Ce / mil-101(Fe) composite material, preparation and application thereof in degrading organic dyes

Abstract

The application relates to a Ce / MIL-101(Fe) composite material and a preparation method and application thereof in degrading organic dyes, and the preparation method comprises the following steps: mixing cerium salt, an iron source and terephthalic acid in an organic solvent, and carrying out a hydrothermal reaction to obtain the Ce / MIL-101(Fe) composite material; wherein the cerium salt comprises cerium nitrate. Compared with the prior art, the preparation method is environment-friendly, the preparation process is simple and easy to operate, industrial production is facilitated, the doping of the Ce element expands the specific surface area of the composite, increases the adsorption property, to a certain extent, increases the number of active sites, meanwhile, the doping of the Ce replaces part of Fe as a metal center, widens the absorption boundary band of visible light, and has a wide application prospect in degrading organic dyes.

Description

Technical Field

[0001] This invention belongs to the field of materials technology and relates to a Ce / MIL-101(Fe) composite material, its preparation, and its application in the degradation of organic dyes. Background Technology

[0002] With rapid population growth and urbanization / industrialization, water pollution has become increasingly severe over the past 30 years. Organic dyes are widely used not only in printing, leather tanning, textiles, and paint industries, but also in food technology and agricultural research. Due to their toxicity, organic dyes have become a serious threat to aquatic environments. Especially when they are discharged into the aquatic environment along with industrial wastewater, they can harm aquatic life and human health. Therefore, with the ever-increasing demand for dyes, particularly in some developing countries, effectively removing organic dyes has become a critical issue.

[0003] Currently, wastewater treatment technologies mainly include adsorption, photocatalytic oxidation, and biodegradation. However, these technologies are often limited by drawbacks such as slow processing speed, secondary pollution, and high cost. Furthermore, due to the stable molecular structure of dyes, dye wastewater is highly variable and non-biodegradable, meaning that dye-loaded adsorbents still pose a potential threat to the ecological environment before reprocessing. In recent decades, advanced oxidation processes (AOPs) have received widespread attention due to their strong oxidizing power, fast reaction speed, and broad applicability in degrading organic compounds. Compared with other AOPs, Fenton-like systems are relatively low-cost and simple to operate and maintain. In Fenton-like reactions, dyes can be degraded by SO4· - ·OH - and O 2- These reactive free radicals are oxidized and mineralized into small molecule compounds such as CO2 and H2O. Among them, sulfate free radicals (SO4·) have relatively high standard redox potentials (2.5-3.1 eV) and a wide pH adaptability range. - Peroxymonosulfate (PMS) is a relatively safe, strong, and stable oxidant commonly used to generate sulfate radicals. It can typically be activated by ultraviolet (UV) light, heat, and transition metals. Compared to other methods, transition metal activation offers the advantages of efficiency and controllability, and is therefore widely used for activating PMS. Generally, transition metal ions such as Ag... + Co 2+ Fe 2+ and Mn 2+ Both can be used to activate PMS to generate SO4. - However, the problem of secondary pollution caused by metal ions as homogeneous catalysts still exists.

[0004] Metal-organic frameworks (MOFs) are a novel class of porous materials composed of organic bridging ligands and metal ions / clusters, possessing periodic network structures, uniform active metal sites, and multiple functions. Among them, MIL-101(Fe) exhibits unique tunable internal surface properties due to its pore structure, functionalized linkers, and ability to carry active species. Kim et al. successfully prepared a MIL-101(Fe) catalyst with a high adsorption saturation capacity for toluene. This excellent performance may be attributed to its high surface area and large cavity. However, due to its low charge separation efficiency, there are few reports on its use alone in photocatalytic processes. Therefore, significant efforts have been made to expand the photoresponse region and improve chemical stability. Effective studies have been conducted on metal ion doping, organic ligand modification, and semiconductor bonding. In recent years, coupling strategies between MOFs and other semiconductor devices have attracted widespread attention from researchers both domestically and internationally as an efficient method. It can form heterostructures, reduce photoinducible carrier recombination, and further improve photocatalytic performance. He et al. developed MIL-101(Fe) / TiO2, a material exhibiting high photodegradation activity for tetracycline and good reusability. Adding TiO2 to MIL-101(Fe) extended its photoresponse range from ultraviolet light to sunlight. This demonstrates that introducing a suitable semiconductor is beneficial for improving photocatalytic performance. Simultaneously, Fe-MOFs, acting as a redox mediator, can promote electron transfer during oxidation by reducing Fe(III) to Fe(II). Therefore, iron-based MOFs are promising photocatalytic and redox raw materials.

