Method for treating heavy metal lead-organic complex wastewater
By improving the hydrophilicity and mass transfer efficiency of the carbon felt through wetting, a two-chamber reactor was constructed for electrochemical reduction treatment, which solved the problem of efficient treatment and high-value recovery of lead-organic complex wastewater, achieving efficient removal and high-quality lead recovery.
Patent Information
- Application Number
- CN202410991877.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-07-23
- Publication Date
- 2026-01-23
AI Technical Summary
Existing technologies are difficult to efficiently treat stable heavy metal lead-organic complex wastewater. In particular, advanced oxidation and electrochemical oxidation methods suffer from problems such as high catalyst requirements, limited reaction rates, high electrode material costs, and poor selectivity, resulting in low treatment efficiency and low recovery efficiency.
A two-chamber reactor was constructed using wetted carbon felt as the working electrode for electrochemical reduction treatment. Wetting improved the hydrophilicity and mass transfer efficiency of the carbon felt, thereby enhancing the selectivity and electrochemical performance for the heavy metal lead.
This method achieves efficient removal of heavy metal lead from wastewater and yields high-quality elemental lead. The process is simple, low-cost, and suitable for large-scale industrial applications.
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Figure CN121377233A_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The application belongs to the technical field of ecological environment governance, and relates to a method for treating heavy metal lead-organic complex wastewater. BACKGROUND
[0002] In recent years, due to the rapid growth of industrial demand and mining production, a large amount of heavy metal lead wastewater will be generated in the mining, non-ferrous metallurgy, electroplating and other industries. Since heavy metal lead cannot be biodegraded, it is easy to accumulate in organisms and pose a great threat to public health through the food chain. In addition, heavy metal lead is prone to combine with organic ligands (such as ethylenediaminetetraacetic acid (EDTA)) in wastewater to form more stable metal lead-organic complexes. Not only does the heavy metal lead combine with the organic ligands in wastewater, but many industries also use organic ligand-containing eluents to treat heavy metal lead, such as soil washing method for repairing heavy metal lead soil, which will generate a large amount of wastewater containing heavy metal lead-organic complexes. In the electroplating industry, EDTA is used to extract heavy metal lead on printed circuit boards, which will generate a large amount of wastewater containing heavy metal lead-organic complexes. This wastewater containing stable heavy metal lead-organic complexes is more difficult to treat than pure heavy metal lead ion wastewater, so how to treat this wastewater containing heavy metal lead-organic complexes has become one of the research focuses in the environmental field.
[0003] At present, the main treatment processes for wastewater containing such stable heavy metal-organic complexes include advanced oxidation method, electrochemical oxidation method and electrochemical reduction method. The advanced oxidation method relies on active oxygen substances (such as hydroxyl radicals) generated by catalytic reaction to destroy the organic structure in the heavy metal-organic complex, so that the heavy metal ions are released again. This method not only needs to add a large amount of catalyst to promote the generation of oxidizing substances, but also the reaction rate is limited by the generation rate of oxidizing substances. The electrochemical oxidation method uses active oxygen substances (such as hydroxyl radicals) generated by the anode to destroy the heavy metal complex and oxidize it into small molecular substances to release heavy metal ions, which are then precipitated and recovered on the cathode. Although this method solves the problem of subsequent heavy metal treatment, it has the problem of low heavy metal recovery efficiency. The electrochemical reduction method recovers the metal as an element on the cathode through the reduction of the cathode, but the modification method of the electrode material currently has the problems of high cost, complex process and inability to be applied on a large scale. In addition, the selectivity of the electrode material to heavy metal lead is poor, and it is difficult to recover high-quality elemental lead. Therefore, it is of great significance to obtain an electrode material with simple preparation process, low cost, excellent electrochemical performance and high selectivity to heavy metal lead for efficient treatment of wastewater containing heavy metal lead-organic complexes and high-value recovery of lead in wastewater. SUMMARY
[0004] The technical problem solved by the present application is to overcome the shortcomings of the prior art, and provide a method for treating heavy metal lead-organic complex wastewater, which is simple in process, convenient to operate and low in cost, can efficiently remove heavy metal lead in the wastewater, and can obtain high-quality elemental lead.
[0005] To solve the above technical problems, the present application adopts the following technical solutions:
[0006] A method for treating heavy metal lead-organic complex wastewater, wherein the method is to use wetted carbon felt as a working electrode to perform electrochemical reduction treatment on the heavy metal lead-organic complex wastewater.
[0007] The above method is further improved, wherein the wetted carbon felt is prepared by the following method: using ultrapure water to flush the carbon felt until the carbon felt is completely wetted by water to obtain the wetted carbon felt.
