Preparation method of water purification filler with adsorption and photo-fenton performance

Abstract

The application relates to a preparation method of a water purification filler with adsorption and photo-Fenton performance, and particularly relates to a preparation method of a water purification filler with adsorption and photo-Fenton performance. The application provides a preparation method of a water purification filler with adsorption and photo-Fenton performance. The application comprises the following steps: step 1) FeCl3.6H2O is dissolved in deionized water, and after uniform orange solution is obtained through stirring, the solution is placed in a reaction kettle for hydrothermal treatment; after the reaction kettle is naturally cooled to room temperature, the obtained product is washed with ethanol and deionized water to obtain a solid product; step 2) the product obtained in step 1) is placed in an oven for drying to obtain deep red powder FeOOH; the obtained FeOOH and L-cysteine are dissolved in deionized water, and after stirring, the product is collected and washed with ethanol; after drying in an oven, wine red powder L-FeOOH is obtained.

Description

Technical Field

[0001] The invention belongs to the technical field of preparation of water purification fillers, and in particular relates to a method for preparing a water purification filler with adsorption and photo-Fenton properties. Background Art

[0002] In recent years, up to 60% of natural rivers have been contaminated by antibiotics. Tetracycline hydrochloride (TC-HCl) is a readily available and inexpensive antibiotic widely used in healthcare, animal husbandry, and aquaculture. Due to its widespread use, TC-HCl inevitably seeps into natural ecosystems, prompting extensive research into environmental solutions. The photo-Fenton reaction is an advanced oxidation technology that eliminates organic pollutants such as antibiotics by decomposing hydrogen peroxide (H2O2) to produce hydroxyl radicals (·OH). This process is driven by photoelectrons and facilitated by photocatalysts through the establishment of an Fe(III) / Fe(II) cycle.

[0003] FeOOH is a narrow-bandgap semiconductor that exhibits excellent visible-light response and stability in heterogeneous photocatalysis. It is widely used in the photo-Fenton reaction due to its low cost, non-toxicity, and wide pH range. However, the photogenerated electron-hole pairs in FeOOH are prone to recombination, resulting in slow Fe(III) / Fe(II) conversion, which affects the pollutant degradation efficiency in practical applications.

[0004] Over the past few decades, metal-organic frameworks (MOFs) have emerged as the next generation of excellent solid-state porous crystalline materials. MIL-125 (Ti) is a Ti-MOF that has been widely used in a variety of fields, including adsorption, photocatalysis, electrode materials, and viral therapy. It possesses an ultrahigh surface area, large porosity, tunable structure, variable functionality, and multiple active sites, enabling photocatalytic reactions. This process can proceed spontaneously under illumination, making it a new generation of catalytic materials with self-cleaning properties. Summary of the Invention

[0005] The present invention aims to solve the above problems and provides a method for preparing a water purification filler with adsorption and photo-Fenton properties.

[0006] To achieve the above object, the present invention adopts the following technical solution, which includes the following steps:

[0007] Step 1) dissolving FeCl3·6H2O in deionized water, stirring to obtain a uniform orange solution, and then placing the solution in a reactor for hydrothermal treatment; after the reactor is naturally cooled to room temperature, the obtained product is washed with ethanol and deionized water to obtain a solid product;

[0008] Step 2) The product obtained in step 1) is dried in an oven to obtain a deep red powder material FeOOH; the obtained FeOOH and L-cysteine are dissolved in deionized water, stirred, collected and washed with ethanol; after drying in an oven, a wine red powder material L-FeOOH is obtained;

[0009] Step 3) The obtained L-FeOOH is mixed with N,N-dimethylformamide (DMF) and methanol under ultrasonic to obtain a uniform solution;

[0010] Step 4) Terephthalic acid is added to the solution obtained in step 3), and after stirring uniformly, tetrabutyl titanate is added dropwise;

[0011] Step 5) The solution obtained in step 4) is placed in a reaction kettle and hydrothermally treated; after washing the solid material obtained after hydrothermal treatment with ethanol, drying in an oven, a wine red powder material FeOOH / aMIL-125-0.3 is finally obtained.

[0012] As a preferred solution, the mass ratio of FeCl3·6H2O to deionized water in step 1) of the present application is 3:200.

[0013] As another preferred solution, the volume ratio of deionized water to the volume of the reaction kettle in step 1) of the present application is 2:5; which can better ensure the pressure during the hydrothermal reaction process to promote the synthesis of the material.

