Fe3O4 composite catalyst, preparation method and application thereof

Abstract

The application discloses an Fe3O4 composite catalyst and a preparation method and application thereof, relates to the technical field of catalysts, and comprises Fe3O4, ferrous oxide, a transition metal oxide and a porous carrier, wherein the transition metal oxide accounts for 1-10% of the total mass, and the porous carrier accounts for 65-85% of the total mass; the porous carrier is a functional carrier subjected to internal doping modification treatment and external functionalization treatment; the internal doping modification treatment is that a metal or a nonmetal acts on a bulk phase or a near-surface deep layer of the porous carrier; and the external functionalization treatment is that a polymer is linked to a surface layer of the porous carrier. The application has the effects of improving the wastewater treatment efficiency and reducing the wastewater treatment cost.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of catalysts, in particular to a Fe3O4 composite catalyst, a preparation method and application thereof. BACKGROUND

[0002] High-salt and high-COD wastewater treatment refers to a process of treating wastewater containing high-concentration salt and high-chemical oxygen demand to meet discharge standards or recycling requirements.

[0003] A high-salt environment can cause microbial cells to dehydrate, resulting in reduced intracellular enzyme activity, affecting microbial metabolism and growth, and thus inhibiting the effect of the commonly used biological treatment process in wastewater treatment. To address this problem, special salt-tolerant microorganisms or microbial domestication are required, which increases the complexity and cost of the treatment process. High-COD wastewater often contains a large amount of refractory organic matter, such as polycyclic aromatic hydrocarbons and heterocyclic compounds, which are difficult to completely decompose by traditional treatment methods. Advanced oxidation technology, activated carbon adsorption, and other methods may be required, but these methods have high operating costs and large equipment investments.

[0004] In the prior art, a single treatment technology is usually difficult to meet the requirements of high-salt and high-COD wastewater treatment, so a combination of multiple treatment processes is often used, which prolongs the treatment process cycle and significantly increases the operation and management difficulty. In actual operation, there is no catalyst suitable for high-salt and high-COD wastewater treatment, and the time and cost requirements for high-salt and high-COD wastewater treatment are high, which needs to be improved. SUMMARY

[0005] Therefore, the first object of the present application is to provide a Fe3O4 composite catalyst to improve the efficiency of wastewater treatment and reduce the cost of treatment. The specific scheme is as follows:

[0006] A Fe3O4 composite catalyst, comprising Fe3O4, ferrous oxide, transition metal oxide, and a porous carrier, wherein the transition metal oxide accounts for 1-10% of the total mass, and the porous carrier accounts for 65-85% of the total mass; the porous carrier is a functional carrier treated by internal doping modification and external functionalization; the internal doping modification treatment is to use metal or non-metal to act on the bulk phase or near-surface deep layer of the porous carrier; and the external functionalization treatment is to use a polymer to link to the surface layer of the porous carrier.

[0007] Preferably, the transition metal oxide is manganese oxide, copper oxide, or cobalt oxide.

[0008] Preferably, the functional carrier is modified activated carbon or modified zeolite; the specific surface area S bet≥ 800 m2 / g.

[0009] Preferably, the functional carrier is modified activated carbon, and a preparation method of the modified activated carbon comprises the following steps:

[0010] Step ① raw material treatment: washing the activated carbon with deionized water and drying the activated carbon at 80°C to obtain dry activated carbon for standby;

[0011] Step ② doping modification: mixing urea and activated carbon at a mass ratio of 10:2.8-3.2, adding deionized water to stir uniformly to obtain an activated carbon solution with a concentration of 1 g / ml, heating the activated carbon solution in a water bath at 58-62°C for 2-3 h, and then sequentially performing pre-drying, calcination, cooling, washing, and post-drying treatment to obtain nitrogen-doped activated carbon;

[0012] Step ③ functionalization treatment: stirring the nitrogen-doped activated carbon in concentrated nitric acid to obtain a doping solution with a concentration of 0.5 g / ml, heating and stirring the doping solution in a water bath at 78-82°C for 4-5 h, cooling the reaction solution, and then washing and drying the reaction solution at 78-82°C for 10-12 h to obtain modified activated carbon subjected to internal doping modification and external functionalization treatment.

[0013] Preferably, in Step ②, the pre-drying temperature is 78-82°C, and the pre-drying time is 8 h; the calcination is heating to 500°C at a gas flow rate of nitrogen gas greater than or equal to 50 mL / min, and the heating rate is controlled at 5°C / min, and the temperature is maintained at 500°C for 2 h; and the post-drying temperature is 78-82°C, and the post-drying time is 11-13 h.

[0014] Preferably, the functional carrier is modified zeolite, and a preparation method of the modified zeolite comprises the following steps:

[0015] Step ① raw material treatment: stirring and removing the supernatant repeatedly to obtain clean zeolite, and then soaking the clean zeolite in a 1 mol / L hydrochloric acid solution for 1.5-2.5 h, with a solid-liquid ratio of 1:5, and finally washing and drying the pretreated zeolite with deionized water to obtain pretreated zeolite;

[0016] Step ② doping modification: dissolving titanium tetrachloride in anhydrous ethanol to obtain a 0.1 g / L titanium tetrachloride ethanol solution, and then soaking the pretreated zeolite in the titanium tetrachloride ethanol solution and heating in a water bath at 58-62°C for 3.5-5 h, with a mass ratio of titanium tetrachloride to pretreated zeolite of 1:9-11, and finally sequentially performing filtration, anhydrous ethanol washing, pre-drying, calcination, and cooling treatment to obtain titanium-doped zeolite;

[0017] Step 3: functional treatment: put the titanium-doped zeolite into a toluene solution of 3-aminopropyl triethoxysilane, control the amount ratio of titanium-doped zeolite, 3-aminopropyl triethoxysilane and toluene to be 25:1.95-2.05:50, under the protection of inert gas atmosphere, control the temperature to be 78-82℃, and stir reflux for 6-7h, after the reaction is completed, cool to room temperature, remove 3-aminopropyl triethoxysilane, wash with anhydrous ethanol and dry at 78-82℃ for 8-9h, to obtain a modified zeolite treated by internal doping modification and external functionalization.

