A molybdenum disulfide substrate-anchored iron monatomic catalyst and a preparation method thereof

Abstract

The application belongs to the field of environmental functional materials and water treatment technology, and particularly relates to a molybdenum disulfide-based substrate-anchored iron monatomic catalyst and a preparation method thereof, and application of the catalyst in activating peroxymonosulfate (PMS) for degrading antibiotics (such as sulfamethoxazole) and / or refractory organic pollutants in water. x The Fe / MoS2-D-PA monatomic catalytic material realizes directional and extremely fast activation of PMS by constructing highly dispersed iron (Fe) monatomic active centers on the surface of the material. The efficient non-radical oxidation path constructed between the Fe active site and PMS exhibits high degradation efficiency for SMX in water. The catalytic system provided by the application is simple to operate, has good stability, and is strong in broad-spectrum applicability, and has a wide application prospect in the field of industrial antibiotic wastewater treatment.

Description

Technical Field

[0001] This invention belongs to the field of environmental functional materials and water treatment technology, specifically relating to a molybdenum disulfide-based anchored iron single-atom catalyst and its preparation method, as well as the application of using the catalyst to activate persulfate (PMS) in the degradation of antibiotics (e.g., sulfamethoxazole (SMX)) and / or recalcitrant organic pollutants in water. Background Technology

[0002] As is well known, the residue and diffusion of emerging pollutants (especially antibiotics) in the aquatic environment has become a global environmental problem. Sulfamethoxazole (SMX), a widely used sulfonamide antibiotic, is chemically stable and poorly biodegradable, making it highly prone to accumulation in natural water bodies, medical wastewater, and pharmaceutical wastewater. It can bioaccumulate through the food chain, posing a serious threat to human health and aquatic ecosystems. Therefore, developing green and efficient water treatment strategies or technologies is crucial.

[0003] Advanced oxidation processes (AOPs), especially persulfate (PMS)-based sulfate radical advanced oxidation technology (SR-AOPs), are beneficial because they generate highly oxidizing sulfate radicals (SO4). ·- PMS, along with other reactive oxygen species (ROS), has attracted much attention for the removal of recalcitrant organic pollutants. However, PMS itself is relatively stable and requires highly efficient catalysts for activation to rapidly generate reactive species.

[0004] Single-atom catalysts (SACs) anchor metal atoms in an atomically dispersed manner on a support through strong ligand bonds, making each metal atom a potential active site. Compared to traditional metal nanoparticle catalysts, SACs significantly improve atom utilization, catalytic activity, and stability, while effectively avoiding metal aggregation and metal ion loss. However, single-atom catalysts are prone to metal atom aggregation into nanoparticles during preparation. Achieving stable single-atom dispersion of metal atoms on the support surface under mild conditions is a key problem that urgently needs to be solved in the field of single-atom catalysis.

[0005] Transition metal chalcogenides, especially molybdenum disulfide (MoS2), are widely recognized as ideal single-atom support substrates due to their abundant edge active sites, excellent chemical stability, and tunable semiconductor electronic structure. However, the preparation of existing MoS2-based single-atom catalysts often relies on complex multi-step processes or harsh reducing atmospheres, and the interaction between the metal precursor and the support is weak, resulting in unsatisfactory anchoring effects and a high tendency for metal agglomeration, making it difficult to achieve large-scale, stable, and controllable single-atom-level dispersion.

[0006] D-penicillamine (D-PA), also known as β,β-dimethyl-D-cysteine, has the molecular formula C5H10H2O. 11 NO2S, containing three functional groups—thiol (-SH), carboxyl (-COOH), and amino (-NH2)—is a highly promising polydentate ligand. Its β-dimethyl structure endows it with stronger steric hindrance and metal chelating capabilities than cysteine, enabling more stable anchoring of metal ions and effectively inhibiting the aggregation of metal atoms during synthesis.

[0007] The existing technology has the following problems: 1. Simple MoS2 system: Although MoS2 has abundant surface functional groups, its activation ability for PMS is limited. Without the application of external energy (such as light or electricity), its degradation efficiency for structurally stable organic pollutants such as SMX needs to be improved.

[0008] 2. Traditional metal ion / nanoparticle catalytic system: Traditional homogeneous Fe 2+ / Fe 3+ When ion or Fe-based nanoparticle catalysts are used to activate PMS, problems such as metal ion loss, easy shielding of active sites, and great influence from the background composition of water bodies often occur, and secondary pollution is easily introduced.

[0009] 3. Controllable preparation of MoS2-based single-atom catalysts: The preparation of existing MoS2-based single-atom catalysts mostly relies on complex multi-step processes or harsh reaction conditions, and it is difficult to avoid the aggregation of metal atoms. There is still considerable room for improvement in the controllable adjustment of single-atom dispersion and catalytic activity. Summary of the Invention

[0010] The core objective of this invention is to provide a single-atom catalyst (Fe) that uses molybdenum disulfide (MoS2) as a substrate, D-penicillamine (D-PA) as a sulfur source / reducing agent / chelating ligand, and achieves atomic-level dispersion and anchoring of iron single atoms on a MoS2 nanosheet substrate via a one-step hydrothermal method. x The catalyst, MoS2-D-PA, was used to efficiently activate persulfate (PMS) in the degradation of antibiotics and / or recalcitrant organic pollutants.

