A method for degrading bisphenol a in a mud-water system

Abstract

The application discloses a method for degrading bisphenol A in a mud-water system, which is carried out in an electro-optical catalysis combined degradation device, and the electro-optical catalysis combined degradation device comprises a reactor and a light source. The reactor is divided into an anode reservoir, a reaction chamber and a cathode reservoir by a filter membrane, the reaction chamber is located between the anode reservoir and the cathode reservoir, an electrode anode is inserted into the anode reservoir, an electrode cathode is inserted into the cathode reservoir, and the electrode anode and the electrode cathode are respectively connected to the positive and negative poles of a power supply. The light source sends simulated sunlight into the anode reservoir. Na2SO4 and simulated seawater solution are respectively added into the anode reservoir and the cathode reservoir, a mud-water mixture to be treated is added into the reaction chamber, the light source and the power supply are turned on, bisphenol A in the mud-water mixture is degraded, and the mud-water mixture is kept oscillating or stirring during the degradation process. The electro-optical catalysis combined degradation device combines an electro process with photoelectrocatalysis, and degrades bisphenol A in a mud-water system in a synergistic manner, so that a good degradation effect is achieved in a relatively short time.

Description

Technical Field

[0001] This application relates to the field of pollutant degradation technology, specifically to a method for degrading bisphenol A in a mud-water system. Background Technology

[0002] Bisphenol A (BPA) is the common name for 2,2-(4,4'-dihydroxydiphenyl)propane, 4,4'-isopropylidene diphenol, or 2,2'-bis(4-hydroxyphenyl)propane, and it is an aerosol compound containing two phenolic moieties. Its key properties include low vapor pressure, moderate water solubility, and low volatility. It is a solid at room temperature.

[0003] Bisphenol A (BPA) was first reported in 1891. It was then synthesized from phenol and acetone in 1905. As an important industrial chemical, BPA is primarily used as an intermediate in the production of polycarbonate (PC) plastics and epoxy resins. They are widely used in various everyday products, including digital media (typically CDs and DVDs), electronic devices, automobiles, architectural glass, sports safety equipment, medical devices (such as dental sealants), tableware, reusable bottles (such as baby bottles), and food storage containers. Epoxy resins are also used as internal coatings for food and beverage cans to protect food and beverages from direct contact with metals. Children's toys may contain BPA, which is used as an additive in other types of plastics.

[0004] Meanwhile, bisphenol A (BPA) is structurally stable and difficult to degrade naturally in the environment, leading to its easy accumulation in large quantities. To date, increasing research indicates that significant amounts of BPA exist in the air, soil, and sediments of rivers and lakes. With changes in environmental pH and temperature, the release of BPA into the environment increases the potential exposure for humans, posing a potential risk to the human reproductive system and child development, which has attracted widespread attention from the public and academia.

[0005] Traditional bisphenol A (BPA) treatment technologies in sludge-water systems rely on microbial treatment, primarily using activated sludge (aerobic process) to remove suspended solids containing BPA from the mixed liquor generated during wastewater treatment. However, this method has limitations: microorganisms are susceptible to the toxicity of pollutants, leading to reduced activity, and its application scenarios are limited. Therefore, finding a highly efficient, stable, and versatile BPA treatment method for sludge-water systems is of great significance. Summary of the Invention

[0006] This application provides a method for degrading bisphenol A in a mud-water system. The method accelerates the separation of bisphenol A from mud-water and its migration to the target area during an electrokinetic process. The bisphenol A is effectively degraded through a photocatalytic process. Compared with traditional microbial methods, the method described in this application is more stable in operation and has a wider range of applications. It is an ideal method for degrading pollutants in mud-water systems.

[0007] A method for degrading bisphenol A in a mud-water system is carried out in an electro-photocatalytic co-degradation device. The device includes a reactor and a light source. The reactor is divided into an anode reservoir, a reaction chamber, and a cathode reservoir by a filter membrane. The reaction chamber is located between the anode and cathode reservoirs. An anode electrode is inserted into the anode reservoir, and an cathode electrode is inserted into the cathode reservoir. The anode and cathode electrodes are respectively connected to the positive and negative terminals of a power supply. The light source emits simulated sunlight to the anode electrode in the anode reservoir.

