CN111167506B - Sr2FeO4/SBA-15 composite catalyst material and preparation method thereof - Google Patents

Abstract

Sr₂FeO₄/SBA‑15 a composite material characterized by: sr₂FeO₄The metal oxide is uniformly attached to the surface of the SBA-15 molecular sieve and in the mesoporous track, wherein the bimetallic oxide is uniformly dispersed in the track and is arranged in order, Sr₂FeO₄The total loading on SBA-15 was 20%. The preparation method of the invention effectively controls Sr₂FeO₄The load capacity on SBA-15 is 20 percent, and prepared Sr₂FeO₄Sr in SBA-15₂FeO₄The size is small, the load uniformity on SBA-15 is good, agglomeration does not occur, the catalytic activity is high and can reach 98.9%, the time for degrading sulfapyridine is short, the sulfapyridine has excellent catalytic performance in a large-range pH change environment, the catalytic performance is good in stability and can be recycled, the catalytic activity can still reach 93.5%, the stability is kept and is not reduced, and the stability in recycling is excellent.

Description

Sr2FeO4/SBA-15 composite catalyst material and preparation method thereof

Technical Field

The invention relates to the technical field of advanced oxidation, in particular to Sr₂FeO₄An SBA-15 composite material and a preparation method thereof.

Background

Antibiotics are widely applied to prevention and treatment of bacterial infectious diseases of human beings and livestock, so that various bacteria can generate antibodies, and meanwhile, residual antibiotics in medical and medical wastewater can also be used as pollutants to cause serious threats to human bodies, animals and environment protection after entering the environment. Since antibiotics are difficult to degrade by microorganisms, the residual resistance to organisms in the environment will increase if no reasonably effective measures are taken. Research on antibiotic pollution by the Chinese academy of sciences shows that more than 5 ten thousand tons of antibiotics are discharged into the water and soil environment in China in a year. Therefore, a fast and efficient method for degrading residual antibiotics in water is urgently needed. Sulfonamides are a class of widely used synthetic antibiotics, are main potential pollutants introduced into the environment, are spread in the environment, pose threats to the health of human beings and animals, and also damage the ecological environment. Therefore, it is highly desirable to have a highly sensitive and reliable degradation of such compounds.

The advanced oxidation technology utilizes the generation of free radicals (SO) with extremely strong activity in the reaction₄·^－、OH·^－Etc.) to oxidize and decompose organic pollutants in the water body, so that most of the organic pollutants are rapidly degraded into carbon dioxide and water. There are many methods for catalyzing persulfate to generate sulfate radical, among which, at present, the homogeneous catalyst-Fe is widely used²⁺Although the persulfate activation method has the advantages of high oxidation efficiency, strong oxidation capacity, good selectivity, wide application range and the like, the method also has the defects that metal ions can be remained in a single metal or metal oxide in the catalysis process, the catalyst is not easy to recycle, secondary pollution is easy to cause and the like. To overcome the above disadvantages, heterogeneous advanced oxidation techniques have been developed, such as the use of metals or their oxides (Fe)₃O₄、Co₃O₄Etc.) are immobilized on a suitable support to produce a supported catalyst composite. In the process of preparing the compound, the technical problems to be overcome are that the carrier and the catalyst are not suitable, the adaptability between the carrier and the catalyst is poor, the catalyst cannot be successfully loaded on the carrier or the loading capacity is low, the particle size growth of the catalyst on the carrier is uncontrollable, the dispersibility is poor, the agglomeration is easy to occur, the catalytic activity of the catalyst loaded on the carrier is reduced, the catalyst is easy to fall off from the carrier in the use process, the stability is poor, the service life is short and the like.

Disclosure of Invention

The invention aims to provide Sr with excellent catalytic degradation performance on sulfonamides₂FeO₄the/SBA-15 composite material.

Another object of the present invention is to provide the above Sr₂FeO₄A preparation method of the/SBA-15 composite material.

