Preparation method of transition metal Co-loaded blast furnace fly ash-based iron-carbon particle electrode and application of transition metal Co-loaded blast furnace fly ash-based iron-carbon particle electrode in treatment of refractory organic wastewater
By preparing Co-loaded blast furnace dust removal ash-based iron carbon particle electrode, the problems of low reaction rate and passivation of active positions of the iron carbon system are solved, and efficient treatment of difficult-to-degrade organic wastewater is achieved, and good economic and environmental benefits are achieved.
Patent Information
- Application Number
- CN202510661290.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-05-22
- Publication Date
- 2025-07-25
AI Technical Summary
The existing iron-carbon system has low reaction rate and passivation of active sites when dealing with difficult-to-degrade organic wastewater. The traditional treatment methods have problems of high cost and low efficiency.
The method of preparing a transition metal Co-loaded blast furnace dust removal ash-based iron carbon particle electrode is adopted. By blast furnace dust removal ash as a substrate, carbon black, urea, clay and EDTA are added, and spherical particle electrodes are made by bonding with Co(NO3)2·6H2O solution, and the Co-Fe-C particle electrode is calcined under nitrogen conditions to form a Co-Fe-C particle electrode.
It significantly improves the adsorption performance and catalytic activity of iron-carbon microelectrolysis, improves the treatment efficiency of difficult-to-degrade organic wastewater, has reusability, and reduces production and use costs.
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Figure CN120364804A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to a preparation method and application of a transition metal Co-loaded blast furnace dust-based iron-carbon particle electrode, belonging to the technical field of electrochemical water treatment. Background Art
[0002] Refractory organic wastewater refers to wastewater containing organic pollutants with high concentration, high toxicity and complex structures (such as benzene rings, heterocycles or long-chain alkanes), which are commonly found in industries such as pesticides, pharmaceuticals, petrochemicals, and printing and dyeing. Typical pollutants include organochlorine pesticides, antibiotics, polycyclic aromatic hydrocarbons and azo dyes. Such wastewater has high chemical stability and strong biological toxicity, and is difficult to be effectively degraded by traditional biological treatment methods. Currently, common treatment methods include: physicochemical methods (such as activated carbon adsorption and membrane separation technology, but facing difficulties in adsorbent regeneration or membrane fouling problems), advanced oxidation technologies (such as Fenton method and ozone oxidation, which can generate reactive free radicals to degrade pollutants, but have defects such as large amounts of iron sludge and low ozone utilization rate), and biological enhancement technologies (by domesticating highly efficient strains to improve the degradation efficiency, but with high requirements for strain stability).
[0003] The iron-carbon internal electrolysis method is an electrochemical treatment technology without external power supply, which uses the potential difference between iron and carbon to form a micro-galvanic cell system in wastewater. An oxidation reaction occurs at the iron anode (Fe → Fe 2+ + 2e - ), and a reduction reaction occurs at the carbon cathode (O2 + 4H + + 4e - → 2H2O), and pollutants are removed through the synergistic effects of oxidation-reduction, adsorption and flocculation. This method has low energy consumption and simple operation, and is widely used in the treatment of refractory organic wastewater.
[0004] Blast furnace dust (BFD) is a by-product of soot collected during the production process of the iron and steel industry, with iron and carbon contents as high as 45%-65%. These natural components endow BFD with excellent electrochemical reaction activity and are high-quality raw materials for preparing iron-carbon particle materials. Compared with iron-carbon materials synthesized by chemical proportioning, the preparation of BFD helps in the resource utilization of iron and steel solid waste. However, there are still problems such as low reaction rate and passivation of active sites in the single iron-carbon system when treating refractory organic wastewater. Therefore, subsequent research introduced the doping of transition metal Co to optimize the performance of the iron-carbon system. Transition metal Co improves the redox cycle of Fe 2+ / Fe 3+ , can effectively activate the H2O2 generated in the system, enhance the Fenton-like reaction process, and synergistically improve the removal effect. Summary of the Invention
[0005] In view of problems such as low reaction rate and passivation of active sites, the present invention provides a preparation method of a transition metal Co-loaded blast furnace dust-based iron-carbon particle electrode for treating refractory organic wastewater. After pretreating the blast furnace dust, using the blast furnace dust as a substrate, adding carbon black, urea, clay and EDTA, mixing the above materials in a certain mass ratio and stirring evenly, preparing a Co(NO3)2·6H2O solution to replace deionized water for bonding, making a particle electrode by a granulator, and then sintering it into a Co-Fe-C particle electrode by a calcination method. The adsorption performance and catalytic activity of the modified Co-Fe-C are significantly improved, thereby improving the treatment efficiency of refractory organic wastewater.