[0008] Na2SO4 solution was added to the anode and cathode reservoirs respectively. The mud-water mixture to be treated was added to the reaction chamber. The light source and power supply were turned on to degrade bisphenol A in the mud-water mixture. During the degradation process, the mud-water mixture was kept shaken or stirred.

[0009] The preparation process of the electrode anode includes:

[0010] (1) Place the FTO electrode in a hydrothermal reactor, add tetrabutyl titanate dissolved in hydrochloric acid to the hydrothermal reactor, and prepare the TiO2-NRs electrode by hydrothermal treatment.

[0011] (2) The prepared TiO2-NRs electrode was immersed in a Co3O4 suspension and then loaded under a dielectric barrier discharge plasma to obtain a Co3O4 / TiO2-NRs electrode.

[0012] In the processing method of this application, a Co3O4 / TiO2-NRs electrode is used as the anode electrode and a titanium sheet is used as the cathode electrode. They are placed in the anode and cathode reservoirs of the electro-photocatalytic synergistic treatment device, respectively. The mud-water mixture is placed in the intermediate reaction chamber and bisphenol A is degraded under simulated sunlight and applied bias conditions.

[0013] The mud-water system demands higher electrochemical properties, primarily serving the purpose of electron migration. The binary electrode material used in this application is easy to prepare, highly conductive, and resistant to corrosion, enabling it to respond to solar photocatalysis with guaranteed results, thus providing a foundation for subsequent large-size electrode fabrication. The electrode fabrication method employed in this application is characterized by its simplicity, readily available and readily purchasable chemical reagents, low equipment requirements, low experimental costs, and good electrode stability.

[0014] The substrate electrode used in this application is a commercially available FTO electrode with high transmittance, low resistance, and high conductivity. Compared to TiO2-NRs electrodes alone, the Co3O4 / TiO2-NRs composite electrode exhibits higher photoresponse capability, lower impedance, and better stability.

[0015] The following are some alternative methods, but they do not further restrict the above general solution; they only add to or optimize it. If there are no technical or logical inconsistencies, each alternative method can be combined individually with the above general solution, or multiple alternative methods can be combined.

[0016] Optionally, the soil may be derived from at least one of kaolin, natural soil, or seawater sediment.

[0017] The soil can be directly added to the reaction chamber and then mixed with the solution in the anode and cathode storage chambers to form a mud-water mixture, or it can be mixed with the solution beforehand to form a mud-water mixture before being added.

[0018] Optionally, the solution is derived from at least one of Na2SO4 solution, simulated seawater, or actual seawater.

[0019] Optionally, regardless of the method of addition, the mass-to-volume ratio of soil to solution in the entire reaction system, including the anode reservoir, cathode reservoir, and reaction chamber, is 35g to 60g: 100mL.

[0020] Optionally, the simulated seawater contains 2.5% NaCl, 1.1% MgCl2, 0.40% Na2SO4 and 0.16% CaCl2.

[0021] Optionally, the concentration of the Na2SO4 solution is 0.1 mol / L.

[0022] Optionally, the simulated sunlight intensity is 90–100 mW·cm². -2 .

[0023] Optionally, the external bias voltage applied by the power supply is 3 to 5V.

[0024] The filter membrane is used to prevent mud-water mixture from entering the anode and cathode reservoirs. Optionally, the filter membrane is filter paper, nylon mesh, or glass fiber filter; the light source is a xenon lamp light source.

[0025] Optionally, the distance between the electrode anode and the cathode anode is 7.5–8.5 cm; the distance between the reaction chambers is 3.5–4.5 cm. Here, the distance between the reaction chambers refers to the distance between the anode reservoir and the cathode reservoir.

[0026] Furthermore, the spacing between the reaction chambers is 3.5–4.5 cm, the distance between the anode and cathode electrodes is 8 cm, the filter membrane is filter paper, a regulated voltage and current of 4V is applied, the light source is a xenon lamp (500W), and the ultraviolet-visible light intensity is 100 mW·cm². -2 .

[0027] In step (1) of the electrode anode preparation process:

[0028] Optionally, in the hydrochloric acid solution of tetrabutyl titanate, the solvent is hydrochloric acid with a hydrogen chloride mass fraction of 18-19%; the tetrabutyl titanate accounts for 1.5-3% of the total volume of the solution.

