A method for treating sulfamethoxazole in reclaimed water based on catalytic membrane

Abstract

The application provides a catalytic membrane-based treatment method for sulfamethoxazole in reclaimed water, which comprises the following steps: step 10, preparing a nano catalytic material; step 20, preparing the powdered nano catalytic material into a catalytic membrane; step 30, installing the catalytic membrane in a reactor, injecting an oxidizing agent solution into the reactor, and feeding reclaimed water containing sulfamethoxazole into the reactor to flow through the catalytic membrane in a circulating manner; and simultaneously, irradiating the catalytic membrane. The catalytic membrane-based treatment method for sulfamethoxazole in reclaimed water can prolong the service life of the catalytic membrane and improve the removal effect of sulfamethoxazole.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of water treatment, and particularly relates to a sulfamethoxazole treatment method in reclaimed water based on a catalytic membrane. BACKGROUND

[0002] With the wide application of reclaimed water in the fields of ecological water replenishment in urban and rural areas and agricultural irrigation in China, the reuse safety of the reclaimed water has attracted extensive attention. Various new pollutants such as the neonicotinoid insecticide nitenpyram, the antiepileptic drug carbamazepine and the antibiotic sulfamethoxazole contained in the reclaimed water can migrate to the receiving water body during the reuse process, and are enriched and transformed through the water-soil-plant continuum, thereby posing a potential threat to ecological safety and human health. Due to the strong oxidation ability, the advanced oxidation technology shows application potential in the treatment of complex new pollutants.

[0003] Among them, the most commonly used Fenton oxidation technology can be divided into traditional homogeneous Fenton oxidation technology and improved heterogeneous Fenton oxidation technology according to its reaction form. The traditional homogeneous Fenton oxidation technology utilizes ferrous ions and hydrogen peroxide to react in an acidic aqueous solution to generate hydroxyl radicals with strong reactivity to remove harmful substances in wastewater. Unlike the homogeneous catalytic process (whose reaction is distributed throughout the liquid medium), the heterogeneous Fenton method ingeniously transfers the reaction interface to the surface of the solid catalyst, realizes efficient adsorption and conversion of the oxidant on the active site of the catalyst, and widens the application scope. For example, the solid catalyst is prepared into a catalytic membrane, and the catalytic membrane is used to treat new pollutants such as sulfamethoxazole in reclaimed water.

[0004] However, after the existing catalytic membrane is used for several cycles, the electron donor near the active site is gradually oxidized, and the electron donor cannot continue to provide electrons for the oxidant, finally resulting in the loss of activity of the site, the reduction of the oxidation reaction rate, and the short service life of the catalytic membrane. SUMMARY

[0005] The technical problem to be solved by the present application is to provide a sulfamethoxazole treatment method in reclaimed water based on a catalytic membrane, which can prolong the service life of the catalytic membrane and improve the removal effect of sulfamethoxazole.

[0006] To solve the above technical problems, the present application adopts the following technical solutions:

[0007] The present application provides a sulfamethoxazole treatment method in reclaimed water based on a catalytic membrane, comprising the following steps:

[0008] Step 10, preparing a nano-catalytic material;

[0009] Step 20, preparing the powdered nano-catalytic material into a catalytic membrane;

[0010] Step 30, install the catalytic membrane in the reactor, inject the oxidant solution into the reactor; deliver the regenerated water containing sulfamethoxazole to the reactor to pass through the catalytic membrane in a circulating flow mode; and meanwhile, irradiate the catalytic membrane.

[0011] As a further improvement of the present application, the step 10 specifically comprises:

[0012] Step 101, prepare a metal organic framework material;

[0013] Step 102, prepare iron oxide particles inside the metal organic framework material to obtain a confined iron nanomaterial;

[0014] Step 103, vertically grow molybdenum disulfide nanosheets on the surface of the confined iron nanomaterial to obtain a nanocatalytic material.

[0015] As a further improvement of the present application, the step 102 specifically comprises:

[0016] Step 1021, prepare a 2-tert-butyl-p-cresol diethyl ether solution with diethyl ether as a solvent and 2-tert-butyl-p-cresol as a solute, mix the 2-tert-butyl-p-cresol diethyl ether solution with the metal organic framework material under airtight conditions to obtain a mixed solution;

[0017] Step 1022, heat the mixed solution obtained in step 1021 to a constant weight;

[0018] Step 1023, disperse the mixed solution treated in step 1022 in an FeCl2·4H2O aqueous solution and perform a shock reaction at room temperature;

[0019] Step 1024, centrifugally collect the precipitated product obtained in step 1023, repeatedly wash the product with an ethanol solution and deionized water, and then place the product in an oven for aging to obtain a confined iron nanomaterial.

[0020] As a further improvement of the present application, in the step 1021, the mass ratio of 2-tert-butyl-p-cresol to the metal organic framework material is 1:3-7.

[0021] In the step 1022, the mixed solution obtained in step 201 is heated to a constant weight by using an inert gas stream at 100-120°C.

[0022] As a further improvement of the present application, in the step 1023, the pH of the reaction solution is controlled to be in the range of 5-10 during the reaction.

[0023] As a further improvement of the present application, in the step 1024, the temperature in the oven is 130-140°C.