[0008] The above method is further improved, wherein the temperature of the water is 20-25 DEG C.
[0009] The above method is further improved, wherein when the wetted carbon felt is used as the working electrode to perform electrochemical reduction treatment on the heavy metal lead-organic complex wastewater, the method comprises the following steps:
[0010] S1, using the wetted carbon felt as the working electrode to construct an electrochemical device with a double-chamber reactor;
[0011] S2, passing the heavy metal lead-organic complex wastewater into the electrochemical device with the double-chamber reactor to perform electrochemical reduction treatment, thereby completing the treatment of the heavy metal lead-organic complex wastewater.
[0012] The above method is further improved, wherein in step S1, the electrochemical device with the double-chamber reactor further comprises a cation exchange membrane as a separator and carbon felt as an anode.
[0013] The above method is further improved, wherein in step S2, the voltage is controlled to be 6-10 V during the electrochemical reduction treatment.
[0014] The above method is further improved, wherein in step S2, the electrochemical reduction treatment time is 0.5-3 h.
[0015] The above method is further improved, wherein in step S2, the initial concentration of the heavy metal lead-organic complex in the heavy metal lead-organic complex wastewater is ≤100 mg / L. -1 The organic ligand in the heavy metal lead-organic complex wastewater is EDTA-Na2.
[0016] The method is further improved, and the initial pH value of the heavy metal lead-organic complex wastewater in step S2 is 3-12.
[0017] Compared with the prior art, the application has the advantages that:
[0018] (1) In the application, the wetted carbon felt can change the performance of the carbon felt, improve the mass transfer efficiency of the carbon felt and the selectivity to heavy metal lead. Specifically, all the pores in the carbon felt are filled with water, which can improve the surface energy of the carbon felt and convert the carbon felt from hydrophobicity to superhydrophilicity. This can significantly improve the mass transfer efficiency between the carbon felt and the electrolyte solution. The method of wetting the carbon felt is a physical modification method, which does not change the morphology, structure, physical and chemical properties of the carbon felt, and can make the carbon felt maintain long-term stable use. More importantly, the wetted carbon felt can significantly improve the electrochemical performance of the carbon felt and the selectivity to heavy metal lead. Therefore, using the wetted carbon felt as the working electrode to electrochemically reduce the heavy metal lead-organic complex wastewater can not only efficiently remove the heavy metal lead in the wastewater, but also obtain high-quality elemental lead. Moreover, the method for treating heavy metal lead-organic complex wastewater has the advantages of simple process, easy operation, low cost and the like, and has very important significance for efficiently treating heavy metal lead-organic complex wastewater and realizing high-value recovery of lead in the wastewater.
[0019] (2) The preparation method of the wetted carbon felt has the advantages of simple process, low cost and the like, is suitable for large-scale preparation, is convenient for industrial application, and has good application prospect in industry. BRIEF DESCRIPTION OF DRAWINGS
[0020] In order to make the purpose, technical scheme and advantages of the embodiments of the application clearer, the technical scheme in the embodiments of the application will be described clearly and completely below in combination with the drawings of the embodiments of the application.
[0021] Figure 1 The SEM images of the original carbon felt (a) and the wetted carbon felt (b) in Example 1 of the application.
[0022] Figure 2 The XPS images of the original carbon felt (a) and the wetted carbon felt (b) in Example 1 of the application.
[0023] Figure 3 The FTIR images of the original carbon felt (a) and the wetted carbon felt (b) in Example 1 of the application.
[0024] Figure 4 The contact angle test images of the original carbon felt (a) and the wetted carbon felt (b) in Example 1 of the application.
[0025] Figure 5 CV graph of the raw carbon felt and the wetted carbon felt in Example 1 of the present application.
[0026] Figure 6 Removal effect graph of the heavy metal lead-organic complex wastewater by the raw carbon felt and the wetted carbon felt as the working electrode in Example 1 of the present application.
[0027] Figure 7 Removal effect graph of different heavy metal-organic complex wastewater by the wetted carbon felt as the working electrode in Example 2 of the present application. DETAILED DESCRIPTION
[0028] The present application is further described below in conjunction with the accompanying drawings and specific preferred embodiments, but the protection scope of the present application is not limited thereby.
[0029] In the following examples of the present application, the materials and instruments used are commercially available, the equipment used is conventional equipment, and the data obtained are the average values of more than three repeated experiments, unless otherwise specified.
[0030] Example 1
[0031] A method for treating heavy metal lead-organic complex wastewater, specifically, electrochemical reduction treatment of heavy metal lead-organic complex wastewater by using wetted carbon felt as the working electrode, comprising the following steps:
[0032] S1, using wetted carbon felt as the working electrode, non-wetted carbon felt as the anode, cation exchange membrane as the diaphragm, to construct an electrochemical device with a double-chamber reactor.