[0005] Cerium oxide (CeO2) is a noteworthy rare-earth metal oxide, commonly used as an important semiconductor material due to its abundant energy levels, unique electronic orbital structure, distinctive optical properties, and thermal stability. It has been applied in CO2 reduction, supercapacitors, and the degradation of 2,4-dichlorophenol. However, CeO2 exhibits certain limitations in visible light utilization efficiency and photoinducible carrier separation. To overcome these shortcomings, many researchers have focused on broadening the photoresponse range and improving photocatalytic performance by combining CeO2 with other semiconductors. Li et al. synthesized a CeO2 / attapulgite / MoS2 composite material and investigated its photocatalytic desulfurization performance. They found that the CeO2 / MoS2 coupled CeO2 / ATP exhibited excellent optical properties due to the formation of the CeO2 / MoS2 heterojunction, promoting charge separation and broadening the photoresponse range. Therefore, forming a heterojunction structure through the coupling of two matched semiconductors is beneficial for improving pod performance. However, loading CeO2 leads to a decrease in its specific surface area, resulting in weakened adsorption performance.

[0006] Therefore, this invention changes the method of using CeO2 for deloading, and instead uses Ce(NO3)3·6H2O as the cerium source to directly prepare Ce / MIL-101(Fe) composite material via in-situ substitution and hydrothermal method. In the prepared material, Ce can be incorporated into MIL-101(Fe) as a metal center to replace a small amount of Fe, thereby enhancing the overall specific surface area and improving the overall photocatalytic performance. The preparation process is simple, easy to implement, and has a high reproducibility. Summary of the Invention

[0007] The purpose of this invention is to provide a Ce / MIL-101(Fe) composite material, its preparation, and its application in the degradation of organic dyes. The preparation method of this invention is environmentally friendly, with simple and easy-to-operate procedures, facilitating industrial production. The doping of Ce increases the specific surface area of ​​the composite material, enhancing its adsorption capacity and, to some extent, increasing the number of active sites. Simultaneously, the Ce doping replaces some Fe as a metal center, broadening the absorption boundary band for visible light, thus showing broad application prospects in the degradation of organic dyes.

[0008] The objective of this invention can be achieved through the following technical solutions:

[0009] A method for preparing a Ce / MIL-101(Fe) composite material, comprising:

[0010] Cerium salt, iron source, and terephthalic acid are mixed in an organic solvent and subjected to a hydrothermal reaction to obtain Ce / MIL-101(Fe) composite material.

[0011] The cerium salts mentioned include cerium nitrate.

[0012] Furthermore, the iron source includes ferric chloride; the organic solvent includes N,N-dimethylformamide.

[0013] Furthermore, the molar ratio of cerium to iron is 1:99 to 8:92.

[0014] Furthermore, the ratio of the total amount of cerium and iron to the amount of terephthalic acid is 1:1.5 to 1:2.5.

[0015] Furthermore, in the hydrothermal reaction, the reaction temperature is 110–130°C, and the reaction time is 11–14 h.

[0016] Furthermore, the mixing process of cerium salt, iron source, and terephthalic acid in an organic solvent includes the following steps:

[0017] 1) Mix cerium salt with an organic solvent, and sonicate and stir to obtain solution A; mix iron source with an organic solvent, and sonicate and stir to obtain solution B; mix terephthalic acid with an organic solvent, and sonicate and stir to obtain solution C;

[0018] 2) Mix solutions A, B, and C to obtain a mixed solution of cerium salt / iron source / terephthalic acid.

[0019] Furthermore, the hydrothermal reaction also includes washing and drying processes;

[0020] The washing process includes: centrifugation 6 times, the first 3 centrifugations at 10,000 rpm for 5 min, using N,N-dimethylformamide as the washing agent, and the last 3 centrifugations at 10,000 rpm for 5 min, using anhydrous ethanol at 60℃ as the washing agent.

