Preparation method of multifunctional water treatment separation membrane based on sulfate radical advanced oxidation

Abstract

A method for preparing a multifunctional water treatment separation membrane based on advanced oxidation of sulfate radicals is disclosed. This invention utilizes reduced graphene oxide-modified cobalt molybdate as a catalyst layer to activate PS and induce sulfate radical generation, and a fiber membrane as the filtration separation layer. Through vacuum filtration and high-pressure fixation, the catalytic functional layer and the fiber membrane filtration layer are combined to form an integrated multifunctional separation membrane. This coupling of membrane separation technology with advanced oxidation technology enables the membrane to perform both filtration and degradation of organic pollutants. While reducing membrane fouling, it also enhances the mass transfer between PS, organic pollutants, and the catalyst layer during filtration, thereby increasing the degradation rate of pollutants. The mixture is subjected to hydrothermal treatment and calcination to obtain a reduced graphene oxide-modified cobalt molybdate catalyst layer. Finally, through vacuum filtration and high-pressure fixation, the catalytic functional layer is combined with the fiber membrane filtration layer to form an integrated multifunctional separation membrane.

Description

Technical Field

[0001] This invention relates to a method for preparing a water treatment separation membrane, and more particularly to a method for preparing a multifunctional water treatment separation membrane based on advanced oxidation of sulfate radicals. Background Technology

[0002] With societal development, organic dyes are widely used in industries such as leather, textiles, and tanning. Statistics show that the world's industrial sector discharges 30,000 to 150,000 tons of dye materials annually. Dye wastewater is characterized by high color, high salinity, high organic load, poor biodegradability, and high toxicity. It has significant mutagenic effects on humans and aquatic organisms; large-scale discharge of dyes into waterways poses a threat to ecosystems and seriously endangers human health. Therefore, thorough treatment of dye wastewater is essential. Membrane separation technology offers advantages such as high efficiency and stability. However, traditional membrane separation technologies can only perform filtration and cannot directly decompose organic pollutants in wastewater. Currently, sulfate radical advanced oxidation technology (AOPs) offers advantages such as high efficiency, speed, and low secondary pollution, and is widely used in water treatment. Therefore, coupling membrane separation technology with sulfate radical-based AOPs to prepare a multifunctional separation membrane, enabling the membrane to both filter and induce sulfate radical degradation of organic pollutants, has promising practical application prospects for dye wastewater treatment. Electron transfer exists between the two metals in bimetallic oxides, which facilitates accelerated valence state cycling between the metals, thereby generating more active oxygen species and enhancing the catalytic activity of the catalyst. The unique two-dimensional sheet-like structure of reduced graphene oxide acts as a connector during membrane formation, effectively maintaining the membrane's filtration characteristics. Therefore, this invention uses reduced graphene oxide modified with cobalt molybdate as a catalytic layer to activate PS-induced sulfate radical generation, and a fiber membrane as the filtration separation layer. Through vacuum filtration and high-pressure fixation, the catalytic functional layer and the fiber membrane filtration layer are combined to form a multifunctional separation membrane. This multifunctional separation membrane possesses both filtration and catalytic functions, improving the quality of the effluent and reducing membrane fouling. It exhibits excellent catalytic activity and stability for removing dye wastewater. Summary of the Invention

[0003] The purpose of this invention is to provide a method for preparing a multifunctional water treatment separation membrane based on sulfate radical advanced oxidation. This method is based on the coupling of sulfate radical AOPs with membrane technology, so that the membrane itself has the functions of filtering and degrading organic pollutants. While reducing membrane fouling, it can also enhance the mass transfer between PS and organic pollutants and the catalyst layer during the filtration process, effectively improving the degradation rate of pollutants.

[0004] The present invention adopts the following technical solution: A method for preparing a multifunctional water treatment separation membrane based on advanced oxidation of sulfate radicals is disclosed. The method uses reduced graphene oxide modified with cobalt molybdate as a catalyst layer to activate PS and induce sulfate radical generation, and a fiber membrane as a filtration separation layer. The catalytic functional layer and the fiber membrane filtration layer are combined through vacuum filtration and high-pressure fixation to form a multifunctional separation membrane. The preparation method is as follows: First, reduced graphene oxide is prepared using the Hummer method; then, 0.01-1.0 g of reduced graphene oxide is dispersed in 20-80 mL of deionized water and the mixture is centrifuged; the supernatant after centrifugation is mixed with 0.05-0.5 g of soluble cobalt salt, 0.05-0.5 g of soluble molybdenum salt, and 0.1-0.7 g of polyvinylpyrrolidone; the mixture is subjected to hydrothermal treatment and calcination to obtain a reduced graphene oxide modified with cobalt molybdate catalyst layer; finally, the catalytic functional layer and the fiber membrane filtration layer are combined through vacuum filtration and high-pressure fixation to form a multifunctional separation membrane.