[0024] As a further improvement of the present application, the step 103 specifically comprises:

[0025] Step 1031, dispersing the confined iron nanomaterial in deionized water to obtain a confined iron nanoparticle dispersion;

[0026] Step 1032, adding ammonium molybdate and thiourea to the confined iron nanoparticle dispersion and stirring;

[0027] Step 1033, transferring the mixture obtained in step 1032 to a high-pressure reaction kettle equipped with a polytetrafluoroethylene lining, and placing it in an oven for reaction;

[0028] Step 1034, centrifuging to collect the precipitated product in the high-pressure reaction kettle in step 1033, repeatedly washing the product with deionized water and an ethanol solution, and then vacuum drying the product in an oven to obtain a nanocatalytic material.

[0029] As a further improvement of the present application, in step 1032, the mass ratio of ammonium molybdate, thiourea, and confined iron nanomaterial is 1:1-2:2-3;

[0030] In step 1033, the temperature in the oven is 185-195°C;

[0031] In step 1034, the temperature in the oven is 40-60°C.

[0032] As a further improvement of the present application, the step 101 specifically comprises:

[0033] Step 1011, dissolving cobalt nitrate hexahydrate in a methanol solution to obtain a cobalt nitrate hexahydrate methanol solution, and dissolving 2-methylimidazole in a methanol solution to obtain a 2-methylimidazole methanol solution;

[0034] Step 1012, adding the cobalt nitrate hexahydrate methanol solution dropwise to the 2-methylimidazole methanol solution, stirring, and then aging by standing;

[0035] Step 1013, centrifuging to collect the precipitated product obtained in step 1012, repeatedly washing the product with an ethanol solution, and then drying it in an oven to obtain a zeolitic imidazolate framework material containing metal Co coordination.

[0036] As a further improvement of the present application, the step 20 specifically comprises:

[0037] Step 201, adding powdered nanocatalytic material to deionized water and performing ultrasonic dispersion treatment to obtain a catalytic dispersion;

[0038] Step 202, loading the catalytic dispersion onto the surface of a polytetrafluoroethylene membrane using vacuum filtration;

[0039] Step 203, the polytetrafluoroethylene film loaded with the catalytic dispersion liquid is placed in an oven for vacuum drying to obtain a catalytic film.

[0040] Compared with the prior art, the technical scheme of the present application has the following beneficial effects:

[0041] (1) The method for treating sulfamethoxazole in reclaimed water based on a catalytic film provided by the present application prepares a catalytic film from a powdered nanocatalytic material, uses the catalytic film to treat reclaimed water, and irradiates the catalytic film during the treatment process. By applying irradiation, the active sites are induced to repair, the cyclic stability of the catalytic film is enhanced, and the service life of the catalytic film can be prolonged. By applying irradiation, a non-radical pathway is added to the radical pathway, a variety of oxidizing substances are generated, the catalytic reaction speed is accelerated, and the effective degradation of sulfamethoxazole is promoted.

[0042] (2) The nanocatalytic material prepared in the method has a limited structure, which can protect the Fe reaction sites inside the nanospace, reduce the leaching of Fe, thereby reducing the generation of secondary pollutants of iron sludge, reducing the impact on the membrane flux, and maintaining the integrity of the membrane structure. The Fe in the limited structure and the MoS2 loaded on the surface can enhance the electrical conductivity of the catalytic film, which is conducive to improving the carrier migration rate on the surface of the catalytic film. Under the condition of irradiation, Mo(IV) can act as a cocatalyst to transfer electrons in the reaction, induce Fe(III) and Co(IV) to be reduced to highly active low-valence states, promote the Fe(II) / Fe(III) cycle of the catalyst, prolong the service life of the catalytic film, and at the same time reduce the leaching of Fe, thereby reducing the generation of secondary pollutants of iron sludge. The reaction system relies on the electron transfer between the multivalent transition metals inside the catalytic film to activate the oxidizing agent to generate •SO4 - and •OH to participate in the degradation of pollutants; under the condition of irradiation, the catalytic film utilizes its own photocatalytic ability to react with dissolved oxygen in the water environment to generate •O2, and then generates more selective active 1 O2 through the surface electron transfer mechanism of the catalytic film, and forms a variety of radical pathways with •SO4- to jointly participate in the degradation of sulfamethoxazole.

[0043] The nanocatalytic material prepared in the method is used to prepare a catalytic film, and under the condition of irradiation, the active sites can be restored, the stability of the catalytic film is maintained, the service life of the catalytic film is prolonged, and at the same time the leaching of Fe is reduced, thereby reducing the generation of iron sludge; during the reaction, there are both radical pathways and non-radical pathways, which provides a faster way for carbon transfer of sulfamethoxazole in reclaimed water, and improves the removal effect of sulfamethoxazole. BRIEF DESCRIPTION OF DRAWINGS

[0044] Figure 1The flow chart of the preparation method of the sulfamethoxazole treatment method in reclaimed water based on the catalytic membrane provided by the present application is shown in the figure.

[0045] Figure 2 The synthesis schematic diagram of the nanometer catalytic material in the method of the present application is shown in the figure.

[0046] Figure 3 The column chart of the SMX removal efficiency of Example 1, Comparative Example 1 and Comparative Example 2 is shown in the figure.

[0047] Figure 4 The permeability and Fe ion leaching concentration chart of the catalytic membrane in Comparative Example 1 and Comparative Example 2 is shown in the figure.

[0048] Figure 5 The SEM images of the ZFM catalytic membrane before and after the reaction in Comparative Example 1 and Comparative Example 2 are shown in the figure, wherein (a) is the SEM images of the ZFM catalytic membrane before and after the reaction in Comparative Example 1, and (b) is the SEM images of the ZFM-OUT catalytic membrane before and after the reaction in Comparative Example 2. DETAILED DESCRIPTION

[0049] The technical solutions of the present application will be described in detail below.

