A supported FeP catalyst, its preparation method and application

Abstract

The present invention relates to the technical field of inorganic catalyst materials, and specifically discloses a supported FeP catalyst, a preparation method thereof and an application. The supported FeP catalyst includes: a porous alumina sphere carrier and FeP nanoparticles supported on the surface and in the pores of the porous alumina sphere carrier. In the present invention, ferrous sulfate is used as an iron source, and polyferric sulfate solution is prepared by oxidative polymerization. The porous alumina spheres are impregnated with polyferric sulfate, and then aged under specific conditions to convert the polyferric sulfate into jarosite-like substances on the surface and in the pores of the alumina spheres. Through subsequent phosphidation, the jarosite-like substances are converted into FeP, thereby realizing the firm loading of FeP nanoparticles on the surface and in the pores of the alumina spheres, significantly increasing the loading amount of FeP, and further ensuring the high catalytic activity of the supported FeP catalyst. At the same time, the catalyst can still maintain a high catalytic activity after being recycled multiple times, and has high popularization and application value.

Description

Technical Field

[0001] The present invention relates to the technical field of inorganic catalyst materials, and particularly relates to a supported FeP catalyst, a preparation method thereof, and an application thereof. Background Art

[0002] In recent years, with the rapid development of society and science and technology, the discharge amount of wastewater not only increases year by year, but also the content of COD in water, which is a core index, is reduced to 50 mg / L, 30 mg / L according to different standard requirements, and even below 20 mg / L in order to realize the reuse value. The application of advanced oxidation technology in the advanced treatment of sewage treatment plants is increasing. At present, industrial wastewater has various types, and is characterized by complex composition, high chroma, high chemical oxygen demand (COD), and large discharge amount. The traditional homogeneous Fenton catalytic system constructed by Fe 2+ and H2O2 can be used to degrade persistent organic pollutants. However, since iron-containing sludge will be generated after the reaction of this system, it is easy to cause secondary pollution. Therefore, its practical application is subject to certain limitations. After this, various heterogeneous (pseudo) Fenton systems constructed by transition metal oxides, composite oxides, etc. and H2O2 have been developed subsequently. Compared with the homogeneous Fenton system, the heterogeneous Fenton system overcomes the characteristic of the homogeneous Fenton system that is easy to generate iron-containing sludge. However, the degradation time of pollutants in such systems requires several hours, and the degradation efficiency is low.

[0003] Recently, we found that FeP has high catalytic activity for the decomposition of H2O2. Induced by trace amounts of Fe 2+ or Fe 3+ ·OH can be rapidly generated in a wide range, realizing the rapid degradation of organic pollutants. However, as a powdered FeP catalyst, it is easy to lose during the degradation of pollutants and it is difficult to achieve complete recycling, resulting in a high catalyst cost. Therefore, the development of a new catalyst with low cost, high catalytic activity, and recyclability is of great significance for the degradation of pollutants. Summary of the Invention

[0004] Aiming at the problem that the powdered FeP catalyst used in the prior art is difficult to recycle, resulting in a high catalyst cost, the present invention provides a supported FeP catalyst, a preparation method thereof, and an application thereof. By loading FeP onto the surface and pores of an alumina support, while ensuring the high activity of the supported catalyst, the recycling times of the catalyst are significantly increased, the usage amount and cost of the catalyst are significantly reduced, and it has high practical value.

[0005] To solve the above technical problems, the technical solution provided by the present invention is:

[0006] On the one hand, the present invention provides a supported FeP catalyst, which comprises: a porous alumina sphere carrier and FeP nanoparticles supported on the surface and in the pores of the porous alumina sphere carrier.

[0007] Compared with the prior art, for the supported FeP catalyst provided by the present invention, FeP is loaded on the surface and in the pores of the porous alumina sphere, and the dispersion of FeP nanoparticles is improved by the large specific surface area of the alumina sphere, greatly enhancing the catalytic activity and stability. At the same time, the catalyst is convenient for recycling and can still maintain a high catalytic activity after being recycled multiple times, having high popularization and application value.

