A method for preparing materials for a self-circulating photocatalytic Fenton system

Abstract

This invention discloses a material preparation method for a self-circulating photocatalytic Fenton system, which does not require the additional addition of H2O2 and Fe. 3+ Both are entirely provided or generated by the catalyst itself. This invention relates to the field of oxidation process technology, and is composed of the following materials: MnCl2·4H2O, thiourea, and foam-like metal materials (foamed nickel, foamed iron-nickel, foamed copper, foamed titanium, etc.). MnS nanosheets are synthesized on the surface of a metal foam substrate, and the metal elements in the foam substrate are used to supply metal ions for the Fenton reaction. This material for a self-circulating photocatalytic Fenton system achieved COD removal rates of 46.3% and 81.4% (under sunlight) for two actual wastewater samples. Simultaneously, the water samples after the reaction were clearer, demonstrating good environmental and economic benefits. The preparation method of this process is simple, the material is magnetic and easy to separate, and it not only opens up a new avenue for the use of 3D magnetic heterojunction materials in self-circulating photocatalytic Fenton systems.

Description

Technical Field

[0001] This invention relates to the field of oxidation process technology, specifically to a material preparation method for a self-circulating photocatalytic Fenton system. Background Technology

[0002] Water pollution is becoming increasingly serious, drawing global attention and creating a widespread demand for clean water. Large amounts of organic pollutants and industrial wastewater are discharged into rivers, significantly increasing the accumulation of pollutants in the aquatic environment and jeopardizing water resource security. Fenton technology, as an advanced oxidation process (AOP), has received widespread attention in the field of environmental remediation. This technology utilizes the highly oxidizing ·OH free radicals generated by the Fenton reaction to effectively degrade organic pollutants. However, the large-scale application of Fenton technology also has many drawbacks, such as the need for the additional addition of H2O2 or Fe. 2+ Iron ions are difficult to recycle and can lead to problems such as iron-containing sludge. Therefore, to avoid these problems, researchers have begun to focus on exploring novel Fenton technologies that do not weaken oxidation activity without the external addition of H2O2 or iron salts.

[0003] On the other hand, solar energy is an abundant renewable resource with the potential to replace all total energy supply. Heterogeneous Fenton systems utilize easily separable and recyclable heterogeneous catalysts, broadening the applicable pH range and significantly reducing iron sludge production, effectively overcoming many shortcomings of homogeneous Fenton systems, and are currently a research hotspot in the field of water pollution control chemistry. Zhu et al. proposed a photocatalytic self-Fenton system by coupling photocatalysis with Fenton technology. To date, many strategies have been dedicated to constructing photocatalytic self-Fenton systems. For example, using rosette-shaped g-C3N4 materials with carbon defects can generate H2O2 in situ to degrade pollutants. Subsequently, scientists successfully prepared red mud / cadmium sulfide S-type heterojunction materials on the surface of CdS nanospheres for photocatalytic self-Fenton systems. This system can generate H2O2 in situ and simultaneously activate H2O2 to generate hydroxyl radicals (·OH) active substances, which can efficiently degrade amoxicillin antibiotic pollutants under visible light irradiation. However, these reports are mostly about g-C3N4 and its modifications and composites, and all require the addition of iron salts.

[0004] Some phenol degradation products that do not require the addition of iron salts, however, do require the addition of H2O2, persulfate (S2O8), etc. For example, Zhu Yongfa et al. successfully prepared a core-shell BiOCl@Fe-BiOCl nanosheet material and used it as a catalyst for the self-Fenton reaction to promote the degradation of phenol. With the addition of a certain amount of H2O2, this catalyst exhibited good performance in degrading phenol. Furthermore, Xu Yan et al. prepared Fe2O3 / BiVO4 nanocomposite materials via a one-pot hydrothermal method. This material, in the presence of H2O2 (added separately), can rapidly degrade methylene blue and rhodamine B dye molecules, exhibiting excellent photo-Fenton catalytic activity. Gan Tao et al. synthesized starch-coated Fe3O4 (Fe3O4@SC) magnetic nanocomposite materials using cassava starch as a carbon source, employing a combination of mechanical activation treatment and high-temperature pyrolysis. With the addition of H2O2, Fe3O4@SC exhibited excellent catalytic performance and good stability against tetracycline hydrochloride. In addition, studies have found that carbon-coated Fe3O4 materials exhibit good degradation performance of tetracycline under persulfate (PS) and light irradiation conditions.