[0050] The present application provides a sulfamethoxazole treatment method in reclaimed water based on a catalytic membrane, as shown in the figure, comprising the following steps: Figure 1

[0051] Step 10, preparing a nanometer catalytic material;

[0052] Step 20, preparing the powdery nanometer catalytic material into a catalytic membrane;

[0053] Step 30, installing the catalytic membrane in a reactor, injecting an oxidant solution into the reactor, and conveying reclaimed water containing sulfamethoxazole into the reactor to flow through the catalytic membrane in a circulating manner; at the same time, the catalytic membrane is irradiated.

[0054] The method of the present application uses a catalytic membrane to treat reclaimed water, and the catalytic membrane is irradiated during the treatment process. By applying light, the active site is induced to repair, the cyclic stability of the catalytic membrane is enhanced, and the service life of the catalytic membrane can be prolonged; by applying light, a non-radical pathway is added to the free radical pathway, a variety of oxidizing substances are generated, the catalytic reaction speed is accelerated, and the effective degradation of sulfamethoxazole is promoted.

[0055] Preferably, as shown in the figure, step 10 specifically comprises: Figure 2

[0056] Step 101, preparing a metal organic framework material;

[0057] ​​Step 102, preparing iron oxide particles inside the metal organic framework material to obtain a confined iron nanomaterial;

[0058] Step 103, vertically growing molybdenum disulfide nanosheets on the surface of the confined iron nanomaterial to obtain a nanocatalytic material.

[0059] Step 101 specifically includes:

[0060] Step 1011, dissolving cobalt nitrate hexahydrate in a methanol solution to obtain a cobalt nitrate hexahydrate methanol solution; dissolving 2-methylimidazole in a methanol solution to obtain a 2-methylimidazole methanol solution. The methanol solution is used as a solvent. Preferably, the mass (mg) of cobalt nitrate hexahydrate to the volume (mL) of the methanol solution is 15-19:1, and the mass (mg) of 2-methylimidazole to the volume (mL) of the methanol solution is 13-17:1. When preparing, the cobalt nitrate hexahydrate methanol solution and the 2-methylimidazole methanol solution have the same volume of methanol solution.

[0061] Step 1012, adding the cobalt nitrate hexahydrate methanol solution into the 2-methylimidazole methanol solution drop by drop, stirring and then standing for aging.

[0062] Step 1013, centrifuging the precipitate obtained in step 1012, repeatedly washing the product with an ethanol solution, and then drying the product in an oven to obtain a zeolitic imidazolate framework material (ZIF) containing metal Co coordination. Preferably, the temperature in the oven is 40-60°C.

[0063] Preferably, step 102 specifically includes:

[0064] Step 1021, preparing a 2-tert-butyl-p-cresol diethyl ether solution with diethyl ether solution as a solvent and 2-tert-butyl-p-cresol as a solute, and mixing the 2-tert-butyl-p-cresol diethyl ether solution with the metal organic framework material under airtight conditions to obtain a mixed solution. In this process, 2-tert-butyl-p-cresol (tBMP) is introduced into the cavity of the metal organic framework material under the action of diethyl ether, as shown in Figure 2 Preferably, the mass (mg) of 2-tert-butyl-p-cresol to the volume of diethyl ether solution (mL) is 5-15:1. The mass ratio of 2-tert-butyl-p-cresol to the metal organic framework material is 1:3-7.

[0065] Step 1022, heating the mixed solution obtained in step 1021 to a constant weight to remove diethyl ether and tBMP outside the metal organic framework material.

[0066] Step 1023, dispersing the mixed solution treated in step 1022 in an FeCl2·4H2O aqueous solution, performing a shock reaction at room temperature, and generating FeO x hydrate inside the metal organic framework material, as shown inFigure 2 Preferably, the concentration of the aqueous solution of FeCl2·4H2O is 15-25 mM.

[0067] In step 1024, the precipitated product obtained in step 1023 is collected by centrifugation, and the product is repeatedly washed with ethanol and deionized water to remove residual organic reagents. The product is aged in an oven to obtain the confined iron nanomaterial.

[0068] Preferably, in step 1022, the mixed solution obtained in step 1021 is heated to a constant weight by using an inert gas stream at 100-120°C. The mixed solution is heated by using an inert gas stream to isolate oxygen, so that the FeCl2·4H2O in the cavity of the metal-organic framework material is converted into FeO x under the action of 2-tert-butyl-p-cresol. The inert gas stream can be a nitrogen stream, an argon stream, etc. The temperature of the inert gas stream is 100-120°C, which can maintain the structural stability of the metal-organic framework material.

[0069] Preferably, in step 1023, the pH of the reaction solution is controlled in the range of 5-10 during the reaction. Controlling the pH in the range of 5-10 regulates the redox potential, thereby driving the reduction reaction to proceed, which is beneficial for synthesizing FeO x .

[0070] Preferably, in step 1024, the temperature in the oven is 130-140°C, which is convenient for material solidification.

[0071] In step 102 of the method, based on the difference between the redox sites of the compounds and the pH value, 2-tert-butyl-p-cresol (tBMP) is introduced into the cavity of the metal-organic framework material by using diethyl ether, thereby preparing FeO x nanoparticles inside the metal-organic framework material, and synthesizing the nanomaterial with a confined iron structure. The FeO x nanoparticles mainly grow in the pores of the metal-organic framework material instead of being aggregated outside the pores, so as not to hinder the passage of the catalytic material, thereby ensuring effective mass transfer in the catalytic process. Secondly, the FeO x nanoparticles in the pores increase the specific surface area in the micropores, provide more adsorption sites for the reactants, and promote the adsorption and reaction of the reactants in the catalytic material. The confined structure can protect the Fe reaction sites inside the nanospace, reduce the leaching of Fe, thereby reducing the generation of secondary pollutants such as iron sludge, reducing the impact on the membrane flux, and maintaining the integrity of the membrane structure.