[0008] The supported FeP catalyst provided by the embodiments of the present invention has excellent catalytic activity, can achieve the full degradation of organic pollutants within 1 minute, and the catalyst can be recycled multiple times, effectively reducing the use cost of the catalyst, conforming to the concept of green environmental protection and having extremely high practical value.

[0009] Preferably, the pores of the porous alumina sphere carrier are not completely filled with the FeP nanoparticles.

[0010] The pores of the porous alumina sphere carrier not being completely filled with the FeP nanoparticles can not only increase the loading amount of the FeP nanoparticles, but also ensure that the prepared supported FeP catalyst has a large pore volume and specific surface area, and is beneficial to exposing more FeP active sites, thus significantly enhancing the catalytic activity of the supported FeP catalyst.

[0011] Preferably, the porous alumina sphere carrier is a porous alumina sphere with a size of more than millimeter level.

[0012] Preferably, a catalyst using a porous alumina sphere as the carrier is more conducive to the recycling of the catalyst, and the prepared supported catalyst is not only applicable to a batch reactor, but also can be filled into a fluidized bed reactor for use, with more application forms.

[0013] Exemplarily, the particle size of the porous alumina sphere carrier is 4 mm to 6 mm.

[0014] Preferably, the FeP nanoparticles are rod-shaped particles with a diameter of 20 nm to 80 nm and a length of 0.4 μm to 0.6 μm.

[0015] The preferred FeP nanoparticles are beneficial to improving the catalytic activity of the catalyst.

[0016] Preferably, the loading amount of the FeP nanoparticles is 0.03 g / g carrier to 0.07 g / g carrier.

[0017] Preferably, the specific surface area of the supported FeP catalyst is 160 m 2 / g to 220 m2 / g.

[0018] Preferably, the pore volume of the supported FeP catalyst is 0.2 mL / g to 0.3 mL / g.

[0019] On the other hand, the present invention also provides a method for preparing the supported FeP catalyst described in any one of the above, and the preparation method includes the following steps:

[0020] Step a: Wash or acid-wash the porous alumina balls, and dry them to obtain pretreated alumina balls;

[0021] Step b: Add the pretreated alumina balls into a polyferric sulfate solution, disperse them evenly, impregnate them, age them, and dry them to obtain a jarosite / alumina composite material;

[0022] Step c: Phosphatize the jarosite / alumina composite material under an inert atmosphere to obtain the supported FeP catalyst.

[0023] During the R & D process, the inventors tried a method of impregnating porous alumina balls into a ferric salt solution, then dropping sodium hydroxide solution, and phosphating to prepare a supported FeP catalyst. However, it was found that the loading amount of FeP particles in the prepared catalyst was very low, and the catalytic activity of the catalyst was significantly lower than that of the catalyst prepared with polyferric sulfate. Through electron microscopy analysis, it was found that only a small amount of FeP particles were loaded on the surface of the porous alumina balls, and very few entered the pores of the alumina balls.

[0024] Through creative thinking, the inventors found that using ferrous sulfate solution as the iron source, polyferric sulfate was obtained through oxidation polymerization, and then the porous alumina balls were impregnated with polyferric sulfate and aged under specific conditions, so that the polyferric sulfate was converted into jarosite substances on the surface and in the pores of the alumina balls. The jarosite substances obtained by this method have a strong binding force with the porous alumina balls. By subsequent phosphating, the jarosite substances on the surface and in the pores of the alumina balls are converted into FeP, thereby realizing the firm loading of FeP nanoparticles on the surface and in the pores of the alumina balls, significantly increasing the loading amount of FeP, and further ensuring the high catalytic activity of the supported FeP catalyst; at the same time, due to the high binding strength between FeP and the alumina balls, the loss of FeP during the recovery process is reduced, thereby ensuring that the catalyst still has high catalytic activity after being reused multiple times, and further being beneficial to significantly reducing the use cost of the catalyst, and having broad application prospects.