[0021] The drying process includes vacuum drying, with a drying temperature of 50–70℃ and a drying time of 10–15 hours.

[0022] A Ce / MIL-101(Fe) composite material was prepared using the method described above.

[0023] An application of a Ce / MIL-101(Fe) composite material includes using the composite material for photodegradation of Rhodamine B in water, wherein the oxidant used is sodium persulfate.

[0024] This invention uses FeCl3·6H2O, terephthalic acid, and Ce(NO3)3·6H2O as raw materials to prepare a Ce / MIL-101(Fe) composite material via a hydrothermal method. The resulting Ce / MIL-101(Fe) composite material exhibits a regular octahedral morphology and a surface with noticeable pits, enhancing its overall specific surface area. Compared to MIL-101(Fe), Ce doping improves the overall photocatalytic performance. The preparation process is simple, easy to implement, and has a high reproducibility.

[0025] Compared with the prior art, the present invention has the following characteristics:

[0026] 1) In this invention, the material is transformed into a Ce / MIL-101(Fe) composite material through a hydrothermal method.

[0027] 2) This invention uses Ce(NO3)3·6H2O, terephthalic acid, and FeCl3·6H2O as raw materials to prepare composite materials. The raw materials are readily available, have designability, and are inexpensive.

[0028] 3) In this invention, the direct doping of Ce(NO3)3 to replace the loading of CeO2 can increase the specific surface area of ​​the material and enhance its adsorption performance;

[0029] 4) The Ce / MIL-101(Fe) composite material prepared by the method of the present invention has good photocatalytic performance and good cycle stability, and has broad application prospects in the field of dye wastewater degradation. Attached Figure Description

[0030] Figure 1 Scanning electron microscope (SEM) images of Ce / MIL-101(Fe) composite material (left) and CeO2 / MIL-101(Fe) (right) obtained in Example 3;

[0031] Figure 2 FT-IR of Ce / MIL-101(Fe) composite material, CeO2 / MIL-101(Fe) and MIL-101(Fe) obtained in Example 3;

[0032] Figure 3 The UV-vis spectra of the single Ce / MIL-101(Fe) composite material, CeO2 / MIL-101(Fe) and MIL-101(Fe) obtained in Example 3 are shown.

[0033] Figure 4 The adsorption and desorption isotherms of the single Ce / MIL-101(Fe) composite material, CeO2 / MIL-101(Fe) and MIL-101(Fe) obtained in Example 3 are shown.

[0034] Figure 5XRD patterns of the single Ce / MIL-101(Fe) composite material obtained in Example 3, and the single CeO2 / MIL-101(Fe) and MIL-101(Fe) obtained in Example 5. Detailed Implementation

[0035] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments.

[0036] A Ce / MIL-101(Fe) composite material, the preparation method of which includes the following steps:

[0037] 1) Mix cerium salt with an organic solvent, and sonicate and stir to obtain solution A; mix iron source with an organic solvent, and sonicate and stir to obtain solution B; mix terephthalic acid with an organic solvent, and sonicate and stir to obtain solution C;

[0038] The cerium salt includes cerium nitrate, preferably Ce(NO3)3·6H2O; the iron source includes ferric chloride, preferably FeCl3·6H2O; the organic solvent includes N,N-dimethylformamide; and the purity is preferably AR grade.

[0039] The molar ratio of cerium to iron is 1:99 to 8:92, preferably 6:94; the total amount of cerium and iron, in relation to the amount of terephthalic acid, is 1:1.5 to 1:2.5, preferably 1:2; the amount of organic solvent added depends on the need for complete dissolution.

[0040] 2) Mix solutions A, B, and C to obtain a mixed solution of cerium salt / iron source / terephthalic acid; during the stirring process, the stirring temperature is 25-45℃, preferably 25℃, and the stirring time is 40-60min, preferably 40min;

[0041] 3) Place the mixed solution of cerium salt / iron source / terephthalic acid in a polytetrafluoroethylene reactor and carry out a hydrothermal reaction at 110-130°C for 11-14 hours. Filter to obtain the solid material; preferably, the hydrothermal temperature is 120°C and the hydrothermal time is 12 hours.

