Circulation type photoelectric concerted catalytic filtration system for removing new pollutant wastewater by efficiently activating molecular oxygen and application of circulation type photoelectric concerted catalytic filtration system

Abstract

The invention discloses a circulation-type photoelectric synergistic catalytic filtration system for removing new pollutant wastewater by efficiently activating molecular oxygen, which has multiple advantages of efficiently activating molecular oxygen, realizing photoelectric synergistic interaction and enhancing mass transfer by a flow system, and is beneficial to realizing efficient removal of new pollutants. The circulation type photoelectric synergistic catalysis filtering system comprises a shell, a negative electrode, a positive electrode and an interlayer, wherein an anode, a non-woven fabric interlayer, a cathode and a sealing ring are sequentially arranged in the shell; wherein the anode is a bismuth oxybromide / carbon nitride / samarium-bismuth vanadate photoelectrode, and the cathode is a ferrocobalt diatom confinement carbon nanotube electrode; the broadband spectral response material and the novel catalyst design significantly improve the anti-interference performance, and adapt to complex water quality and low-concentration pollution scenes. New pollutant wastewater can be efficiently removed after being illuminated and electrified in the circulation type photoelectric concerted catalytic filtration system in a circulation flow mode, and the removal rate of ibuprofen within 2 hours can reach 96%. The method is simple in design, easy to operate, low in cost and small in energy consumption, solves the problems of low removal efficiency, high energy consumption and the like of a common treatment system, further reduces the operation cost in cooperation with solar full spectrum utilization and low catalyst dosage design, and shows the comprehensive advantages of high efficiency, stability, economy and environmental protection.

Description

Technical Field

[0001] This invention relates to a flow-through photoelectric co-catalytic filtration system for removing new pollutants from wastewater by activating molecular oxygen and its application, particularly to a flow-through photoelectric co-catalytic filtration system for treating new pollutants from wastewater by activating molecular oxygen in the air, belonging to the fields of photoelectrochemistry and water treatment technology. Background Technology

[0002] The global aquatic environment currently faces a severe challenge from emerging pollutants (covering over 120,000 trace organic compounds, including perfluorinated compounds, pharmaceuticals, and endocrine disruptors). These pollutants are characterized by chemical diversity, environmental persistence, and bioaccumulation, resulting in conventional physicochemical treatment technologies achieving removal rates of less than 40%, and also suffering from limitations such as high energy consumption and secondary pollution. These pollutants can threaten aquatic ecosystems and human health at concentrations in the ng / L range, and the associated treatment costs are increasing year by year. Therefore, there is an urgent need to develop innovative technologies that are highly efficient in degradation, low in cost, and free from secondary pollution, to address the core challenges of detecting, removing, and controlling these emerging pollutants.

[0003] Advanced oxidation techniques can be used to activate molecular oxygen to produce reactive oxygen species (ROS), which convert ground-state molecular oxygen into highly reactive singlet oxygen through energy input (light, electricity, or heat). 1 Oxygen spores (ROS) include superoxide radicals (·O2-) and hydroxyl radicals (·OH). These ROS possess strong oxidizing properties and can efficiently degrade organic pollutants. In recent years, photoelectrocatalysis technology has been widely used in the field of pollutant treatment due to its dual advantages of photocatalysis and electrocatalysis. Green oxidation technology, which utilizes light and electrical energy to drive molecular oxygen activation, generates photogenerated electron-hole pairs under light irradiation through photoelectrocatalysts, which then react with molecular oxygen to generate ROS, achieving the deep treatment of new pollutant wastewater.

[0004] However, the common photoelectrocatalytic system for treating new pollutants is limited by low light energy utilization efficiency, poor catalyst activity and stability, difficult control of intermediate products, system design defects and bottlenecks in large-scale application, resulting in low treatment efficiency, high cost and difficulty in long-term stable operation. It is urgent to break through the technical bottleneck by strategies such as efficient catalyst design, optical near-field catalysis technology and reactor optimization. The oxygen self-provided fluid bipolar electrochemical filtration system invented by Liu Yanbiao et al. includes a shell, a reference electrode and a titanium ring, an anode, a polytetrafluoroethylene membrane, a cathode and a titanium sheet arranged in the shell in sequence. After connecting with a three-electrode system and conducting, the organic micro-pollutants are removed, solving the problems of long reaction time, many by-products and high energy consumption (patent number 117699920A). However, the single catalytic mode of the electrocatalytic system has low efficiency and insufficient treatment depth, and the consumption of external energy is large, and the utilization efficiency is low. Therefore, the existing photoelectrocatalytic system for removing new pollutants still has the following shortcomings: (1) the design of static reaction tank has low mass transfer efficiency and slow diffusion of reactants, which limits the reaction activity; (2) the catalyst surface is easy to accumulate by-products, resulting in poor catalyst stability and short service life; (3) the system design has low integration degree, inconvenient operation and high application cost.