[0072] Preferably, step 103 specifically includes:

[0073] Step 1031, the confined iron nanomaterial is dispersed in deionized water to obtain a confined iron nanoparticle dispersion. The mass (mg) of the confined iron nanomaterial to the volume (mL) of the deionized water is 1.5-1.8:1.

[0074] Step 1032, ammonium molybdate and thiourea are added to the confined iron nanoparticle dispersion and stirred. Preferably, the mass ratio of ammonium molybdate, thiourea and confined iron nanomaterial is 1:1-2:2-3.

[0075] Step 1033, the mixture obtained in step 1032 is transferred to a high-pressure reaction kettle equipped with a polytetrafluoroethylene lining, and the high-pressure reaction kettle is placed in an oven for reaction.

[0076] Step 1034, the precipitated product in the high-pressure reaction kettle in step 1033 is collected by centrifugation, and the product is repeatedly washed with deionized water and ethanol, and then vacuum dried in an oven to obtain a nanocatalytic material.

[0077] Preferably, in step 1033, the temperature in the oven is 185-195℃. Too low a temperature can easily lead to MoS2 nanosheet morphology being too thick, affecting the photoelectric conversion efficiency, and too high a temperature can cause MoS2 nanosheet morphology to break, and reaction within the above temperature range can ensure successful generation of MoS2 nanosheets.

[0078] Preferably, in step 1033, the reaction time is 9-24 hours. A shorter reaction time can only form simple structures such as nanosheets or nanorods, and as the reaction time is prolonged, these nanosheets will gradually assemble into flower-like structures, but too long a reaction time will affect the stability of the confined iron nanomaterial.

[0079] Preferably, in step 1034, the temperature in the oven is 40-60℃.

[0080] Step 103 of the method of the present application, as shown in Figure 2 The hydrothermal method is used to vertically grow MoS2 nanosheets on the surface of the confined iron nanomaterial by controlling the reaction temperature, reaction time and reactant mass ratio. The active sites of MoS2 are concentrated on the edges of the nanosheets, and this vertical growth mode can maximize the exposure of the edge active sites of MoS2, which is conducive to the occurrence of catalytic reactions. Under light conditions, Mo(IV) can act as a cocatalyst to transfer electrons in the reaction, induce Fe(III) and Co(IV) to be reduced to highly active low-valence states, promote the Fe(II) / Fe(III) cycle of the catalyst, prolong the service life of the catalytic film, and reduce the leaching of Fe, thereby reducing the generation of secondary pollutants such as iron sludge.

[0081] The nano-catalytic material prepared in the method has a limited structure, and when a catalytic membrane is made and reacts, the limited structure can protect the Fe reaction site inside the nano space, reduce the leaching of Fe, thereby reducing the generation of secondary pollutants of iron sludge, reducing the influence on the membrane flux, and maintaining the integrity of the membrane structure. At the same time, most of the natural organic matter is excluded from the reaction space, reducing the interference of competitive adsorption of coexisting substances near the active site, thereby providing a more superior catalytic environment for sulfamethoxazole, having excellent anti-interference ability under complex water quality matrix, improving the reaction activity. The Fe in the limited structure and the MoS2 loaded on the surface can enhance the conductivity of the catalytic membrane, which is beneficial to improve the carrier migration rate of the catalytic membrane surface and improve the activity of the catalytic membrane. At the same time, under light conditions, Mo(IV) can act as a cocatalyst to transfer electrons in the reaction, induce Fe(III) and Co(IV) to be reduced to highly active low-valence states, and promote the Fe(II)-Fe(III) cycle of the catalyst: Mo 4+ + Fe 3+ → Mo 5+ + Fe 2+ . The nano material prepared in the method is used to prepare a catalytic membrane, and under light conditions, the active site can be restored, maintaining the stability of the catalytic membrane, prolonging the service life of the catalytic membrane, and reducing the leaching of Fe, thereby reducing the generation of iron sludge.

[0082] The catalytic membrane activates the oxidizing agent through electron transfer between the multivalent transition metals inside the catalytic membrane to generate •SO4 - and •OH to participate in the degradation of pollutants: e metal - + HSO5 - → •SO4 - + OH - , e metal - + HSO5 - → SO4 2- + •OH. Under light conditions, the catalytic membrane utilizes its own photocatalytic ability to react with dissolved oxygen in the water environment to generate •O2: e CB - + O2 → •O2, and then generates more degradation-selective active 1 O2: •O2 + •OH → 1 O2 + OH - , and •SO4 - to form multiple free radical pathways and participate in the degradation of sulfamethoxazole: 1 O2 / •SO4 -+SMX→H2O+CO2. The nanomaterial prepared by the method of the application is used to prepare a catalytic membrane, and under light conditions, the reaction has both a free radical pathway and a non-free radical pathway, which provides a faster pathway for carbon transfer of sulfamethoxazole in reclaimed water, and improves the removal effect of sulfamethoxazole.

[0083] Preferably, step 20 specifically comprises:

[0084] Step 201, the powdered nanocatalytic material is added to deionized water and ultrasonic dispersion treatment is performed to obtain a catalytic dispersion liquid.

[0085] Step 202, the catalytic dispersion liquid is loaded onto the surface of the polytetrafluoroethylene membrane using a vacuum filtration method.

