An anode membrane module for treating high-salinity organic wastewater and a method of manufacturing the same

Abstract

The application provides an anode membrane assembly for treating high-salt organic wastewater and a preparation method thereof, and belongs to the technical field of water treatment. The preparation method of the anode membrane assembly comprises the following steps: (1) cleaning and etching of a titanium mesh substrate; (2) citric acid and ethylene glycol are poured into a beaker, tin tetrachloride SnCl4.5H2O and antimony trichloride SbCl3 are added while water bath heating, stirring and maintaining water bath heating to form a sol-gel; (3) the substrate is immersed in the sol-gel, and then drying is carried out in an electric heating air drying oven, the above steps are repeated, and the immersed and coated titanium mesh is placed into a muffle furnace for high-temperature calcination to obtain a titanium substrate tin-antimony anode membrane; (4) two pieces of the titanium substrate tin-antimony anode membrane are fixed on the two sides of a PVC membrane support respectively, and ABS glue is used for bonding and sealing at the edge, so that the anode membrane assembly is obtained. The application solves the technical problem that the high Cl ‑ concentration in high-salt wastewater affects the removal of organic matters by electro-oxidation.

Description

Technical Field

[0001] This invention relates to the field of water treatment technology, and in particular to an anode membrane assembly for treating high-salt organic wastewater and its preparation method. Background Technology

[0002] Dimethyl sulfoxide (DMSO) is widely used as an organic solvent in the chemical industry due to its excellent thermal stability and solubility. It is used in the production of pharmaceuticals, semiconductors, thin-film transistors, liquid crystal displays, thin films, and polymers, and is therefore frequently detected in chemical wastewater effluents. Long-term exposure to DMSO poses a significant threat to human health. However, considering the high salinity and low organic matter concentration of chemical wastewater, biological methods are not efficient at removing organic matter from high-salinity chemical wastewater. Therefore, the advanced treatment of DMSO in high-salinity chemical wastewater remains a challenging problem in the field of water treatment.

[0003] However, Cl in high-salinity wastewater - High concentrations of hydroxyl radicals (•OH) can quench the reactive species system, weakening its ability to remove organic matter. Therefore, chlorine-mediated free radical species (Cl•, Cl2) are more susceptible to quenching. •- Electrode materials (such as ClO•) may play an important role in the removal of organic matter in the system. However, current electrode materials suffer from problems such as poor stability, selective oxidation of organic matter, and excessively high chlorine evolution potential. At the same time, electrocatalytic systems also suffer from poor mass transfer performance.

[0004] To address the mass transfer problem in single electrocatalytic systems, coupling electrocatalysis with membrane separation can enhance the contact between organic matter and active species in wastewater, improve mass transfer efficiency, and simultaneously achieve effective solid-liquid separation, showing promising application prospects. For example, CN110129821A provides a method for preparing tin- and antimony-doped titanium-based ruthenium dioxide coated electrodes. However, the electrodes used in this technology are common plate electrodes, often used for batch experiments and suitable for theoretical research in the laboratory. They cannot be used for continuous flow experiments or long-term stable operation experiments, severely limiting their widespread application in actual wastewater treatment processes.

[0005] Therefore, developing efficient and stable anode membrane modules is the key to the application and development of the above technologies and a breakthrough point for realizing the electrochemical oxidation method for treating high-salt organic wastewater. Summary of the Invention

[0006] To address the aforementioned problems in existing technologies, this invention provides an anode membrane module for treating high-salinity organic wastewater and its preparation method. This invention solves the problem of Cl in high-salinity wastewater... - Excessive concentration poses a technical challenge to the removal of organic matter by electro-oxidation.

[0007] The technical solution of the present invention is as follows:

[0008] An anode membrane module for treating high-salt organic wastewater, the preparation method of the anode membrane module includes the following steps:

[0009] (1) Cleaning and etching of titanium mesh substrate: After cleaning and drying, the titanium mesh is placed in oxalic acid solution for etching. After etching, it is cleaned and dried for later use.

[0010] (2) Preparation of sol-gel: Citric acid and ethylene glycol are poured into a beaker, and tin tetrachloride SnCl4·5H2O and antimony trichloride SbCl3 are added while heating in a water bath. Stir and keep heating in a water bath to form a sol-gel.

[0011] (3) Preparation of tin-antimony anode film: The titanium mesh substrate obtained in step (1) is immersed in sol-gel, and then dried in an electric heating drying oven. The above steps are repeated at least 8 times and the dip-coated titanium mesh is placed in a muffle furnace for high-temperature calcination to obtain a titanium-based tin-antimony anode film.