[0025] The preparation method of the supported FeP catalyst provided by the present invention is simple in operation, suitable for large-scale production, provides a new idea for the preparation of Fenton-like catalyst materials, and has high popularization and application value.

[0026] Exemplarily, in step a, magnetic stirring water washing, ultrasonic water washing, or washing with dilute sulfuric acid with a mass concentration of 6% to 10% can all achieve substantially equivalent technical effects. It is preferred to pretreat the porous alumina spheres by water washing. The washing is based on the criterion that no white particulate matter appears in the washing liquid.

[0027] By performing the above treatment on the porous alumina spheres, not only can the loading amount of FeP nanoparticles be increased, but also the FeP nanoparticles can partially fill the pores of the alumina spheres, without forming closed pores, ensuring that the prepared supported FeP catalyst has a large pore volume and specific surface area, providing more transport channels for the reactants, and being beneficial to exposing more FeP active sites, thereby significantly improving the catalytic activity of the supported FeP catalyst.

[0028] In the present invention, the inert atmosphere is provided by an inert gas, and the inert gas is a conventional inert gas in the art, such as nitrogen, argon, etc.

[0029] Preferably, in step b, the preparation method of the polyferric sulfate solution includes the following steps:

[0030] At 35°C to 45°C, concentrated sulfuric acid is added to the aqueous solution of ferrous sulfate, mixed evenly, an oxidant solution is added dropwise. After the addition is completed, the temperature is raised to 50°C to 55°C and reacted for 50 min to 70 min, then a sodium salt solution is added, and the reaction is kept warm for 90 min to 120 min, and then cooled to obtain the polyferric sulfate solution.

[0031] As a specific embodiment of the present invention, the aqueous solution of ferrous sulfate can be the waste liquid from steel pickling.

[0032] Combined with the above, the concentration of the aqueous solution of ferrous sulfate is 0.3 g / mL - 0.5 g / mL.

[0033] Further, combined with the above, the addition amount of the concentrated sulfuric acid is based on adjusting the pH of the system to 1.0 to 2.0. The concentrated sulfuric acid is concentrated sulfuric acid with a commercially available mass concentration of 98%.

[0034] Combined with the above, the oxidant solution is a hydrogen peroxide solution, a sodium hypochlorite solution, a sodium chlorate solution, or a potassium chlorate solution.

[0035] Preferably, the oxidant solution is a hydrogen peroxide solution with a mass concentration of 25% to 35%.

[0036] Further, Fe in the aqueous solution of ferrous sulfate 2+ and the molar ratio of H2O2 in the hydrogen peroxide solution is 1:1.9 to 2.1.

[0037] Combined with the above, the sodium salt solution is a sodium bicarbonate solution or a sodium carbonate solution. Preferably, it is a sodium bicarbonate solution.

[0038] Further, the concentration of the sodium bicarbonate solution is 0.45 mol / L to 0.55 mol / L. In the aqueous solution of ferrous sulfate, the molar ratio of Fe 2+ to sodium bicarbonate is 5.7 to 6.6:1.

[0039] It should be noted that when preparing the polymeric ferric sulfate solution, if potassium chlorate is used as the oxidant, the obtained product in step b is a jarosite / aluminum oxide composite material; if hydrogen peroxide, sodium hypochlorite or sodium chlorate is used as the oxidant, the obtained product in step b is a natrojarosite / aluminum oxide composite material. Regardless of the form of the jarosite-based compound obtained in step b, it does not affect the performance of the supported FeP catalyst prepared in the final step c.

[0040] Preferably, in step b, the concentration of ferric ions in the polymeric ferric sulfate solution is 55 g / L to 65 g / L, and the mass-volume ratio of the pretreated alumina spheres to the polymeric ferric sulfate solution is 50 to 60:55 to 70, where the unit of mass is grams and the unit of volume is milliliters.