[0018] Preferably: in step 2, the pre-drying temperature is 78-82℃, and the time is 6h; the calcination is to control the temperature rising rate to be 5℃ / min to rise to 500℃ under air atmosphere, and to keep the temperature at 500℃ for 3h.

[0019] The second object of the present application is to provide a preparation method of Fe3O4 composite catalyst, for preparing the Fe3O4 composite catalyst as described above, comprising the following steps:

[0020] Step 1: take porous carriers, Fe3O4, ferrous oxide, transition metal oxides, polyvinyl alcohol and anhydrous ethanol for use;

[0021] Step 2: put the polyvinyl alcohol into anhydrous ethanol to stir and dissolve to obtain a polyvinyl alcohol ethanol solution with a concentration of 0.02g / ml;

[0022] Step 3: take Fe3O4, ferrous oxide and transition metal oxides, mix and stir until uniform to obtain mixed active materials;

[0023] Step 4: mix the porous carriers with the mixed active materials and the polyvinyl alcohol ethanol solution, under the condition of an oil bath at 78-82℃, stir for 6-8h, after the reaction is completed, centrifuge, wash with ethanol and vacuum dry to obtain the Fe3O4 composite catalyst.

[0024] Preferably: in step 4, the centrifugation speed is 8000r / min, and the time is 10min; the vacuum drying temperature is 105℃, and the time is 12h.

[0025] The third object of the present application is to provide an application of Fe3O4 composite catalyst, which comprises using the Fe3O4 composite catalyst as described above and applying it to wastewater treatment coupled with ozone.

[0026] It can be known from the above scheme that the application provides a Fe3O4 composite catalyst, a preparation method and application thereof. The Fe3O4 composite catalyst is obtained by modifying and functionalizing a porous carrier through internal doping to obtain a functional carrier, so as to significantly improve the electron transfer rate and catalytic activity, and make the functional carrier have the ability to effectively adsorb and combine pollutants, so that after being combined with Fe3O4, ferrous oxide and transition metal oxide, the Fe3O4 composite catalyst significantly improves the synergistic effect with ozone and improves the degradation efficiency of wastewater. The preparation method of the Fe3O4 composite catalyst has the effects of convenient control and stable preparation, and is suitable for industrial production. The application of the Fe3O4 composite catalyst has the effects of significantly improving the wastewater treatment efficiency and reducing the wastewater treatment cost. DETAILED DESCRIPTION

[0027] The technical solutions in the embodiments of the application will be described below in a clear and complete manner. Obviously, the described embodiments are only part of the embodiments of the application, rather than all the embodiments. Based on the embodiments in the application, all other embodiments obtained by those skilled in the art without creative work fall within the scope of protection of the application.

[0028] It should be noted that the mass ratio of Fe3O4, ferrous oxide and transition metal oxide in the Fe3O4 composite catalyst in the embodiments of the application is 3:1:1.6, and of course, other ratios are also applicable to wastewater treatment, which will not be described here.

[0029] The Fe3O4 composite catalyst, the preparation method and application thereof will be specifically described below.

[0030] The Fe3O4 composite catalyst comprises Fe3O4, ferrous oxide, transition metal oxide and a porous carrier. The transition metal oxide accounts for 1-10% of the total mass, and the porous carrier accounts for 65-85% of the total mass. The porous carrier is a functional carrier which is modified and treated by internal doping and external functionalization, and the internal doping modification treatment is to use metal or non-metal to act on the bulk phase or near-surface deep layer of the porous carrier. The external functionalization treatment is to use a polymer to link to the surface layer of the porous carrier.

[0031] It should be noted that the transition metal oxide in the embodiments of the application is manganese oxide, copper oxide or cobalt oxide. The functional carrier is modified activated carbon or modified zeolite, and the specific surface area S bet ≥800m² / g.

[0032] When the functional carrier is modified activated carbon, the preparation method of the modified activated carbon comprises the following steps:

[0033] Step 1: raw material treatment: the activated carbon is washed with deionized water and dried at 80°C to obtain the dried activated carbon for standby;

[0034] Step 2: doping modification: urea and activated carbon are mixed in a mass ratio of 10:2.8-3.2, deionized water is added and stirred to obtain an activated carbon solution with a concentration of 1 g / ml, the activated carbon solution is heated in a water bath at 58-62°C for 2-3h, and then pre-drying, calcination, cooling, washing and post-drying are sequentially performed to obtain nitrogen-doped activated carbon;

[0035] Step 3: functionalization treatment: the nitrogen-doped activated carbon is stirred in concentrated nitric acid to obtain a doping solution with a concentration of 0.5 g / ml, and then heated and stirred in a water bath at 78-82°C for 4-5h, after the reaction is completed, the solution is cooled and washed with deionized water and dried at 78-82°C for 10-12h to obtain modified activated carbon treated by internal doping modification and external functionalization.

[0036] In step 2, the pre-drying temperature is 78-82°C, and the time is 8h. The calcination is heated to 500°C in a nitrogen atmosphere with a gas flow rate greater than or equal to 50mL / min, the heating rate is controlled at 5°C / min, and the temperature is maintained at 500°C for 2h. The post-drying temperature is 78-82°C, and the time is 11-13h.