[0086] Step 203, the polytetrafluoroethylene membrane loaded with the catalytic dispersion liquid is placed in an oven for vacuum drying to obtain a catalytic membrane. Preferably, the working temperature of the oven is 20-30°C.

[0087] Three examples and two comparative examples are provided below to verify the performance of the method of the application.

[0088] In the following examples and comparative examples, the methanol solution used is anhydrous methanol, the ethanol solution is anhydrous ethanol, and the diethyl ether solution is anhydrous diethyl ether.

[0089] Example 1

[0090] Step 1, preparation of zeolitic imidazolate framework material containing Co coordination (referred to as ZIF)

[0091] 837 mg of cobalt nitrate hexahydrate is dissolved in 50 mL of methanol solution to prepare a cobalt nitrate hexahydrate methanol solution. 730 mg of 2-methylimidazole is dissolved in 50 mL of methanol solution to prepare a 2-methylimidazole methanol solution.

[0092] The cobalt nitrate hexahydrate methanol solution is added dropwise to the 2-methylimidazole methanol solution, stirred for 5 minutes, and then left to stand for 24 h for aging and precipitation. The precipitate is collected by centrifugation, washed repeatedly with an ethanol solution to remove residual organic reagents on the surface, and dried in an oven at 60°C for 12 h to obtain a purple product ZIF.

[0093] Step 2, preparation of nanomaterial ZIF-FeO with limited structure x (referred to as ZF)

[0094] A 2-tert-butyl-p-cresol ethyl ether solution tBMP / DE was prepared by adding 10 mg of 2-tert-butyl-p-cresol into 1 mL of ethyl ether solution. The 2-tert-butyl-p-cresol ethyl ether solution was mixed with 50 mg of ZIF under airtight conditions, and the mixed solution was heated to a constant weight at 120°C under a nitrogen stream. The treated mixed solution tBMP@ZIF was dispersed in an excess of a 20 mM FeCl2·4H2O aqueous solution, and shaken at room temperature for 4 h, with a pH of 8 during the reaction. The product was collected by centrifugation, washed repeatedly with an ethanol solution and deionized water to remove residual organic reagents, and aged in an oven at 140°C for 2 h to obtain ZF.

[0095] Step 3, preparation of catalytic material ZIF-FeO x @ MoS2 (referred to as ZFM)

[0096] A ZF nanoparticle dispersion was prepared by adding 50 mg of ZF to 30 mL of deionized water. 20 mg of ammonium molybdate and 34.5 mg of thiourea were added to the ZF nanoparticle dispersion and stirred for 30 min. The mixture was transferred to a high-pressure reaction kettle equipped with a 100 mL polytetrafluoroethylene liner and placed in an oven at 190°C for 15 h. After the reaction was completed, the precipitated product was collected by centrifugation and washed repeatedly with deionized water and an ethanol solution to remove residual organic reagents on the surface. The obtained product was placed in an oven at 60°C for vacuum drying for 6 h to obtain a black nanomaterial ZFM.

[0097] Step 4, preparation of ZFM catalytic film

[0098] A 50 mg of powdered ZFM was added to 50 mL of deionized water and subjected to ultrasonic dispersion treatment for 10 h. A 15 mL ZFM dispersion was loaded onto the surface of a PTFE film with a diameter of 10 cm using vacuum suction filtration. The film was placed in an oven at 25°C for vacuum drying for 24 h to obtain a ZFM catalytic film, with an effective diameter of the material on the film being 9 cm.

[0099] Step 5, treatment of reclaimed water

[0100] The ZFM catalytic film was installed in a reactor, and a 0.5 mM peroxymonosulfate (PMS) solution was injected into the reactor. Reclaimed water with a sulfamethoxazole (SMX) mass concentration of 0.1 mg / L was fed into the reactor to flow through the catalytic film in a circulating manner, and the catalytic film was subjected to light irradiation.

[0101] Example 2

[0102] Step 1, preparation of metal Co-containing zeolitic imidazolate framework material (referred to as ZIF)

[0103] Co(NO3)2.6H2O was dissolved in 50 mL methanol to prepare Co(NO3)2.6H2O methanol solution. 650 mg 2-methylimidazole was dissolved in 50 mL methanol to prepare 2-methylimidazole methanol solution.

[0104] Co(NO3)2.6H2O methanol solution was added dropwise into 2-methylimidazole methanol solution. After stirring for 5 min, the mixture was left to stand for 24 h for aging of the precipitate. The precipitate was collected by centrifugation and washed repeatedly with ethanol solution to remove the residual organic reagents on the surface. The product was dried in an oven at 40 °C for 12 h to obtain purple product ZIF.

[0105] Step 2, preparation of nanomaterial ZIF-FeO with limited domain structure x (ZF)

[0106] 2-tert-butyl-p-cresol was dissolved in 1 mL diethyl ether to prepare 2-tert-butyl-p-cresol diethyl ether solution tBMP / DE. 2-tert-butyl-p-cresol diethyl ether solution was mixed with 15 mg ZIF under airtight condition. The mixture was heated to constant weight at 100 °C under argon flow. The treated mixture tBMP@ZIF was dispersed in excess 15 mM FeCl2.4H2O aqueous solution. The reaction was carried out at room temperature for 4 h with pH 5. The product was collected by centrifugation and washed repeatedly with ethanol solution and deionized water to remove the residual organic reagents. The product was aged in an oven at 130 °C for 2 h to obtain ZF.