[0041] Preferably, in step b, the impregnation temperature is 20°C to 30°C, and the impregnation time is 12 h to 24 h.

[0042] Preferably, in step b, the aging temperature is 65°C to 75°C, and the aging time is 3 h to 5 h.

[0043] Optionally, in step c, the specific steps of phosphating are as follows: Place the phosphorus source and the jarosite-based / aluminum oxide composite material at the upstream and downstream of a tubular furnace respectively. Introduce an inert atmosphere at the upstream of the tubular furnace and carry out phosphating at 300°C to 350°C for 1 h to 3 h to obtain the supported FeP catalyst.

[0044] Combined with the above, the phosphorus source is NaH2PO2 or AlP3.

[0045] Further, the mass ratio of the jarosite-based / aluminum oxide composite material to the phosphorus source is 2:1 to 5.

[0046] Further, during the phosphating process, first heat up at a rate of 4°C / min to 6°C / min to 200°C to 250°C, and then heat up at a rate of 1°C / min to 3°C / min to 300°C to 350°C.

[0047] The preferred phosphating conditions can fully convert the jarosite-based substances in the pores and on the surface of the porous alumina spheres into FeP particles.

[0048] In a third aspect, the present invention also provides the application of the above-mentioned supported FeP catalyst in constructing a Fenton-like catalytic system.

[0049] Furthermore, in combination with the above, when the supported FeP catalyst prepared by the present invention is applied to construct a Fenton-like catalytic system, a trace amount of Fe can be added. 2+ To activate the activity of the FeP catalyst and improve the degradation rate of pollutants.

[0050] Exemplarily, the specific steps for degrading organic pollutants using the supported FeP catalyst provided by the present invention are as follows:

[0051] Add the pollutants into the degradation device, then add the above-mentioned supported FeP catalyst and hydrogen peroxide solution, mix evenly, and add a trace amount of Fe 2+ solution, and the pollutants can be rapidly degraded.

[0052] It should be noted that the supported FeP catalyst provided by the present invention can be used in a batch reactor or a fluidized bed continuous degradation device.

[0053] Furthermore, the mass ratio of the supported FeP catalyst to the inducer Fe 2+ in the solution of Fe 2+ is 900 - 1100:1.

[0054] When the supported FeP catalyst in the present invention is applied to degrade organic pollutants, the pH of the wastewater should be ≤ 10. Within the above range, there is no need to adjust the pH of the wastewater, and the organic pollutants can be rapidly degraded under the natural pH of the wastewater.

[0055] Under the condition of not adding any binder, the present invention firmly loads FeP on the surface and pores of the porous alumina spheres, which can be used as a catalyst for the Fenton-like reaction. Adding a small amount of Fe 2+ as an inducer can achieve the degradation of organic pollutants in a very short time. Using the supported FeP catalyst provided by the present invention to degrade pollutants can solve the problem that traditional homogeneous Fenton catalysts cannot be reused multiple times, and it has extremely high practical application value. Description of the Drawings

[0056] Figure 1 It is the XRD pattern of single jarosite in Example 1;

[0057] Figure 2 It is the SEM image of single jarosite in Example 1;

[0058] Figure 3 It is the XRD pattern of the jarosite / alumina composite material in Example 1;

[0059] Figure 4 It is the SEM image of the jarosite / alumina composite material in Example 1;

[0060] Figure 5SEM image of the surface of the supported FeP catalyst prepared in Example 1;

[0061] Figure 6 SEM image of the cross-section of the supported FeP catalyst prepared in Example 1;

[0062] Figure 7 Photo of the cross-section of the supported FeP catalyst prepared in Example 1. Detailed implementation manners

[0063] In order to make the objectives, technical solutions and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0064] To better illustrate the present invention, further examples are given below by way of examples.