[0014] As another preferred solution, in step 1) of the present application, 0.5-0.6 g of FeCl3·6H2O is dissolved in 30-50 mL of deionized water, and a multi-head magnetic stirrer is used at a frequency of 30-35 Hz (preferably 33.33 Hz) to stir for 10-15 minutes; after obtaining a uniform orange solution, it is placed in a 90-120 mL reaction kettle and hydrothermally treated at 150-200℃ for 700-750 min; after the reaction kettle is naturally cooled to room temperature, the obtained product is centrifuged at a speed of 8000-9000 rpm for 3-5 minutes to wash with ethanol and deionized water respectively, to obtain a solid product. The frequency and stirring time of the magnetic stirrer can limit the degree of mixing and control the particle size of the catalyst. The magnetic stirrer can use a HJ-4 type magnetic stirrer. Centrifugal washing helps to wash and separate the solid-liquid, and a centrifuge (TG16) of 220V 60Hz can be used for centrifugal washing.

[0015] As another preferred solution, in step 2) of the present application, the mass ratio of FeOOH, L-cysteine and deionized water is 1:1:12.

[0016] When FeOO and L-cysteine are 1:1, the composite synthesis can be better, and when the solid material and deionized water are in a ratio of 1:12, it is helpful for the uniform dissolution of the solid.

[0017] As another preferred embodiment, in step 2) of the present invention, the product obtained in step 1) is placed in an oven at 60-80° C. and dried for 9-12 hours to obtain a dark red powder substance FeOOH; 0.3-0.5 g of FeOOH and 0.3-0.5 g of L-cysteine ​​are dissolved in 30-40 mL of deionized water, stirred for 20-30 hours, and then collected and washed with ethanol; after drying in an oven at 60-80° C. for 9-12 hours, a wine red powder substance L-FeOOH is obtained.

[0018] As another preferred embodiment, in step 3) of the present invention, the mass ratio of L-FeOOH, N,N-dimethylformamide and methanol is 1:120:14.

[0019] This ratio helps N,N-dimethylformamide and methanol to be mutually soluble and react well with L-FeOOH.

[0020] As another preferred embodiment, in step 3) of the present invention, 0.1 to 0.6 g of the obtained L-FeOOH is mixed with 35 to 40 mL of N,N-dimethylformamide and 3 to 5 mL of methanol, and ultrasonically cleaned (i.e., ultrasonically cleaned for mixing) at a frequency of 80 to 100 Hz for 10 to 15 minutes using an ultrasonic cleaner (Kunshan Shumei KQ2200 ultrasonic cleaner can be used) to obtain a uniform solution.

[0021] As another preferred embodiment, in step 4) of the present invention, the mass ratio of the solution obtained in step 3), terephthalic acid, and tetrabutyl titanate is 49:1:1.

[0022] This ratio facilitates the reaction of the solution obtained in step 3) with terephthalic acid and tetrabutyl titanate.

[0023] As another preferred embodiment, in step 4) of the present invention, 0.8-0.9 g of terephthalic acid is added to the solution obtained in step 3), and the mixture is stirred for 10-15 minutes using a multi-head magnetic stirrer at a frequency of 30-50 Hz (preferably 33.33 Hz). After uniform stirring, 0.8-1 mL of tetrabutyl titanate is added dropwise, and the mixture is stirred for 1-3 hours. A HJ-4 magnetic stirrer can be used. The frequency and stirring time of the magnetic stirrer can be used to control the degree of mixing and the catalyst particle size.

[0024] Secondly, in step 5) of the present invention, the ratio of the volume of the solution obtained in step 4) to the volume of the reactor is 1:25.

[0025] This ratio contributes to good pressurization in the hydrothermal reaction and facilitates the synthesis.

[0026] In addition, in step 5 of the present invention, the solution obtained in step 4) is placed in a 90-120 mL reactor and hydroheated at 140-160° C. for 700-730 min. The hydroheated substance is then washed with ethanol and dried in an oven at 80-90° C. for 10-12 h to obtain a wine-red powder substance FeOOH / aMIL-125.

[0027] The present invention has beneficial effects.