[0006] In view of the problems existing in the prior art, the present invention provides the following technical solutions:
[0007] A preparation method of a transition metal Co-loaded blast furnace dust-based iron-carbon particle electrode, the method having the following steps.
[0008] (1) Pretreatment of blast furnace dust: First, pickling with hydrochloric acid solution to remove inorganic impurities, then alkali washing with sodium hydroxide solution to remove surface oil stains, and then washing with deionized water to be neutral. The washed blast furnace dust is placed in a blast drying oven to be fully dehydrated and dried, and then pulverized by a ball mill to obtain blast furnace dust.
[0009] (2) Preparation of particle electrode: Using blast furnace dust as the main substrate, adding carbon black, urea, clay and EDTA, mixing, using a Co(NO3)2·6H2O solution to replace deionized water for bonding, and making a spherical particle electrode by a granulator.
[0010] (3) Drying the prepared particle electrode, and then placing it in a muffle furnace with nitrogen passing through for calcination.
[0011] Preferably, in step (1), the particle size of the blast furnace dust is 90-110 mesh, and the optimal particle size is 110 mesh.
[0012] Preferably, in step (2), the particle size of the Co-Fe-C particle electrode is 3-5 mm, and the optimal particle size is 4 mm, which is beneficial to separation from water.
[0013] Preferably, in step (2), the proportion of the blast furnace dust is 60-70%, the proportion of urea is 6%-7%, the proportion of clay is 30%-35%, and the proportion of carbon black is 3%-5%.
[0014] Preferably, in step (2), the EDTA is used as a pore structure regulator, and the Fe:EDTA ratio is 1:1-3:1, which can react with Fe 3+ 、Co 2+Form a complex, which produces a hierarchical pore structure after pyrolysis at high temperature. The optimal ratio of Fe:EDTA = 3:1, with a specific surface area of 7.53 m 2 / g and a pore diameter of 8.36 nm.
[0015] Preferably, in step (2), the concentration of the Co(NO3)2·6H2O solution is 0-1 mol / L, and the optimal concentration is 1 mol / L.
[0016] Preferably, in step (3), the calcination is carried out at 800-900 °C under nitrogen for 1-2 h, and the optimal condition is calcination at 900 °C for 1 h.
[0017] The advantages and effects of the present invention are as follows:
[0018] The transition metal Co-loaded blast furnace dust-based iron-carbon particle electrode prepared by the present invention. From the perspective of raw materials, the blast furnace dust selected in the present invention is inexpensive and easily available, without relying on expensive and difficult-to-purchase chemical reagents. This not only reduces the production cost but also realizes the resource utilization of steel solid waste, with good environmental benefits. In terms of performance, the particle electrode significantly enhances the adsorption performance and the generation ability of active substances of the iron-carbon microelectrolysis by loading the transition metal Co. This enables it to more efficiently remove color and COD when treating actual printing and dyeing wastewater, improving the overall effect of wastewater treatment. In addition, the electrode also has the characteristic of being reusable. After secondary cleaning, it can be reused, greatly improving the resource utilization rate and further reducing the use cost, with high economic benefits and practical value. Description of the Drawings
[0019] Figure 1 It is a SEM image of the unloaded Co iron-carbon particle electrode at a magnification of 5K.
[0020] Figure 2 It is a SEM image of the Co-loaded Co-Fe-C particle electrode at a magnification of 5K.