[0065] Example 1

[0066] The embodiment of the present invention provides a method for preparing a supported FeP catalyst, which includes the following steps:

[0067] Step a, preparing a polyferric sulfate solution:

[0068] Weigh 20 g of FeSO4·7H2O into a beaker, add 25 mL of distilled water to dissolve it, place it in a 40°C constant temperature water bath, under stirring conditions, add concentrated sulfuric acid with a mass concentration of 98% to adjust the pH to 1.5, then dropwise add 15 mL of hydrogen peroxide solution with a mass concentration of 30%, raise the temperature of the constant temperature water bath to 55°C, react for 1 h, then slowly add 25 mL of 0.5 M sodium bicarbonate solution, add it within 15 min, keep warm and stir for 90 min, and cool to obtain a polyferric sulfate solution.

[0069] Step b, preparing a jarosite / aluminum oxide composite material:

[0070] Add porous alumina balls with a particle size of 4.5 - 5.5 mm into water, ultrasonically clean until no white particles appear in the washing liquid, and dry to obtain pretreated porous alumina balls;

[0071] Immerse 55 g of pretreated porous alumina balls into 65 mL of the polyferric sulfate solution prepared above, impregnate at room temperature for 24 h, take out, age at 70°C for 3 h, and dry to obtain a jarosite / aluminum oxide composite material.

[0072] Step c, preparing a supported FeP catalyst:

[0073] Weigh sodium hypophosphite and the prepared jarosite / aluminum oxide composite material obtained above according to a mass ratio of 1:2, and place them at the upstream and downstream of a tubular furnace respectively. Introduce nitrogen gas at the upstream of the tubular furnace, then heat it to 250 °C at a rate of 5 °C / min, and then heat it to 300 °C at a rate of 2 °C / min, keep it warm for phosphating for 1 h, and cool it to room temperature to obtain a supported FeP catalyst (FeP@Al2O3 catalyst).

[0074] Before the start of the experiment, weigh the mass of the porous alumina bare balls, and weigh the mass of the prepared supported FeP catalyst after the experiment. Calculate the loading amount of FeP. On average, each 0.1 g of the porous alumina bare balls can load 0.0056 g of FeP particles on average.

[0075] Perform nitrogen physical adsorption isotherm characterization on the porous alumina bare balls and the prepared supported FeP catalyst in this example. The results show that the specific surface area of the porous alumina bare balls before loading is 309.96 m 2 / g, the pore volume is 0.43 mL / g, and the specific surface area of the catalyst after loading is 196.77 m 2 / g, and the pore volume is 0.29 mL / g. On the one hand, the decrease in the specific surface area and pore volume is due to the loading of FeP on the surface and in the pores of alumina. On the other hand, it also shows that the alumina pores are not completely blocked, which is one of the main reasons for the high catalytic activity of the supported FeP catalyst.

[0076] For comparison, prepare jarosite according to the following steps:

[0077] Age the polyferric sulfate solution prepared in step a at 70 °C for 3 h, filter, and dry to obtain jarosite.

[0078] The XRD pattern and SEM image of the single jarosite prepared above are respectively as Figure 1 and Figure 2 shown.

[0079] The XRD pattern and SEM of the jarosite / aluminum oxide composite material prepared in this example are as Figure 3 and Figure 4 shown. It can be seen from the figure that the peak positions of the composite material correspond one by one to the main peak positions of the separate jarosite (PDF#30-1203) and the separate Al2O3 (JCPDS#80-0956), indicating that the composition of the composite material is jarosite and alumina. From Figure 3 it can be seen that jarosite is loaded on the surface of alumina in a flaky structure.

[0080] The SEM images of the outer surface and cross-section of the supported FeP catalyst prepared in this example are as Figure 5 and Figure 6As shown, it can be seen from the figure that FeP nanoparticles are uniformly dispersed on the alumina spheres, and FeP has a nanorod-like structure. The diameter of the FeP nanoparticles is mainly distributed in the range of 20 nm to 80 nm, and the length is 0.4 μm to 0.6 μm. From Figure 6 it can be observed that FeP is also formed inside the pores of the alumina spheres.