The purpose of the invention is realized by the following technical scheme:

sr₂FeO₄the/SBA-15 composite material is characterized in that: said Sr₂FeO₄the/SBA-15 composite material is of a bundle-shaped structure, Sr₂FeO₄Bimetallic oxidationThe substances are uniformly attached to the surface of the SBA-15 molecular sieve and in the mesoporous orbit, wherein Sr is₂FeO₄The bimetal oxide is uniformly dispersed in the rail and is arranged in order, Sr₂FeO₄The total loading on SBA-15 was 20%.

Further, Sr is as defined above₂FeO₄The preparation method of the/SBA-15 composite material is characterized by comprising the following steps: sr (NO)₃)₂And Fe (NO)₃)₃·5H₂Dissolving O in distilled water to form a mixed solution A, adding SBA-15 into the mixed solution A while stirring to form a mixed solution B, heating the mixed solution B into paste, drying in vacuum, grinding and calcining at high temperature.

Further, before adding SBA-15, adding surfactant polyethylene glycol 4000(PEG) with the mass fraction of 10-15% into the mixed solution A, and carrying out ultrasonic treatment for 5-10 min.

The inventors found that the addition of molecular sieve SBA-15 had a great effect on the surfactant performance of surfactant polyglycol 4000: the surfactant is added before the SBA-15, which is beneficial to controlling the particle size of the product, well disperses the metal particles on the surface of the SBA-15 and in the mesoporous track, avoids particle agglomeration, increases active sites and improves the catalytic activity of the final product; the surfactant is added after the SBA-15, only the metal ions on the surface of the SBA-15 can be dispersed, the metal particles entering the mesoporous track cannot be acted, the particle size in the track is large, and the pore channel is blocked, so that the active sites of the product are reduced, and the catalytic activity is inhibited. Therefore, the invention adopts the mode of firstly adding the surfactant and then adding the molecular sieve SBA-15, thereby effectively controlling the particle size and the dispersity of the metal ions.

Further, the heating to paste is specifically to heat and stir to paste on a magnetic stirrer with the rotating speed of 100r/min, the stirring temperature is 55 ℃, and the phenomenon that the heating is too fast inhibits the action of the surfactant, so that the dispersion degree is reduced.

Further, the above Sr (NO)₃)₂、Fe(NO₃)₃·5H₂The ratio of the amount of O to the amount of distilled water was 0.7245g, 2.1702g, and 30 mL.

Further, the ratio of SBA-15, surfactant and distilled water in the mixed solution a was 1g:3 to 4.5mL:30 mL.

Further, Sr (NO)₃)₂And Fe (NO)₃)₃·5H₂Dissolving O in distilled water, performing ultrasonic treatment for 10-20min, adding SBA-15 into the mixed solution A, and performing ultrasonic treatment for 40-45 min.

Further, the above vacuum drying is to dry the pasty material in a vacuum drying oven at a constant temperature of 100 ℃ for 12 h.

Further, the high-temperature calcination is to take out the dried material, cool the material, grind the material into powder, put the powder into a bar-shaped ceramic boat, and calcine the material in the air at the temperature of 700-900 ℃ for 4-5h in a tube furnace, wherein the heating rate is 10 ℃/min.

Most specifically, Sr₂FeO₄The preparation method of the/SBA-15 composite material is characterized by comprising the following steps:

(1) sr (NO)₃)₂And Fe (NO)₃)₃·5H₂Dissolving O in distilled water, ultrasonic dissolving for 10-20min to obtain mixed solution A, Sr (NO)₃)₂、Fe(NO₃)₃·5H₂The dosage ratio of O to distilled water is 0.7245g, 2.1702g and 30 mL;

(2) adding 10-15% by mass of polyethylene glycol 4000 into the mixed solution A while stirring, performing ultrasonic homogenization for 5-10min, adding SBA-15, and performing ultrasonic treatment for 40-45min to form mixed solution B, wherein the stirring speed is 100r/min, and the mass volume ratio of the SBA-15 to the polyethylene glycol 4000 to the mixed solution A is 1g:3-4.5mL:30 mL;

(3) placing the mixed solution B on a magnetic stirrer at 55 ℃, and heating and stirring until the suspension liquid becomes a pasty material;

(4) drying the pasty material in a vacuum drying oven at constant temperature of 100 ℃ for 12 h;

(5) and taking out the dried material, cooling, grinding to powder, putting into a bar-shaped ceramic boat, and calcining in a tube furnace in air at the temperature of 700 ℃ and 900 ℃ for 4-5h at the heating temperature-rising speed of 10 ℃/min.