[0042] 4) Wash and dry the solid material to obtain the Ce / MIL-101(Fe) composite material;

[0043] The washing process includes: centrifugation 6 times, the first 3 centrifugations at 10,000 rpm for 5 minutes, using N,N-dimethylformamide as the washing agent, and the last 3 centrifugations at 10,000 rpm for 5 minutes, using 60℃ anhydrous ethanol as the washing agent.

[0044] The drying process includes vacuum drying, with a drying temperature of 50–70°C (preferably 60°C) and a drying time of 10–15 h (preferably 12 h).

[0045] An application of a Ce / MIL-101(Fe) composite material includes using the composite material to degrade dye wastewater, further including photodegradation of Rhodamine B (Rhb) in water, wherein the oxidant used is sodium persulfate. Specifically, it includes the following steps:

[0046] 1) Measure 100 mL of 20 mg / L Rhodamine B aqueous solution and pour it into a 250 mL Erlenmeyer flask, then adjust the pH to 2-10;

[0047] 2) Place the Ce / MIL-101(Fe) composite material (10-40 mg) into the conical flask mentioned above;

[0048] 3) Place the conical flask in a shaker and set the speed to 150 r / min. Carry out the adsorption reaction for 30 min in the dark.

[0049] 4) After the adsorption reaches equilibrium, turn on the tritium lamp, add 10-40 mg of sodium persulfate, and start timing;

[0050] 5) Take 1 mL of the supernatant every 5 min, quench it with a small amount of methanol, dilute it and measure its absorbance at 554 nm.

[0051] This embodiment is implemented based on the technical solution of the present invention, and provides detailed implementation methods and specific operation processes. However, the scope of protection of the present invention is not limited to the following embodiment.

[0052] Example 1:

[0053] A Ce / MIL-101(Fe) composite material, the preparation method of which includes the following steps:

[0054] 1) Take 0.034g Ce(NO3)3·6H2O and sonicate it in 10mL N,N-dimethylformamide solution at 25℃ for 30min, and stir it magnetically to obtain solution A.

[0055] Take 1.059g FeCl3·6H2O and sonicate it in 10mL N,N-dimethylformamide solution at 25℃ for 30min, and stir it magnetically to obtain solution B.

[0056] Take 0.332g of terephthalic acid and sonicate it in 10mL of N,N-dimethylformamide solution at 25℃, and stir it magnetically to obtain solution C.

[0057] 2) Mix solutions A, B, and C and stir magnetically at 25°C for 30 minutes to form solution D; place solution D into a 100 mL polytetrafluoroethylene reactor and react at 120°C for 12 hours to obtain solution E;

[0058] 3) Centrifuge solution E 6 times using different detergents. Specifically, the first 3 centrifugations were performed at 10,000 rpm for 5 min, using N,N-dimethylformamide as the detergent; the next 3 centrifugations were performed at 10,000 rpm for 5 min, using anhydrous ethanol at 60℃ as the detergent.

[0059] After centrifugation, the product was placed in a vacuum drying oven and dried at 60°C for 12 hours to obtain powder F, which is Ce / MIL-101(Fe) with a Ce doping ratio of 2wt%.

[0060] Degradation experiment:

[0061] The dried Ce / MIL-101(Fe) was thoroughly ground. 20 mg of the ground material was mixed and added to 100 mL of a 20 mg / L Rhb aqueous solution. A 250 mL Erlenmeyer flask was used as the reactor. The flask was placed in a shaker with the parameters set (150 rpm, 30 min, 24 °C, darkness). After the shaker was completed, a tritium lamp was turned on, 20 mg of sodium persulfate was added, and the timing was started. The above procedure was repeated, and every five minutes, 1 mL of the supernatant in the Erlenmeyer flask was aspirated, filtered through a syringe, and the absorbance of the solution was measured and recorded at 554 nm. The total measurement time was 30 min. The Rhb removal rate of the complex was calculated from the obtained absorbance.

[0062] The complex was found to have a 85% removal rate of Rhb within 30 minutes.