[0029] Optionally, the hydrothermal reaction temperature is controlled at 160–180℃, and the reaction time is controlled at 3–5 hours.

[0030] Furthermore, the hydrochloric acid solution of tetrabutyl titanate contains 18% hydrogen chloride by mass. Tetrabutyl titanate accounts for 1.875% of the total solution volume; the hydrothermal reaction temperature is 170℃, and the reaction time is 4 hours.

[0031] Optionally, to remove surface impurities, brand new FTO glass is ultrasonically washed in acetone, ethanol, and distilled water, respectively, and then dried for the next experiment.

[0032] Specifically, a clean FTO glass with the conductive side facing up is placed at an angle in a hydrothermal reactor, and tetrabutyl titanate dissolved in hydrochloric acid is added to carry out a hydrothermal reaction.

[0033] In step (2) of the electrode anode preparation process:

[0034] Optionally, the TiO2-NRs electrode is placed at the bottom of the quartz dish, and a Co3O4 suspension is added to the quartz dish. The plasma dielectric baffle is placed horizontally above the quartz dish containing the Co3O4 suspension, and the discharge region is between the TiO2-NRs electrode at the bottom of the quartz dish and the plasma dielectric baffle.

[0035] Optionally, the distance between the plasma dielectric baffle and the surface of the Co3O4 suspension is 2-4 mm.

[0036] Optionally, the plasma load voltage is 30–40V and the load time is 5–15min.

[0037] Optionally, the concentration of Co3O4 in the Co3O4 suspension is 0.3 to 0.8 mg / mL.

[0038] Furthermore, the distance between the plasma dielectric baffle and the surface of the Co3O4 suspension is 3 mm; the plasma load voltage is 35 V, the load time is 10 min; and the concentration of Co3O4 in the Co3O4 suspension is 0.5 mg / mL.

[0039] Optionally, the Co3O4 is prepared by the MOF template method: cobalt nitrate and 2-methylimidazole are dissolved in distilled water, the mixture is stirred to obtain a purple precursor, which is then washed, dried and calcined in a crucible to obtain the Co3O4 material.

[0040] Optionally, the cobalt nitrate is cobalt nitrate hexahydrate, and the mass molar ratio of cobalt nitrate hexahydrate to 2-methylimidazole is 1:10.

[0041] Optionally, the stirring time is 6 hours.

[0042] Optionally, the drying temperature is 60°C.

[0043] Optionally, the calcination is performed by calcining in a muffle furnace at 300°C for 3 hours.

[0044] Compared with the prior art, this application has at least one of the following advantages:

[0045] (1) In this application, the Co3O4 / TiO2-NRs nanocomposite material is prepared by a simple process, in which TiO2 and Co3O4 form a heterojunction; the photoelectrocatalytic activity of the material is enhanced, thereby improving the efficiency of photoelectrocatalytic degradation of bisphenol A.

[0046] (2) This application combines the electrochemical process with photoelectrocatalysis to synergistically degrade bisphenol A in the mud-water system, achieving a good degradation effect in a short time.

[0047] (3) The mud-water mixture in this application can be derived from laboratory simulations or from the actual mixing of seawater sediment and seawater, which has strong practical significance. (4) This application is simple to operate, easy to prepare electrodes, easy to build the device, and has a wide range of applications. Attached Figure Description

[0048] Figure 1 This is a schematic diagram of the reaction apparatus in Application Example 1;

[0049] Figure 2 The image shows the treatment effect of Example 1 applied to simulated seawater. Detailed Implementation

[0050] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0051] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the application.

[0052] Example 1

[0053] 1. The preparation method of TiO2-NRs is as follows:

[0054] (1) Removal of impurities on FTO surface: FTO was ultrasonically cleaned in sequence with acetone, ethanol and distilled water.

[0055] (2) Preparation of tetrabutyl titanate hydrochloric acid solution: Add 40 mL of hydrochloric acid to 40 mL of distilled water, stir thoroughly, then add 1.2 mL of tetrabutyl titanate and stir until completely dissolved.

[0056] (3) Preparation of TiO2-NRs: FTO with the conductive side facing up was placed in a polytetrafluoroethylene liner and the mixed solution was added. TiO2-NRs were obtained by hydrothermal treatment at 170℃ for 4 hours.

