation process is simple, the cost is low, and it is easy to promote on a large scale. Attached Figure Description
[0030] Figure 1 The image shows the XRD pattern of the hierarchical porous iron-carbon microelectrolysis material prepared in Example 1. Detailed Implementation
[0031] The technical solution of the present invention will be further described below with reference to the accompanying drawings.
[0032] Example 1
[0033] (1) Add red mud to a ball mill and grind it for 1 hour. Add the red mud powder to a 3 mol / L hydrochloric acid solution at a mass-volume ratio of 20:100 g / mL. After mixing, place it in a stainless steel reactor with a polytetrafluoroethylene liner and heat it in an oven to 180℃ for 10 hours. Filter to separate the leachate and solid residue.
[0034] (2) Add polyacrylamide to the leachate, the mass of polyacrylamide being 0.2% of the mass of the leachate. Stir until completely dissolved, then add 2 mol / L NaOH solution to adjust the pH of the solution to 4 until no Fe(OH)3 precipitate appears. Filter to separate the solid Fe(OH)3 precipitate, and then dry the precipitate at 100℃ for 10h.
[0035] (3) Add KOH to Fe(OH)3 product at a mass ratio of 1:0.2, grind for 30 min, then add waste lubricating oil at a mass ratio of Fe(OH)3:waste oil of 1:0.5, and stir evenly to obtain a mixture;
[0036] (4) The above mixture was transferred to a flat-bottomed crucible, placed in a sealed muffle furnace, heated to 750°C, treated for 1 hour, cooled to room temperature, and the product was added to hot water at a solid-liquid mass-volume ratio of 1:3 g / mL. The mixture was stirred for 30 minutes, washed, filtered, and dried to obtain a multi-level porous iron-carbon microelectrolysis material.
[0037] The multi-level porous iron-carbon microelectrolysis material prepared in this embodiment was subjected to XRD analysis, and the results are as follows: Figure 1 As shown. Figure 1 The XRD pattern of the hierarchical porous iron-carbon microelectrolysis material prepared in Example 1 is shown below. Figure 1 It can be seen that its main product is Fe. 0 The presence of trace amounts of Fe3O4 indicates that both hematite in the red mud and the decomposition products of extracted Fe(OH)3 can be carbothermally reduced to zero-valent iron. However, characteristic diffraction peaks of quartz from the original ore also appeared in the in-situ reduction products of the red mud, indicating that the presence of these impurities can be avoided after acid extraction of iron components.
[0038] Comparative Example 1
[0039] The preparation process is the same as in Example 1, except that there is no acid leaching or precipitation step, that is, no steps (1) and (2). The red mud is directly operated according to the conditions of steps (3) and (4) to obtain the iron-carbon micro-electrolysis material synthesized in situ from the red mud.
[0040] Using an iron-carbon microelectrolysis device, with the multi-level porous iron-carbon microelectrolysis material prepared in Example 1 or the iron-carbon microelectrolysis material synthesized in situ from red mud obtained in Comparative Example 1 as filler, it was used to degrade acidic wastewater from nitroguanidine production. After electrolyzing the nitroguanidine production wastewater with a pH of 1 for 25 minutes, the multi-level porous iron-carbon microelectrolysis material prepared from the acidic red mud leachate of Example 1 reduced the COD of the wastewater from 1100 to 220, with a removal rate of 80%. In contrast, the iron-carbon microelectrolysis material synthesized in situ from red mud in Comparative Example 1 only reduced the COD of the wastewater to 506, with a removal rate of only 54%. This demonstrates that the iron-carbon microelectrolysis material prepared from the acidic red mud leachate of Example 1 has excellent degradation performance for acidic wastewater, far superior to the degradation performance of the iron-carbon microelectrolysis material synthesized in situ from red mud in Comparative Example 1.
[0041] Example 2
[0042] The preparation process is the same as in Example 1.