In Sr₂FeO₄SBA-15 composite materialIn the preparation process, Sr₂FeO₄The load capacity on the molecular sieve is low, the catalytic performance of the molecular sieve is poor, and when the molecular sieve is repeatedly used, the catalytic performance of the molecular sieve is seriously attenuated, so that the degradation rate of the sulfonamide pollutants is reduced; sr₂FeO₄The agglomeration is easy to occur, the grain diameter is large, and the mesoporous channel of the SBA-15 is blocked, the ordered mesoporous structure is damaged, the specific surface area is reduced, the mesoporous structure is reduced, the mesoporous aperture is reduced, and the catalytic activity is reduced. The preparation method of the invention overcomes the technical problems just by matching the steps and effectively controls Sr₂FeO₄Load on SBA-15 such that Sr₂FeO₄Sr in/SBA-15 composite material₂FeO₄The load is high, no agglomeration occurs, the catalyst is uniformly dispersed on the surface of the SBA-15 and in a pore channel, the catalyst has excellent catalytic activity on PMS, the bimetallic oxide is stable, the binding force between the bimetallic oxide and the SBA-15 is large, and the leaching rate of metal ions is low.

The invention has the following technical effects:

the present invention provides a kind of Sr₂FeO₄SBA-15 composite catalyst material, Sr₂FeO₄Small size, large specific surface area of the composite material, uniform loading on the surface of the SBA-15 molecular sieve and in the pore canal structure, Sr in the pore canal₂The particle size of the FeO metal oxide is less than 8nm, no agglomeration exists, more active sites are provided for catalytic reaction, the catalyst has excellent catalytic performance in a large-range pH change environment, the catalytic stability is good, the catalytic activity reaches 98.9%, the time required for degrading Sulfapyridine (SPY) is short, the sulfapyridine can be recycled and reused for 10 times, the catalytic activity can still reach 93.5%, the stability is kept stable and not reduced, the stability in repeated use is excellent, the bimetallic oxide is effectively dispersed in SBA-15 mesopores, the contact surface area is favorably increased, and the metal ion leaching rate is reduced.

The preparation method of the invention effectively controls Sr₂FeO₄The load capacity on SBA-15 is 20 percent, and prepared Sr₂FeO₄Sr in SBA-15₂FeO₄Small size, good load uniformity on SBA-15, no agglomerationThe catalytic activity is high and can reach 98.9%, the time for degrading sulfapyridine is short, the sulfapyridine has excellent catalytic performance in acid, neutral and alkaline environments, the catalytic performance is small in change and good in stability, the sulfapyridine can be recycled, the catalytic activity can still reach 93.5% after being reused for 10 times, the sulfapyridine is stable and does not decrease, and the stability of the sulfapyridine in repeated use is excellent.

Drawings

FIG. 1: sr₂FeO₄The x-ray diffraction (XRD) large and small angle patterns of/SBA-15.

FIG. 2: sr₂FeO₄Scanning Electron Microscope (SEM) picture of/SBA-15.

FIG. 3: sr₂FeO₄Chemical composition distribution (EDS) of SBA-15.

FIG. 4: sr₂FeO₄High resolution Transmission Electron Microscopy (TEM) image of/SBA-15.

FIG. 5: a graph of degradation effect of sulfapyridine by different means.

FIG. 6: sr₂FeO₄the/SBA-15 composite catalyst has a relation curve graph of the catalytic degradation sulfapyridine efficiency and degradation rate constant of PMS with different concentrations.