[0005] Therefore, it is of great significance to develop a flow-through photoelectric synergistic catalytic filtration system for efficient activation of molecular oxygen to remove new pollutant wastewater. SUMMARY

[0006] The purpose of the present application is to provide a flow-through photoelectric synergistic catalytic filtration system for efficient activation of molecular oxygen to remove new pollutant wastewater. The system has the advantages of efficient activation of molecular oxygen, light-electricity synergistic effect and flow system enhanced mass transfer, which is beneficial to the efficient removal of new pollutants.

[0007] The purpose of the present application is achieved by the following technical solutions:

[0008] A flow-through photoelectric synergistic catalytic filtration system for efficient activation of molecular oxygen to remove new pollutant wastewater, characterized in that it comprises a shell, an anode and a cathode, and a spacer layer, wherein the shell is sequentially arranged as an anode, a non-woven fabric spacer layer, a cathode and a sealing ring.

[0009] Preferably, the anode is a bismuth oxybromide / carbon nitride / bismuth samarium-vanadate photoelectrode, and the cathode is a cobalt-iron diatomic confined carbon nanotube electrode.

[0010] Preferably, the structure of the bismuth oxybromide / carbon nitride / bismuth samarium-vanadate photoanode is a double-Z type heterojunction, and has full-spectrum response capability.

[0011] Preferably, the preparation method of the bismuth oxybromide / carbon nitride / bismuth samarium-vanadate photoanode comprises the following steps: layer-by-layer electrodeposition of bismuth oxybromide / carbon nitride / bismuth samarium-vanadate on the surface of a titanium mesh as a cathode and a platinum sheet as an anode in a two-electrode direct current system with an acetone and iodine solution as an electrolyte solution.

[0012] In the electrolyte solution, the concentration of bismuth oxybromide, carbon nitride and bismuth samarium-vanadate is 0.1-0.5 g / L, and the concentration of iodine is 0.3-0.5 g / L.

[0013] The voltage for electrodeposition is 15-32 V, and the electrodeposition time is 1-5 min.

[0014] Preferably, the preparation method of the cobalt-iron double-atom limited carbon nanotube electrode comprises the following steps:

[0015] (1) mixing a nitrogen source and a metal salt solution, drying and high-temperature calcining to obtain a cobalt-iron double-atom limited carbon nanotube catalyst;

[0016] (2) loading the cobalt-iron double-atom limited carbon nanotube powder on a carbon felt to obtain a cobalt-iron double-atom limited carbon nanotube electrode.

[0017] Preferably, in the preparation method of the cobalt-iron double-atom limited carbon nanotube electrode, the metal salt solution comprises an iron nitrate and a cobalt nitrate solution, and the solvent of the metal salt solution comprises pure water or ethanol.

[0018] The addition amount of cobalt and iron in the metal salt solution is 0.5wt%-4wt% of the nitrogen source.

[0019] The high-temperature calcining temperature is 600-900 DEG C, and the calcining time is 2-4 h.

[0020] Preferably, the shell is provided with a water inlet at the end close to the cathode and a water outlet at the end close to the anode.

[0021] The application also provides an application of the above-mentioned flow-through photoelectric cooperative catalytic filtration system in treating new pollutant wastewater, and the specific application method is as follows:

[0022] The new pollutant wastewater and a sulfate are mixed to obtain mixed wastewater, and the mixed wastewater is introduced into the above-mentioned flow-through photoelectric cooperative catalytic filtration system to be treated by light irradiation and electricity in a circulating flow mode to remove the new pollutants.

[0023] Preferably, the new pollutants comprise one or more of ibuprofen, bisphenol A, phthalate and sulfamethoxazole, and the concentration of the new pollutants in the mixed wastewater is 1-20 mg / L; and the concentration of the sulfate in the mixed wastewater is 0.05-0.1 mol / L.

[0024] Preferably, the current density of the electrification treatment is 0.5-4 mA / cm 2 , the electrification treatment time is 0.5-1 h; the light intensity is 0.2-1 kW / cm 2 , and the light time is 0.5-1 h.

[0025] The flow rate of the mixed wastewater into the flow-through photoelectric synergistic catalytic filtration system is 1-5 mL / min.