[0107] Step 3, preparation of catalytic material ZIF-FeO x @ MoS2(ZFM)

[0108] 45 mg ZF was added to 30 mL deionized water to obtain ZF nanoparticle dispersion. 27.5 mg ammonium molybdate and 27.5 mg thiourea were added to the ZF nanoparticle dispersion and stirred for 30 min. The mixture was transferred to a high-pressure reaction kettle equipped with a 100 mL polytetrafluoroethylene liner and placed in an oven at 185 °C for 9 h. After the reaction was completed, the precipitate was collected by centrifugation and washed repeatedly with deionized water and ethanol solution to remove the residual organic reagents on the surface. The obtained product was vacuum dried in an oven at 40 °C for 6 h to obtain black nanomaterial ZFM.

[0109] Step 4, preparation of ZFM catalytic film

[0110] 50 mg of powdered ZFM was added to 50 mL deionized water for ultrasonic dispersion treatment for 10 h. 15 mL ZFM dispersion was loaded onto the surface of a PTFE film with a diameter of 10 cm using vacuum suction filtration. The film was vacuum dried in an oven at 25 °C for 24 h to obtain ZFM catalytic film, and the effective diameter of the material on the film was 9 cm.

[0111] Step 5, treatment of reclaimed water

[0112] The ZFM catalytic membrane was installed in the reactor, and a solution of persulfate (PMS) with a mass concentration of 0.5 mM was injected into the reactor. The reclaimed water containing sulfamethoxazole (SMX) with a mass concentration of 0.1 mg / L was delivered to the reactor to flow through the catalytic membrane in a circulating manner, and the catalytic membrane was irradiated.

[0113] Example 3

[0114] Step 1, preparation of metal Co-containing coordination zeolitic imidazolate framework material (ZIF)

[0115] 950 mg of cobalt nitrate hexahydrate was dissolved in 50 mL of methanol solution to prepare a cobalt nitrate hexahydrate methanol solution. 850 mg of 2-methylimidazole was dissolved in 50 mL of methanol solution to prepare a 2-methylimidazole methanol solution.

[0116] The cobalt nitrate hexahydrate methanol solution was added dropwise to the 2-methylimidazole methanol solution, stirred for 5 minutes, and then aged for 24 h for precipitation. The precipitated product was collected by centrifugation, repeatedly washed with ethanol solution to remove residual organic reagents on the surface, and dried in an oven at 50°C for 12 h to obtain a purple product ZIF.

[0117] Step 2, preparation of nanomaterial ZIF-FeO with limited structure x (ZF)

[0118] 15 mg of 2-tert-butyl-p-cresol was added to 1 mL of diethyl ether solution to prepare a 2-tert-butyl-p-cresol diethyl ether solution tBMP / DE. Under sealed conditions, the 2-tert-butyl-p-cresol diethyl ether solution was mixed with 105 mg of ZIF, and the mixed solution was heated to a constant weight at 110°C under a nitrogen stream. The treated mixed solution tBMP@ZIF was dispersed in an excess of 25 mM FeCl2·4H2O aqueous solution at room temperature, and the reaction was shaken for 4 h with a pH of 10. The product was collected by centrifugation, repeatedly washed with ethanol solution and deionized water to remove residual organic reagents, and aged in an oven at 130°C for 2 h to obtain ZF.

[0119] Step 3, preparation of catalytic material ZIF-FeO x @ MoS2 (ZFM)

[0120] ZFM-OUT catalytic membrane. Replace ZFM in Example 1, Step 4 with ZFM-OUT, and the rest is the same, to obtain ZFM-OUT catalytic membrane.

[0121] Step 4, preparation of ZFM catalytic membrane

[0122] Add 50 mg of powdered ZFM into 50 mL of deionized water, and perform ultrasonic dispersion treatment for 10 h. Load 15 mL of ZFM dispersion liquid onto the surface of a PTFE membrane with a diameter of 10 cm using vacuum suction filtration. Place the membrane in an oven at 25 °C and vacuum dry for 24 h to obtain a ZFM catalytic membrane, and the effective diameter of the material on the membrane is 9 cm.

[0123] Step 5, treatment of reclaimed water

[0124] Install the ZFM catalytic membrane in the reactor, and inject a solution of persulfate (PMS) with a mass concentration of 0.5 mM into the reactor. Deliver reclaimed water with a sulfamethoxazole (SMX) mass concentration of 0.1 mg / L to the reactor in a circulating flow manner through the catalytic membrane, and illuminate the catalytic membrane.

[0125] Comparative Example 1

[0126] The same as Example 1, except that the catalytic membrane is not illuminated in Step 5.

[0127] Comparative Example 2

[0128] Step 1, preparation of ZIF. The same as Step 1 of Example 1, to obtain ZIF.

[0129] Step 2, preparation of nanomaterial ZF-OUT without limit domain structure. Replace the diethyl ether solution in Step 2 of Example 1 with deionized water, and the rest is the same, to obtain ZF-OUT.

[0130] Step 3, preparation of catalytic material ZFM-OUT. Replace ZF in Step 3 of Example 1 with ZF-OUT, and the rest is the same, to obtain ZFM-OUT.

[0131] Step 4, preparation of ZFM-OUT catalytic membrane. Replace ZFM in Example 1, Step 4 with ZFM-OUT, and the rest is the same, to obtain ZFM-OUT catalytic membrane.

[0132] Step 5, treatment of the reclaimed water. Replace the ZFM catalytic membrane in Step 5 of Example 1 with ZFM-OUT catalytic membrane, without light irradiation to the catalytic membrane, and the rest is the same.