[0081] The cross-sectional photograph of the supported FeP catalyst prepared in this example is as Figure 7 , from Figure 7 it can be seen that the surface of the alumina microspheres is coated with a layer of FeP.

[0082] Example 2

[0083] The embodiment of the present invention provides a method for preparing a supported FeP catalyst, which includes the following steps:

[0084] Step a, preparing a polyferric sulfate solution:

[0085] Weigh 25 g of FeSO4·7H2O in a beaker, add 30 mL of distilled water to dissolve it, place it in a 35°C constant temperature water bath, under stirring conditions, add concentrated sulfuric acid with a mass concentration of 98% to adjust the pH to 1, then dropwise add 23 mL of hydrogen peroxide solution with a mass concentration of 25%, raise the temperature of the constant temperature water bath to 53°C, react for 50 min, then slowly add 31 mL of 0.45 M sodium bicarbonate solution, add it within 15 min, keep warm and stir for 100 min, and cool to obtain a polyferric sulfate solution.

[0086] Step b, preparing a jarosite / alumina composite material:

[0087] Add porous alumina spheres with a particle size of 4.5 - 5.5 mm to water, ultrasonically clean until no white particles appear in the washing liquid, and dry to obtain pretreated porous alumina spheres;

[0088] Immerse 60 g of the pretreated porous alumina spheres in 70 mL of the polyferric sulfate solution prepared above, impregnate at room temperature for 12 h, take out, age at 75°C for 3 h, and dry to obtain a jarosite / alumina composite material.

[0089] Step c, preparing a supported FeP catalyst:

[0090] Weigh sodium hypophosphite and the above-prepared jarosite / alumina composite material according to a mass ratio of 3:2, place them at the upstream and downstream of a tubular furnace respectively, introduce nitrogen at the upstream of the tubular furnace, then heat up to 250°C at a rate of 6°C / min, and then heat up to 350°C at a rate of 3°C / min, keep warm for phosphating for 1 h, and cool to room temperature to obtain a supported FeP catalyst (FeP@Al2O3 catalyst).

[0091] Example 3

[0092] An embodiment of the present invention provides a method for preparing a supported FeP catalyst, which includes the following steps:

[0093] Step a, preparing a polyferric sulfate solution:

[0094] Weigh 18 g of FeSO4·7H2O into a beaker, add 30 mL of distilled water to dissolve it, place it in a constant temperature water bath at 45 °C, under stirring conditions, add concentrated sulfuric acid with a mass concentration of 98% to adjust the pH to 2, then dropwise add 12 mL of hydrogen peroxide solution with a mass concentration of 35%, raise the temperature of the constant temperature water bath to 50 °C, react for 70 min, then slowly add 19 mL of 0.55 M sodium bicarbonate solution, add it within 15 min, keep warm and stir for 120 min, and cool to obtain a polyferric sulfate solution.

[0095] Step b, preparing a jarosite / aluminum oxide composite material:

[0096] Add porous alumina balls with a particle size of 4.5 - 5.5 mm into water, ultrasonically clean until no white particles appear in the washing liquid, and dry to obtain pretreated porous alumina balls;

[0097] Immerse 50 g of the pretreated porous alumina balls into 55 mL of the polyferric sulfate solution prepared above, impregnate at room temperature for 18 h, take out, age at 65 °C for 5 h, and dry to obtain a jarosite / aluminum oxide composite material.

[0098] Step c, preparing a supported FeP catalyst:

[0099] Weigh sodium hypophosphite and the above-prepared jarosite / aluminum oxide composite material according to a mass ratio of 5:2, place them at the upstream and downstream of a tubular furnace respectively, introduce nitrogen gas at the upstream of the tubular furnace, then heat it to 200 °C at a rate of 4 °C / min, and then heat it to 300 °C at a rate of 1 °C / min, keep warm for phosphating for 3 h, and cool to room temperature to obtain a supported FeP catalyst (FeP@Al2O3 catalyst).