[0037] When the functional carrier is modified zeolite, the preparation method of the modified zeolite comprises the following steps:

[0038] Step 1: raw material treatment: the zeolite is put into deionized water, stirred and repeated to remove the supernatant to obtain clean zeolite, then the clean zeolite is soaked in 1 mol / L hydrochloric acid solution for 1.5-2.5h, the solid-liquid ratio is controlled at 1:5, and finally the pretreated zeolite is obtained by deionized water washing and drying treatment;

[0039] Step 2: doping modification: titanium tetrachloride is dissolved in anhydrous ethanol to obtain a 0.1 g / L titanium tetrachloride ethanol solution, the pretreated zeolite is then put into the titanium tetrachloride ethanol solution and heated in a water bath at 58-62°C for 3.5-5h, the mass ratio of titanium tetrachloride to pretreated zeolite is controlled at 1:9-11, and finally the titanium-doped zeolite is obtained by filtration, anhydrous ethanol washing, pre-drying, calcination and cooling treatment;

[0040] Step 3: functionalization treatment: put the titanium-doped zeolite into a toluene solution of 3-aminopropyl triethoxysilane, control the amount ratio of titanium-doped zeolite, 3-aminopropyl triethoxysilane and toluene to be 25:1.95-2.05:50, under the protection of inert gas atmosphere, control the temperature to be 78-82℃, stir and reflux for 6-7h, after the reaction is completed, cool to room temperature, remove 3-aminopropyl triethoxysilane, wash with anhydrous ethanol and dry at 78-82℃ for 8-9h, to obtain a modified zeolite treated by internal doping modification and external functionalization.

[0041] In step 2, the pre-drying temperature is 78-82℃ and the time is 6h. The calcination is to control the temperature rising rate to be 5℃ / min to rise to 500℃ under air atmosphere, and to keep the temperature at 500℃ for 3h.

[0042] A preparation method of a Fe3O4 composite catalyst, for preparing a Fe3O4 composite catalyst as described above, comprising the following steps:

[0043] Step 1: prepare porous carriers, Fe3O4, ferrous oxide, transition metal oxides, polyvinyl alcohol and anhydrous ethanol;

[0044] Step 2: put the polyvinyl alcohol into anhydrous ethanol and stir to dissolve, to obtain a polyvinyl alcohol ethanol solution with a concentration of 0.02g / ml;

[0045] Step 3: mix Fe3O4, ferrous oxide and transition metal oxides and stir until uniform, to obtain a mixed active material;

[0046] Step 4: mix the porous carriers with the mixed active material and the polyvinyl alcohol ethanol solution, under the condition of an oil bath at 78-82℃, stir and react for 6-8h, after the reaction is completed, centrifuge, wash with ethanol and vacuum dry, the centrifugation speed is 8000r / min and the time is 10min, the vacuum drying temperature is 105℃ and the time is 12h, to obtain a Fe3O4 composite catalyst.

[0047] Application of a Fe3O4 composite catalyst, comprising using a Fe3O4 composite catalyst as described above and applying it to wastewater treatment coupled with ozone.

[0048] Example 1

[0049] A Fe3O4 composite catalyst, comprising Fe3O4, ferrous oxide, transition metal oxides and porous carriers. The porous carriers account for 65% of the total mass. The porous carriers are functional carriers treated by internal doping modification and external functionalization, and the internal doping modification is to use metals or non-metals to act on the bulk phase or near-surface deep layer of the porous carriers. The external functionalization is to use polymers to link to the surface layer of the porous carriers.

[0050] It needs to be mentioned that the transition metal oxide in the embodiments of the present application is manganese oxide. The functional carrier is modified activated carbon, and the specific surface area S bet ≥ 800 m² / g.

[0051] In the embodiments of the present application, the preparation method of the modified activated carbon comprises the following steps:

[0052] Step 1, raw material treatment: washing the activated carbon with deionized water, and drying the activated carbon at 80℃ for treatment until dry for standby;

[0053] Step 2, doping modification: mixing urea and activated carbon at a mass ratio of 10:2.8, adding deionized water to stir uniformly to obtain an activated carbon solution with a concentration of 1 g / ml, heating the activated carbon solution in a 58℃ water bath for 2h, and then sequentially performing pre-drying, calcination, cooling, washing and post-drying treatment to obtain nitrogen-doped activated carbon;

[0054] Step 3, functionalization treatment: putting the nitrogen-doped activated carbon into concentrated nitric acid to stir uniformly to obtain a doping solution with a concentration of 0.5 g / ml, heating and stirring reflux treatment for 4h in a 78℃ water bath, and after the reaction is completed, cooling and washing with deionized water, and drying at 78℃ for 10h to obtain modified activated carbon treated by internal doping modification and external functionalization.

[0055] In step 2, the pre-drying temperature is 78℃, and the time is 8h. The calcination is to control the gas flow rate to be greater than or equal to 50 mL / min of nitrogen atmosphere to heat to 500℃, control the heating rate to be 5℃ / min, and keep the temperature at 500℃ for 2h. The post-drying temperature is 78℃, and the time is 11h.

[0056] A preparation method of a Fe3O4 composite catalyst, for preparing a Fe3O4 composite catalyst as described above, comprising the following steps:

[0057] Step 1, taking a porous carrier, Fe3O4, ferrous oxide, transition metal oxide, polyvinyl alcohol and anhydrous ethanol for standby;

[0058] Step 2, putting the polyvinyl alcohol into anhydrous ethanol to stir and dissolve to obtain a polyvinyl alcohol ethanol solution with a concentration of 0.02 g / ml;

[0059] Step 3, taking Fe3O4, ferrous oxide and transition metal oxide to mix and stir uniformly to obtain a mixed active material;

[0060] Step 4, mixing the porous carrier with the mixed active material, polyvinyl alcohol ethanol solution, stirring the reaction at 78℃ in the oil bath for 6h, after the reaction is completed, centrifugation, ethanol washing and vacuum drying, the centrifugal speed is 8000r / min, the time is 10min, the vacuum drying temperature is 105℃, the time is 12h, to obtain the Fe3O4 composite catalyst.