[0063] Example 2:

[0064] A Ce / MIL-101(Fe) composite material, the preparation method of which differs from that in Example 1 only in that:

[0065] The amount of Ce(NO3)3·6H2O used was 0.068g, the amount of FeCl3·6H2O used was 1.037g, and the Ce doping ratio in the resulting Ce / MIL-101(Fe) was 4wt%.

[0066] The rest is the same as in Example 1.

[0067] The Ce / MIL-101(Fe) composite material was evaluated using the same degradation experiment as in Example 1. The results showed that its degradation efficiency of Rhodamine B was 90% in 30 min.

[0068] Example 3:

[0069] A Ce / MIL-101(Fe) composite material, the preparation method of which differs from that in Example 1 only in that:

[0070] The amount of Ce(NO3)3·6H2O used was 0.102g, the amount of FeCl3·6H2O used was 1.016g, and the Ce doping ratio in the resulting Ce / MIL-101(Fe) was 6wt%.

[0071] The rest is the same as in Example 1.

[0072] The Ce / MIL-101(Fe) composite material was evaluated using the same degradation experiment as in Example 1. The results showed that its degradation efficiency of Rhodamine B was 99.98% in 30 min.

[0073] The SEM results are attached. Figure 1 It can be seen that it is roughly octahedral with obvious holes on the surface.

[0074] The results of analyzing its FT-IR spectrum are attached. Figure 2 The signal can be obtained at 741cm. -1 This can be attributed to the out-of-plane bending vibration of the CH group originating from the benzene ring in H2BDC. Peak heights are 1667 and 1502 cm⁻¹. -1 It is the asymmetric stretching of the partition peak to the carboxyl group in the ligand, and at 1389 cm⁻¹ -1 The distribution peak at 551 cm⁻¹ is generated by its symmetrical stretching. -1 The absorption peak at 500-900 cm⁻¹ is likely attributed to the stretching vibration of the Fe-O bond formed by the coordination of the trivalent ferrous ion of MIL-101(Fe) with a carboxyl group. However, the absorption peak for CeO₂ at 500-900 cm⁻¹ is... -1 The figure shows broad peaks within a certain range, describing the stretching vibrations of the Ce-O bond. Furthermore, the figure reveals that Ce / MIL-101(Fe) exhibits vibrational peaks similar to those of Fe-MOF, confirming the presence of the MIL-101 phase. Notably, the peaks at 1389 and 1667 cm⁻¹ are particularly prominent. -1 At this point, the stretching vibration band of the carboxyl group exhibits a redshift behavior in the composite material. This phenomenon indicates that an interaction effect is formed between MIL-101(Fe) and the Ce phase, which is beneficial to improving the separation and transfer performance of the photogenerated support.

[0075] The results of analyzing its UV-vis diffuse reflectance spectrum are shown in the appendix. Figure 3 As can be seen from the figure, the boundary band of Ce / MIL-101(Fe) is larger than that of MIL-101(Fe), indicating that Ce doping can effectively reduce the band gap of the sample and further enhance the efficient utilization of visible light irradiation.

[0076] The analysis of its BET results is attached. Figure 4 As can be seen from the data, the Type I isotherm for MIL-101(Fe) basically matches its adsorption characteristics, showing a pore-filling effect at p / p0 = 0.9–1.0. From the upper right figure, it is clear that Ce / MIL-101(Fe) belongs to the Type IV adsorption-desorption isotherm, indicating that the sample has a porous structure. Furthermore, analysis shows that the specific surface area of ​​Ce / MIL-101(Fe) is greater than that of MIL-101(Fe).

[0077] The XRD pattern analysis results are attached. Figure 5 Characteristic diffraction peaks matching those of the MIL-101(Fe) spectrum (2θ = 9.42°, 9.66°, 18.88°) were obtained, indicating that the sample with the confirmed MIL-101(Fe) spectrum has been successfully synthesized. Furthermore, the diffraction peaks of the Ce / MIL-101(Fe) composite material maintained a high degree of similarity to those of MIL-101(Fe) in the 5-20° wavelength range, indicating that the high doping of Ce has not completely destroyed the crystal structure of MIL-101(Fe). A red shift of the characteristic peaks of Ce / MIL101(Fe) was also observed compared to the XRD pattern of MIL-101(Fe), which is due to Ce doping.