[0011] To achieve the above-mentioned technical objectives, the present invention adopts the following technical solution: A method for preparing a molybdenum disulfide-based anchored iron single-atom catalyst includes the following steps: (I) Preparation of iron-ligand complex solution 1) Dissolve D-penicillamine (D-PA) in a first solvent to obtain a D-PA solution; add an aqueous solution of ferric nitrate to the D-PA solution and stir continuously at room temperature for 20-40 min to allow the iron ions to fully complex with D-PA to obtain an iron-D-PA complex solution; (II) Preparation of molybdenum precursor solution 2) Dissolve sodium molybdate dihydrate (Na2MoO4·2H2O) in the first solvent to obtain a molybdenum precursor solution; adjust the pH of the molybdenum precursor solution to 5.5~7.5 with an acid adjuster; (iii) Fe x One-step hydrothermal synthesis of / MoS2-D-PA single-atom catalyst 3) Mix the iron-D-PA complex solution obtained in step 1) with the molybdenum precursor solution obtained in step 2) to obtain a homogeneous mixture; 4) Transfer the homogeneous mixture from step 3) to a reaction vessel and hydrothermally react at 180–220 °C for 24–48 h. After the reaction is complete, allow it to cool naturally to room temperature, centrifuge, collect the precipitate, wash, dry, and grind to obtain the molybdenum disulfide-based anchored iron single-atom catalyst Fe. x / MoS2-D-PA; where the subscript x represents the exact mass (mg) of Fe element introduced during the synthesis process, and its value ranges from 5 to 30.

[0012] Furthermore, the first solvent is any one of deionized water, ultrapure water, and distilled water.

[0013] Furthermore, the acid regulator is any one of dilute hydrochloric acid, dilute sulfuric acid, and dilute nitric acid.

[0014] Furthermore, in step 1), the ratio of D-penicillamine (D-PA) to the first solvent is (0.02~0.03) g: 1 mL, preferably (1.0~1.5) g: 50 mL.

[0015] Furthermore, in step 1), the mass concentration of the ferric nitrate aqueous solution is 0.08~0.12 g / mL.

[0016] Furthermore, in step 1), the volume of the added ferric nitrate aqueous solution is 850~1600µL.

[0017] Furthermore, in step 4), the molybdenum disulfide substrate anchors the iron single-atom catalyst Fe. x The precise mass x of Fe introduced in / MoS2-D-PA ranges from 5 to 30 mg, preferably from 12 to 21 mg.

[0018] Further preferably, in step 4), the molybdenum disulfide substrate anchored iron single-atom catalyst Fex The precise mass x of Fe introduced in / MoS2-D-PA is 12, 15, 18 or 21 mg, which correspond to the volumes of ferric nitrate aqueous solution (concentration of 0.1 g / mL) added in step 1) being 880, 1100, 1320 and 1540 µL, respectively.

[0019] Furthermore, in step 2), the ratio of sodium molybdate dihydrate (Na2MoO4·2H2O) to the first solvent is (0.008~0.012) g : 1 mL, preferably (0.40~0.60) g : 50 mL.

[0020] Furthermore, in step 2), the pH value of the molybdenum precursor solution is adjusted to 6.0~7.0, preferably 6.5.

[0021] Furthermore, in step 3), the iron-D-PA complex solution and the molybdenum precursor solution are mixed by adding the molybdenum precursor solution dropwise to the iron-D-PA complex solution under vigorous stirring conditions, or by adding the iron-D-PA complex solution dropwise to the molybdenum precursor solution; the volume ratio of the iron-D-PA complex solution to the molybdenum precursor solution is approximately 1:1.

[0022] Furthermore, in step 4), the temperature of the hydrothermal reaction is 190~210℃, preferably 200℃.

[0023] Furthermore, in step 4), the hydrothermal reaction time is 30-42 h, preferably 36 h.

[0024] Furthermore, in step 4), the centrifugation speed is 8000~12000 rpm and the centrifugation time is 15~45 min; preferably, the centrifugation speed is 10000 rpm and the centrifugation time is 30 min.

[0025] Furthermore, in step 4), the washing process involves alternating or separate washing with deionized water and anhydrous ethanol, for a total of 3 to 6 washes.

[0026] Furthermore, in step 4), the drying is vacuum drying, the drying temperature is 50~70℃, and the drying time is 4~10h; preferably, the drying temperature is 60℃ and the drying time is 6h.

[0027] Furthermore, in steps 1) and 2), the D-PA simultaneously acts as a sulfur source, a reducing agent, and a metal (Fe) chelating ligand in the reaction system.

[0028] Furthermore, the present invention also provides a molybdenum disulfide substrate-anchored iron single-atom catalyst Fe prepared by the above method.x / MoS2-D-PA. Specifically, the above method utilizes the multidentate coordination of D-PA and the steric hindrance effect of β-dimethyl groups to achieve atomic-level dispersion and anchoring of Fe single atoms during the in-situ growth of MoS2 nanoflowers, ultimately producing a molybdenum disulfide substrate-anchored Fe single-atom catalyst. x / MoS2-D-PA.

[0029] Furthermore, based on a general inventive concept, the present invention also provides the molybdenum disulfide substrate-anchored iron single-atom catalyst Fe. x Application of / MoS2-D-PA in the degradation of pollutants in water bodies.

[0030] Furthermore, based on a general inventive concept, the present invention also provides the molybdenum disulfide substrate-anchored iron single-atom catalyst Fe. x Application of / MoS2-D-PA in the degradation of water pollutants by activating PMS oxidant.