[0033] S2, the initial concentration of heavy metal lead-organic complex (Pb-EDTA-Na2) is 100 mg / L -1 , the initial pH value of the heavy metal lead-organic complex wastewater is 3, and the wastewater is introduced into the electrochemical device with a double-chamber reactor for electrochemical reduction treatment for 60 min, and the voltage is controlled at 8 V during the electrochemical reduction treatment, to complete the treatment of the heavy metal lead-organic complex wastewater.
[0034] Control group: using raw carbon felt as the working electrode, and other conditions are the same as in Example 1.
[0035] In this example, the wetted carbon felt is prepared by the following method:
[0036] The carbon felt is rinsed with ultrapure water at a temperature of 20-25℃ until the carbon felt is completely wetted with water, to obtain the wetted carbon felt.
[0037] The above-mentioned water rinsing method for wetting modifies the carbon felt without causing any changes to the morphology, structure, physical and chemical properties of the carbon felt, and the specific test results are as follows:
[0038] Figure 1 These are SEM images of the original carbon felt (a) and the wetted carbon felt (b) in Embodiment 1 of the present invention. Figure 1 It can be seen that the water wetting modification method does not modify the carbon felt fibers in any way, such as not creating pores or making the fibers rougher, and the morphology of the carbon felt does not change before and after wetting.
[0039] Figure 2 These are XPS images of the original carbon felt (a) and the wetted carbon felt (b) in Embodiment 1 of the present invention. Figure 2 It was observed that the modification method did not change the valence state of the elements on the carbon felt, nor did it change the original chemical bonds.
[0040] Figure 3 These are FTIR images of the original carbon felt (a) and the wetted carbon felt (b) in Embodiment 1 of the present invention. From... Figure 3 It can be observed that no new functional groups are generated before and after the carbon felt is wetted, and the existing functional groups are not changed.
[0041] Depend on Figure 1 , Figure 2 , Figure 3 The results show that the modification method of wetting carbon felt with water in this invention does not cause any change to the morphology and chemical properties of carbon felt, indicating that this modification method can ensure the stable chemical properties of carbon felt.
[0042] Figure 4 These are contact angle test diagrams of the original carbon felt (a) and the wetted carbon felt (b) in Embodiment 1 of the present invention. From... Figure 4 The results shown in the paper show that the original carbon felt has strong hydrophobicity (contact angle = 121.2°); however, after the carbon felt is wetted with water, it becomes superhydrophilic (contact angle = 0°). This indicates that when the carbon felt is wetted with water, it can accelerate the electron transfer between the electrode and electrolyte interface and improve the mass transfer efficiency of the heavy metal recovery reaction.
[0043] Figure 5 This is a CV diagram of the original carbon felt and the wetted carbon felt in Embodiment 1 of the present invention. From... Figure 5 It was observed that the curve of the wetted carbon felt was fuller than that of the original carbon felt, and the area enclosed by the closed curve was larger, indicating that the wetted carbon felt had better electrochemical performance. At the same time, the CV curve of the wetted carbon felt showed reduction peaks at -0.5V and -0.8V, indicating that the wetted carbon felt could recover heavy metal lead from the solution through reduction reaction.
[0044] During the reaction, the reduction of Pb in Pb-EDTA by the cathode 2+The reduction of Pb to elemental Pb is deposited on the electrode, while the separated EDTA anion migrates to the anode, but due to the presence of the cation membrane, the EDTA ion cannot pass through the membrane to reach the anode, thereby ensuring that the EDTA is not oxidized. At the same time, the residual concentration of Pb-EDTA in the test wastewater is determined during the reaction process, and the removal rate of lead in the wastewater is calculated, and the results are shown in Figure 6 .
[0045] Figure 6 Figure 1 shows the removal effect of heavy metal lead-organic complex wastewater when the original carbon felt and the wetted carbon felt are used as the working electrode in Example 1. It can be seen from Figure 6 that when the fully wetted carbon felt is used as the working electrode and the electrochemical device with a double-chamber reactor is used to treat the Pb-EDTA solution, Pb can be completely removed within 60 minutes. The original carbon felt can only remove about 10% of Pb at 60 minutes, which shows that the wetted carbon felt has a great advantage in removing Pb-EDTA.
[0046] Example 2
[0047] The removal effect of different heavy metal-organic complex wastewaters when the wetted carbon felt is used as the working electrode is investigated, including the following steps:
[0048] S1, using the wetted carbon felt prepared in Example 1 as the working electrode, the un-wetted carbon felt as the anode, and the cation exchange membrane as the diaphragm, an electrochemical device with a double-chamber reactor is constructed.