[0061] The application of the Fe3O4 composite catalyst, including using the Fe3O4 composite catalyst as described above and applying it to the wastewater treatment coupled with ozone.

[0062] Example two

[0063] A Fe3O4 composite catalyst, including Fe3O4, ferrous oxide, transition metal oxide and porous carrier. The porous carrier accounts for 75% of the total mass. The porous carrier is a functional carrier treated by internal doping modification and external functionalization, and the internal doping modification is to use metal or non-metal to act on the bulk phase or near-surface deep layer of the porous carrier. The external functionalization is to use polymer to link to the surface layer of the porous carrier.

[0064] It should be noted that the transition metal oxide in the embodiments of the present application is manganese oxide. The functional carrier is modified activated carbon, and the specific surface area S bet ≥800m² / g.

[0065] In the embodiments of the present application, the preparation method of the modified activated carbon includes the following steps:

[0066] Step 1, raw material treatment: washing the activated carbon with deionized water, and drying the activated carbon at 80℃ to dry for standby;

[0067] Step 2, doping modification: mixing urea and activated carbon according to the mass ratio of 10:3, adding deionized water to stir uniformly to obtain an activated carbon solution with a concentration of 1g / ml, heating the activated carbon solution in a 60℃ water bath for 2.5h, and then sequentially performing pre-drying, calcination, cooling, washing and post-drying treatment to obtain nitrogen-doped activated carbon;

[0068] Step 3, functionalization treatment: putting the nitrogen-doped activated carbon into concentrated nitric acid to stir uniformly to obtain a doping solution with a concentration of 0.5g / ml, heating and stirring refluxing the doping solution in an 80℃ water bath for 4-5h, cooling after the reaction is completed, and washing with deionized water and drying at 80℃ for 11h to obtain the modified activated carbon treated by internal doping modification and external functionalization.

[0069] In step ②, the pre-drying temperature is 80℃, and the time is 8h. The calcination is to control the nitrogen atmosphere to be greater than or equal to 50mL / min, and the temperature is increased to 500℃ at a rate of 5℃ / min, and the temperature is kept at 500℃ for 2h. The post-drying temperature is 80℃, and the time is 12h.

[0070] A preparation method of a Fe3O4 composite catalyst, for preparing a Fe3O4 composite catalyst as described above, comprising the following steps:

[0071] Step 1, take the porous carrier, Fe3O4, ferrous oxide, transition metal oxide, polyvinyl alcohol and anhydrous ethanol;

[0072] Step 2, stir and dissolve the polyvinyl alcohol in anhydrous ethanol to obtain a polyvinyl alcohol ethanol solution with a concentration of 0.02g / ml;

[0073] Step 3, mix and stir the Fe3O4, ferrous oxide and transition metal oxide until uniform to obtain a mixed active material;

[0074] Step 4, mix the porous carrier with the mixed active material and the polyvinyl alcohol ethanol solution, and stir under the condition of an 80℃ oil bath for 7h. After the reaction is completed, centrifugation, ethanol washing and vacuum drying are performed. The centrifugation speed is 8000r / min, and the time is 10min. The vacuum drying temperature is 105℃, and the time is 12h. A Fe3O4 composite catalyst is obtained.

[0075] Application of a Fe3O4 composite catalyst, comprising using a Fe3O4 composite catalyst as described above and applying it to wastewater treatment coupled with ozone.

[0076] Example three

[0077] A Fe3O4 composite catalyst, comprising Fe3O4, ferrous oxide, transition metal oxide and a porous carrier. The porous carrier accounts for 85% of the total mass. The porous carrier is a functional carrier subjected to internal doping modification treatment and external functionalization treatment, and the internal doping modification treatment is to use metal or non-metal to act on the bulk phase or near-surface deep layer of the porous carrier. The external functionalization treatment is to use a polymer to link to the surface layer of the porous carrier.

[0078] It should be noted that the transition metal oxide in the embodiments of the present application is manganese oxide. The functional carrier is modified activated carbon, and the specific surface area S bet ≥800m² / g.

[0079] In the embodiments of the present application, the preparation method of the modified activated carbon comprises the following steps:

[0080] Step 1: raw material treatment: the activated carbon is washed with deionized water, and the activated carbon is dried at 80℃ for treatment and ready for use;

[0081] Step 2: doping modification: urea and activated carbon are mixed in a mass ratio of 10:3.2, deionized water is added and stirred uniformly to obtain an activated carbon solution with a concentration of 1g / ml, the activated carbon solution is heated at 62℃ for 3h, and then pre-drying, calcination, cooling, washing and post-drying are carried out in sequence to obtain nitrogen-doped activated carbon;

[0082] Step 3: functionalization treatment: the nitrogen-doped activated carbon is stirred in concentrated nitric acid to obtain a doping solution with a concentration of 0.5g / ml, and then heated and stirred under reflux at 82℃ for 5h, after the reaction is completed, the solution is cooled and washed with deionized water, and then dried at 82℃ for 12h to obtain modified activated carbon treated by internal doping modification and external functionalization.

[0083] In step 2, the pre-drying temperature is 82℃, and the time is 8h. The calcination is controlled in a nitrogen atmosphere with a gas flow rate greater than or equal to 50mL / min, and the temperature is raised to 500℃ at a rate of 5℃ / min, and then maintained at 500℃ for 2h. The post-drying temperature is 82℃, and the time is 13h.