[0005] The method for preparing a multifunctional water treatment separation membrane based on advanced oxidation of sulfate radicals is described above. The catalyst layer of the method is prepared by hydrothermal and calcination methods. The hydrothermal temperature is 100-300 ℃ and the hydrothermal time is 2-12 h. The calcination temperature is 100-500 ℃ and the calcination time is 0.5-15 h.

[0006] The method for preparing a multifunctional water treatment separation membrane based on sulfate radical advanced oxidation is described above. The water treatment uses potassium persulfate (PMS) as an oxidant and a multifunctional separation membrane to treat dye wastewater. When the PMS concentration is 0.3 mM, the multifunctional separation membrane can remove 100% of dye wastewater with a concentration of 10-50 mg / L.

[0007] The present invention has the following beneficial effects: This invention couples sulfate radical-based AOPs with membrane technology, enabling the membrane to function as both a filter and a degrader of organic pollutants. While reducing membrane fouling, it also enhances the mass transfer between PS, organic pollutants and the catalyst layer during the filtration process, effectively improving the degradation rate of pollutants. Attached Figure Description

[0008] Figure 1 Diagram of a multifunctional separation membrane water treatment system; Figure 2 This is a graph showing the stability of the multifunctional separation membrane. Implementation

[0009] The outstanding features and significant advancements of the present invention are further illustrated below with reference to embodiments, which are intended to illustrate the invention but are not limited to the following examples.

[0010] This invention uses reduced graphene oxide modified cobalt molybdate as a catalytic layer to activate PS and induce sulfate radical generation, and a fiber membrane as a filtration and separation layer. Through vacuum filtration and high-pressure fixation, the catalytic functional layer and the fiber membrane filtration layer are combined to form a multifunctional separation membrane. The preparation method is as follows: 1) Mix concentrated sulfuric acid and graphite powder evenly.

[0011] The volume of concentrated sulfuric acid is 1-10 mL, and the mass of graphite powder is 0.5-5 g.

[0012] 2) Place the substance from step 1) above in an ice-water bath and add potassium permanganate in batches.

[0013] The mass of potassium permanganate is 1-10 g.

[0014] 3) The mixed solution in step 2) is subjected to ultrasonic treatment.

[0015] The ultrasound time is 5-15 hours.

[0016] 4) Add deionized water and stir continuously.

[0017] The volume of deionized water is 20-60 mL, and the stirring time is 1-10 h.

[0018] 5) Cool the mixture obtained in step 4) to room temperature.

[0019] Cooling time is 1-10 hours.

[0020] 6) Add deionized water and hydrogen peroxide to the mixture, stir quickly and let stand overnight.

[0021] The volume of deionized water is 50-150 mL, and the volume of hydrogen peroxide is 5-15 mL.

[0022] 7) Discard the supernatant and add hydrochloric acid solution to the precipitate, then wash with deionized water.

[0023] The concentration of the hydrochloric acid solution is 5 wt.%.

[0024] 8) Vacuum dry the solid obtained in step 7).

[0025] The vacuum drying temperature is 10-60 ℃, and the vacuum drying time is 1-6 days.

[0026] 9) Disperse the solid obtained in step 8) in deionized water by ultrasonic treatment.

[0027] The solid mass is 0.01-1.0 g, the deionized water volume is 20-80 mL, and the ultrasonic time is 1-6 h.

[0028] 10) Centrifuge the solution in a centrifuge and collect the supernatant.

[0029] The centrifuge speed is 3000-9000 r / min.

[0030] 11) Soluble cobalt salt, soluble molybdenum salt, and polyvinylpyrrolidone are dissolved in the collected supernatant.

[0031] The mass of soluble cobalt and molybdenum salts is 0.05-0.5 g, the mass of polyvinylpyrrolidone is 0.1-0.7 g, the volume of supernatant is 20-80 mL, and the proportion of reduced graphene oxide is 0.1%-20%.

[0032] 12) Transfer the mixture to a polytetrafluoroethylene high-pressure reactor for hydrothermal reaction.

[0033] The hydrothermal temperature is 100-300 ℃, and the hydrothermal time is 2-12 h.

[0034] 13) Place the obtained substance in a centrifuge, wash it with ethanol and deionized water, and dry it in an oven.