FIG. 7: sr₂FeO₄A graph of relationship between degradation rate and degradation rate constant of PMS catalyzed by the/SBA-15 composite catalyst to sulfapyridine with different concentrations.

FIG. 8: different amounts of Sr₂FeO₄A relation curve diagram of PMS (polymeric ferric phosphate) sulfapyridine degradation rate and rate constant catalyzed by the/SBA-15 composite catalyst.

FIG. 9: sr₂FeO₄The activation performance of the/SBA-15 composite catalyst under different pH conditions.

FIG. 10: sr₂FeO₄A relationship graph of the recycling of the/SBA-15 composite catalyst and the degradation rate.

FIG. 11: sr₂FeO₄Ion leaching rate curve diagram of the/SBA-15 composite catalyst in the recycling process.

Detailed Description

The present invention is described in detail below by way of examples, it should be noted that the following examples are only for illustrating the present invention and should not be construed as limiting the scope of the present invention, and those skilled in the art can make some insubstantial modifications and adaptations of the present invention based on the above-mentioned disclosure.

Example 1

Sr₂FeO₄The preparation method of the/SBA-15 composite material comprises the following steps:

(1) sr (NO)₃)₂And Fe (NO)₃)₃·5H₂Dissolving O in distilled water, ultrasonic dissolving for 15min to obtain mixed solution A, Sr (NO)₃)₂、Fe(NO₃)₃·5H₂The dosage ratio of O to distilled water is 0.7245g, 2.1702g and 30 mL;

(2) adding polyethylene glycol 4000 into the mixed solution A while stirring, performing ultrasonic homogenization for 8min, then adding SBA-15, and performing ultrasonic treatment for 42min to form mixed solution B, wherein the stirring speed is 100r/min, and the mass-volume ratio of the SBA-15 to the mixed solution A is 1g: 4mL of: 30 mL;

(3) placing the mixed solution B on a magnetic stirrer at 55 ℃, and heating and stirring until the suspension liquid becomes a pasty material;

(4) drying the pasty material in a vacuum drying oven at constant temperature of 100 ℃ for 12 h;

(5) and taking out the dried material, cooling, grinding into powder, putting into a strip ceramic boat, and calcining in a tube furnace at 800 ℃ for 4.5h at a heating rate of 10 ℃/min.

Example 2

Sr₂FeO₄The preparation method of the/SBA-15 composite material comprises the following steps:

(1) sr (NO)₃)₂And Fe (NO)₃)₃·5H₂Dissolving O in distilled water, ultrasonic dissolving for 20min to obtain mixed solution A, Sr (NO)₃)₂、Fe(NO₃)₃·5H₂The dosage ratio of O to distilled water is 0.7245g, 2.1702g and 30 mL;

(2) adding polyethylene glycol 4000 into the mixed solution A while stirring, performing ultrasonic treatment for 5min, adding SBA-15, performing ultrasonic treatment for 45min to form mixed solution B, wherein the stirring speed is 100r/min, and the mass-volume ratio of the SBA-15 to the mixed solution A is 1g: 3mL of: 30 mL;

(3) placing the mixed solution B on a magnetic stirrer at 55 ℃, and heating and stirring until the suspension liquid becomes a pasty material;

(4) drying the pasty material in a vacuum drying oven at constant temperature of 100 ℃ for 12 h;

(5) and taking out the dried material, cooling, grinding into powder, putting into a strip ceramic boat, and calcining in a tube furnace at 900 ℃ for 4h at a heating rate of 10 ℃/min.