[0021] Figure 3 It is an EDS energy spectrum diagram of the Co-Fe-C particle electrode.
[0022] Figure 4 It is an adsorption curve of the Co-Fe-C particle electrode.
[0023] Figure 5 It is a graph of the removal rates of COD and color of the Co-Fe-C particle electrode for degrading actual printing and dyeing wastewater.
[0024] Figure 6 It is an 8-cycle experiment graph of the Co-Fe-C particle electrode. Detailed Embodiments
[0025] Example 1: Preparation of Co-Fe-C Particle Electrode
[0026] The blast furnace dust was pretreated by screening the dust below 105 mesh. 60 g of blast furnace dust, 30 g of clay, 7 g of urea, 3 g of carbon black and 10 g of EDTA were mixed, and 1 mol / L Co(NO3)2·6H2O solution was used instead of deionized water for bonding, and 4 mm spherical particle electrodes were made by a granulator. Then the made small balls were placed in a blast drying oven and dried at 105 °C. The dried particle electrodes were calcined in a muffle furnace with nitrogen passing through, where the heating rate was 5 °C / min and the nitrogen flow rate was 80 mL / min. After heating to 900 °C, it was held at a high temperature for 1 h. The Co-Fe-C particle electrodes were obtained.
[0027] From Figure 1 the SEM, it can be seen that the surface of the iron-carbon particle electrode without Co loading is smooth. From Figure 2 the SEM, it can be clearly seen that after Co loading, the surface of the Fe-C particle electrode undergoes significant structural reconstruction, forming a rough surface with a rich mesoporous structure, increasing the contact area between the particle electrode and the wastewater. This is beneficial for the pollutants in the wastewater to enter the interior of the particle electrode, improving the mass transfer effect, and enabling the degradation reaction of the pollutants to occur simultaneously on the particle surface and inside. This is due to the thermal decomposition of the EDTA chelate during the high-temperature sintering process. The EDTA chelate decomposes to produce gases at high temperature, and these gases form microporous channels during the escape process, thus promoting the roughening of the particle electrode surface and the formation of the mesoporous structure.
[0028] The elemental distribution on the surface of the Co-Fe-C particle electrode EDS electrode ( Figure 3 ) shows that the atomic percentage of Co is 7.25%, indicating that the transition metal Co is doped onto the iron-carbon particle electrode. It shows that the Co-Fe-C material is successfully prepared.
[0029] Example 2: Adsorption Performance of Co-Fe-C Particle Electrode
[0030] 10 g of the iron-carbon particle electrode without Co doping and the iron-carbon particle electrode doped with Co were taken respectively and added into 100 ml of actual printing and dyeing wastewater, and then placed in a shaking box (rotation speed: 80 rpm). Then 3 mL of the actual printing and dyeing wastewater was taken at 12 time points (10, 20, 40, 60, 80, 120, 150, 180, 300, 420, 540, 720 min) respectively to measure the COD concentration and calculate the adsorption capacity. From Figure 4 it can be seen that the adsorption capacity of the Co-catalyzed modified particle electrode is higher than that of the iron-carbon particle electrode without Co doping.
[0031] Example 3: Removal effect of Co-Fe-C granular electrode on actual printing and dyeing wastewater
[0032] Using graphite electrodes as the anode and cathode, both with dimensions of 10 cm × 5 cm, 60 g of iron-carbon granular electrodes without Co doping and 60 g of iron-carbon granular electrodes doped with Co were respectively placed in the middle of the electrodes. The electrode spacing was 20 mm, and the current density was 15 mA / cm 2 , and 500 ml of actual printing and dyeing wastewater was degraded for the electrocatalytic oxidation ability test.
[0033] After 4 hours of reaction, from Figure 5 It can be seen that the removal rates of COD and chromaticity of the Co-Fe-C granular electrode for actual printing and dyeing wastewater are 78.60% and 85.50% respectively, and the removal rates of COD and chromaticity of the Fe-C granular electrode for actual printing and dyeing wastewater are 30.10% and 32.09% respectively, indicating that Co doping not only enhances the micro-electrolysis effect (Fe 2+ / Fe 3+ cycle), but also promotes the synergistic generation of various active species (·OH, H*, and 1 O2) through the electrocatalytic process.