[0028] The present invention provides a method for preparing a hydrothermally synthesized FeOOH / aMIL-125 composite catalyst. The FeOOH / aMIL-125 water purification filler prepared using this method can combine photocatalysis with the Fenton reaction. The photocatalyst can continuously provide photogenerated electrons that combine with Fe ions in FeOOH, promoting the separation of electrons and holes and the Fe(III) / Fe(II) cycle in the Fenton reaction, thus exhibiting a self-cleaning function. Therefore, the practical application value of the FeOOH / aMIL-125 water purification filler is enhanced through the photo-Fenton reaction process.

[0029] In the steps 1) to 3) of the present invention, good adsorption performance is established by depositing FeOOH with L-cysteine.

[0030] The present invention composites amorphous MIL-125 and dopes FeOOH through steps 3) to 5), so that FeOOH / aMIL-125 has good photocatalytic and Fenton-like synergistic effects.

[0031] The present invention can control the doping amount of L-FeOOH by changing the addition amount, thereby regulating its size, structure and performance, thereby obtaining a catalyst with better H2O2 addition and pH conditions. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] The present invention is further described below with reference to the accompanying drawings and specific embodiments. The scope of protection of the present invention is not limited to the following description.

[0033] Figure 1 Schematic diagram of the preparation of the FeOOH / aMIL-125-0.3 composite photocatalyst of the present invention.

[0034] Figure 2 This is the SEM spectrum of FeOOH / aMIL-125-0.3 of the present invention.

[0035] Figure 3 The Tafel curves of FeOOH and aMIL-125 under light or no light conditions.

[0036] Figure 4 This is a diagram showing the degradation effect of TC-HCl by the FeOOH / aMIL-125-0.3 sample of the present invention.

[0037] Figure 5 This is a diagram showing the degradation effect of TC-HCl by FeOOH / aMIL-125-0.1 and FeOOH / aMIL-125-0.6 samples of the present invention.

[0038] Figure 6 Schematic diagram of the energy band structure of FeOOH / aMIL-125-0.3 and FeOOH.

[0039] Figure 7 This is the effect diagram of FeOOH / aMIL-125-0.3 degrading TC-HCl under different pH conditions.

[0040] Figure 8 This is the effect diagram of FeOOH / aMIL-125-0.3 degrading TC-HCl under different H2O2 addition amounts.

[0041] Figure 9 This is the SEM spectrum of FeOOH / aMIL-125-0.1 of the present invention.

[0042] Figure 10 This is the SEM spectrum of FeOOH / aMIL-125-0.6 of the present invention. DETAILED DESCRIPTION

[0043] Example

[0044] Step 1) Dissolve 0.59 g of FeCl₃·6H₂O in 40 mL of deionized water and stir to obtain an orange liquid. Place the liquid in a 100 mL reactor and heat at 180°C for 720 minutes. After cooling the reactor to room temperature, wash the resulting product with ethanol and deionized water to obtain a solid product.

[0045] Step 2) The product from step 1) was dried in a 70°C oven for 10 hours to obtain a deep red powder, FeOOH. 0.3 g of FeOOH and 0.3 g of L-cysteine ​​were dissolved in 35 mL of deionized water, stirred for 24 hours, and then collected and washed with ethanol. After drying in a 70°C oven for 10 hours, L-FeOOH was obtained as a wine-red powder.

[0046] Step 3) 0.3 g of the obtained L-FeOOH, 36 mL of N,N-dimethylformamide, and 4 mL of methanol were ultrasonically treated for 10 minutes to obtain a homogeneous solution.

[0047] Step 4) Add 0.83 g of terephthalic acid to the solution obtained in step 3), stir evenly, then add 0.9 mL of tetrabutyl titanate dropwise, and stir to react for 2 h.

[0048] Step 5) The solution obtained in step 4) was placed in a 100 mL reactor and hydroheated at 150°C for 720 min. The hydrothermal solution was then washed with ethanol and dried in an oven at 70°C to obtain a wine red powder FeOOH / aMIL-125-0.3. The preparation process of FeOOH / aMIL-125-0.3 of the present invention is as follows: Figure 1 shown. Figure 2 It can be seen that the synthesized material exhibits a core-shell structure, with the inner layer of FeOOH being small spheres and the outer layer being wrapped with flocculent aMIL-125. Example

[0049] Without FeOOH, DMF (36 mL) and methanol (4 mL) were ultrasonically stirred for 20 minutes to obtain a homogeneous solution. 0.83 g of terephthalic acid was then added to the solution, stirred thoroughly, and 0.9 mL of tetrabutyl titanate was added dropwise. The reaction was stirred for 2 hours. The resulting solution was placed in a 100 mL reactor and hydroheated at 150°C for 720 minutes. After washing with ethanol, the mixture was dried in an oven at 70°C for 10 hours to obtain a white powder, i.e., aMIL-125.