[0100] Comparative Example 1

[0101] This comparative example provides a method for preparing a supported FeP catalyst, and the specific steps are as follows:

[0102] Measure 50 mL of 0.5 M FeCl3 solution, adjust the pH = 1.0 with 0.5 M Na2CO3, and keep warm and react at 40 °C for 1 h to obtain a polyferric chloride solution;

[0103] Add porous alumina balls with a particle size of 4.5 - 5.5 mm into water, ultrasonically clean until no white particles appear in the washing liquid, and dry to obtain pretreated porous alumina balls;

[0104] Immerse 40 g of pretreated porous alumina spheres into 50 mL of the above-prepared polyferric chloride solution, impregnate at room temperature for 24 h, take out, age at 70 °C for 3 h, dry, and then weigh sodium hypophosphite and the above-treated and dried alumina spheres according to a mass ratio of 1:2, place them at the upstream and downstream of a tubular furnace respectively, introduce nitrogen gas at the upstream of the tubular furnace, then heat up to 250 °C at a rate of 5 °C / min, and then heat up to 300 °C at a rate of 2 °C / min, keep the temperature for phosphating for 1 h, cool to room temperature to obtain the supported FeP catalyst.

[0105] Catalytic activity evaluation:

[0106] 1.1 Degradation of methylene blue

[0107] The degradation reaction is carried out at room temperature without adjusting the pH value of the waste liquid. Weigh a certain amount of methylene blue, dissolve it in water to prepare a methylene blue solution with a concentration of 100 mg / L, transfer 100 mL of the above methylene blue solution into a beaker, and respectively add 0.5 mL of 1.0 mol / L hydrogen peroxide solution and 0.4 g of the above-prepared FeP@Al2O3 catalyst under stirring conditions, and then add 1.0 mL of 0.4 g / L (Fe 2+ concentration) ferrous sulfate solution, take samples regularly, filter with a filter membrane with a pore size of 0.22 μm, and measure the absorbance at a wavelength of 660 nm to calculate the degradation rate of methylene blue.

[0108] The degradation rate of methylene blue by the FeP@Al2O3 catalyst prepared in Example 1 was 93% at 1 min. The degradation rates of methylene blue by the FeP@Al2O3 catalysts prepared in Examples 2-3 were 90%-91% at 1 min.

[0109] Perform performance evaluation on the supported FeP catalyst prepared in Comparative Example 1 according to the exactly same method as above, only the addition amount of the catalyst is 0.5 g, and the degradation rate of methylene blue is 67% at 4 min.

[0110] 1.2 Degradation of malachite green

[0111] The degradation reaction is carried out at room temperature without adjusting the pH value of the waste liquid. Add malachite green solution, H2O2 solution and the FeP@Al2O3 catalyst prepared in Example 1 into the reaction vessel respectively, add water to adjust the volume of the solution to 100 mL. At this time, the concentration of malachite green is 100 mg / L, H2O2 is 170 mg / L, Fe 2+ is 4.0 mg / L, and the dosage of FeP@Al2O3 is 4 g / L. The degradation rate of malachite green is 98.7% at 12 s.

[0112] 1.3 Degradation of tetracycline hydrochloride

[0113] The degradation reaction is carried out at room temperature without adjusting the pH value of the waste liquid. Tetracycline hydrochloride solution, H2O2 solution and the FeP@Al2O3 catalyst prepared in Example 1 are respectively added into the reaction vessel, and water is added to adjust the volume of the solution to 100 mL. At this time, the concentration of tetracycline hydrochloride is 145 mg / L, H2O2 is 85 mg / L, Fe 2+ is 2.0 mg / L, and the dosage of FeP@Al2O3 is 5 g / L. The degradation rate of tetracycline hydrochloride at 1 min is 70.0%.