[0031] Furthermore, based on a general inventive concept, the present invention also provides a Fe x The / MoS2-D-PA / PMS oxidant water pollutant degradation reaction system includes the molybdenum disulfide substrate anchored iron single-atom catalyst Fe. x / MoS2-D-PA and PMS oxidants.

[0032] Specifically, molybdenum disulfide substrate anchored iron single-atom catalyst Fe x The mass ratio of MoS2-D-PA to PMS oxidant is 1:(0.2~6.5), preferably 1:(0.26~6.15).

[0033] Furthermore, based on a general inventive concept, the present invention also provides the Fe x Application of the / MoS2-D-PA / PMS oxidant water pollutant degradation reaction system in catalytic degradation of water pollutants.

[0034] Specifically, the contaminants are one or more of antibiotics, anti-inflammatory drugs, phenolic compounds, and organic dyes.

[0035] Preferably, the contaminant is one or more of the following: nonsteroidal contaminants, bisphenol contaminants, sulfonamides, fluoroquinolones, and organic dyes.

[0036] More preferably, the contaminant is one or more of sulfamethoxazole (SMX), sulfadiazine (SDZ), sulfisoxazole (SIZ), sulfamethoxazole (SMR), sulfamethoxazole (SMT), sulfapyridine (SPD), carbamazepine (CBZ), bisphenol A (BPA), bisphenol B (BPB), diclofenac (DCF), indomethacin (IDM), naproxen (NPX), and ciprofloxacin (CIP).

[0037] More preferably, the organic dye is one or more of Rhodamine B (RhB), Methylene Blue (MB), Basic Fuchs Red (BF), Malachite Green (MG), Bengal Rose Red (RB), Acid Chrome Blue K (ACBK), and Naphthol Green B (NGB).

[0038] Specifically, the water body is one or more of the following: tap water, rainwater, domestic sewage, industrial wastewater, industrial pharmaceutical wastewater, agricultural wastewater, river water, lake water, seawater, well water, and secondary sedimentation tank effluent.

[0039] Specifically, the PMS oxidant is persulfate (PMS); preferably, the PMS oxidant is one or more of potassium persulfate complex salt (Oxone, KHSO5·KHSO4·K2SO4), sodium persulfate (NaHSO5), and ammonium persulfate ((NH4)2SO5).

[0040] Furthermore, based on a general inventive concept, the present invention also provides the use of the aforementioned molybdenum disulfide substrate to anchor an iron single-atom catalyst Fe. x The method for degrading water pollutants using MoS2-D-PA-activated PMS oxidant includes the following steps: The molybdenum disulfide substrate is used to anchor the iron single-atom catalyst Fe. x / MoS2-D-PA was mixed with an aqueous pollutant solution to obtain a mixed solution, and adsorption equilibrium was achieved. The molybdenum disulfide substrate-anchored iron single-atom catalyst Fe... x After the adsorption equilibrium between / MoS2-D-PA and water pollutants is reached, PMS oxidant solution is added to the mixed solution to start the reaction, and the reaction is carried out at 25±5℃ for 1~10 min. After the reaction is completed, the content of pollutants in the mixed solution is measured.

[0041] Specifically, the molybdenum disulfide substrate anchored iron single-atom catalyst Fe x The mass ratio of / MoS2-D-PA to the volume ratio of the water pollutant solution is 0.10~0.30 g:1 L.

[0042] Preferably, the volume of the water pollutant solution ranges from 50 mL to 1000 mL.

[0043] Specifically, the initial concentration of the pollutant solution in the water body is (5~20) mg / L.

[0044] Specifically, the initial pH value of the pollutant solution in the water is 3.0 to 9.0.

[0045] Specifically, the initial concentration of the PMS oxidant solution is 50~200 mM; during the reaction, the PMS oxidant solution is added to the mixed solution to make the working concentration of the PMS oxidant reach 0.25~2.00 mM.

[0046] Preferably, during the reaction, the molybdenum disulfide substrate anchors the iron single-atom catalyst Fe. x / MoS2-D-PA is Fe 18 The dosage of / MoS2-D-PA was 0.20 g / L; the concentration of PMS oxidant in the mixed solution was 1.0 mM, the initial concentration of water pollutants was 10 mg / L, and the reaction time was 2 min.

[0047] Specifically, the water pollutants are one or more of antibiotics, anti-inflammatory drugs, phenolic compounds, and organic dyes.

[0048] Preferably, the PMS oxidant is persulfate (PMS); preferably, the PMS oxidant is one or more of potassium persulfate complex salt (Oxone, KHSO5·KHSO4·K2SO4), sodium persulfate (NaHSO5), and ammonium persulfate ((NH4)2SO5).

[0049] More preferably, the contaminant is one or more of sulfamethoxazole (SMX), sulfadiazine (SDZ), sulfisoxazole (SIZ), sulfamethoxazole (SMR), sulfamethoxazole (SMT), sulfapyridine (SPD), carbamazepine (CBZ), bisphenol A (BPA), bisphenol B (BPB), diclofenac (DCF), indomethacin (IDM), naproxen (NPX), and ciprofloxacin (CIP).

[0050] More preferably, the organic dye is one or more of Rhodamine B (RhB), Methylene Blue (MB), Basic Fuchs Red (BF), Malachite Green (MG), Bengal Rose Red (RB), Acid Chrome Blue K (ACBK), and Naphthol Green B (NGB).