[0005] Currently, a self-circulating photoelectric Fenton system based on artificial blades has been reported. Through optimized photoanode and cathode coupling, the H2O2 yield of the artificial blades reaches 0.77 μmol / (min cm⁻¹). 2 Subsequently, a novel BIO / Fe... III Piezoelectric catalytic self-Fenton system exhibits strong oxidizing ability for pollutants. Studies have found that the addition of Fe(III) not only provides a continuous supply of Fe(II) for the Fenton reaction but also promotes the generation of H2O2 in water, both of which significantly enhance Fenton degradation performance. Melamine foam / polyaniline / N,O,P covalent organic polymer photocatalysts have also been developed for in-situ H2O2 generation, promoting the Fe(II) / Fe(III) cycle and thus degrading high-color wastewater. Currently, the preparation and application of photocatalytic self-Fenton materials include: ① A photocatalytic self-Fenton catalyst and its preparation method and application (Publication No.: CN202310361353.3); ② A photocatalytic self-Fenton water treatment method based on S, K co-doped g-C3N4 nanosheets (Publication No.: CN202310957069.2); ③ A photocatalytic self-Fenton water treatment method based on cobalt iron oxide / polyperylimide supramolecular (CN202310065794.9); ④ An in-situ photocatalytic H2O2 production self-Fenton pollutant degradation device (CN202310053797.0). To date, no reports have been found of a self-circulating photocatalytic Fenton system that does not require the addition of H2O2 or iron salts without weakening its oxidation activity under the influence of external fields such as electricity or ultrasound.

[0006] Three-dimensional (3D) nickel-iron-nickel composites are magnetic three-dimensional structural materials with abundant active sites, excellent mechanical strength, and high specific surface area, making them widely used in electrocatalysis, catalysis, and energy storage. Manganese sulfide (MnS), a typical wide-gap p-type semiconductor (Eg = 3.1-3.7 eV), has been reported to form pn heterojunctions with other nanomaterials and be applied in photocatalysis. Based on this, we synthesized MnS / INF materials for a self-circulating photocatalytic Fenton system. The three-dimensional Z-type MnS / INF heterojunction material not only overcomes the secondary pollution problem caused by catalyst separation difficulties but also eliminates the need for additional H2O2 and Fe in the Fenton reaction. 2+ Under visible light irradiation, H2O2 is generated in situ and rapidly degrades the organic dye Rhodamine B (RhB). At pH=7, the degradation rate of RhB (10.0 mg / L) is nearly 100% within 7 minutes, which far exceeds the degradation rate of related systems reported in the literature. Simultaneously, the MnS / INF material can also be used to treat fluorinated nitrobenzene wastewater and wastewater from school sewage treatment plants, exhibiting excellent degradation performance. This invention provides a new approach for further developing a magnetically separable, highly efficient, self-circulating photocatalytic Fenton system with a three-dimensional Z-shaped heterostructure, which can degrade without the need for external H2O2 and Fe. 2+ This study provides a new strategy for the Fenton process and promotes the further development of self-circulating photocatalytic Fenton systems, thereby reducing the generation and accumulation of iron-containing sludge. Summary of the Invention

[0007] To achieve the above objectives, the present invention is implemented through the following technical solution: a material for a self-circulating photocatalytic Fenton system, comprising the following materials: MnCl2·4H2O, thiourea, and foam-like metal materials.

[0008] Preferably, the composition consists of 2 parts by mass of MnCl2·4H2O, 2 parts by mass of thiourea, and 2000 parts by mass of deionized water.

[0009] A method for preparing materials for a self-circulating photocatalytic Fenton system includes the following steps:

[0010] Step 1: Weigh a fixed amount of MnCl2·4H2O and put it into a polytetrafluoroethylene reaction vessel. Add deionized water and stir. This solution is labeled as solution A.

[0011] Step 2: Weigh a certain amount of thiourea and add it to solution A, then stir. This solution is called solution B.

[0012] Step 3: Place the cleaned foamed iron-nickel into solution B, sonicate for a certain time, and record this as mixture C;

[0013] Step 4: Process mixture C through methods such as mixing, settling, preheating, gradient heating, hydrothermal reaction, or a combination of the above methods.