[0043] (1) Red mud was added to a ball mill and ground for 1 hour. The red mud powder was added to a 4 mol / L sulfuric acid solution at a mass-volume ratio of 25:100 g / mL. After mixing, the mixture was placed in a stainless steel reactor with a polytetrafluoroethylene liner and heated to 170℃ in an oven for 12 hours. The leachate and solid residue were separated by filtration.
[0044] (2) Add polyacrylamide to the leachate, the mass of polyacrylamide being 0.15% of the mass of the leachate. Stir until completely dissolved, then add 2 mol / L NaOH solution to adjust the pH of the solution to 4 until no Fe(OH)3 precipitate appears. Filter to separate the solid precipitate, and then dry the precipitate at 110℃ for 9 hours.
[0045] (3) Add KOH to Fe(OH)3 product at a mass ratio of 1:0.3, grind for 40 min, then add waste decolorized white oil at a mass ratio of Fe(OH)3:waste oil of 1:0.8, and stir evenly to obtain a mixture;
[0046] (4) The mixture was transferred to a flat-bottomed crucible, placed in a sealed muffle furnace, heated to 650°C, treated for 2 hours, cooled to room temperature, and the product was added to hot water at a solid-liquid ratio of 1:3. The mixture was stirred for 30 minutes, washed, filtered, and dried to obtain a multi-level porous iron-carbon microelectrolysis material.
[0047] Using the multi-level porous iron-carbon micro-electrolysis material obtained in this embodiment as a filler, it was used to degrade acidic wastewater from nitroguanidine production. After electrolyzing nitroguanidine production wastewater with a pH of 1 for 25 minutes, its COD decreased from 1100 to 250, with a removal rate of 77.3%.
[0048] Example 3
[0049] The preparation process is the same as in Example 1.
[0050] (1) Red mud was added to a ball mill and ground for 1 hour. The red mud powder was added to a 5 mol / L sulfuric acid solution at a mass-volume ratio of 30:100 g / mL. After mixing, the mixture was placed in a stainless steel reactor with a polytetrafluoroethylene liner and heated to 160℃ in an oven for 14 hours. The leachate and solid residue were separated by filtration.
[0051] (2) Add sodium hydroxymethyl cellulose to the leachate, the mass of sodium hydroxymethyl cellulose being 0.1% of the mass of the leachate. Stir until completely dissolved, then add 2 mol / L NaOH solution to adjust the pH of the solution to 4 until no Fe(OH)3 precipitate appears. Filter to separate the solid precipitate, and then dry the precipitate at 115℃ for 8 hours.
[0052] (3) Add KOH to Fe(OH)3 product at a mass ratio of 1:0.5, grind for 30 min, then add catering waste oil at a mass ratio of Fe(OH)3:waste oil of 1:1.5, and stir evenly to obtain a mixture;
[0053] (4) The mixture was transferred to a flat-bottomed crucible, placed in a sealed muffle furnace, heated to 700°C, treated for 1.5 h, cooled to room temperature, and the product was added to hot water at a solid-liquid ratio of 1:3. The mixture was stirred for 30 min, washed, filtered, and dried to obtain a multi-level porous iron-carbon microelectrolysis material.
[0054] Using the multi-level porous iron-carbon micro-electrolysis material obtained in this embodiment as a filler, it was used to degrade acidic wastewater from nitroguanidine production. After electrolyzing nitroguanidine production wastewater with a pH of 1 for 25 minutes, its COD decreased from 1100 to 210, with a removal rate of 80.9%.
[0055] Example 4
[0056] The preparation process is the same as in Example 1.
[0057] (1) Red mud was added to a ball mill and ground for 1 hour. The red mud powder was added to a 4 mol / L hydrochloric acid solution at a mass-volume ratio of 25:100 g / mL. After mixing, it was placed in a stainless steel reactor with a polytetrafluoroethylene liner and heated to 150℃ in an oven for 18 hours. The leachate and solid residue were separated by filtration.