[0035] The centrifuge speed is 5000-8000 r / min, and the drying temperature is 20-90 ℃.

[0036] 14) The dried solid is placed in a tube furnace for calcination and then dispersed on a cellulose membrane.

[0037] The calcination temperature of the tube furnace is 100-500 ℃, the calcination time is 0.5-15 h, and the heating rate is 2-8 ℃ / min.

[0038] Example 1: A 100 mL volume of methylene blue (MB) solution with a concentration of 20 mg / L was treated using a multifunctional separation membrane. 100-500 μL of PMS (0.5 mol / L) was added before filtration. Under specific flow rates and pressures, when the PMS concentration was 0.3 mM, the multifunctional separation membrane could remove 100% of the dye wastewater with a concentration of 10-50 mg / L.

[0039] Example 2: 0.01-0.2 g of reduced graphene oxide modified cobalt molybdate was dispersed in deionized water as a catalyst layer for activating PS to induce sulfate radical generation, forming a suspension of a certain concentration. The suspension was then vacuum filtered and high-pressure fixed onto the surface of a cellulose membrane to form a multifunctional separation membrane.

[0040] Example 3: 0.01-0.5 g of reduced graphene oxide was dispersed in 20-80 mL of deionized water and mixed with 0.05-0.5 g of soluble cobalt salt, 0.05-0.5 g of soluble molybdenum salt, and 0.1-0.7 g of polyvinylpyrrolidone. After hydrothermal treatment and calcination, the mixture was vacuum filtered and then fixed onto the surface of a cellulose membrane under high pressure to form a multifunctional separation membrane.

[0041] Example 4: 0.5-1.0 g of reduced graphene oxide was dispersed in 20-80 mL of deionized water and mixed with 0.05-0.5 g of soluble cobalt salt, 0.05-0.5 g of soluble molybdenum salt, and 0.1-0.7 g of polyvinylpyrrolidone. After hydrothermal treatment and calcination, the mixture was vacuum filtered and then fixed onto the surface of a cellulose membrane under high pressure to form a multifunctional separation membrane.

[0042] Example 5: 0.01-1.0 g of reduced graphene oxide was dispersed in 20-80 mL of deionized water and mixed with 0.05-0.2 g of soluble cobalt salt, 0.2-0.5 g of soluble molybdenum salt, and 0.1-0.7 g of polyvinylpyrrolidone. After hydrothermal treatment and calcination, the mixture was vacuum filtered and then fixed onto the surface of a cellulose membrane under high pressure to form a multifunctional separation membrane.

[0043] Example 6: 0.01-1.0 g of reduced graphene oxide was dispersed in 20-80 mL of deionized water and mixed with 0.2-0.5 g of soluble cobalt salt, 0.05-0.2 g of soluble molybdenum salt, and 0.1-0.7 g of polyvinylpyrrolidone. After hydrothermal treatment and calcination, the mixture was vacuum filtered and then fixed onto the surface of a cellulose membrane under high pressure to form a multifunctional separation membrane.

Claims

1. A method for preparing a multifunctional water treatment separation membrane based on sulfate radical advanced oxidation, characterized in that, The method uses reduced graphene oxide modified cobalt molybdate as a catalyst layer to activate PS and induce sulfate radical generation, and a fiber membrane as a filtration separation layer. The catalytic functional layer and the fiber membrane filtration layer are combined through vacuum filtration and high-pressure fixation to form a multifunctional separation membrane. The preparation method is as follows: First, reduced graphene oxide is prepared using the Hummer method; then, 0.01-1.0 g of reduced graphene oxide is dispersed in 20-80 mL of deionized water and the mixture is centrifuged; the supernatant after centrifugation is mixed with 0.05-0.5 g of soluble cobalt salt, 0.05-0.5 g of soluble molybdenum salt, and 0.1-0.7 g of polyvinylpyrrolidone; the mixture is subjected to hydrothermal treatment and calcination to obtain a reduced graphene oxide modified cobalt molybdate catalyst layer; finally, the catalytic functional layer and the fiber membrane filtration layer are combined through vacuum filtration and high-pressure fixation to form a multifunctional separation membrane. The catalyst layer of the method is prepared by hydrothermal and calcination methods; the hydrothermal temperature is 100-300 ℃ and the hydrothermal time is 2-12 h; the calcination temperature is 100-500 ℃ and the calcination time is 0.5-15 h. The water treatment process uses potassium persulfate (PMS) as an oxidant and a multifunctional separation membrane to treat dye wastewater.

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