Example 3

Sr₂FeO₄The preparation method of the/SBA-15 composite material comprises the following steps:

(1) sr (NO)₃)₂And Fe (NO)₃)₃·5H₂Dissolving O in distilled water, ultrasonic dissolving for 20min to obtain mixed solution A, Sr (NO)₃)₂、Fe(NO₃)₃·5H₂The dosage ratio of O to distilled water is 0.7245g, 2.1702g and 30 mL;

(2) adding polyethylene glycol 4000 into the mixed solution A while stirring, performing ultrasonic treatment for uniform 10min, then adding SBA-15, and performing ultrasonic treatment for 40-45min to form mixed solution B, wherein the stirring speed is 100r/min, and the mass-volume ratio of the SBA-15 to the polyethylene glycol 4000 to the mixed solution A is 1g: 4.5mL:30 mL;

(3) placing the mixed solution B on a magnetic stirrer at 55 ℃, and heating and stirring until the suspension liquid becomes a pasty material;

(4) drying the pasty material in a vacuum drying oven at constant temperature of 100 ℃ for 12 h;

(5) and taking out the dried material, cooling, grinding into powder, putting into a strip ceramic boat, and calcining in a tube furnace at 700 ℃ for 5h at a heating rate of 10 ℃/min.

FIG. 1(a) is a XRD large angle scan image of the product at a scan speed of 1 deg./min and 2 theta of 10 deg. -80 deg.. The XRD large-angle spectrum and the standard chart are comparedSpectrum (Reference Sr)₂FeO₄) In contrast, four diffraction peaks with good resolution are shown in the image, and the Sr and the Fe can be obtained to form the oxide Sr₂FeO₄The material obtained by firing is Sr₂FeO₄/SBA-15。

SBA-15 and Sr₂FeO₄The small angle XRD pattern of/SBA-15 is shown in FIG. 1 (b). Three different diffraction peaks (100), (110) and (200) exist on the SBA-15, and the resolution of the three diffraction peaks is better, which indicates that the three diffraction peaks have obvious hexagonal symmetry. In Sr₂FeO₄Diffraction peaks associated with the (100), (110) and (200) reflections were also observed in SBA-15, although at reduced intensities, indicating that SBA-15 retains very good mesoporous properties after metal loading. This is probably due to the fact that the increase in the amount of Sr, Fe metal particles loaded by SBA-15 results in a decrease in electron density, and thus a certain decrease in porosity in SBA-15.

FIG. 2 is Sr₂FeO₄SEM picture of/SBA-15 composite catalyst, from which Sr can be seen₂FeO₄Loaded on the surface of SBA-15, arranged uniformly, tidily and stably attached, the bimetal particles are basically consistent in size and are about 100-125nm, the growth of the bimetal oxide crystal entering the mesoporous orbit of the SBA-15 is limited by the mesoporous aperture of the SBA-15, and the diameter is less than 8nm under the influence of a surfactant. Meanwhile, the SBA-15 presents a bundle-shaped structure, so that the specific surface area of the catalyst can be effectively increased, and more catalytic active sites can be provided.

FIG. 3 shows the use of an energy spectrometer (EDS) for catalyst Sr₂FeO₄Analysis of the chemical components of the/SBA-15 composite catalyst shows that Sr and Fe appear at the same position, and the elements are uniformly distributed. The results show that the sintered material is essentially bimetallic Sr₂FeO₄Consistent with the results of the large angle XRD scans. Through comparative analysis of spectral data, the loading amount of Sr is 20.09 wt%, the loading amount of Fe is 13.47 wt%, and the appearance positions of the two metals are the same, and the catalyst is proved to be the bimetallic oxide Sr₂FeO₄And the load on the SBA-15 is uniform.

FIG. 4 is Sr₂FeO₄High resolution Transmission Electron Microscope (TEM) image of/SBA-15 composite catalyst, Sr₂FeO₄The nano particles are uniformly dispersed on the surface of the SBA-15 and in the mesoporous orbit. Sr on SBA-15₂FeO₄The arrangement of the oxides is ordered. The bimetallic oxide existing in the mesoporous orbitals stably exists in the mesoporous orbitals. Because the small-particle metal oxide is loaded on the surface and in the pore canal of the SBA-15, the ordered mesoporous structure of the SBA-15 part is damaged, the mesoporous aperture is reduced, and the Sr are used₂FeO₄The small angle XRD measurement results of the SBA-15 are consistent; meanwhile, the surfactant changes the electronic structures of the molecular sieve and the bimetallic oxide, so that the formed bimetallic oxide is more stable, the binding force between the bimetallic oxide and SBA-15 is large, the leaching of metal ions is reduced, and the prepared Sr is prepared₂FeO₄the/SBA-15 composite catalyst has better stability and high-efficiency catalytic performance.