[0014] Step 5: Allow the treated C mixture to cool to room temperature, remove it, wash it with a cleaning solution, and dehydrate it for later use.

[0015] Preferably, the oven heating temperature in step four is 120℃~180℃, and the oven heating time is 0.5~5 hours.

[0016] Preferably, in step five, the washing is performed several times with ultrapure water and ethanol.

[0017] Preferably, the dehydration method is natural air drying.

[0018] Preferably, steps one, two, three, and five are all performed at room temperature.

[0019] Preferably, this material used in self-circulating photocatalytic Fenton systems is applied for the degradation of organic pollutants.

[0020] This catalyst can also be used for the photodegradation of fluorinated nitrobenzene wastewater and organic pollutant wastewater from school sewage treatment plants, achieving COD removal rates of 46.3% and 81.4% (under sunlight), respectively. Simultaneously, the water samples after the reaction are clearer, demonstrating good environmental and economic benefits. The preparation method is simple, the material is magnetic and easily separated, opening a new avenue for the use of 3D magnetic heterostructure materials in self-circulating photocatalytic Fenton systems. It also promotes the possibility of MnS / INF becoming a practical wastewater purification method and being applied in other fields, using a simple method with water as a solvent. MnS nanosheet materials were synthesized on a foamed iron-nickel substrate; this material can both produce hydrogen peroxide and provide an iron source, exhibiting excellent self-circulating photocatalytic self-Fenton performance.

[0021] This invention provides a material for a self-circulating photocatalytic Fenton system. The beneficial effects of this invention are: the catalyst can also be used for the photodegradation of fluorinated nitrobenzene wastewater and organic pollutant wastewater from school sewage treatment plants, achieving COD removal rates of 46.3% and 81.4% (under sunlight) for the two types of water, respectively. Simultaneously, the water samples after the reaction are clearer, demonstrating good environmental and economic benefits.

[0022] In summary, compared with the prior art, the present invention has the following technical effects: the preparation method of the material is simple, the material is magnetic and easy to separate, which not only opens up a new way for 3D magnetic heterojunction materials to be used in self-circulating photocatalytic Fenton systems, but also promotes the possibility of MnS / INF becoming a practical wastewater purification method and being applied in other fields. Attached Figure Description

[0023] Figure 1The attached figures show the XRD and TEM images of the MnS / INF material prepared according to the present invention;

[0024] Figure 2 The attached figure shows SEM images of MnS / INF materials prepared at different temperatures (150℃, 160℃, 170℃, 180℃, 190℃, and 200℃, respectively) obtained in accordance with the present invention.

[0025] Figure 3 The attached image is as follows:

[0026] (a) Photograph of the MnS / INF catalyst (magnetic);

[0027] (b) Photographs of RhB after 9 degradation cycles;

[0028] (c) XRD pattern of MnS / INF catalyst after nine reactions;

[0029] (d) Scanning electron micrograph of the MnS / INF catalyst after nine reactions.

[0030] Figure 4 The attached image is as follows:

[0031] (a) Self-Fenton degradation of RhB within 5 min;

[0032] (b) Plot of first-order kinetic constants for RhB degradation;

[0033] (c) Cyclic stability of the MnS / INF catalyst;

[0034] (d) Wettability diagrams after two cycles of INF, MnS / INF pre-reaction and MnS / INF;

[0035] (e) Performance diagram of photocatalytic degradation of nitrobenzene wastewater and school wastewater by MnS / INF catalyst;

[0036] (f) Schematic diagram of a small-scale reactor for continuous degradation. Detailed Implementation

[0037] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments. The embodiments of the present invention are given for illustrative and descriptive purposes only, and are not intended to be exhaustive or to limit the invention to the forms disclosed. Many modifications and variations will be apparent to those skilled in the art. The embodiments were chosen and described to better illustrate the principles and practical application of the invention, and to enable those skilled in the art to understand the invention and design various embodiments with various modifications suitable for a particular purpose.

[0038] See Figure 1-4 The present invention provides a technical solution:

[0039] A material for a self-circulating photocatalytic Fenton system comprises: 2 parts by mass of MnCl2·4H2O, 2 parts by mass of thiourea, and 2000 parts by mass of deionized water.