[0078] Example 4:

[0079] A Ce / MIL-101(Fe) composite material, the preparation method of which differs from that in Example 1 only in that:

[0080] The amount of Ce(NO3)3·6H2O used was 0.136g, the amount of FeCl3·6H2O used was 0.995g, and the Ce doping ratio in the resulting Ce / MIL-101(Fe) was 8wt%.

[0081] The rest is the same as in Example 1.

[0082] The Ce / MIL-101(Fe) composite material was evaluated using the same degradation experiment as in Example 1. The results showed that its degradation efficiency of Rhodamine B was 95% in 30 min.

[0083] Example 5:

[0084] A CeO2 / MIL-101(Fe) composite material, the preparation method of which differs from that in Example 1 only in that:

[0085] Ce(NO3)3·6H2O was replaced with CeO2 at a dosage of 0.028g and FeCl3·6H2O at a dosage of 1.081g, resulting in CeO2 / MIL-101(Fe) with a Ce loading of 4wt%.

[0086] The degradation experiment was compared with Example 1. The only difference was that the adsorption equilibrium time was 50 minutes; otherwise, it was the same as Example 1. The degradation experiment of Example 3 was used to evaluate the CeO2 / MIL-101(Fe) composite material. The results showed that it required 50 minutes to reach adsorption equilibrium, and at that time, the adsorption degradation of Rhodamine B was only 51%. In contrast, in Example 3, it only took 30 minutes, and the adsorption degradation was 73.2% at equilibrium. Ultimately, the CeO2 / MIL-101(Fe) composite material achieved a degradation efficiency of 99.45% for Rhodamine B within 30 minutes of reaching adsorption equilibrium.

[0087] The SEM analysis is attached. Figure 1 It can be seen that it is a regular octahedron, unlike Ce / MIL-101(Fe) which has no pores on its surface and has small particles loaded on its surface.

[0088] The results of analyzing its FT-IR spectrum are attached. Figure 2 It can be seen that the vibration of its chemical bond energy is not much different from that of Ce / MIL-101(Fe).

[0089] The results of analyzing its UV-vis diffuse reflectance spectrum are shown in the appendix. Figure 3 It can be seen that its boundary band is larger than that of MIL-101(Fe) and similar to Ce / MIL-101(Fe). Excluding errors, it can be concluded that the optical properties of the two are not much different.

[0090] The analysis of its BET results is attached. Figure 4 The type I isotherm of CeO2 / MIL-101(Fe) basically matches its adsorption characteristics, showing a pore-filling effect at p / p0 = 0.9–1.0. It can be seen that its specific surface area is smaller than that of MIL-101(Fe).

[0091] The XRD pattern analysis results are attached. Figure 5 The diffraction peaks of the CeO2 / MIL-101(Fe) composite material maintained a high degree of similarity to those of MIL-101(Fe) in the 5-20° wavelength range, indicating that the high doping of Ce material has not completely destroyed the crystal structure of MIL-101(Fe). Diffraction peaks at 2θ = 28.6°, 33.1°, and 47.5° are found, which belong to CeO2, indicating the insertion of Ce-O clusters. These diffraction peaks correspond to Ce metal. Analysis confirms that it is a CeO2-supported MIL-101(Fe) composite.

[0092] Example 6:

[0093] The degradation experiment of Rhodamine B by a Ce / MIL-101(Fe) composite material differed from that in Example 1 only in that:

[0094] The Ce / MIL-101(Fe) composite material used was prepared using the same method as in Example 3;

[0095] The catalyst dosages were 10 mg, 20 mg, 30 mg, and 40 mg, respectively.

[0096] The rest is the same as in Example 1. The results are shown in Table 1.

[0097] Table 1 Effect of catalyst dosage on the degradation of Rhodamine B

[0098] Catalyst dosage (mg) 10 20 30 40 Rhodamine B degradation rate 88％ 99.8％ 100％ 100％

[0099] Example 7:

[0100] The degradation experiment of Rhodamine B by a Ce / MIL-101(Fe) composite material differed from that in Example 1 only in that:

[0101] The Ce / MIL-101(Fe) composite material used was prepared using the same method as in Example 3;

[0102] Before turning on the tritium lamp, adjust the initial pH of the solution to: pH=2.96, pH=5.03, pH=7.01, and pH=9.14 respectively.