[0057] 2. The preparation method of Co3O4 nanomaterials is as follows:

[0058] (1) Preparation of solution: Weigh 0.003 mol of cobalt nitrate hexahydrate into a beaker, add 10 mL of deionized water and stir to dissolve to form solution I; add 0.03 mol of 2-methylimidazole into 10 mL of deionized water and stir to form solution II.

[0059] (2) Stirring: Solution II was added to solution I under rapid stirring and magnetic stirring was performed for 6 hours to obtain Co-MOF (ZIF-67).

[0060] (3) Washing: The obtained purple precursor was repeatedly filtered and washed with ethanol and deionized water and then dried at 60°C.

[0061] (4) Calcination: Finally, the precursor was placed in a crucible and calcined in a muffle furnace at 300°C for 3 hours to obtain Co3O4 material.

[0062] 3. The preparation method of Co3O4 / TiO2-NRs is as follows:

[0063] (1) Dispersion process: Weigh 0.05g of Co3O4 and dissolve it in 100mL of distilled water. Stir the mixture with ultrasound for 30min until it is evenly dispersed to obtain a Co3O4 suspension.

[0064] (2) Plasma loading: TiO2-NRs electrode is placed at the bottom of quartz dish, Co3O4 suspension is added to quartz dish, plasma dielectric baffle is placed horizontally above quartz dish containing Co3O4 suspension, discharge area is between TiO2-NRs electrode and dielectric baffle at the bottom of quartz dish, and then quartz dish is placed in plasma equipment (dielectric barrier discharge reactor CTR-2000K).

[0065] The input voltage and discharge time are controlled separately for load application. In this embodiment, the distance between the dielectric baffle and the surface of the Co3O4 suspension is 3mm; the plasma load voltage is 35V and the load time is 10min.

[0066] (3) Preparation of Co3O4 / TiO2-NRs: The treated electrode was dried at room temperature to obtain Co3O4 / TiO2-NRs.

[0067] Application Example 1

[0068] This application example uses photoelectric and electrodynamic synergistic degradation of bisphenol A in mud-water mixtures.

[0069] Soil samples were collected from a rapeseed field in a certain area, sieved, and weighed to 60g. The samples were then placed in the reaction chamber of the degradation device. The cathode and anode reservoirs were separated from the reaction chamber using filter paper. After adding electrode materials, 50mL of 0.1mol / L Na2SO4 or simulated seawater solution was added to the cathode and anode reservoirs, respectively. At the same time, the light source and power supply were turned on.

[0070] The photoelectric and electrodynamic synergistic process takes place in a reaction chamber made of stainless steel, which is equipped with a 500W xenon lamp source with a visible light intensity of 100mW·cm². -2 The degradation apparatus was placed on a magnetic stirrer, using the Co3O4 / TiO2-NRs electrode prepared in Example 1 as the anode and a titanium sheet as the cathode, with an electrode spacing of 8 cm and an input voltage adjusted to 4 V. The treatment system is as follows. Figure 1 As shown.

[0071] Sampling was performed at a 0.5-hour interval, with samples taken from the anode reservoir, reaction chamber, and cathode reservoir.

[0072] The reaction chamber is divided into two parts, one near the anode reservoir and the other near the cathode reservoir, named S1 and S2.

[0073] The muddy water samples obtained from reaction chambers S1 and S2 were added to centrifuge tubes with 2 mL, 1 mL, and 1 mL of n-hexane:acetone (v / v = 1:1), respectively. The mixtures were shaken at 160 rpm for 1 h in a water bath, followed by centrifugation at 10000 rpm for 3 min. The supernatant was collected, and this process was repeated three times. The collected supernatants were mixed, dried under a gentle N2 atmosphere, and finally dissolved again in 1 mL of anhydrous methanol. After filtration through a 22 μm filter membrane, the concentration of bisphenol A was determined using a Tianmei high-performance liquid chromatograph equipped with a Diamonsil C18 analytical column.

[0074] The Co3O4 / TiO2-NRs electrode exhibits superior degradation performance of bisphenol A (BPA) in the mud-water system. In a Na2SO4 solution system, it achieves a 20% degradation rate of BPA after 210 minutes of reaction, significantly higher than traditional microbial treatment methods, which require 1-1.25 days to degrade 20% of BPA. This is attributed to the application of a low-voltage DC electric field at both ends of the electrode within the contaminated mud-water reservoir. Driven by the DC current, water-soluble or adsorbed BPA particles move towards the anode reservoir, where they are enriched for separation or centralized treatment. Simultaneously, the high photoresponse capability of the Co3O4 / TiO2-NRs electrode in the anode reservoir enhances the photoelectric degradation effect of BPA.