[0049] S2, the mixed wastewater containing heavy metal lead-organic complex (Pb-EDTA-Na2) and heavy metal manganese-organic complex (Mn-EDTA-Na2) (the initial concentrations of Pb-EDTA-Na2 and Mn-EDTA-Na2 in the wastewater are the same, both are 100 mg / L -1 , and the initial pH value is 3) is introduced into the electrochemical device with a double-chamber reactor for electrochemical reduction treatment for 60 minutes, and the voltage is controlled at 8V during the electrochemical reduction treatment to complete the treatment of the heavy metal lead-organic complex wastewater.
[0050] In this example, the removal effects of the mixed wastewater containing heavy metal lead-organic complex (Pb-EDTA-Na2) and heavy metal iron-organic complex (Fe-EDTA-Na2), and the mixed wastewater containing heavy metal lead-organic complex (Pb-EDTA-Na2) and heavy metal cadmium-organic complex (Cd-EDTA-Na2) when the wetted carbon felt is used as the working electrode are also investigated, and the conditions are the same except for the types of complexes.
[0051] After the reaction is completed, the residual concentrations of different heavy metal-organic complexes in the wastewater are tested, and the removal rates of different heavy metal-organic complexes in the wastewater are calculated, and the results are shown in Table 2. Figure 7
[0052] Figure 7 The figure is the removal effect of different heavy metal-organic complex wastewater when the wetted carbon felt is used as the working electrode in the embodiment 2 of the present application. Figure 7 It can be seen that the wetted carbon felt can achieve high selective removal rate of Pb when treating Pb-EDTA and Mn-EDTA, Pb-EDTA and Fe-EDTA, and Pb-EDTA and Cd-EDTA with the same concentration, which shows that the wetted carbon felt can selectively remove lead from different heavy metal-organic complex wastewater and has very good removal effect.
[0053] From the above results, it can be seen that in the present application, the wetted carbon felt is used as the working electrode to perform electrochemical reduction treatment on the heavy metal lead-organic complex wastewater, which can not only efficiently remove the heavy metal lead in the wastewater, but also obtain high-quality elemental lead, and the method for treating the heavy metal lead-organic complex wastewater has the advantages of simple process, convenient operation, low cost, etc., which has very important significance for efficiently treating the heavy metal lead-organic complex wastewater and realizing high-value recovery of lead in the wastewater.
[0054] The above embodiments are only preferred embodiments of the present application, and the protection scope of the present application is not limited to the above embodiments. Any technical scheme falling within the idea of the present application belongs to the protection scope of the present application. It should be pointed out that the improvements and decorations of the ordinary skilled in the art without departing from the principles of the present application should also be considered as the protection scope of the present application.
Claims
1. A method of treating heavy metal lead-organic complex wastewater, characterized by, The method is to use the wetted carbon felt as a working electrode to carry out electrochemical reduction treatment on heavy metal lead-organic complex wastewater.
2. The method of claim 1, wherein, The wetted carbon felt is prepared by the following method: the carbon felt is washed with ultrapure water until the carbon felt is completely wetted by water to obtain the wetted carbon felt.
3. The method of claim 2, wherein, The temperature of the water is 20-25 DEG C.
4. The method according to any one of claims 1 to 3, characterized in that, When the wetted carbon felt is used as a working electrode to carry out electrochemical reduction treatment on heavy metal lead-organic complex wastewater, the following steps are included: S1, using the wetted carbon felt as a working electrode to construct an electrochemical device with a double-chamber reactor; S2, passing the heavy metal lead-organic complex wastewater into the electrochemical device with the double-chamber reactor to carry out electrochemical reduction treatment, and completing the treatment of the heavy metal lead-organic complex wastewater.
5. The method of claim 4, wherein, In step S1, the electrochemical device with the double-chamber reactor further includes a cation exchange membrane as a diaphragm and a carbon felt as an anode.
6. The method of claim 4, wherein, In step S2, the voltage is controlled to be 6-10 V during the electrochemical reduction treatment.
7. The method of claim 6, wherein, In step S2, the electrochemical reduction treatment time is 0.5-3 h.
8. The method of claim 6, wherein, In step S2, the initial concentration of the heavy metal lead-organic complex in the heavy metal lead-organic complex wastewater is ≤ 100 mg / L -1 ; the organic ligand in the heavy metal lead-organic complex wastewater is EDTA-Na2.
9. The method of claim 8, wherein, In step S2, the initial pH value of the heavy metal lead-organic complex wastewater is 3-12.