[0012] (4) Preparation of anode film assembly: two titanium-based tin-antimony anode films obtained in step (3) are fixed on both sides of a PVC film support, and the edges are sealed with ABS glue to obtain the anode film assembly.

[0013] Preferably, the titanium mesh in step (1) has a mesh size of 100-500.

[0014] Preferably, the oxalic acid solution in step (1) has a mass fraction of 5-10% and an etching time of 20-40 min.

[0015] Preferably, the molar ratio of each substance in the sol-gel in step (2) is citric acid: ethylene glycol: SnCl4·4H2O: SbCl3 = 120-160: 25-35: 7-11: 1.

[0016] Preferably, the water bath heating temperature in step (2) is 50-70°C. o C, the reaction time is 30-40 min.

[0017] Preferably, the impregnation time in step (3) is 0.5-1.5 min, the drying time is 8-15 min, and the drying temperature is 120-160°C. o C.

[0018] Preferably, the roasting temperature in step (3) is 400-700°C. o C, roasting time is 1-5 h.

[0019] The present invention also provides the application of the aforementioned anode membrane module in the treatment of high-salt organic wastewater, comprising the following steps:

[0020] a: The anode membrane assembly is placed inside the reactor and connected to the positive terminal of a DC power supply with titanium wire as the anode. A titanium mesh, copper mesh, or stainless steel wire mesh is used as the cathode. A peristaltic pump is connected to the outside of the reactor.

[0021] b: Apply voltage and start the peristaltic pump. When the anode membrane module filters high-salt organic wastewater, it carries out an electro-oxidation reaction to remove organic matter from the water.

[0022] Preferably, the current density applied to the anode in step b is 1-8 mA cm⁻¹. -2 The filtered water flux is 25-100 Lm -2 h -1 .

[0023] Preferably, the chloride ion concentration in the high-salt organic wastewater is 500-8000 mg / L. -1 The substance in the organic wastewater is dimethyl sulfoxide (DMSO), with a concentration range of 10-500 mg / L. -1 .

[0024] The beneficial technical effects of this invention are as follows:

[0025] The anode membrane module prepared in this invention can remove recalcitrant organic matter from high-salinity wastewater. Utilizing the chlorine evolution reaction of the tin-antimony electrochemical active layer, it generates a high concentration of chlorine free radicals and active chlorine components, oxidizing the recalcitrant organic matter in the water, thereby achieving efficient degradation of organic pollutants. This anode membrane module solves the problem of high-salinity wastewater Cl in electrochemical advanced oxidation. - The technical challenge lies in addressing the issue of excessively high organic matter concentrations affecting organic matter removal efficiency. Simultaneously, the anode membrane module involved in this invention possesses excellent mechanical strength and filtration performance, demonstrating significant effectiveness in removing recalcitrant organic matter, and is suitable for the efficient removal of organic matter from high-salinity wastewater. Attached Figure Description

[0026] Figure 1 This is a schematic diagram of the process for preparing the anode film assembly in Example 1.

[0027] Figure 2 This is a physical image of the anode film assembly prepared in Example 1.

[0028] Figure 3 The graphs show the removal effects of DMSO and COD in Application Examples 1 and 2. Figure 3 'a' represents application example 1. Figure 3 b is application example 2.

[0029] Figure 4 Example 1 is used to determine the valence state of sputtered metal.

[0030] Figure 5This is a comparison of the steady-state concentrations of various free radicals in Test Example 2 with those reported in the literature. Detailed Implementation

[0031] The present invention will now be described in detail with reference to the accompanying drawings and embodiments. Obviously, the described embodiments are merely some, not all, of the embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0032] Example 1:

[0033] This embodiment provides a method for preparing an anode membrane module for treating organic matter in high-salinity wastewater. The operation process is as follows: Figure 1 As shown, the specific steps are as follows:

[0034] S1. Preparation of tin-antimony anode film:

[0035] (1) After cleaning and drying the 300-mesh titanium mesh, etch it in a 10% oxalic acid solution for 30 min, clean it and dry it for later use.

[0036] (2) Pour citric acid and ethylene glycol into a beaker, and while heating in a water bath, add tin tetrachloride (SnCl4·5H2O) and antimony trichloride (SbCl3), stir and maintain the water bath heating to form a sol-gel; wherein the water bath heating temperature is 60°C. o C, the reaction time is 30 min; the molar ratio of each raw material is citric acid: ethylene glycol: SnCl4·4H2O: SbCl3 = 140:30:9:1.