Example 4

Sr₂FeO₄the/SBA-15 composite catalyst catalyzes PMS to degrade sulfapyridine:

by Sr₂FeO₄The catalyst is SBA-15, potassium Peroxymonosulfate (PMS) is used as oxidant, Sr is added₂FeO₄In the SBA-15 catalytic reaction mode, PMS is catalyzed to generate active sulfate radicals, sulfapyridine is used as a target compound, and the generation of the sulfate radicals plays an important role in the degradation process of the sulfapyridine.

50mL of sulfapyridine Solution (SPY) 50. mu. mol/L was put in a small 100mL beaker with a magnetic stirrer, and 0.05g of Sr was added₂FeO₄SBA-15, placing on a magnetic stirrer, keeping out of the sun, stirring at normal temperature, and making sulfapyridine adsorption-desorption balance, wherein the balance concentration is used as initial concentration (C) for degradation₀) Immediately adding PMS (PMS/sulfapyridine molar ratio is 20:1) to start timing, sampling 1.0mL at certain time intervals, immediately adding into a sample tube containing 200 μ L of sodium thiosulfate inactivator, shaking, filtering with 0.22 μm water phase filter membrane, loading into a sample bottle, and finally analyzing with LC-2010HT high performance liquid chromatograph with wavelength of 254nm and chromatographic column of Agilent Eclipse XDB-C18(150 mm. times.4.6 mm,5.0 μm), a mobile phase composition of 35% methanol and 65% water (volume ratio), a column temperature of 35 ℃, a mobile phase flow rate of 0.3mL/min, and a detection time of 8 min.

1. Different amounts of Sr₂FeO₄Influence of the/SBA-15 composite catalyst on degradation Performance:

same degradation method, using different Sr₂FeO₄The addition amount of SBA-15 is the addition amount in 1L sulfapyridine solution, and the obtained results are shown in the following table 1:

as is clear from Table 1, Sr in accordance with the present invention₂FeO₄The dosage of SBA-15 has little influence on the degradation effect of sulfapyridine, the degradation rate reaches over 90 percent in 60min, and the degradation is more complete in 90min and reaches 98.9 percent. In the system with the same concentration of PMS and sulfapyridine, different dosages of Sr can be seen in the figure₂FeO₄the/SBA-15 composite catalyst has little influence on the final degradation effect of sulfapyridine, as shown in FIG. 8(a), Sr in the figure to be explained₂FeO₄The SBA-15 concentration means that Sr is added into 1L sulfapyridine₂FeO₄Amount of the/SBA-15 composite catalyst. The inset in fig. 8(b) shows the kinetics of sulfapyridine degradation; these figures illustrate the sulfapyridine degradation and first order kinetic model lnC_t/C₀＝–k₁t corresponds well, where C_tAnd C₀The sulfapyridine concentrations at time t and t ═ 0, respectively. FIG. 8(b) clearly shows that the amount of sulfapyridine and PMS used is constant with Sr₂FeO₄The kinetic rate constant increases and then decreases for an increase in the mass of/SBA-15. When Sr is₂FeO₄Rate constant k when SBA-15 increases from 0.04g to 0.08g₁From about 0.0405min^-1Increase to 0.0445min^-1Then the temperature is reduced to 0.0441min^-1. Higher catalyst usage can increase the number of adsorption sites and activate PMSSulfate radical generation provides more active sites, thus leading to a significant increase in the rate of oxidative degradation. However, when the amount of the catalyst is increased to a certain amount, the catalyst is inhibited from each other by further increasing the amount of the catalyst, resulting in Sr₂FeO₄The degradation rate in the system of SBA-15 catalyst and PMS is reduced. In Sr₂FeO₄The maximum reaction rate constant K is obtained when the dosage of the/SBA-15 composite catalyst is 0.07g₁＝0.0445min^-1The rate of degradation is fastest at this point.