[0133] In Example 1, Comparative Example 1 and Comparative Example 2, the concentration of SMX in the water was detected at different reaction times using high performance liquid chromatography (HPLC, 1290, Agilent) to obtain the removal efficiency of SMX, as shown in Table 1. Figure 3 The permeability of the membrane module was tested at different reaction times, and the amount of Fe element in the effluent was quantitatively analyzed using inductively coupled plasma optical emission spectrometer (ICP-OES), as shown in Table 2. Figure 4 The ZFM catalytic membrane before use in Comparative Example 1, the ZFM catalytic membrane after 6 hours of reaction, the ZFM-OUT catalytic membrane before use in Comparative Example 2, and the ZFM-OUT catalytic membrane after 6 hours of reaction were respectively scanned using a scanning electron microscope (SEM, S-4800, Hitachi) to obtain their surface morphologies, as shown in Figure 2. Figure 5 .

[0134] As can be seen from Table 1, Figure 3 , after 5 cycles, the SMX removal efficiencies of the ZFM catalytic membrane and the ZFM-OUT catalytic membrane under dark conditions were 59% and 31%, respectively. The difference in degradation efficiency and catalytic stability between the two is mainly due to the different reaction activities and catalytic environments of the active iron sites in the nano space of the ZFM catalytic material and the exposed iron sites outside the ZFM-OUT. It can be concluded that the confined structure of the ZFM catalytic material enhances the utilization efficiency of reactive oxygen species (ROS) by shortening the mass transfer distance between the pollutant and the internal active site, thereby significantly improving the catalytic reaction efficiency. After 5 cycles, the removal efficiency of SMX by the ZFM catalytic membrane under light irradiation still remained above 95%, which was higher than that of the ZFM catalytic membrane under dark conditions. It can be concluded that the stimulation of light not only accelerates the catalytic reaction rate and promotes the effective degradation of pollutants, but also enhances the recycling stability of the catalyst.

[0135] As can be seen from Table 2, Figure 4 , the leaching concentration of dissolved Fe ions in Comparative Example 2 (i.e., using ZFM-OUT catalytic membrane under dark conditions) was about 100 μg / L, while the leaching concentration of dissolved Fe ions in Comparative Example 1 (i.e., using ZFM catalytic membrane under dark conditions) was less than 10 μg / L. It can be seen that the nano space in the ZFM catalytic membrane effectively protects the FeOx in the metal-organic framework, effectively inhibiting the dissolution of Fe. Moreover, the permeability of the ZFM catalytic membrane decreased by 12.7%, while the permeability of the ZFM-OUT catalytic membrane decreased by 34.7%.

[0136] After 6 hours of continuous reaction, the surface of ZFM catalytic membrane still remained black, while the surface of ZFM-OUT catalytic membrane appeared dark red flocculent substance. The catalytic membrane after reaction was detected by ICP-OES, and the results showed that the red substance was mainly composed of iron mud composed of iron and oxygen elements. It can be seen that another reason for the significant reduction of ZFM-OUT catalytic efficiency is that the dissolved iron ions react with inorganic ions and natural organic matter in wastewater to generate iron mud, which is deposited on the surface of the catalytic membrane, reducing the flux of the catalytic membrane and hindering the mass transfer efficiency of substances in the reactor. The above results confirm that the confined structure of ZFM catalytic membrane promotes the protection of metal-organic framework on the confined FeOx nanoparticles, reduces the leaching of iron ions and maintains the integrity of the membrane structure.

[0137] From Figure 5 As can be seen from Figure 5 (a) can be seen, while the ZFM catalytic membrane maintains structural integrity.

[0138] The free radical quenching experiment was used to evaluate the types of free radicals generated by ZFM catalytic material under dark conditions and ZFM catalytic material under light conditions. Since the reaction rate constant of •SO4- and •OH is similar, methanol solution is used as a universal quencher. At the same time, tert-butyl alcohol (TBA) is commonly used as a •OH scavenger, benzoquinone (BQ) is used as a •O2- quencher, and furfuryl alcohol (FFA) is used to quench 1O2. Under dark reaction conditions, methanol solution has a strong inhibitory effect on the degradation of SMX, while TBA has a weak inhibitory effect. It shows that ZFM catalytic material only has •SO4- active oxygen species under dark conditions. In contrast, under light conditions, the addition of FFA and BQ significantly inhibits the degradation of SMX, while the presence of methanol solution only has a slight inhibitory effect. It shows that ZFM catalytic material has multiple free radical oxidation-reduction pathways composed of 1O2, •O2- and •SO4- under light conditions, which promotes its efficient degradation of SMX under light conditions.

[0139] The oxidation state changes of metal elements (Fe, Mo, Co) in the catalytic material before and after the reaction were analyzed by XPS. Under dark reaction conditions, the metal elements mainly changed from low valence state to high valence state. Before the reaction, Fe(II) dominated in ZFM (70%), and after the dark reaction, a large amount of Fe(II) was converted into Fe(III), resulting in the decrease of Fe(II) / Fe(III) ratio from 1.78 to 0.37. At the same time, a small amount of Co(III) was observed to be converted into high valence state Co(IV). However, under light conditions, the ratio of Fe(II) / Fe(III) increased to 0.86, which was 2.3 times of the dark reaction system. In the photosystem, Mo(IV) was converted into high valence state Mo(V) and Mo(VI), indicating that Mo(IV) can act as a cocatalyst to transfer electrons in the reaction, inducing the reduction of Fe(III) and Co(IV) to highly active low valence state.