[0084] A preparation method of a Fe3O4 composite catalyst, for preparing a Fe3O4 composite catalyst as described above, comprising the following steps:

[0085] Step 1: take porous carriers, Fe3O4, ferrous oxide, transition metal oxides, polyvinyl alcohol and anhydrous ethanol for use;

[0086] Step 2: dissolve the polyvinyl alcohol in anhydrous ethanol to obtain a polyvinyl alcohol ethanol solution with a concentration of 0.02g / ml;

[0087] Step 3: mix Fe3O4, ferrous oxide and transition metal oxides until uniform to obtain a mixed active material;

[0088] Step 4: mix the porous carriers with the mixed active material and the polyvinyl alcohol ethanol solution under an oil bath at 82℃, and stir for 8h, then centrifuge, wash with ethanol and vacuum dry after the reaction is completed, the centrifugation speed is 8000r / min, the time is 10min, the vacuum drying temperature is 105℃, and the time is 12h to obtain a Fe3O4 composite catalyst.

[0089] Application of a Fe3O4 composite catalyst, including using a Fe3O4 composite catalyst as described above and applying it to wastewater treatment coupled with ozone.

[0090] Example Four

[0091] The Fe3O4 composite catalyst comprises Fe3O4, ferrous oxide, transition metal oxide and porous carrier. The porous carrier accounts for 65% of the total mass. The porous carrier is a functional carrier subjected to internal doping modification treatment and external functionalization treatment, and the internal doping modification treatment is to use metal or non-metal to act on the bulk phase or near-surface deep layer of the porous carrier. The external functionalization treatment is to use polymer to link to the surface layer of the porous carrier.

[0092] It should be noted that the transition metal oxide in the embodiments of the present application is manganese oxide. The functional carrier is modified zeolite, and the specific surface area S bet ≥ 800 m² / g.

[0093] In the embodiments of the present application, the preparation method of the modified zeolite comprises the following steps:

[0094] Step 1, the raw material treatment: the zeolite is put into deionized water, after stirring and repeated action of removing supernatant, clean zeolite is obtained, then the clean zeolite is put into 1 mol / L hydrochloric acid solution for soaking for 1.5 h, the solid-liquid ratio is controlled to be 1:5, and finally the pretreated zeolite is obtained after deionized water washing and drying treatment;

[0095] Step 2, doping modification: titanium tetrachloride is dissolved in anhydrous ethanol to obtain a 0.1 g / L titanium tetrachloride ethanol solution, and then the pretreated zeolite is put into the titanium tetrachloride ethanol solution for 58℃ water bath heating treatment for 3.5 h, the mass ratio of titanium tetrachloride to pretreated zeolite is controlled to be 1:9, and finally the titanium-doped zeolite is obtained after filtration, anhydrous ethanol washing, pre-drying, calcination and cooling treatment in sequence;

[0096] Step 3, functionalization treatment: the titanium-doped zeolite is put into a toluene solution of 3-aminopropyl triethoxysilane, the amount ratio of titanium-doped zeolite, 3-aminopropyl triethoxysilane and toluene is controlled to be 25:1.95:50, under the protection of inert gas atmosphere, the stirring reflux treatment is carried out at a temperature of 78℃ for 6 h, after the reaction is completed, the temperature is cooled to room temperature, 3-aminopropyl triethoxysilane is removed, anhydrous ethanol is washed and dried at 78℃ for 8 h, and the modified zeolite subjected to internal doping modification treatment and external functionalization treatment is obtained.

[0097] In step 2, the pre-drying temperature is 78℃, and the time is 6 h. The calcination is to control the temperature rising rate to be 5℃ / min to rise to 500℃, and to keep the temperature at 500℃ for 3 h under air atmosphere.

[0098] A preparation method of a Fe3O4 composite catalyst is used to prepare the Fe3O4 composite catalyst as described above, and comprises the following steps:

[0099] Step 1, take the porous carrier, Fe3O4, ferrous oxide, transition metal oxide, polyvinyl alcohol and anhydrous ethanol for standby use;

[0100] Step 2, put polyvinyl alcohol into anhydrous ethanol and stir to dissolve to obtain a polyvinyl alcohol ethanol solution with a concentration of 0.02 g / ml;

[0101] Step 3, mix Fe3O4, ferrous oxide and transition metal oxide and stir until uniform to obtain mixed active material;

[0102] Step 4, mix the porous carrier with the mixed active material and the polyvinyl alcohol ethanol solution, stir under the condition of an oil bath at 78°C for 6h, after the reaction is completed, centrifuge, wash with ethanol and vacuum dry, the centrifugation speed is 8000r / min, the time is 10min, the vacuum drying temperature is 105°C, and the time is 12h, to obtain the Fe3O4 composite catalyst.

[0103] The application of the Fe3O4 composite catalyst, comprising using the Fe3O4 composite catalyst as described above and applying it to the treatment of wastewater in combination with ozone.

[0104] Example Five

[0105] The Fe3O4 composite catalyst comprises Fe3O4, ferrous oxide, transition metal oxide and porous carrier. The porous carrier accounts for 75% of the total mass. The porous carrier is a functional carrier treated by internal doping modification and external functionalization, and the internal doping modification is to use metal or non-metal to act on the bulk phase or near-surface deep layer of the porous carrier. The external functionalization is to use polymer to link to the surface layer of the porous carrier.

[0106] It should be noted that the transition metal oxide in the embodiments of the present application is copper oxide. The functional carrier is modified zeolite, and the specific surface area S bet ≥800m² / g.