[0034] Example 4: Stability of Co-Fe-C granular electrode
[0035] The experiment was carried out with graphite electrodes as the anode and cathode, both with dimensions of 10 cm × 5 cm. 60 g of iron-carbon granular electrodes loaded with Co were placed in the middle of the electrodes. The electrode spacing was 20 mm, and the current density was 15 mA / cm 2 , and 500 ml of actual printing and dyeing wastewater was degraded. The reaction time was 4 hours. After one experiment, the granular electrode did not need to be separated and re-added to the actual printing and dyeing wastewater for the next experiment. After 8 cycles, from Figure 6 It can be seen that the COD removal rate of the Co-Fe-C granular electrode decreased from 78.60% to 71.11%, and the decolorization rate decreased from 85.50% to 78.20%, indicating that the Co-Fe-C granular electrode has good reusability.
[0036] Therefore, the electrocatalytic oxidation ability of the Co-doped iron-carbon granular electrode has been significantly improved, and it has high application value in the field of refractory organic wastewater.
[0037] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any equivalent modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention shall be included within the scope of the patent of the present invention.
Claims
1. Preparation method of a transition metal Co-loaded iron-carbon particle electrode based on blast furnace dust removal ash: characterized in that The method has the following steps: (1) Pretreatment of blast furnace dust: Firstly, hydrochloric acid solution is used for pickling to remove inorganic impurities, then sodium hydroxide solution is used for alkali washing to remove surface oil stains, and then it is washed with deionized water to be neutral; the washed blast furnace dust is placed in a blast drying oven for sufficient dehydration and drying, and after being pulverized by a ball mill, blast furnace dust is obtained. (2) Preparation of granular electrode: Using blast furnace dust as the main base material, adding carbon black, urea, clay and EDTA, mixing them, using Co(NO3)2·6H2O solution instead of deionized water for bonding, and making spherical granular electrodes by a granulator. (3) The prepared granular electrodes are dried and then placed in a muffle furnace with nitrogen passing through for calcination.
2. The preparation method according to claim 1, wherein In step (1), the particle size of the blast furnace dust is 90 - 110 mesh, and the optimal particle size is 110 mesh.
3. The preparation method according to claim 1, characterized in that, In step (2), the particle size of Co - Fe - C is 3 - 5 mm, and the optimal particle size is 4 mm, which is beneficial to separation from water.
4. The preparation method according to claim 1, characterized in that, In step (2), the proportion of blast furnace dust is 60 - 70%, the proportion of urea is 6% - 7%, the proportion of clay is 30% - 35%, and the proportion of carbon black is 3% - 5%.
5. The preparation method according to claim 1, wherein In step (2), the EDTA is used as a pore structure regulator, and the ratio of Fe:EDTA is 1:1 - 3:1, which can form a complex with Fe 3+ , Co 2+ to form a complex. After high-temperature decomposition, a hierarchical pore structure is generated. The optimal ratio of Fe:EDTA = 3:1, with a specific surface area of 7.53 m 2 / g and a pore diameter of 8.36 nm.
6. The preparation method according to claim 1, characterized in that, In step (2), the concentration of the Co(NO3)2·6H2O solution is 0 - 1 mol / L, and the optimal concentration is 1 mol / L.
7. The preparation method according to claim 1, characterized in that In step (3), the calcination is carried out at 800 - 900 °C in a nitrogen atmosphere for 1 - 2 h.
8. The preparation method according to claim 1, characterized in that: Co-Fe-C forms a highly ordered CoFe2O4 spinel phase, and its unique crystal structure not only promotes electron transport and ion diffusion, but also provides rich redox active centers through the synergistic effect of the multivalent states of Co 3+ / Co 2+ and Fe 3+ / Fe 2+ 9. Application of a granular electrode prepared by the preparation method described in claims 1 - 8 in the treatment of refractory organic wastewater.