[0103] The rest is the same as in Example 1. The results are shown in Table 2.

[0104] Table 2 Effect of initial solution pH on the degradation of Rhodamine B

[0105] pH 2.96 5.03 7.01 9.14 Rhodamine B degradation rate 71％ 91％ 100％ 95％

[0106] Example 8:

[0107] The degradation experiment of Rhodamine B by a Ce / MIL-101(Fe) composite material differed from that in Example 1 only in that:

[0108] The Ce / MIL-101(Fe) composite material used was prepared using the same method as in Example 3;

[0109] The dosages of sodium persulfate were 10 mg, 20 mg, 30 mg, and 40 mg, respectively.

[0110] The rest is the same as in Example 1. The results are shown in Table 3.

[0111] Table 3. Effect of sodium persulfate dosage on the degradation of Rhodamine B

[0112]

[0113]

[0114] The above description of the embodiments is provided to enable those skilled in the art to understand and use the invention. It will be apparent to those skilled in the art that various modifications can be made to these embodiments, and the general principles described herein can be applied to other embodiments without inventive effort. Therefore, the present invention is not limited to the above embodiments, and any improvements and modifications made by those skilled in the art based on the disclosure of the present invention without departing from the scope of the invention should be within the protection scope of the present invention.

Claims

1. Use of a Ce / MIL-101(Fe) composite material, characterized in that, The preparation method of the composite material comprises the following steps: 1) mixing cerium salt with an organic solvent, and ultrasonicating and stirring to obtain solution A; mixing iron source with an organic solvent, and ultrasonicating and stirring to obtain solution B; mixing terephthalic acid with an organic solvent, and ultrasonicating and stirring to obtain solution C; 2) mixing and stirring the solutions A, B and C to obtain a mixed solution of cerium salt / iron source / terephthalic acid; 3) hydrothermal reaction to obtain the Ce / MIL-101(Fe) composite material. The cerium salt comprises cerium nitrate. The composite material is used for photodegradation of rhodamine B in water bodies, and sodium persulfate is used as an oxidant.

2. The use of a Ce / MIL-101(Fe) composite material according to claim 1, characterized in that, The iron source comprises ferric chloride, and the organic solvent comprises N,N-dimethylformamide.

3. The use of a Ce / MIL-101(Fe) composite material according to claim 2, characterized in that, The molar ratio of cerium element to iron element is 1:99-8:

92.

4. The use of a Ce / MIL-101(Fe) composite material according to claim 3, characterized in that, The ratio of the total amount of substance of cerium element and iron element to the amount of substance of terephthalic acid is 1:1.5-1:2.

5.

5. The use of a Ce / MIL-101(Fe) composite material according to claim 1, characterized in that, In the hydrothermal reaction, the reaction temperature is 110-130 DEG C, and the reaction time is 11-14 h.

6. The use of a Ce / MIL-101(Fe) composite material according to claim 1, characterized in that, The mixing process of the cerium salt, the iron source and the terephthalic acid in the organic solvent comprises the following steps: 1) mixing cerium salt with an organic solvent, and ultrasonicating and stirring to obtain solution A; mixing iron source with an organic solvent, and ultrasonicating and stirring to obtain solution B; mixing terephthalic acid with an organic solvent, and ultrasonicating and stirring to obtain solution C; 2) mixing and stirring the solutions A, B and C to obtain a mixed solution of cerium salt / iron source / terephthalic acid.

7. The use of a Ce / MIL-101(Fe) composite material according to claim 6, characterized in that, The washing process after the hydrothermal reaction comprises the following steps: the centrifugation is performed 6 times, the centrifugal speed is 10,000 rpm for the first 3 times, the time is 5 min, the washing agent is N,N-dimethylformamide, the centrifugal speed is 10,000 rpm for the last 3 times, the time is 5 min, and the washing agent is 60 DEG C anhydrous ethanol.

8. The use of a Ce / MIL-101(Fe) composite material according to claim 7, characterized in that, The drying process after the washing comprises the following steps: The drying process comprises vacuum drying, the drying temperature is 50-70 DEG C, and the drying time is 10-15 h.

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