[0026] Compared with the prior art, the present application has the following advantages:

[0027] (1) The flow-through photoelectric synergistic catalytic filtration system breaks through the efficiency bottleneck of single catalytic mode by light-electricity synergistic effect and flow system reinforced mass transfer, and realizes efficient degradation of new pollutants;

[0028] (2) The wide spectrum response material and the new catalyst design significantly improve the anti-interference performance, and adapt to complex water quality and low concentration pollution scenes;

[0029] (3) At the same time, the design of solar full-spectrum utilization and low catalyst dosage further reduces the operation cost, and exhibits the comprehensive advantages of high efficiency, stability, economy and environmental protection. BRIEF DESCRIPTION OF DRAWINGS

[0030] Figure 1 is a structural schematic diagram of the flow-through photoelectric synergistic catalytic filtration system according to the present application;

[0031] Figure 2 is a graph of the degradation efficiency of ibuprofen in water by the system in Example 1. DETAILED DESCRIPTION

[0032] In order to facilitate the understanding of those skilled in the art, the technical solutions in the embodiments of the present application will be described clearly and completely below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.

[0033] Example 1

[0034] (1) Preparation of BiOBr / C3N4 / Bi5SmV5O12 photoelectrode: 5 mmol of Bi(NO3)3·5H2O was added to 10 mL of CH3COOH and stirred for 25 min at room temperature to prepare precursor A; the corresponding molar amount of NH4VO3 was added to 60 mL of deionized water, and stirred in a water bath at 80°C until completely dissolved to prepare a transparent chrysanthemum liquid to form precursor B; B was added to A to form an orange chrysanthemum suspension, and 4wt% of 0.05 mol / L Sm(NO3)3·6H2O solution was added, and the pH of the mixed solution was adjusted to 7 with 1 mol / L NaOH, and then magnetically stirred for 30 min before being transferred to a 100 mL hydrothermal kettle for hydrothermal reaction under optimized process, and then filtered, washed with deionized water and anhydrous ethanol alternately for 3 times, dried at 60°C, and finally put into a tube furnace for annealing at 300°C for 2 h to obtain Bi5SmV5O12 powder. Three kinds of 30 mg photoanode materials (BiOBr, C3N4, and Bi5SmV5O12) were dispersed in 35 mL of acetone solution, and 50 mg of iodine was added for ultrasonic dispersion, and then sequentially layered and deposited on a titanium mesh under the condition of constant voltage of 32 V, and each layer was electrodeposited for 1 min. The electrode sheet after deposition was dried in an oven to obtain a BiOBr / C3N4 / Bi5SmV5O12 photoelectrode.

[0035] (2) Preparation of Co-Fe double-atom confined carbon nanotube electrode: 20 g of melamine was dissolved in 100 mL of ethanol, and then 0.723 g of Fe(NO3)3·9H2O and 0.412 g of Co(NO3)2·6H2O were added to the ethanol solution, and stirred for 2 h to fully dissolve and load; the uniformly mixed precursor solution was heated in a water bath at 60°C to volatilize the ethanol, and then dried in a blast drying oven at 60°C for 12 h to obtain a precursor material; finally, the obtained precursor material was placed in a tube furnace in a nitrogen atmosphere, and calcined at a high temperature of 700°C for 2 h to obtain a Co-Fe double-atom confined carbon nanotube catalyst. 30 mg of the Co-Fe double-atom confined carbon nanotube catalyst was weighed and ultrasonically dispersed in a water-Nafion solution, and then uniformly coated on a carbon felt to prepare a Co-Fe double-atom confined carbon nanotube electrode.

[0036] (3) Assembly of flow-through type photoelectrocatalytic filtration system: the BiOBr / C3N4 / Bi5SmV5O12 photoelectrode prepared in step (1) was used as the anode, and the Co-Fe double-atom confined carbon nanotube electrode prepared in step (2) was used as the cathode to assemble a flow-through type photoelectrocatalytic filtration system. The specific assembly method was to sequentially arrange the anode, non-woven fabric layer, cathode and sealing ring in the shell, and to set a water inlet at one end of the shell close to the cathode, and to set a water outlet at one end of the shell close to the anode. A two-electrode direct current system and a xenon lamp were used to supply energy to the photoelectrocatalytic filtration system, and the wires set at the two ends of the water inlet and the water outlet were respectively connected with the working electrode clamps of the two-electrode system, and then connected with the anode and cathode to supply power, and the xenon lamp was irradiated on the upper end of the anode placement side.