2.Sr₂FeO₄The catalytic activity of the/SBA-15 composite catalyst in different pH environments is as follows:

the same degradation SPY process as in example 4 was carried out under different initial pH conditions, and the degradation results are shown in FIG. 9(a), where C was measured at different times during the degradation of SPY when the pH was 3, 5, 7 and 9, respectively_tAnd C₀The ratio of (a) to (b). It can be seen from the figure that the degradation curve of SPY in the system is not changed much and tends to be consistent with the change of pH value, so that the change of pH environment to Sr is known₂FeO₄The catalytic activity of the/SBA-15 composite catalyst has no great influence; from FIG. 9(b) when the pH is increased from 3 to 9, the rate constant k₁From about 0.0506min^-1Increased to 0.0554min^-1And subsequently tends to stabilize. Thus, Sr can be obtained by analysis₂FeO₄The change span of the PMS degradation rate of the/SBA-15 composite catalyst along with the rising rate of pH is small, the change is less than 0.005, the stability is high, and therefore, Sr is known₂FeO₄the/SBA-15 composite catalyst can keep excellent catalytic performance in acid, neutral and alkaline environments, and the catalytic rate changes with the pH environment, and has small fluctuation and good stability.

3.Sr₂FeO₄SBA-15 stability test:

(1) after finishing degrading sulfapyridine each time, centrifuging the suspension, pouring out supernatant, washing with triple distilled water for three times, and washing away sulfapyridine attached to the surface of the catalyst; washing with absolute ethanol for three times (washing off PMS and degradation products attached to the surface of the catalyst), and washing with triple distilled water for three timesAnd (3) pouring off the supernatant of the absolute ethyl alcohol attached to the surface of the catalyst, drying in a 100 ℃ oven until the catalyst is completely dehydrated, and putting the catalyst into next degradation for use. Circularly use Sr₂FeO₄The specific degradation rate of the catalyst in the PMS degradation of sulfapyridine by SBA-15 is shown in figure 11. The degradation rate of sulfapyridine is not obviously reduced in 10 times of continuous repeated use, and Sr is₂FeO₄The SBA-15 still shows good catalytic activity in the process of repeated use, which indicates that the activation reaction of PMS can be carried out in a mesoporous track, degradation products can be uniformly dispersed, and the service life of the catalyst is prolonged. And the carbonaceous deposits on the surface of the catalyst are effectively removed through high-temperature drying after each experiment to activate the catalytic active site, so that the degradation efficiency of sulfapyridine is kept in a relatively stable range.

(2) As can be seen from FIG. 11, Sr²⁺And Fe³⁺The ion leaching rate is respectively lower than 0.945mg/L and 0.491 mg/L, the ion leaching rate is reduced along with the increase of the cycle number, but the degradation rate is not changed greatly, because the metal ions entering the aqueous solution come from the metal ions loaded on the surface of the SBA-15, and the bimetal in the mesoporous orbit of the SBA-15 plays a catalytic role all the time. Experiments show that Sr₂FeO₄the/SBA-15 composite catalyst can repeatedly and continuously catalyze the oxidant to degrade sulfapyridine, and has high degradation efficiency and good stability.

Comparative example 1

Sintering by adopting Mo and Fe: the Mo and Fe oxide products are prepared respectively, and can degrade sulfapyridine within 90min to a certain extent, but the catalytic action of oxides prepared by mixing and burning Mo and Fe on sulfapyridine is far worse than that of oxides of Mo or Fe alone, the sulfapyridine content for detection is not reduced within 90min through high performance liquid chromatography, after loading, a specific bimetal oxidation peak cannot be obtained through XRD scanning of the products, and the loading effect of the product loaded on SBA-15 is poor; the catalytic performance of the bimetallic oxide/SBA-15 composite catalyst cannot be predicted, and the materials found by people are generated by continuous bimetallic combination and are obtained by measuring and judging the catalytic efficiency, the repeated use efficiency and the ion leaching rate in multiple aspects.