[0051] Specifically, the water body is one or more of the following: tap water, rainwater, domestic sewage, industrial wastewater, industrial pharmaceutical wastewater, agricultural wastewater, river water, lake water, seawater, well water, and secondary sedimentation tank effluent.

[0052] The molybdenum disulfide substrate anchored iron single-atom catalyst Fe of this invention x / MoS2-D-PA, using D-PA as a sulfur source, reducing agent, and metal (Fe) chelating ligand, achieves atomic-level dispersion and anchoring of Fe single atoms during the in-situ growth of MoS2 nanoflowers. This catalyst can efficiently activate permonosulfate (PMS), mainly through a non-radical pathway, which may include singlet oxygen (…). 1 One or more of the following—O2), electron transfer processes (ETP), and high-valence ferric oxide species (Fe(IV)=O)—exhibit extremely high degradation efficiency for various antibiotics such as sulfamethoxazole (SMX) and recalcitrant organic pollutants in water. The catalyst provided by this invention has a simple preparation process, high single-atom dispersion, excellent catalytic activity, and good stability, and has broad application prospects in the treatment of industrial pharmaceutical wastewater and recalcitrant organic pollutants.

[0053] Compared with the prior art, the advantages of the present invention are: 1. Simple process and high single-atom dispersion: This invention uses D-PA as a sulfur source, reducing agent and metal chelating ligand simultaneously. It can achieve atomic-level dispersion and anchoring of Fe single atoms in the in-situ growth of MoS2 nanoflowers in a single hydrothermal method. It does not require complicated multi-step processes or harsh reducing atmospheres. The operation is simple and has good repeatability.

[0054] 2. High density of single-atom active sites and excellent catalytic activity: The Fe prepared by this invention x In the / MoS2-D-PA series catalysts, Fe 18 / MoS2-D-PA exhibits excellent activation efficiency for PMS, with an apparent rate constant k obs =7.8389 min -1 Compared to undoped MoS2-D-PA (k obs =0.0110 min -1 It increases efficiency by 712.63 times, achieving near-complete removal of 10 mg / L SMX within 2 minutes.

[0055] 3. Excellent environmental adaptability and stability: The catalyst of this invention exhibits excellent performance across a wide pH range (3-11, with an optimal range of pH 3-9; even when the pH increases to 11, the removal rate can still reach approximately 80% within 2 minutes) and supports the removal of multiple coexisting ions (H2PO4). - It maintains high efficiency in PMS activation and SMX degradation in various complex water bodies (excluding tap water, natural lake water, seawater, and secondary sedimentation tank effluent), and has excellent broad-spectrum degradation efficiency for various sulfonamide antibiotics, bisphenols, nonsteroidal anti-inflammatory drugs, fluoroquinolones, and various dye pollutants. Attached Figure Description

[0056] Figure 1 Fe prepared in Examples 1-4 12 / MoS2-D-PA, Fe 15 / MoS2-D-PA, Fe 18 / MoS2-D-PA, Fe 21 Degradation curves of SMX by MoS2-D-PA activated PMS in Comparative Example 1 and the apparent rate constant k corresponding to the above catalysts. obs Compare the bar charts; Figure 2 Fe prepared in Examples 1-4 12 / MoS2-D-PA, Fe 15 / MoS2-D-PA, Fe 18 / MoS2-D-PA, Fe 21 XRD spectra of MoS2-D-PA and MoS2-D-PA of Comparative Example 1; Figure 3 Fe prepared in Example 1 18 SEM images of / MoS2-D-PA; Figure 4 Fe prepared in Example 1 18 / TEM and HRTEM images of MoS2-D-PA; Figure 5 Fe under different catalyst dosages (0.10, 0.15, 0.20, 0.30 g / L) 18 Degradation curve of SMX in the / MoS2-D-PA / PMS system; Figure 6 Fe under different initial SMX concentrations (5, 10, 15, 20 mg / L) 18 Degradation curve of SMX in the / MoS2-D-PA / PMS system; Figure 7 Fe under different PMS concentrations (0.25, 0.50, 1.00, 2.00 mM) 18 Degradation curve of SMX in the / MoS2-D-PA / PMS system; Figure 8 For different anions (H2PO4) - SO4 2- Cl - NO3 - Fe under the coexistence of Fe and humic acid (HA) 18 Degradation curve of SMX in the / MoS2-D-PA / PMS system; Figure 9Fe under different water substrates (ultrapure water, tap water, natural lake water, seawater, secondary sedimentation tank effluent) 18 Degradation curve of SMX in the / MoS2-D-PA / PMS system; Figure 10 Fe under different initial pH values ​​(3, 4.4, 5, 7, 9, 11) 18 Degradation curve of SMX in the / MoS2-D-PA / PMS system; Figure 11 For Fe 18 Degradation curves of the / MoS2-D-PA / PMS system for different sulfonamide antibiotics (SMX, SDZ, SIZ, SMR, SMT, SPD) and other contaminants (CBZ, BPA, BPB, DCF, IDM, NPX, CIP). Figure 12 For Fe 18 Degradation curves of the / MoS2-D-PA / PMS system for different dyes (NGB, BF, RhB, MG, ACBK, RB, MB); Figure 13 For Fe 18 Comparison of color changes before and after degradation of different dyes in the / MoS2-D-PA / PMS system; each dye in the figure is in one of four states from left to right: mother liquor, adsorption-desorption equilibrium 10 min, 15 s after adding PMS, and 2 min after adding PMS. Detailed Implementation

[0057] The technical solutions in the embodiments of this application will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments in this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this application. The raw materials or reagents used in the following embodiments and comparative examples are all commercially available or self-made.