[0058] (2) Add sodium polyacrylate to the leachate, the mass of sodium polyacrylate being 0.05% of the mass of the leachate. Stir until completely dissolved, then add 2 mol / L NaOH solution to adjust the pH of the solution to 4 until no Fe(OH)3 precipitate appears. Filter to separate the solid precipitate, and then dry the precipitate at 120℃ for 8 hours.
[0059] (3) Add KOH to Fe(OH)3 product at a mass ratio of 1:0.4, grind for 30 min, then add waste lubricating oil at a mass ratio of Fe(OH)3:waste oil of 1:1.1, and stir evenly to obtain a mixture;
[0060] (4) The mixture was transferred to a flat-bottomed crucible, placed in a sealed muffle furnace, heated to 800°C, treated for 1 hour, cooled to room temperature, and the product was added to hot water at a solid-liquid ratio of 1:3. The mixture was stirred for 30 minutes, washed, filtered, and dried to obtain a multi-level porous iron-carbon microelectrolysis material.
[0061] Using the iron-carbon micro-electrolysis material obtained in this embodiment as a filler, it was used to degrade acidic wastewater from nitroguanidine production. After electrolyzing nitroguanidine production wastewater with a pH of 1 for 25 minutes, its COD decreased from 1100 to 240, with a removal rate of 78.2%.
Claims
1. An iron-carbon micro-electrolysis packing material for the degradation of nitroguanidine wastewater, characterized in that, This includes preparations using red mud as an iron source, liquid waste oil as a carbon source, and potassium hydroxide as a pore-forming agent; The preparation method of the iron-carbon micro-electrolysis packing material for the degradation of nitroguanidine wastewater includes the following steps: (1) The red mud is ground and added to a strong acid solution, heat-treated, filtered, and leachate is obtained; the heat treatment temperature is 150~180℃ and the heat treatment time is 10~18h. (2) Add the organic flocculant to the leachate, stir, adjust the pH of the solution to 4, filter, and dry to obtain precipitated Fe(OH)3; the organic flocculant is polyacrylamide, sodium hydroxymethyl cellulose or sodium polyacrylate, and the mass of the organic flocculant added to the leachate is 0.05~0.2 wt%; (3) Mix Fe(OH)3 with KOH, grind, add liquid waste oil, stir evenly to obtain a mixture; the liquid waste oil is one or more of waste lubricating oil, waste catering waste oil or waste decolorized white oil; the mass ratio of Fe(OH)3 precipitate, KOH and liquid waste oil is 1:0.2~0.5:0.5~1.5; (4) Calcine the mixture, cool, add hot water, stir, filter, dry to obtain multi-level porous iron-carbon micro-electrolysis material; the calcination temperature is 650~800℃, and the calcination time is 1~2h; The iron in the iron-carbon micro-electrolysis packing material used for the degradation of nitroguanidine wastewater exists in the form of zero-valent iron and Fe3O4.
2. The iron-carbon micro-electrolysis packing material for the degradation of nitroguanidine wastewater according to claim 1, characterized in that, In step (1), the strong acid is sulfuric acid or hydrochloric acid, and the concentration of the strong acid is 3~5 mol / L.
3. The iron-carbon micro-electrolysis packing material for the degradation of nitroguanidine wastewater according to claim 1, characterized in that, In step (1), the mass-to-volume ratio of the red mud to the strong acid solution is 20-30:100g / mL.
4. The iron-carbon micro-electrolysis packing material for the degradation of nitroguanidine wastewater according to claim 1, characterized in that, In step (2), the drying temperature is 100~120℃ and the drying time is 8~10h.
5. The iron-carbon micro-electrolysis packing material for the degradation of nitroguanidine wastewater according to claim 1, characterized in that, In step (3), the grinding time is 30~60 minutes.
6. The iron-carbon micro-electrolysis packing material for the degradation of nitroguanidine wastewater according to claim 1, characterized in that, In step (4), the solid-liquid ratio of the calcined mixture to hot water is 1:3~5, and the stirring time is more than 30 minutes.