Claims (6)

1. Sr₂FeO₄The preparation method of the/SBA-15 composite material is characterized by comprising the following steps: sr (NO)₃)₂And Fe (NO)₃)₃·5H₂Dissolving O in distilled water to form a mixed solution A, adding a surfactant polyethylene glycol 4000 into the mixed solution A, performing ultrasonic treatment for 5-10min, adding SBA-15 while stirring to form a mixed solution B, heating the mixed solution B into paste, performing vacuum drying, grinding the mixed solution B into powder, and then performing high-temperature calcination, wherein the high-temperature calcination is to put the ground powder into a strip-shaped ceramic boat, place the ceramic boat in a tubular furnace to calcine the powder for 4-5h in the air at the temperature of 700 plus material and 900 ℃, and the heating rate is 10 ℃/min; prepared Sr₂FeO₄the/SBA-15 composite material is of a bundle-shaped structure, Sr₂FeO₄The bimetal oxide is uniformly attached to the surface of the SBA-15 molecular sieve and in the mesoporous orbit, wherein Sr is₂FeO₄The bimetal oxide is uniformly dispersed in the rail and is arranged in order, Sr₂FeO₄The total loading on SBA-15 was 20%.

2. An Sr as claimed in claim 1₂FeO₄The preparation method of the/SBA-15 composite material is characterized by comprising the following steps: the Sr (NO)₃)₂、Fe(NO₃)₃·5H₂The ratio of the amount of O to the amount of distilled water was 0.7245g, 2.1702g, and 30 mL.

3. An Sr as claimed in claim 1 or 2₂FeO₄The preparation method of the/SBA-15 composite material is characterized by comprising the following steps: the ratio of SBA-15 to surfactant to distilled water in the mixed solution A is =1g:3-4.5mL:30 mL.

4. An Sr as claimed in claim 3₂FeO₄The preparation method of the/SBA-15 composite material is characterized by comprising the following steps: the Sr (NO)₃)₂And Fe (NO)₃)₃·5H₂Dissolving O in distilled water, performing ultrasonic treatment for 10-20min, adding SBA-15 into the mixed solution A, and performing ultrasonic treatment for 40-45 min.

5. An Sr as in claim 4₂FeO₄The preparation method of the/SBA-15 composite material is characterized by comprising the following steps: the vacuum drying is to dry the pasty material in a vacuum drying oven with a constant temperature of 100 ℃ for 12 h.

6. Sr₂FeO₄The preparation method of the/SBA-15 composite material is characterized by comprising the following steps:

(1) sr (NO)₃)₂And Fe (NO)₃)₃·5H₂Dissolving O in distilled water, ultrasonic dissolving for 10-20min to obtain mixed solution A, Sr (NO)₃)₂、Fe(NO₃)₃·5H₂The dosage ratio of O to distilled water is 0.7245g, 2.1702g and 30 mL;

(2) adding polyethylene glycol 4000 into the mixed solution A while stirring, performing ultrasonic homogenization for 5-10min, then adding SBA-15, and performing ultrasonic treatment for 40-45min to form mixed solution B, wherein the stirring speed is 100r/min, and the mass-volume ratio of the SBA-15 to the polyethylene glycol 4000 to the distilled water in the mixed solution A is 1g:3-4.5mL:30 mL;

(3) placing the mixed solution B on a magnetic stirrer, heating and stirring until the suspension becomes pasty material;

(4) drying the pasty material in a vacuum drying oven at constant temperature of 100 ℃ for 12 h;

(5) and taking out the dried material, cooling, grinding to powder, putting into a bar-shaped ceramic boat, and calcining in a tube furnace in air at the temperature of 700 ℃ and 900 ℃ for 4-5h at the heating temperature-rising speed of 10 ℃/min.

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