[0058] In the following examples, comparative examples, or application tests, room temperature or ambient temperature refers to 25±5℃.

[0059] The raw materials used in the following examples, comparative examples, or application tests are as follows: Sodium molybdate dihydrate (Na2MoO4·2H2O): analytical grade, purchased from Aladdin Ltd.; D-Penicillamine (D-PA): 98% purity, purchased from Anaiji Chemical Co., Ltd.; Ferric nitrate nonahydrate (Fe(NO3)3·9H2O): analytical grade, purchased from Aladdin Ltd.; Sulfamethoxazole (SMX): analytical grade, purchased from Aladdin Company; Sodium thiosulfate (Na2S2O3): analytical grade, purchased from Damao Chemical Reagent Factory; Hydrochloric acid (HCl), sodium hydroxide (NaOH), ethanol: analytical grade, purchased from Damao Chemical Reagent Factory; Deionized water and ultrapure water: homemade.

[0060] In the following examples, comparative examples, or application tests, the PMS is potassium peroxymonosulfate complex salt (Oxone, KHSO5·0.5 KHSO4·0.5 K2SO4): ≥42% KHSO5 basis, purchased from Aladdin Company.

[0061] Example 1 Example 1 provides a Fe 18 The preparation method of the / MoS2-D-PA single-atom catalyst is as follows: (I) Preparation of iron-D-PA complex solution 1) Add 1.244 g of D-penicillamine (D-PA) to 50 mL of deionized water and sonicate for 5 min until completely dissolved to obtain a D-PA solution. The sonication power is 80~140 W. 2) Add 1320 µL of Fe(NO3)3·9H2O aqueous solution (0.1 g / mL) dropwise to the above D-PA solution and stir continuously at room temperature for 30 min to allow iron ions to fully complex with D-PA, and obtain an iron-D-PA complex solution (the exact mass of Fe element is about 18 mg). (II) Preparation of molybdenum precursor solution 3) Add 0.50 g Na2MoO4·2H2O to 50 mL of deionized water and sonicate for 5 min until completely dissolved to obtain a molybdenum precursor solution; adjust the pH of the molybdenum precursor solution to 6.5 with 0.1 M HCl solution, and the sonication power is 80~140 W. (III) Mixing and Hydrothermal Synthesis 4) The molybdenum precursor solution from step 3) is added dropwise to the iron-D-PA complex solution from step 2) under vigorous stirring to obtain a homogeneous mixture. The volume ratio of the iron-D-PA complex solution from step 2) to the molybdenum precursor solution from step 3) is approximately 1:1. 5) Transfer the homogeneous mixture from step 4) into a Teflon-lined stainless steel high-pressure reactor, seal it, and keep it at 200°C for 36 h. (iv) Post-processing 6) After the reaction was complete, the mixture was allowed to cool naturally to room temperature, then centrifuged (10,000 rpm, 30 min) to collect the black precipitate. The precipitate was washed four times alternately with deionized water and anhydrous ethanol. The precipitate was then dried in a vacuum oven at 60℃ for 6 h, and finally ground into a fine powder to obtain Fe. 18 / MoS2-D-PA single-atom catalyst (powder).

[0062] Example 2 Example 2 provides a Fe 12 The preparation method of the / MoS2-D-PA single-atom catalyst in Example 2 differs from that in Example 1 in that the amount of Fe(NO3)3·9H2O aqueous solution (0.1 g / mL) added in step 2) is 880 µL (corresponding to an exact mass of about 12 mg of Fe element); the remaining steps are exactly the same as in Example 1.

[0063] Example 3 Example 3 provides a Fe 15 The preparation method of / MoS2-D-PA single-atom catalyst, the difference between the preparation method of Example 3 and Example 1 is that the amount of Fe(NO3)3·9H2O aqueous solution (0.1 g / mL) added in step 2) is 1100 µL (corresponding to an exact mass of about 15 mg of Fe element); the rest of the steps are exactly the same as in Example 1.

[0064] Example 4 Example 4 provides a Fe 21 The preparation method of the / MoS2-D-PA single-atom catalyst in Example 4 differs from that in Example 1 in that the amount of Fe(NO3)3·9H2O aqueous solution (0.1 g / mL) added in step 2) is 1540 µL (corresponding to an exact mass of about 21 mg of Fe element); the remaining steps are exactly the same as in Example 1.

[0065] Comparative Example 1 Comparative Example 1 provides a method for preparing a MoS2-D-PA catalyst. Specifically, the method for preparing the MoS2-D-PA catalyst in Comparative Example 1 differs from that in Example 1 in that no Fe(NO3)3·9H2O aqueous solution is added to the D-PA solution in step 2); the remaining steps are exactly the same as in Example 1.

[0066] Structural characterization and performance testing: Figure 2 The images show the XRD patterns of samples prepared in Examples 1-4 and Comparative Example 1. Figure 2As shown, all samples exhibited characteristic diffraction peaks of the 2H phase MoS2 standard card (PDF#98-000-0313), with its signature (002) crystal plane maintained at 14.1°. Furthermore, no diffraction peaks associated with the Fe species were observed in the spectra, indicating that Fe exists in an atomically dispersed form rather than in clusters or nanoparticles.