[0037] Test Example 1

[0038] The anode and cathode prepared in Example 1 and the assembled flow-through photoelectrocatalytic filtration system were used to treat wastewater containing a new pollutant, ibuprofen, at a concentration of 20 mg / L. Sodium sulfate was added to the wastewater to give a molar concentration of 0.05 mol / L. The current density was set at 4 mA / cm 2 , and the total reaction time was 2 h. The wastewater was treated using a circulating flow operation mode. The mixed solution was introduced into the inlet of the flow-through photoelectrocatalytic filtration system, flowed through the cathode first and then the anode, and then flowed into a beaker. The mixed solution in the beaker was continuously returned to the cathode by a peristaltic pump. The test results (as shown in Table 1) show that the removal rate of the flow-through photoelectrocatalytic filtration system for the typical new pollutant ibuprofen reached 96% within 2 h. Figure 2 ​

Claims

1. A flow-through photoelectric co-catalytic filtration system for efficiently removing new pollutants from wastewater by activating molecular oxygen, characterized in that: S1 includes a housing, anode and cathode electrodes and a separator, with the anode, non-woven fabric separator, cathode and sealing ring arranged sequentially inside the housing; The anode of S2 is a bismuth oxybromide / carbon nitride / smarium-bismuth vanadate photoelectrode, and the cathode is a cobalt-iron two-atom confined carbon nanotube electrode; The structure of the bismuth oxybromide / carbon nitride / smarium-vanadate photoanode described in S3 is a double Z-type heterojunction, and it has full-spectrum response capability; The preparation method of the bismuth oxybromine / carbon nitride / smarium-vanadate photoanode described in S4 includes the following steps: a two-electrode DC current system with a titanium mesh as the cathode and a platinum sheet as the anode, and acetone and iodine solution as the electrolyte solution, and layered electrodeposition of bismuth oxybromine / carbon nitride / smarium-vanadate on the surface of the titanium mesh; The preparation method of the cobalt-iron two-atom confined carbon nanotube electrode described in S5 includes the following steps: (1) A cobalt-iron diatomic confined carbon nanotube catalyst was obtained by mixing a nitrogen source and a metal salt solution, drying and then calcining at high temperature. (2) Cobalt-iron diatomic confined carbon nanotube powder was loaded onto a carbon felt to obtain a cobalt-iron diatomic confined carbon nanotube electrode. S6 The present invention also provides an application of the above-mentioned flow-through photoelectric co-catalytic filtration system in the treatment of new pollutant wastewater, and the specific application method is as follows: The new pollutant wastewater and sulfate are mixed to obtain mixed wastewater. The mixed wastewater is then passed into the above-mentioned flow-through photoelectric synergistic catalytic filtration system for irradiation and electrostatic treatment in a circulating flow mode to remove the new pollutants.

2. The flow-through photoelectric co-catalytic filtration system for removing new pollutants from wastewater with highly efficient activated molecular oxygen as described in claim 1, characterized in that: The S1 housing has an inlet at the end near the cathode and an outlet at the end near the anode.

3. The flow-through photoelectric co-catalytic filtration system for removing new pollutants from wastewater with highly efficient activated molecular oxygen as described in claim 1, characterized in that: The concentrations of bismuth oxybromide, carbon nitride, and bismuth samarium-vanadate in the S4 electrolyte solution are 0.1–0.5 g / L, and the concentration of iodine is 0.3–0.5 g / L; the electrodeposition voltage is 15–32 V, and the electrodeposition time is 1–5 min.

4. The flow-through photoelectric co-catalytic filtration system for removing new pollutants from wastewater with highly efficient activated molecular oxygen as described in claim 1, characterized in that: The S5 metal salt solution includes iron nitrate and cobalt nitrate solutions, and the solvent of the metal salt solution includes pure water or ethanol; the amount of cobalt and iron added in the metal salt solution is 0.5wt% to 4wt% of the nitrogen source; the high-temperature calcination temperature is 600 to 900°C, and the calcination time is 2 to 4 hours.

5. The flow-through photoelectric co-catalytic filtration system for removing new pollutants from wastewater with highly efficient activated molecular oxygen as described in claim 1, characterized in that: The new pollutants in S6 include one or more of ibuprofen, bisphenol A, phthalates and sulfamethoxazole, and the concentration of the new pollutants in the mixed wastewater is 1-20 mg / L; the concentration of sulfate in the mixed wastewater is 0.05-0.1 mol / L.

6. The flow-through photoelectric co-catalytic filtration system for removing new pollutants from wastewater with highly efficient activated molecular oxygen as described in claim 1, characterized in that: The current density of the S6 energization process is 0.5–4 mA / cm². 2 The power-on treatment time is 0.5–1 hour; the light intensity is 0.2–1 kW / cm². 2 The illumination time is 0.5 to 1 hour; the flow rate of the mixed wastewater into the flow-through photoelectric synergistic catalytic filtration system is 1 to 5 mL / min.

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