[0107] In the embodiments of the present application, the preparation method of the modified zeolite comprises the following steps:

[0108] Step 1, raw material treatment: put the zeolite into deionized water, stir and repeat the action of removing supernatant to obtain clean zeolite, then put the clean zeolite into a 1 mol / L hydrochloric acid solution and soak for 2h, control the solid-liquid ratio to be 1:5, and finally obtain pretreated zeolite after deionized water washing and drying treatment;

[0109] Step 2, doping modification: dissolve titanium tetrachloride in anhydrous ethanol to obtain a 0.1 g / L titanium tetrachloride ethanol solution, then put the pretreated zeolite into the titanium tetrachloride ethanol solution and perform 60°C water bath heating treatment for 4h, control the mass ratio of titanium tetrachloride to pretreated zeolite to be 1:10, and finally perform filtration, anhydrous ethanol washing, pre-drying, calcination and cooling treatment in sequence to obtain titanium-doped zeolite;

[0110] Step 3: functionalization treatment: put the titanium-doped zeolite into a toluene solution of 3-aminopropyltriethoxysilane, control the amount ratio of titanium-doped zeolite, 3-aminopropyltriethoxysilane and toluene to be 25:2:50, control the temperature to be 80℃ under the protection of inert gas atmosphere, and stir and reflux for 6.5h, cool to room temperature after the reaction is completed, remove 3-aminopropyltriethoxysilane, wash with anhydrous ethanol and dry at 80℃ for 8.5h to obtain a modified zeolite subjected to internal doping modification treatment and external functionalization treatment.

[0111] In step 2, the pre-drying temperature is 80℃ and the time is 6h. The calcination is to control the temperature rising rate to be 5℃ / min to rise to 500℃ under an air atmosphere, and to keep the temperature at 500℃ for 3h.

[0112] A preparation method of a Fe3O4 composite catalyst, for preparing a Fe3O4 composite catalyst as described above, comprising the following steps:

[0113] Step 1: prepare porous carriers, Fe3O4, ferrous oxide, transition metal oxides, polyvinyl alcohol and anhydrous ethanol;

[0114] Step 2: put the polyvinyl alcohol into anhydrous ethanol and stir to dissolve to obtain a polyvinyl alcohol ethanol solution with a concentration of 0.02g / ml;

[0115] Step 3: mix Fe3O4, ferrous oxide and transition metal oxides and stir until uniform to obtain a mixed active material;

[0116] Step 4: mix the porous carriers with the mixed active material and the polyvinyl alcohol ethanol solution, stir under the condition of an 80℃ oil bath for 7h, centrifuge, wash with ethanol and vacuum dry after the reaction is completed, the centrifugation speed is 8000r / min and the time is 10min, the vacuum drying temperature is 105℃ and the time is 12h to obtain a Fe3O4 composite catalyst.

[0117] Application of a Fe3O4 composite catalyst, comprising using a Fe3O4 composite catalyst as described above and applying it to wastewater treatment coupled with ozone.

[0118] Example six

[0119] A Fe3O4 composite catalyst, comprising Fe3O4, ferrous oxide, transition metal oxides and a porous carrier. The porous carrier accounts for 85% of the total mass. The porous carrier is a functional carrier subjected to internal doping modification treatment and external functionalization treatment, and the internal doping modification treatment is to use metals or non-metals to act on the bulk phase or near-surface deep layer of the porous carrier. The external functionalization treatment is to use polymers to link to the surface layer of the porous carrier.

[0120] It should be mentioned that the transition metal oxide in the embodiments of the present application is cobalt oxide. The functional carrier is modified zeolite, and the specific surface area S bet ≥ 800 m² / g.

[0121] In the embodiments of the present application, the preparation method of the modified zeolite comprises the following steps:

[0122] Step 1, raw material processing: the zeolite is put into deionized water, after repeated stirring and removal of supernatant, clean zeolite is obtained, then the clean zeolite is soaked in 1 mol / L hydrochloric acid solution for 2.5 h, the solid-liquid ratio is controlled to be 1:5, and finally the pretreated zeolite is obtained after deionized water washing and drying treatment;

[0123] Step 2, doping modification: titanium tetrachloride is dissolved in anhydrous ethanol to obtain a 0.1 g / L titanium tetrachloride ethanol solution, and then the pretreated zeolite is put into the titanium tetrachloride ethanol solution for 62℃ water bath heating treatment for 5 h, the mass ratio of titanium tetrachloride to pretreated zeolite is controlled to be 1:11, and finally the titanium-doped zeolite is obtained after filtration, anhydrous ethanol washing, pre-drying, calcination and cooling treatment in sequence;

[0124] Step 3, functionalization treatment: the titanium-doped zeolite is put into a toluene solution of 3-aminopropyl triethoxysilane, the amount ratio of titanium-doped zeolite, 3-aminopropyl triethoxysilane and toluene is controlled to be 25:2.05:50, under the protection of inert gas atmosphere, the temperature is controlled to be 82℃ for stirring reflux treatment for 7 h, after the reaction is completed, the temperature is cooled to room temperature, 3-aminopropyl triethoxysilane is removed, anhydrous ethanol is washed and dried at 82℃ for 9 h, and the modified zeolite treated by internal doping modification and external functionalization is obtained.

[0125] In step 2, the pre-drying temperature is 82℃, and the time is 6 h. The calcination is to control the temperature rising rate to 5℃ / min to rise to 500℃, and to keep the temperature at 500℃ for 3 h under air atmosphere.

[0126] A preparation method of a Fe3O4 composite catalyst, for preparing a Fe3O4 composite catalyst as described above, comprising the following steps:

[0127] Step 1, take the porous carrier, Fe3O4, ferrous oxide, transition metal oxide, polyvinyl alcohol and anhydrous ethanol for standby;

[0128] Step 2, the polyvinyl alcohol is put into anhydrous ethanol to be dissolved by stirring to obtain a 0.02 g / ml polyvinyl alcohol ethanol solution;

[0129] Step 3, take the Fe3O4, ferrous oxide and transition metal oxide to mix and stir until uniform to obtain a mixed active material;

[0130] Step 4, mixing the porous carrier with the mixed active material, polyvinyl alcohol ethanol solution, stirring the reaction under the condition of 82℃ oil bath for 8h, after the reaction is finished, centrifugation, ethanol washing and vacuum drying, the speed of centrifugation is 8000r / min, the time is 10min, the temperature of vacuum drying is 105℃, the time is 12h, Fe3O4 composite catalyst is obtained.