[0067] Figure 3 SEM image of Fe18 / MoS2-D-PA prepared in Example 1. Figure 3 As shown, the sample exhibits a three-dimensional flower-shaped structure formed by the self-assembly of ultrathin nanosheets. The surface texture of the nanosheets is smooth and clean, ruling out the possibility of a large number of Fe atoms aggregating to form large particles.

[0068] Figure 4 Fe prepared in Example 1 18 TEM and HRTEM images of / MoS2-D-PA. For example... Figure 4 As shown, Fe 18 / MoS2-D-PA exhibits a well-defined nanoflower-like structure assembled from ultrathin nanosheets; clear 2H-MoS2 lattice stripes are visible on the sample surface in high-resolution images, and the complete absence of dark spots or discrete particle characteristics confirms that the introduced Fe species did not aggregate to form identifiable nanoparticles or nanoclusters.

[0069] Application Experiment 1: Effect of Different Fe Loadings on SMX Degradation Performance Weigh out 10 mg of Fe prepared in Examples 1-4 and Comparative Example 1 respectively. 18 / MoS2-D-PA, Fe 12 / MoS2-D-PA, Fe 15 / MoS2-D-PA, Fe 21 MoS2-D-PA and MoS2-D-PA catalyst powders were dispersed in 50 mL and 10 mg / L SMX solutions, respectively, and subjected to a 10 min dark reaction to reach adsorption-desorption equilibrium. Then, 0.50 mL and 100 mM PMS stock solutions were added to bring the PMS working concentration in the system to 1.0 mM, and the reaction was initiated at room temperature. Samples of 1 mL were taken at specified time points (0, 0.25, 0.5, 0.75, 1, 1.5, and 2 min), filtered through a 0.45 µm aqueous filter membrane, and quenched with 80 µL of 100 mM sodium thiosulfate. The remaining SMX concentration was determined by high-performance liquid chromatography (HPLC). The removal rate was calculated using the following formula.

[0070]

[0071] Test results are as follows Figure 1As shown, with increasing Fe content, the catalyst's activity for SMX degradation exhibits a volcanic trend, first increasing and then decreasing. The apparent rate constant k of MoS2-D-PA... obs Only 0.0110 min -1 After the introduction of Fe, Fe 12 / MoS2-D-PA, Fe 15 / MoS2-D-PA, Fe 18 / MoS2-D-PA and Fe 21 / MoS2-D-PA of k obs The times were increased to 1.6751, 2.3164, 7.8389, and 3.9170 min respectively. -1 Fe 18 / MoS2-D-PA exhibited the highest activity, being 712.63 times that of MoS2-D-PA. This indicates that the introduction of an appropriate amount of Fe single atoms can significantly enhance the activation ability of the MoS2 substrate for PMS, while excessive introduction may lead to a decrease in activity due to Fe atom aggregation.

[0072] Application Experiment 2: Effect of Catalyst Dosage on SMX Degradation Performance With the initial SMX concentration fixed at 10 mg / L and the PMS concentration at 1.0 mM, the Fe catalyst was investigated. 18 The degradation kinetics of the system were investigated when the / MoS2-D-PA dosage was 0.10, 0.15, 0.20, and 0.30 g / L. The remaining procedures were the same as in Application Experiment 1.

[0073] Test results are as follows Figure 5 As shown, when the catalyst dosage increased from 0.10 g / L to 0.20 g / L, the SMX degradation rate increased significantly; when it was further increased to 0.30 g / L, the degradation rate tended to stabilize and no longer increased significantly, indicating that 0.20 g / L is the optimal catalyst dosage for this system.

[0074] Application Experiment 3: Effect of Initial SMX Concentration on Degradation Performance With a fixed catalyst dosage of 0.20 g / L and a PMS concentration of 1.0 mM, the degradation kinetics of the system were investigated at initial SMX concentrations of 5, 10, 15, and 20 mg / L. All other procedures were the same as in Application Experiment 1.

[0075] Test results are as follows Figure 6 As shown: In the SMX concentration range of 5~10 mg / L, Fe 18The / MoS2-D-PA / PMS system can completely remove SMX within 30 s to 1 min; when the SMX concentration increases to 15-20 mg / L, the removal rate decreases within 2 min due to PMS dosage limitations. Considering both degradation efficiency and treatment capacity, an initial SMX concentration of 10 mg / L is recommended.

[0076] Application Experiment 4: Effect of PMS Concentration on Degradation Performance With a fixed catalyst dosage of 0.20 g / L and an initial SMX concentration of 10 mg / L, the degradation kinetics of the system were investigated at PMS working concentrations of 0.25, 0.50, 1.00, and 2.00 mM. All other procedures were the same as in Application Experiment 1.

[0077] Test results are as follows Figure 7 As shown, when the PMS concentration was increased from 0.25 mM to 1.00 mM, the degradation rate of SMX was significantly improved; when it was further increased to 2.00 mM, the improvement in degradation rate was limited, indicating that 1.0 mM is the optimal PMS concentration for this system.

[0078] Application Experiment 5: Effects of Coexisting Anions and Natural Organic Matter on Degradation Performance Under optimal conditions (catalyst concentration: 0.20 g / L, initial SMX concentration: 10 mg / L, working PMS concentration: 1.0 mM), the effects of adding 10 mM Cl were investigated. - SO4 2- NO3 - H2PO4 - And Fe at 5 mg-C / L humic acid (HA) 18 The degradation kinetics of SMX by the / MoS2-D-PA / PMS system. The remaining procedures are the same as in Application Experiment 1.