[0050] Figure 3 The Tafel curves of FeOOH and aMIL-125 under light or no light conditions are shown in Figure 2. Comparing the two conditions in the dark and the light, it can be seen that the potential of FeOOH in the dark is lower than that of aMIL-125, indicating that electrons flow from FeOOH to aMIL-125. 2+ Converted to Fe 3+ And Ti 4+ Transformed into Ti 3+ After adding light, the redox potential of aMIL-125 shifted to a more negative direction, while FeOOH shifted to a more positive direction under light, indicating that light caused electrons to flow from aMIL-125 to FeOOH. Therefore, after the composite, the Fe required for the Fenton reaction can be obtained by light. 2+ ions and promotes Fe 2+ / Fe 3+ The photo-Fenton catalytic activity was enhanced by the cyclic process. This interfacial current transfer and reversal between FeOOH and aMIL-125 under visible light irradiation indicates that the conduction band electrons of FeOOH combine with the valence band holes of aMIL-125, confirming the existence of a Z-type heterojunction.

[0051] Take 0.3 g of FeOOH / aMIL-125-0.3 and add it to 100 mL of TC-HCl (20 mg / L) aqueous solution (20 mg / L means that 1 L of TC-HCl aqueous solution contains 20 mg of TC-HCl), and stir in the dark for the first 30 min to reach adsorption equilibrium. Then, under light conditions, 50 μL of H2O2 is added to the solution for degradation testing. Under the dark condition (i.e. no light) for the first 30 min, the concentration of TC-HCl in the drinking water treated by the FeOOH / aMIL-125-0.3 material decreases significantly, showing a strong adsorption effect. And after the light is added (light condition), the excellent photo-Fenton performance is exhibited (as shown in Figure 4 , further degradation is completed only after the light and H2O2 are added), and 88% of TC-HCl is degraded within 60 min (60 min under light condition after the first 30 min of stirring in the dark to reach adsorption equilibrium). Figure 4 Figure 4 The light condition means that external natural light is added, and the dark condition means that no external natural light is added.

[0052] Figure 4 The ordinate is C0 / C, i.e. the ratio of the initial concentration of the organic pollutant TC-HCl in the degradation experiment to the concentration after the reaction, which indicates the degradation efficiency of the catalyst. Examples

[0053] The amount of L-FeOOH in step 3) in Example 1 is reduced to 0.1 g or increased to 0.6 g, respectively, and then mixed with DMF (36 mL) and methanol (4 mL) to repeat the above experiment, obtaining two control materials FeOOH / aMIL-125-0.1 or FeOOH / aMIL-125-0.6. Take 20 mg (Example 2 is the synthesis process, and 0.3 g of FeOOH / aMIL-125-0.3 is taken. Example 3 is used for photo-Fenton reaction performance testing, and 20 mg of FeOOH / aMIL-125-0.1 or FeOOH / aMIL-125-0.6 is taken) of FeOOH / aMIL-125-0.1 or FeOOH / aMIL-125-0.6, and add it to 100 mL of TC-HCl (20 mg / L) solution, and stir in the dark for 30 min to reach adsorption equilibrium. Then, under light conditions, 50 μL of H2O2 is added to the solution for degradation testing.

[0054] As Figure 5 ​It can be seen that FeOOH / aMIL-125-0.1 and FeOOH / aMIL-125-0.6 also showed adsorption degradation in the first 30 minutes and photo-Fenton degradation in the last 60 minutes (the whole reaction was an adsorption equilibrium reaction in the dark without light for the first 30 minutes, and a photo-Fenton reaction of the catalyst on TC-HCl under light and H2O2 addition after 30 minutes of reaction). The degradation efficiency of the two was 63% and 82%, respectively, which were lower than that of FeOOH / aMIL-125-0.3, indicating that FeOOH / aMIL-125-0.3 had the highest adsorption and photo-Fenton degradation efficiency for the organic pollutant TC-HCl in water and the best catalytic activity.