[0037] (3) Immerse the titanium mesh obtained in step (1) in the sol-gel for 1 min, and then at 140°C o Dry in an electric heating drying oven for 10 minutes; repeat the above steps 10 times and place the coated titanium mesh in a muffle furnace, in an air atmosphere and at 500°C. o A titanium-based tin-antimony anode film was prepared by high-temperature calcination at C for 2 h.

[0038] S2. Preparation of the anode film assembly: Two titanium-based tin-antimony anode films prepared above are fixed to both sides of a PVC film support (external dimensions: 5 cm × 8 cm; internal dimensions: 3 cm × 6 cm). The edges are sealed with ABS adhesive, thus forming the anode film assembly. The resulting physical object is shown below. Figure 2 As shown.

[0039] Application Example 1:

[0040] The anode membrane assembly prepared in Example 1 was used with a titanium wire connected to the positive terminal of a DC power supply as the anode and a titanium mesh as the cathode. The object being treated was a DMSO solution containing high salt, with an initial DMSO concentration of 100 mg / L. -1 The chloride ion concentration is 3550 mg / L. -1 The current density is 8 mA cm⁻¹ -2 The removal effect is as follows Figure 3 As shown in Figure a, the removal rate of DMSO can reach 100% within 5 minutes, and the removal rate of COD can reach 86% after 120 minutes.

[0041] Application Example 2:

[0042] The anode membrane assembly prepared in Example 1 was used with a titanium wire connected to the positive terminal of a DC power supply as the anode and a titanium mesh as the cathode. The object being treated was a DMSO solution containing high salt, with an initial DMSO concentration of 100 mg / L. -1 The chloride ion concentration is 3550 mg / L. -1 The membrane flux is 25 L / m². -2 h -1 The current density is 8 mA cm⁻¹ -2 At that time, the removal effect after 24 hours of continuous operation is as follows Figure 3 As shown in b, this system can run continuously for 24 hours, and the removal rate of DMSO can reach 100% and the removal rate of COD can reach 87% within 5 minutes.

[0043] Test Example 1:

[0044] The valence state of the electrochemical anode membrane assembly prepared in Example 1 was determined, and the materials were characterized by X-ray diffraction and X-ray photoelectron diffraction, respectively.

[0045] Test results are as follows Figure 4 As shown. Figure 4 a is the X-ray diffraction (XRD) test result of the electrochemical anolyte assembly, indicating that Sn and Sb are uniformly loaded on the surface of the titanium mesh substrate. Figure 4 b and Figure 4 The X-ray photoelectron spectroscopy (XPS) results of c indicate that Sn and Sb exist in the forms of SnO2 and Sb2O3, respectively.

[0046] Test Example 2:

[0047] Based on Application Example 1, the concentration of free radicals in the system during the treatment of high-salinity wastewater was tested. The test method was as follows: nitrobenzene, benzoic acid, dimethyl terephthalate, and carbamazepine were selected as hydroxyl radicals, Cl·, ClO·, and Cl2, respectively. •-Chemical probes were used. These probes exhibited significantly different reaction rate constants with several free radicals, all of which are parameters known in the art. The initial concentration of each of the four probe reagents was 50 μM, and the concentrations were determined by high-performance liquid chromatography (HPLC). The degradation kinetic constants of the four chemical probes were calculated using peak area-concentration standard curves according to conventional formulas in the art. Finally, the kinetic constants for hydroxyl radicals, Cl·, ClO·, and Cl2 were calculated. •- The concentration.

[0048] After testing, the Cl2 in this system •- The steady-state concentration reached 4.08 × 10⁻⁶. -11 M, followed by ClO•(7.87 × 10) - 13 M), •OH (1.06 × 10⁻⁶) -13 M) and Cl• (6.03 × 10 -14 M).

[0049] As a comparative reference, the inventors selected four prior art documents, namely:

[0050] ① Impact of EfOM in the Elimination of PPCPs by UV / Chlorine: RadicalChemistry and Toxicity Bioassays. Wang et al., Water Res. 2021, 204, 117634;

[0051] ② Facile Ammonium Oxidation to Nitrogen Gas in Acid Wastewater by inSitu Photogenerated Chlorine Radicals. Yan et al., Water Res. 2021, 205, 117678;

[0052] ③ A Bipolar Membrane-Integrated Electrochlorination Process for Highly Efficient Ammonium Removal in Mature Landfill Leachate: The Importance of ClO· Generation. Kuang et al., Environ. Sci. Technol. 2022;

[0053] ④ Multiple Roles of Dissolved Organic Matter in Advanced OxidationProcesses. Yang et al., Environ. Sci. Technol. 2022, 56 (16), 11111–11131.