[0079] Test results are as follows Figure 8 As shown: Cl - SO4 2- NO3 - The introduction of HA did not significantly inhibit the degradation of SMX; while H2PO4 - This significantly inhibited the degradation of SMX, indicating that H2PO4 - It may strongly coordinate with the Fe single-atom active site and occupy the active site.

[0080] Application Experiment 6: Effects of Different Aquatic Matrix on Degradation Performance Under optimal conditions (catalyst concentration: 0.20 g / L, initial SMX concentration: 10 mg / L, PMS working concentration: 1.0 mM), SMX was dissolved in ultrapure water, tap water, natural lake water, seawater, and secondary sedimentation tank effluent, respectively, and the Fe content was investigated.18 The degradation kinetics of SMX by the / MoS2-D-PA / PM system in different aquatic matrices. The remaining procedures were the same as in Application Experiment 1.

[0081] Test results are as follows Figure 9 As shown: Among the five water matrix types investigated, Fe... 18 The / MoS2-D-PA / PMS system can achieve near-complete removal of SMX within 2 min, indicating that the catalyst of this invention has excellent adaptability to real complex water bodies.

[0082] Application Experiment 7: Effect of Initial pH on Degradation Performance Under optimal conditions (catalyst concentration: 0.20 g / L, initial SMX concentration: 10 mg / L, PMS working concentration: 1.0 mM), the initial pH of the SMX solution was adjusted to 3, 4.41 (original pH), 5, 7, 9, and 11 using 0.1 M HCl or 0.1 M NaOH, respectively, to investigate Fe... 18 The degradation kinetics of SMX by the / MoS2-D-PA / PMS system. The remaining procedures are the same as in Application Experiment 1.

[0083] Test results are as follows Figure 10 As shown: Fe... 18 The / MoS2-D-PA / PMS system maintained excellent SMX degradation activity; when the pH increased to 11, the degradation activity decreased to some extent, but the removal rate could still reach about 80% within 2 minutes. This indicates that the catalyst of the present invention has a wide pH range of applicability.

[0084] Application Experiment 8: Broad-spectrum degradation performance of different antibiotics and recalcitrant organic pollutants Under optimal conditions (catalyst concentration: 0.20 g / L, initial SMX concentration: 10 mg / L, PMS working concentration: 1.0 mM), sulfamethoxazole (SMX), sulfadiazine (SDZ), sulfaisoxazole (SIZ), sulfamethoxazole (SMR), sulfamethazine diazole (SMT), sulfapyridine (SPD), carbamazepine (CBZ), bisphenol A (BPA), bisphenol B (BPB), diclofenac (DCF), indomethacin (IDM), naproxen (NPX), and ciprofloxacin (CIP) were selected as target pollutants (initial concentration: 10 mg / L) to investigate Fe 18 The degradation kinetics of each pollutant in the / MoS2-D-PA / PMS system were analyzed. All other procedures were the same as in Application Experiment 1.

[0085] Test results are as follows Figure 11 As shown: The present invention Fe 18The / MoS2-D-PA / PMS system achieved nearly 100% removal efficiency for all 13 antibiotics and recalcitrant organic pollutants investigated within a very short time (≤1 min), demonstrating excellent broad-spectrum degradation capabilities.

[0086] Application Experiment 9: Broad-spectrum decolorization performance of different dyes Under optimal conditions (catalyst concentration: 0.20 g / L, initial SMX concentration: 10 mg / L, working PMS concentration: 1.0 mM), naphthol green B (NGB), basic fuchsin (BF), rhodamine B (RhB), malachite green (MG), acid chrome blue K (ACBK), Bengal rose red (RB), and methylene blue (MB) were selected as target dyes (initial concentration: 10 mg / L) to investigate Fe 18 The decolorization kinetics of each dye in the / MoS2-D-PA / PMS system were investigated. All other procedures were the same as in Application Experiment 1.

[0087] Test results are as follows Figure 12 , Figure 13 As shown: The present invention Fe 18 The / MoS2-D-PA / PMS system showed that all seven dyes investigated rapidly lost their color after the addition of PMS, and all dyes were essentially decolorized to colorless and transparent within 2 minutes.

[0088] In summary, the Fe prepared by this invention 18 The / MoS2-D-PA single-atom catalyst exhibits significant catalytic effects on the degradation of various pollutants such as SMX, and demonstrates good adaptability to various anions and a wide pH range. Its degradation effect is not easily affected by other factors in the environment, making it highly suitable for the degradation treatment of various antibiotics such as SMX and recalcitrant organic pollutants in water.

[0089] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

[0090] The foregoing has shown and described the basic principles and main features of the present invention, as well as its advantages. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the present invention as claimed. The scope of protection of this invention is defined by the appended claims and their equivalents.