[0075] like Figure 2 As shown, the Co3O4 / TiO2-NRs electrode exhibits significant degradation effects of bisphenol A in the mud-water system within simulated seawater, achieving a degradation rate exceeding 60% after 240 minutes of reaction. This significant degradation effect is attributed to the presence of a large amount of chloride ions in the simulated seawater. Applying an external bias during the photocatalytic process promotes the reaction of chloride ions with the active components to generate active chlorine components (RCS), including HClO / ClO. - Cl2 ·- ClO· and Cl· are used to enhance the ability to oxidatively remove bisphenol A.

[0076] Soil electrokinetic processes are slow and involve long-term treatment, thus requiring high electrode stability. This application improves soil electrokinetic processes and coupled catalytic effects through electrode selection, thereby shortening the treatment time.

[0077] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this patent application should be determined by the appended claims.

Claims

1. A method for degrading bisphenol A in a mud-water system, characterized in that, The degradation is carried out in an electro-photocatalytic co-degradation device, which includes a reactor and a light source; The reactor is divided into an anode reservoir, a reaction chamber, and a cathode reservoir by a filter membrane. The reaction chamber is located between the anode reservoir and the cathode reservoir. An anode electrode is inserted into the anode reservoir, and an cathode electrode is inserted into the cathode reservoir. The anode electrode and the cathode electrode are respectively connected to the positive and negative terminals of a power supply. The distance between the anode and cathode is 7.5-8.5 cm; the distance between the reaction chambers is 3.5-4.5 cm. The light source emits simulated sunlight to the anode electrode within the anode reservoir. The light source is a xenon lamp, and the intensity of the simulated sunlight is 90~100 mW•cm². -2 ; Solution is added to the anode and cathode reservoirs respectively. Soil or mud-water mixture to be treated is added to the reaction chamber. The light source and power supply are turned on. The applied bias voltage of the power supply is 3~5 V. Bisphenol A in the mud-water mixture is degraded. The mud-water mixture is kept shaken or stirred during the degradation process. The soil is derived from at least one of kaolin, natural soil, or seawater sediment; the mud-water mixture is prepared by pre-mixing the soil with the solution; the solution is derived from at least one of Na2SO4 solution, simulated seawater, or actual seawater. The preparation process of the electrode anode includes: (1) Place the FTO electrode in a hydrothermal reactor, add tetrabutyl titanate dissolved in hydrochloric acid to the hydrothermal reactor, and prepare the TiO2-NRs electrode by hydrothermal treatment; (2) Place the prepared TiO2-NRs electrode at the bottom of a quartz dish, add a Co3O4 suspension to the quartz dish to immerse the TiO2-NRs electrode, the concentration of Co3O4 in the Co3O4 suspension is 0.3~0.8 mg / mL, place the plasma dielectric baffle horizontally 2~4 mm above the quartz dish containing the Co3O4 suspension, the discharge region is between the TiO2-NRs electrode at the bottom of the quartz dish and the plasma dielectric baffle, control the plasma load voltage to be 30~40 V, the load time to be 5~15 min, and obtain the Co3O4 / TiO2-NRs electrode.

2. The method according to claim 1, characterized in that, The filter membrane is a filter paper, nylon mesh, or glass fiber filter.

3. The method according to claim 1, characterized in that, In step (1) of the electrode anode preparation process: In the hydrochloric acid solution of tetrabutyl titanate, the solvent is hydrochloric acid with a hydrogen chloride mass fraction of 18-19%; the tetrabutyl titanate accounts for 1.5-3% of the total volume of the solution. The hydrothermal reaction temperature is controlled at 160~180°C, and the reaction time is controlled at 3~5h.

4. The method according to claim 1, characterized in that, The Co3O4 was prepared by the MOF template method: cobalt nitrate and 2-methylimidazole were dissolved in distilled water, the mixture was stirred to obtain a purple precursor, which was then washed, dried and calcined in a crucible to obtain the Co3O4 material.

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