[0131] The application of Fe3O4 composite catalyst, including using the Fe3O4 composite catalyst as described above and applying it to the wastewater treatment coupled with ozone.

[0132] Comparative Example 1

[0133] Comparative Example 1 and Example 2, the modified activated carbon in Comparative Example 1 is not subjected to doping treatment.

[0134] Comparative Example 2

[0135] Comparative Example 2 and Example 2, the modified activated carbon in Comparative Example 2 is not subjected to functionalization treatment.

[0136] Comparative Example 3

[0137] Comparative Example 3 and Example 2, the activated carbon is used instead of the modified activated carbon in Comparative Example 3.

[0138] Comparative Example 4

[0139] Comparative Example 4 and Example 4, the modified zeolite in Comparative Example 4 is not subjected to doping treatment.

[0140] Comparative Example 5

[0141] Comparative Example 5 and Example 4, the modified zeolite in Comparative Example 5 is not subjected to functionalization treatment.

[0142] Comparative Example 6

[0143] Comparative Example 6 and Example 4, the zeolite is used instead of the modified zeolite in Comparative Example 6.

[0144] Performance test:

[0145] Take 20g of Fe3O4 composite catalyst obtained in the above Examples 1 to 6 and Comparative Examples 1 to 6, and divide them into 4 groups, 5g in each group; take 500ml of sewage with COD concentration of 1000mg / L for standby. Use intermittent reaction device, equipped with ozone generator, control the ozone production of 50mg / h, the speed of magnetic stirrer of 300r / min.

[0146] For each embodiment and comparative example, first, 5 g of Fe3O4 composite catalyst was added to a beaker, stirring was started to uniformly disperse the catalyst, ozone was introduced, the gas flow was controlled at 0.5 L / min and timing was started, 50 mL was sampled at 0.5 h, 1 h, 2 h and 3 h of the reaction, excess Na2S2O3 solution was added to the sampling sample, and the reaction was terminated, the filtrate was filtered through a 0.45 μm filter membrane, and the COD value of the filtrate was determined by potassium dichromate method, the test results were averaged, and the results are shown in Table 1 below.

[0147] Table 1 Performance test results

[0148] 0.5 h removal rate (%) 1 h removal rate (%) 2 h removal rate (%) 3 h removal rate (%) Example 1 36.2 56.8 73.5 83.9 Example 2 42.2 67.0 82.0 90.6 Example 3 34.3 51.3 69.5 82.1 Example 4 32.0 50.8 70.6 79.5 Example 5 38.4 59.7 76.1 85.3 Example 6 40.2 62.4 79.1 87.6 Comparative Example 1 26.3 42.9 57.4 67.5 Comparative Example 2 21.7 37.1 52.8 61.2 Comparative Example 3 16.5 26.3 36.1 45.0 Comparative Example 4 23.3 38.2 51.7 58.1 Comparative Example 5 18.0 32.6 45.4 56.2 Comparative Example 6 11.4 21.6 31.0 43.6

[0149] From Table 1 above, it can be seen that in the embodiments of the present application, the removal rate at 0.5 h mainly depends on the functionalized adsorption groups of the functional support, and because the adsorption capacity in Example 2 and Example 6 is high, it makes them have excellent removal rate in the early stage, and Comparative Example 2 and Comparative Example 5 have the problem of low efficiency. In the embodiments of the present application, the removal rate at 1-2 h mainly depends on the catalytic degradation effect itself, so as to make the functional support doped with nitrogen or titanium and the mixed active material synergistically improve the removal rate effect, so that Example 2, Example 5 and Example 6 have a relatively excellent growth rate of removal rate. At 3 h, the sustained degradation ability of the corresponding Fe3O4 composite catalyst reflects its treatment effect in sewage treatment, and through the synergistic effect of internal doping and external functionalization, Example 2 has the most excellent and highest removal rate, and because the single modification such as internal doping or external functionalization cannot achieve effective synergistic effect, it is difficult to break through the bottleneck of the existing removal rate, and it is difficult to achieve the purpose of significantly improving the sewage treatment efficiency and reducing the sewage treatment cost.

[0150] In summary, the present application provides a Fe3O4 composite catalyst and a preparation method and application thereof. The porous support is modified by internal doping and externally functionalized to obtain a functional support, so as to achieve the effect of significantly improving the electron transfer rate and the catalytic activity, and the functional support has the ability to effectively adsorb and combine pollutants, so that after being compounded with Fe3O4, ferrous oxide and transition metal oxide, it significantly improves the synergistic effect with ozone and improves the degradation efficiency of sewage. The preparation method of the Fe3O4 composite catalyst has the effects of convenient control and stable preparation, and is suitable for industrial production. The application of the Fe3O4 composite catalyst has the effects of significantly improving the sewage treatment efficiency and reducing the sewage treatment cost.

[0151] The use of "first", "second", "third", "fourth" etc. (if any) in this disclosure is only to distinguish similar objects, and does not necessarily indicate a particular order or sequence. It should be understood that the data thus used can be interchanged under appropriate circumstances, so that the embodiments described herein can be implemented in an order other than that described herein. In addition, the terms "comprise" and "have" and any variations thereof are intended to cover non-exclusive inclusion, for example, a process, method or device comprising a series of steps or units does not necessarily limit to those clearly listed steps or units, but can include other steps or units not clearly listed or inherent to these processes, methods or devices.

[0152] It should be noted that the description involving "first", "second" and the like in this application is only for the purpose of description, and cannot be understood as indicating or implying the relative importance of the indicated technical features or implicitly indicating the number of the indicated technical features. Therefore, the features defined with "first", "second" can explicitly or implicitly include at least one of the features. In addition, the technical solutions of various embodiments can be combined with each other, but it must be based on the realization of ordinary skilled in the art, when the combination of technical solutions appears contradictory or unachievable, it should be considered that the combination of technical solutions does not exist, nor within the scope of protection claimed in this application.