Claims

1. A method for preparing a molybdenum disulfide-based anchored iron single-atom catalyst, characterized in that, Includes the following steps: (I) Preparation of iron-ligand complex solution 1) Dissolve D-penicillamine in a first solvent to obtain a D-PA solution; add an aqueous solution of ferric nitrate to the D-PA solution and stir continuously at room temperature for 20-40 min to allow the iron ions to fully complex with D-PA to obtain an iron-D-PA complex solution; (II) Preparation of molybdenum precursor solution 2) Dissolve sodium molybdate dihydrate in the first solvent to obtain a molybdenum precursor solution; The pH of the molybdenum precursor solution was adjusted to 5.5-7.5 using an acid adjuster. (iii) Fe x One-step hydrothermal synthesis of MoS2-D-PA single-atom catalyst 3) Mix the iron-D-PA complex solution obtained in step 1) with the molybdenum precursor solution obtained in step 2) to obtain a homogeneous mixture; 4) Transfer the homogeneous mixture from step 3) to a reaction vessel and hydrothermally react at 180–220 °C for 24–48 h. After the reaction is complete, allow it to cool naturally to room temperature, centrifuge, collect the precipitate, wash, dry, and grind to obtain the molybdenum disulfide-based anchored iron single-atom catalyst Fe. x / MoS2-D-PA; The first solvent is any one of deionized water, ultrapure water, or distilled water; The acid regulator is any one of dilute hydrochloric acid, dilute sulfuric acid, or dilute nitric acid.

2. The preparation method according to claim 1, characterized in that, In step 1), the ratio of D-penicillamine to the first solvent is (0.02~0.03) g : 1 mL; In step 1), the mass concentration of the ferric nitrate aqueous solution is 0.08~0.12 g / mL; In step 1), the volume of the ferric nitrate aqueous solution added is 850~1600µL.

3. The preparation method according to claim 1, characterized in that, In step 2), the ratio of sodium molybdate dihydrate to the first solvent is (0.008~0.012) g : 1 mL; In step 2), the pH value of the molybdenum precursor solution is adjusted to 6.0~7.

0.

4. The molybdenum disulfide substrate-anchored iron single-atom catalyst Fe prepared by the method described in any one of claims 1 to 3. x / MoS2-D-PA; where the subscript x represents the exact mass (mg) of Fe element introduced during the synthesis process, and its value ranges from 5 to 30.

5. The application of the molybdenum disulfide-based anchored iron single-atom catalyst of claim 4 in the degradation of water pollutants by activated PMS oxidant, characterized in that, The contaminants are one or more of antibiotics, anti-inflammatory drugs, phenolic compounds, and organic dyes; The water body is one or more of the following: tap water, rainwater, domestic sewage, industrial wastewater, industrial pharmaceutical wastewater, agricultural wastewater, river water, lake water, seawater, well water, and secondary sedimentation tank effluent.

6. The application as described in claim 5, characterized in that, The contaminant is one or more of the following: sulfamethoxazole, sulfadiazine, sulfaisoxazole, sulfamethoxazole, sulfamethazine, sulfamethiadiazole, sulfapyridine, carbamazepine, bisphenol A, bisphenol B, diclofenac, indomethacin, naproxen, and ciprofloxacin. The organic dye is one or more of the following: Rhodamine B, Methylene Blue, Basic Fuchsin, Malachite Green, Bengal Rose, Acid Chrome Blue K, and Naphthol Green B.

7. A Fe x The / MoS2-D-PA / PMS oxidant water pollutant degradation reaction system is characterized by... Including the molybdenum disulfide substrate-anchored iron single-atom catalyst Fe as described in claim 4 x / MoS2-D-PA and PMS oxidants, wherein the molybdenum disulfide substrate anchors the iron single-atom catalyst Fe x The mass ratio of MoS2-D-PA to PMS oxidant is 1:(0.2~6.5).

8. The Fe as described in claim 7 x The application of the / MoS2-D-PA / PMS oxidant water pollutant degradation reaction system in the catalytic degradation of water pollutants is characterized by... The water pollutants are one or more of the following: antibiotics, anti-inflammatory drugs, phenolic compounds, and organic dyes; The water body is one or more of the following: tap water, rainwater, domestic sewage, industrial wastewater, industrial pharmaceutical wastewater, agricultural wastewater, river water, lake water, seawater, well water, and secondary sedimentation tank effluent.

9. Using the molybdenum disulfide substrate anchored iron single-atom catalyst Fe as described in claim 4 x The method for degrading water pollutants using MoS2-D-PA-activated PMS oxidant is characterized by... Includes the following steps: The molybdenum disulfide substrate is used to anchor the iron single-atom catalyst Fe. x / MoS2-D-PA was mixed with an aqueous pollutant solution to obtain a mixed solution, and adsorption equilibrium was achieved. The molybdenum disulfide substrate-anchored iron single-atom catalyst Fe... x After the adsorption equilibrium between / MoS2-D-PA and pollutants is reached, PMS oxidant solution is added to the mixed solution to start the reaction, and the reaction is carried out at 25±5℃ for 1~10 min. After the reaction is completed, the content of pollutants in the mixed solution is measured. The water pollutants are one or more of the following: antibiotics, anti-inflammatory drugs, phenolic compounds, and organic dyes; The water body is one or more of the following: tap water, rainwater, domestic sewage, industrial wastewater, industrial pharmaceutical wastewater, agricultural wastewater, river water, lake water, seawater, well water, and secondary sedimentation tank effluent.

10. The method as described in claim 9, characterized in that, The molybdenum disulfide substrate anchored iron single-atom catalyst Fe x The dosage ratio of MoS2-D-PA to the water pollutant solution is 0.10~0.30 g:1 L; The initial concentration of the pollutant solution in the water body is (5~20) mg / L; The initial pH value of the pollutant solution in the water body is 3.0~9.0; During the reaction, a PMS oxidant solution is added to the mixed solution to make the concentration of PMS oxidant reach 0.25~2.00 mM.

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