[0055] contrast Figure 6 It can be seen that the band gap of FeOOH / aMIL-125-0.3 is significantly smaller than that of FeOOH. This indicates that the recombination efficiency of photogenerated electrons and holes in FeOOH / aMIL-125-0.3 is low, indicating that the composite of aMIL-125 and FeOOH is not only an important active site for the photo-Fenton reaction, but also effectively inhibits the rapid recombination of electrons and holes in the catalyst, thereby improving the photocatalytic performance. Example

[0056] The sample of Example 1 was subjected to a TC-HCl degradation experiment at different pH values ​​and different H2O2 addition amounts. Figure 7 As shown in the figure, the degradation efficiency of the sample increases first and then decreases in the pH range of 3 to 11, indicating that the FeOOH / aMIL-125-0.3 of the present invention has the best performance when it is neutral (i.e., pH 7). Figure 8 As shown in the figure, when the amount of H2O2 added increased from 30 μL to 100 μL, the degradation rate changed from high to low, and the performance was best at 50 μL, indicating that FeOOH / aMIL-125-0.3 has a good pH application range and a lower H2O2 dosage, so the present invention has better practical application value.

[0057] Comparative Example 1

[0058] The 0.3 g of L-FeOOH in step 3) of Example 1 was replaced with 0.1 g of L-FeOOH or 0.6 g of L-FeOOH, while the other steps and material amounts remained unchanged, to obtain FeOOH / aMIL-125-0.1 or FeOOH / aMIL-125-0.6.

[0059] The morphology of the material changed significantly after changing the amount of L-FeOOH added, such as Figure 9 As shown in Figure 2, the shape of the FeOOH / aMIL-125-0.1 pellet is more obvious and the particles attached to the pellet are relatively sparse. Figure 10 As shown, the FeOOH / aMIL-125-0.6 small ball has more attachments, and even forms a network connection between each small ball. The change of the ratio of the small ball and the flocculation corresponds to the change of the ratio of FeOOH and aMIL-125, and when the ratio is 1:1 and 1:5, the degradation performance is not as good as the adsorption and photo-Fenton performance of FeOOH / aMIL-125-0.3 in the present application.

[0060] It can be understood that the above specific description of the present application is only used to illustrate the present application and is not limited to the technical solutions described in the embodiments of the present application. Those skilled in the art should understand that the present application can still be modified or replaced equivalently to achieve the same technical effect; as long as the use needs are met, it is within the protection scope of the present application.

Claims

1. Application of a water purification filler in the adsorption and photo-Fenton degradation of the organic pollutant TC-HCl, characterized by: Weigh 0.3 g of FeOOH / aMIL-125-0.3 and add it to 100 mL of 20 mg / L TC-HCl aqueous solution. After stirring in the dark for 30 min to reach adsorption equilibrium, 50 μL of H2O2 was added to the solution under light conditions for degradation test. The pH value of the degradation reaction system is 7; The preparation method of the FeOOH / aMIL-125-0.3 is: Step 1) Dissolve 0.59 g of FeCl3·6H2O in 40 mL of deionized water, stir to obtain an orange liquid, and place in a 100 mL reactor and hydroheat at 180°C for 720 min; after the reactor is naturally cooled to room temperature, wash the resulting product with ethanol and deionized water to obtain a solid product; Step 2) The product obtained in step 1) was placed in a 70°C oven and dried for 10 hours to obtain a dark red powder, namely FeOOH; 0.3 g of the obtained FeOOH and 0.3 g of L-cysteine ​​were dissolved in 35 mL of deionized water, stirred for 24 hours, collected, and washed with ethanol; after drying in a 70°C oven for 10 hours, a wine-red powder, L-FeOOH, was obtained; Step 3) 0.3 g of the obtained L-FeOOH, 36 mL of N,N-dimethylformamide, and 4 mL of methanol were ultrasonically treated for 10 minutes to obtain a homogeneous solution; Step 4) Add 0.83 g of terephthalic acid to the solution obtained in step 3), stir evenly, then dropwise add 0.9 mL of tetrabutyl titanate, and stir to react for 2 h; Step 5) The solution obtained in step 4) was placed in a 100 mL reactor and hydroheated at 150°C for 720 min. The hydroheated solution was then washed with ethanol and dried in an oven at 70°C to obtain a wine-red powder FeOOH / aMIL-125-0.3.

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