[0153] The principles and implementation modes of the present application are described by applying specific examples herein, and the above description of the embodiments is only for the purpose of helping to understand the method and its core idea of the present application; at the same time, for those skilled in the art, according to the idea of the present application, the specific implementation mode and application range will be changed, and the above description of the present application should not be understood as a limitation.

Claims

1. Use of a Fe3O4 composite catalyst comprising Fe3O4, ferrous oxide, a transition metal oxide and a porous support, characterized in that: The Fe3O4 composite catalyst is applied to the wastewater treatment by coupling with ozone and Na2S2O3 solution; The transition metal oxide accounts for 1-10% of the total mass, and the transition metal oxide is manganese oxide, copper oxide or cobalt oxide; the porous carrier accounts for 65-85% of the total mass; the porous carrier is a functional carrier treated by internal doping modification and external functionalization; the functional carrier is modified activated carbon or modified zeolite; The preparation method of the modified activated carbon comprises the following steps: Step 1: raw material treatment: the activated carbon is washed with deionized water, and the activated carbon is dried at 80 DEG C to dry for standby; Step 2: doping modification: urea and activated carbon are mixed in a mass ratio of 10:2.8-3.2, deionized water is added and stirred uniformly to obtain an activated carbon solution with a concentration of 1 g / ml, the activated carbon solution is heated in a water bath at 58-62 DEG C for 2-3 h, and then pre-drying, calcination, cooling, washing and post-drying treatment are sequentially carried out to obtain nitrogen-doped activated carbon; Step 3: functionalization treatment: the nitrogen-doped activated carbon is stirred uniformly in concentrated nitric acid to obtain a doping solution with a concentration of 0.5 g / ml, and then heated and stirred in a water bath at 78-82 DEG C for 4-5 h, after the reaction is completed, the solution is cooled, washed with deionized water and dried at 78-82 DEG C for 10-12 h to obtain modified activated carbon treated by internal doping modification and external functionalization; The preparation method of the modified zeolite comprises the following steps: Step 1: raw material treatment: the zeolite is put into deionized water, after repeated stirring and removing supernatant, clean zeolite is obtained, then the clean zeolite is put into 1 mol / L hydrochloric acid solution and soaked for 1.5-2.5 h, the solid-liquid ratio is controlled to be 1:5, and finally the pretreated zeolite is obtained by deionized water washing and drying treatment; Step 2: doping modification: titanium tetrachloride is dissolved in anhydrous ethanol to obtain a 0.1 g / L titanium tetrachloride ethanol solution, and then the pretreated zeolite is put into the titanium tetrachloride ethanol solution and heated in a water bath at 58-62 DEG C for 3.5-5 h, the mass ratio of titanium tetrachloride to pretreated zeolite is controlled to be 1:9-11, and finally filtration, anhydrous ethanol washing, pre-drying, calcination and cooling treatment are sequentially carried out to obtain titanium-doped zeolite; Step 3: functionalization treatment: the titanium-doped zeolite is put into a toluene solution of 3-aminopropyl triethoxysilane, the amount ratio of titanium-doped zeolite, 3-aminopropyl triethoxysilane and toluene is controlled to be 25:1.95-2.05:50, under the protection of inert gas atmosphere, the temperature is controlled to be 78-82 DEG C, stirring and reflux treatment is carried out for 6-7 h, after the reaction is completed, the solution is cooled to room temperature, 3-aminopropyl triethoxysilane is removed, anhydrous ethanol is washed and dried at 78-82 DEG C for 8-9 h to obtain modified zeolite treated by internal doping modification and external functionalization.

2. Use of a Fe3O4 composite catalyst according to claim 1, characterized in that: The specific surface area S of the modified activated carbon and the modified zeolite bet ≥ 800 m² / g.

3. Use of a Fe3O4 composite catalyst according to claim 1, characterized in that: In the step ② of the preparation method of the modified activated carbon, the temperature of the pre-drying is 78-82℃, and the time is 8h; the calcination is heating to 500℃ at a heating rate of 5℃ / min under a nitrogen atmosphere with a gas flow rate of 50mL / min or more, and the temperature is maintained at 500℃ for 2h; the temperature of the post-drying is 78-82℃, and the time is 11-13h.

4. Use of a Fe3O4 composite catalyst according to claim 1, characterized in that: In the step ② of the preparation method of the modified zeolite, the temperature of the pre-drying is 78-82℃, and the time is 6h; the calcination is heating to 500℃ at a heating rate of 5℃ / min under an air atmosphere, and the temperature is maintained at 500℃ for 3h.

5. Use of a Fe3O4 composite catalyst according to claim 1, characterized in that: The preparation method of the Fe3O4 composite catalyst comprises the following steps: Step 1, prepare the porous carrier, Fe3O4, ferrous oxide, transition metal oxide, polyvinyl alcohol and anhydrous ethanol; Step 2, stir and dissolve the polyvinyl alcohol in anhydrous ethanol to obtain a polyvinyl alcohol ethanol solution with a concentration of 0.02g / ml; Step 3, mix and stir the Fe3O4, ferrous oxide and transition metal oxide until uniform to obtain a mixed active material; Step 4, mix the porous carrier with the mixed active material and the polyvinyl alcohol ethanol solution, stir and react under an oil bath at 78-82℃ for 6-8h, then centrifuge, wash with ethanol and vacuum dry to obtain the Fe3O4 composite catalyst.

6. Use of a Fe3O4 composite catalyst according to claim 5, characterized in that: In step 4, the centrifugation is performed at a speed of 8000r / min for 10min; the vacuum drying is performed at a temperature of 105℃ for 12h.