[0114] 1.4 Recyclability

[0115] The degradation reaction is carried out at room temperature without adjusting the pH value of the waste liquid. Malachite green solution, H2O2 solution and the FeP@Al2O3 catalyst prepared in Example 1 are respectively added into the reaction vessel, and water is added to adjust the volume of the solution to 100 mL. At this time, the concentration of malachite green is 100 mg / L, H2O2 is 170 mg / L, Fe 2+ is 4.0 mg / L, and the dosage of FeP@Al2O3 is 4 g / L. After the catalytic reaction for 1 min, the FeP@Al2O3 catalyst is recovered by filtration, and the FeP@Al2O3 catalyst is washed with absolute ethanol and distilled water, and the above-mentioned malachite green degradation test is repeated.

[0116] The test results prove that after the FeP@Al2O3 catalyst is recycled 10 times, the degradation rate at 1 min still reaches 96%.

[0117] The above results prove that the supported FeP catalyst prepared in this example has good catalytic stability.

[0118] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements or improvements made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A preparation method of a supported FeP catalyst, characterized in that, It includes the following steps: Step a: Wash or acid-wash the porous alumina spheres, and dry them to obtain pretreated alumina spheres; Step b: Add the pretreated alumina spheres into a polyferric sulfate solution, disperse them evenly, impregnate, age, and dry to obtain a jarosite / alumina composite material; Step c: Under an inert atmosphere, phosphorate the jarosite / alumina composite material to obtain a supported FeP catalyst.

2. The preparation method of the supported FeP catalyst according to claim 1, characterized in that, In step b, the preparation method of the polyferric sulfate solution includes the following steps: At 35°C to 45°C, add concentrated sulfuric acid to an aqueous solution of ferrous sulfate, mix evenly, dropwise add an oxidant solution, after the dropping is completed, raise the temperature to 50°C to 55°C and react for 50 min to 70 min, then add a sodium salt solution, keep the temperature for reaction for 90 min to 120 min, and cool to obtain a polyferric sulfate solution.

3. The preparation method of the supported FeP catalyst according to claim 1 or 2, characterized in that, In step b, the concentration of iron ions in the polyferric sulfate solution is 55 g / L to 65 g / L, and the mass-volume ratio of the pretreated alumina spheres to the polyferric sulfate solution is 50 - 60:55 - 70, where the unit of mass is grams and the unit of volume is milliliters; and / or In step b, the impregnation temperature is 20°C to 30°C, and the impregnation time is 12 h to 24 h; and / or In step b, the aging temperature is 65°C to 75°C, and the aging time is 3 h to 5 h.

4. The preparation method of the supported FeP catalyst according to claim 1, wherein In step c, the specific steps of phosphoration are: Place the phosphorus source and the jarosite / alumina composite material at the upstream and downstream of a tubular furnace respectively, introduce an inert atmosphere at the upstream of the tubular furnace, and carry out phosphoration at 300°C to 350°C for 1 h to 3 h to obtain a supported FeP catalyst.

5. A supported FeP catalyst, characterized in that, Prepared by the preparation method of the supported FeP catalyst according to any one of claims 1 - 4, and includes: a porous alumina sphere support and FeP nanoparticles supported on the surface and in the pores of the porous alumina sphere support.

6. The supported FeP catalyst according to claim 5, wherein, The FeP nanoparticles do not completely fill the pores of the porous alumina sphere support.

7. The supported FeP catalyst according to claim 5 or 6, characterized in that, The FeP nanoparticles are rod-shaped particles with a diameter of 20 nm to 80 nm and a length of 0.4 µm to 0.6 µm; and / or The porous alumina sphere support is a millimeter-scale porous alumina sphere.

8. The supported FeP catalyst according to claim 5, wherein The loading amount of the FeP nanoparticles is 0.03 g / g support to 0.07 g / g support.

9. The supported FeP catalyst according to claim 5, wherein The specific surface area of the supported FeP catalyst is 160 m 2 / g to 220 m 2 / g; and / or The pore volume of the supported FeP catalyst is 0.2 mL / g to 0.3 mL / g.

10. Application of the supported FeP catalyst according to any one of claims 5 - 9 in constructing a Fenton-like catalytic system.

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