[0140] Through the above experiments, it can be verified that the nano material prepared by the method of the present application is used to prepare a catalytic membrane, and under light conditions, the active sites of the catalytic membrane can be restored, the stability of the catalytic membrane is maintained, the service life of the catalytic membrane is prolonged, and the leaching of Fe is reduced, thereby reducing the generation of iron sludge; during the reaction, there are both free radical pathways and non-free radical pathways, which provides a faster way for carbon transfer of sulfamethoxazole in reclaimed water, and improves the removal effect of sulfamethoxazole.

[0141] The above shows and describes the basic principles, main features and advantages of the present application. Those skilled in the art should understand that the present application is not limited to the above specific embodiments, and the above specific embodiments and descriptions in the specification are only for further illustration of the principles of the present application. Without departing from the spirit and scope of the present application, various changes and improvements can be made, which fall within the scope of the present application.

Claims

1. A method for the treatment of sulfamethoxazole in reclaimed water based on catalytic membrane, characterized by, The method comprises the following steps: Step 10, preparing a nano-catalytic material; Step 20, preparing the nano-catalytic material in powder into a catalytic film; Step 30, installing the catalytic film in a reactor, injecting an oxidant solution into the reactor, and feeding regenerated water containing sulfamethoxazole into the reactor to flow through the catalytic film in a circulating manner, while irradiating the catalytic film; The step 10 specifically comprises: Step 101, preparing a metal organic framework material; the metal organic framework material is a zeolitic imidazolate framework material containing Co coordination; Step 102, preparing iron oxide particles inside the metal organic framework material to obtain a confined iron nano material; Step 103, vertically growing molybdenum disulfide nanosheets on the surface of the confined iron nano material to obtain a nano-catalytic material; The step 102 specifically comprises: Step 1021, preparing a 2-tert-butyl-p-cresol ethyl ether solution by taking anhydrous ethyl ether as a solvent and 2-tert-butyl-p-cresol as a solute, mixing the 2-tert-butyl-p-cresol ethyl ether solution with the metal organic framework material under airtight conditions to obtain a mixed solution; Step 1022, heating the mixed solution obtained in step 1021 to a constant weight; Step 1023, dispersing the mixed solution treated in step 1022 in an FeCl2·4H2O aqueous solution and performing a shock reaction at room temperature; Step 1024, centrifuging to collect the precipitated product obtained in step 1023, repeatedly washing the product with anhydrous ethanol and deionized water, and then placing the product in an oven for aging to obtain a confined iron nano material.

2. The catalytic membrane based method for the treatment of sulfonamidomethoxazole in reclaimed water according to claim 1, characterized in that, In the step 1021, the mass ratio of 2-tert-butyl-p-cresol to the metal organic framework material is 1:3-7; In the step 1022, the mixed solution obtained in step 1021 is heated to a constant weight by using an inert gas flow at 100-120°C.

3. The catalytic membrane based method for the treatment of sulfonamidomethoxazole in reclaimed water according to claim 1, characterized in that, In the step 1023, the pH of the reaction solution is controlled to be in the range of 5-10 during the reaction.

4. The catalytic membrane based method for the treatment of sulfonamidomethoxazole in reclaimed water according to claim 1, characterized in that, In the step 1024, the temperature in the oven is 130-140°C.

5. The catalytic membrane based method for the treatment of sulfonamidomethoxazole in reclaimed water according to claim 1, characterized in that, The step 103 specifically comprises: Step 1031, dispersing the confined iron nano material in deionized water to obtain a confined iron nano particle dispersion liquid; Step 1032, adding ammonium molybdate and thiourea to the confined iron nano particle dispersion liquid and stirring; Step 1033, transferring the mixed solution obtained in step 1032 to a high-pressure reaction kettle equipped with a polytetrafluoroethylene lining and placing it in an oven for reaction; Step 1034, centrifuging to collect the precipitated product in the high-pressure reaction kettle in step 1033, repeatedly washing the product with deionized water and anhydrous ethanol, and then placing the product in an oven for vacuum drying to obtain a nano-catalytic material.

6. The catalytic membrane based method of treatment of sulfonamidomethoxazole in reclaimed water according to claim 5, characterized in that, In the step 1032, the mass ratio of ammonium molybdate, thiourea, and the confined iron nano material is 1:1-2:2-3; In the step 1033, the temperature in the oven is 185-195°C; In the step 1034, the temperature in the oven is 40-60°C.

7. The catalytic membrane based method of treatment of sulfonamidomethoxazole in reclaimed water of claim 1, wherein, The step 101 specifically comprises: Step 1011, dissolving cobalt nitrate hexahydrate in anhydrous methanol to obtain a cobalt nitrate hexahydrate methanol solution; dissolving 2-methylimidazole in anhydrous methanol to obtain a 2-methylimidazole methanol solution; Step 1012, dropwise adding the cobalt nitrate hexahydrate methanol solution into the 2-methylimidazole methanol solution, stirring and then standing and aging; Step 1013, centrifuging the precipitate obtained in step 1012, repeatedly washing the product with anhydrous ethanol, and then drying the product in an oven to obtain a zeolitic imidazolate framework material containing metal Co coordination.

8. The catalytic membrane based method of treating sulfonamidomethoxazole in reclaimed water of claim 1, wherein, The step 20 specifically comprises: Step 201, adding a powdered nano-catalytic material into deionized water and performing ultrasonic dispersion treatment to obtain a catalytic dispersion liquid; Step 202, loading the catalytic dispersion liquid onto the surface of a polytetrafluoroethylene film by using a vacuum filtration method; Step 203, vacuum drying the polytetrafluoroethylene film loaded with the catalytic dispersion liquid in an oven to obtain a catalytic film.

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