[0054] The concentrations of various free radicals given in the above four articles are as follows: Figure 5 As shown in the figure. It can be seen from the graph that at high concentrations of Cl... - In the electrocatalytic process present, the Cl2 of this invention •- The steady-state concentration was significantly higher than that reported in comparative literature, approximately five times the highest concentration reported in the literature. This indicates that the electrode material in this invention can significantly promote the generation of Cl2 in the electrochemical system. •- This enhances the efficiency of electrochemical systems in removing organic pollutants.

[0055] Compared with CN110129821A, this invention innovates the structure of wastewater treatment equipment, and produces a filter-type anode membrane module (such as...). Figure 1 and Figure 2 As shown), and a long-term stable operation experiment was conducted (as shown). Figure 3 As shown in b), the electrode membrane assembly of the present invention maintains stable performance during 24-hour long-term operation, and the wastewater treatment effect does not show significant attenuation or weakening, making it promising for broad application in the field of practical wastewater treatment. Simultaneously, when applied to an electrochemical system, the anode membrane assembly of the present invention can significantly promote the reaction of ClO· and Cl2. •- The generation of two types of free radicals enhances the electrochemical system's ability to remove and mineralize organic matter in wastewater. Furthermore, the plate electrode in CN110129821A suffers from low system mass transfer efficiency, while the anode membrane assembly in this invention is a filter electrode, which significantly enhances system mass transfer and improves the system's wastewater treatment efficiency.

[0056] Although the embodiments of the present invention have been disclosed above, they are not limited to the applications listed in the specification and embodiments. They can be applied to various fields suitable for the present invention. For those skilled in the art, and for those of ordinary skill in the art, various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principles and spirit of the present invention. Therefore, the present invention is not limited to the specific details without departing from the general concept defined by the claims and their equivalents.

Claims

1. An application of an anode membrane module in the treatment of high-salt organic wastewater, characterized in that, Includes the following steps: a: The anode membrane assembly is placed inside the reactor and connected to the positive terminal of a DC power supply with titanium wire as the anode. A titanium mesh is used as the cathode. A peristaltic pump is connected to the outside of the reactor. b: Apply voltage and start the peristaltic pump. When the anode membrane assembly filters high-salt organic wastewater, it performs an electro-oxidation reaction to remove organic matter from the water. The substance in the organic wastewater is dimethyl sulfoxide (DMSO). This system can run continuously for 24 hours and can achieve a 100% removal rate of DMSO within 5 minutes. The method for preparing the anode film assembly includes the following steps: (1) Cleaning and etching of titanium mesh substrate: After cleaning and drying, the titanium mesh is placed in oxalic acid solution for etching. After etching, it is cleaned and dried for later use. (2) Preparation of sol-gel: Citric acid and ethylene glycol are poured into a beaker, and tin tetrachloride SnCl4·5H2O and antimony trichloride SbCl3 are added while heating in a water bath. Stir and keep heating in a water bath to form a sol-gel. (3) Preparation of tin-antimony anode film: The titanium mesh substrate obtained in step (1) is immersed in sol-gel, and then dried in an electric heating drying oven. The above steps are repeated at least 8 times and the dip-coated titanium mesh is placed in a muffle furnace for high-temperature calcination to obtain a titanium-based tin-antimony anode film. (4) Preparation of anode film assembly: two titanium-based tin-antimony anode films obtained in step (3) are fixed on both sides of a PVC film support, and the edges are sealed with ABS glue to obtain the anode film assembly. The molar ratio of each substance in the sol-gel in step (2) is citric acid: ethylene glycol: SnCl4·4H2O: SbCl3 = 120-160: 25-35: 7-11:

1.

2. The application according to claim 1, characterized in that, The titanium mesh used in step (1) is 100-500 mesh.

3. The application according to claim 1, characterized in that, The oxalic acid solution in step (1) has a mass fraction of 5-10% and an etching time of 20-40 min.

4. The application according to claim 1, characterized in that, The water bath heating temperature in step (2) is 50-70°C. o C, the reaction time is 30-40 min.

5. The application according to claim 1, characterized in that, The soaking time in step (3) is 0.5-1.5 min, the drying time is 8-15 min, and the drying temperature is 120-160°C. o C.

6. The application according to claim 1, characterized in that, The roasting temperature in step (3) is 400-700°C. o C, roasting time is 1-5 h.

7. The application according to claim 1, characterized in that, In step b, the current density applied to the anode is 1-8 mA cm⁻¹. -2 The filtered water flux is 25-100 L / m³. -2 h -1 .

8. The application according to claim 1, characterized in that, The high-salt organic wastewater contains chloride ion concentrations of 500-8000 mg / L. -1 The concentration range of the dimethyl sulfoxide is 10-500 mg / L. -1 .

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