[0040] A method for preparing a self-circulating photo-Fenton catalytic material includes the following steps:

[0041] Step 1: Weigh a fixed amount of MnCl2·4H2O and put it into a polytetrafluoroethylene reaction vessel. Add deionized water and stir. This solution is labeled as solution A.

[0042] Step 2: Weigh a certain amount of thiourea and add it to solution A, then stir. This solution is called solution B.

[0043] Step 3: Cut the two cleaned pieces of foamed iron-nickel into pieces, place the cut pieces of foamed iron-nickel into solution B, sonicate for a certain time, and record this as mixture C.

[0044] Step 4: Transfer mixture C into an oven and heat.

[0045] Step 5: Remove the heated C mixture from the reactor after it has cooled to room temperature, wash it with ultrapure water and ethanol, and let it air dry for later use.

[0046] In step four, the oven heating temperature is 120℃~180℃, and the oven heating time is 0.5~5 hours.

[0047] In step five, the device is washed several times with ultrapure water and ethanol.

[0048] Steps one, two, three, and five are all performed at room temperature.

[0049] This self-circulating photo-Fenton catalytic material is used for the degradation of organic pollutants.

[0050] This catalyst can also be used for the photodegradation of fluorinated nitrobenzene wastewater and organic pollutant wastewater from school sewage treatment plants, achieving COD removal rates of 46.3% and 81.4% (under sunlight), respectively. Simultaneously, the water samples after the reaction are clearer, demonstrating good environmental and economic benefits. The preparation method is simple, the material is magnetic and easily separated, opening a new avenue for the use of 3D magnetic heterostructure materials in self-circulating photocatalytic Fenton systems. It also promotes the possibility of MnS / INF becoming a practical wastewater purification method and being applied in other fields, using a simple method with water as a solvent. MnS nanosheet materials were synthesized on a foamed iron-nickel substrate; this material can both produce hydrogen peroxide and provide an iron source, exhibiting excellent self-circulating photocatalytic self-Fenton performance.

[0051] This invention provides a material for a self-circulating photocatalytic Fenton system. The beneficial effects of this invention are: the catalyst can also be used for the photodegradation of fluorinated nitrobenzene wastewater and organic pollutant wastewater from school sewage treatment plants, achieving COD removal rates of 46.3% and 81.4% (under sunlight) for the two types of water, respectively. Simultaneously, the water samples after the reaction are clearer, demonstrating good environmental and economic benefits.

[0052] In summary, compared with the prior art, the present invention has the following technical effects: the preparation method of the material is simple, the material is magnetic and easy to separate, which not only opens up a new way for 3D magnetic heterojunction materials to be used in self-circulating photocatalytic Fenton systems, but also promotes the possibility of MnS / INF becoming a practical wastewater purification method and being applied in other fields.

[0053] Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. All other embodiments obtained by those skilled in the art and related fields based on the embodiments of the present invention without inventive effort should fall within the scope of protection of the present invention. Structures, devices, and operating methods not specifically described and explained in the present invention, unless otherwise specified or limited, shall be implemented according to conventional means in the art.

Claims

1. A method for preparing materials for a self-circulating photocatalytic Fenton system, characterized in that: In this self-circulating photocatalytic Fenton system, no external H2O2 is required; H2O2 can be generated in situ on the material. Furthermore, no additional iron ions need to be added externally; the metal ions are provided by the foamed metal substrate, and iron will spontaneously form Fe in the system. 2+ and Fe 3+ The transformation cycle; The preparation method includes the following steps: Step 1: Weigh out MnCl2·4H2O and put it into the reaction vessel. Add water and stir. This solution is called solution A. Step 2: Weigh out thiourea, add it to solution A and stir; this is called solution B. Step 3: Place the cleaned foamed iron-nickel into solution B, and after ultrasonic treatment, label it mixture C. Step 4: The C mixture is subjected to one or more combined processes, including mixing, settling, preheating, gradient heating, and hydrothermal reaction. Step 5: After the heated C mixture has cooled, remove it, wash it several times with cleaning solution, and dehydrate it for later use.

2. The method according to claim 1, characterized in that: Step 1: MnS material was successfully synthesized on the surface of the foam substrate through a reaction.

3. The method according to claim 1, characterized in that: The cleaning solution in step five consists of one or more of water, ethanol, and methanol.

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