Double-vacancy Fe0. 96S (at) MoS2 nano composite material as well as wet-type mechanochemical synthesis method and application thereof

Abstract

The invention relates to the technical field of environmental chemistry, in particular to a double-vacancy Fe0. 96S (at) MoS2 nano composite material as well as a wet-type mechanochemical synthesis method and application thereof. The preparation method comprises the following steps: firstly carrying out co-ball milling by utilizing a wet mechanical chemical synthesis method to obtain a low-crystallinity Fe0. 96S (at) MoS2 precursor, and then carrying out further calcination treatment to accelerate the thermal reaction of the precursor, improve the crystallinity and remove redundant sulfur powder impurities, thereby obtaining the high-crystallinity Fe0. 96S (at) MoS2 nano composite material. Iron powder is introduced in the process of preparing MoS2 nanosheets from molybdenum powder and sulfur powder, the reaction activity of the molybdenum powder and the sulfur powder is improved and the formation energy of MoS2 is reduced by utilizing the characteristic of ball-milling heat release of the iron powder and the sulfur powder, the reaction barrier that MoS2 is difficult to prepare between Mo and S through a mechanical ball-milling process originally is broken, and the generation of the MoS2 nanosheets is promoted.

Description

TECHNICAL FIELD

[0001] The application relates to the technical field of environmental chemistry, and particularly relates to a double-vacancy Fe 0.96 S@MoS2 nanocomposite, a wet mechanical-chemical synthesis method thereof and application. BACKGROUND

[0002] The advanced oxidation process (AOPs) based on the peroxymonosulfate (PMS) system is a highly efficient wastewater treatment technology. In the Fe(II) / PMS system, Fe(II) is used to activate PMS to generate SO4 ·- and other active oxygen species, which can effectively degrade refractory organic pollutants in water. However, the traditional homogeneous Fenton or homogeneous-like Fenton system using soluble iron salts (such as ferrous sulfate, ferrous chloride, etc.) as an iron source has defects such as the limitation of acidic pH reaction conditions, the slow cycle conversion rate of Fe(III) to Fe(II), the continuous large-dose addition of oxidants, and the generation of a large amount of solid hazardous waste iron sludge, which greatly limits the practical application of the oxidation process. On this basis, the heterogeneous-like Fenton catalytic system is considered to be an important means to solve the above defects.

[0003] Molybdenum sulfide (Mo x S y , including MoS2, MoS3, Mo3S4, Mo2S3, etc.) is a co-catalyst that can effectively regulate the PMS activation ability of functional materials. In the reaction process, the exposed Mo(IV) can exchange electrons with Fe(III) in the solution to generate Mo(VI) and Fe(II), thereby providing a continuous source of Fe(II) for PMS activation. Subsequently, with the oxidation of PMS and the presence of a large number of unsaturated sulfur species, Mo(VI) is converted into original Mo(IV). This makes a series of valence changes between Mo and Fe species improve the utilization rate of PMS and provides the possibility for continuous degradation of pollutants during the reaction.

[0004] Mechanical ball milling method realizes material preparation through mechanical chemical reaction process, and is widely concerned due to the advantages of simple overall preparation process operation, low energy consumption, no secondary pollution, and easy realization of large-scale industrial production. Takuya Matsuyama (①T. Matsuyama, et al. Electrochemical properties of all-solid-state lithium batteries with amorphous MoS3 electrodes prepared by mechanical milling, J. Mater. Chem. A 3 (2015) 14142-14147. ②T. Matsuyama, et al. Structure Analyses of Amorphous MoS3 Active Materials in All-solid-state Lithium Batteries, Electrochemistry 83 (2015) 889-893.) mixed Mo metal and sulfur powder, and prepared amorphous MoS3 by using a high-energy ball mill (ball mill: Pulverisette 7; Fritsch micro planetary high-energy ball mill. Ball milling conditions: rotation speed 370 rpm, time 80 h). However, the crystallinity of the MoS3 material prepared by this method is low, and the catalytic activity is weak. In addition, the long reaction time and large energy consumption of the ball milling preparation process hinder its practical application.

[0005] Therefore, how to prepare a high-crystallinity molybdenum sulfide material by a simple ball milling method is a problem to be solved; in this way, the problem of efficient catalytic degradation of organic wastewater by molybdenum sulfide material can be solved. SUMMARY

[0006] The application provides a double-vacancy Fe 0.96 S@MoS2 nanocomposite and a wet mechanical chemical synthesis method and application thereof. The double-vacancy Fe 0.96 The S@MoS2 nanocomposite has high crystallinity and can efficiently degrade various organic pollutants.

[0007] In order to achieve the above purpose, the application provides the following technical scheme:

[0008] The application provides a double-vacancy Fe 0.96 S@MoS2 nanocomposite, the double-vacancy Fe 0.96 The S@MoS2 nanocomposite includes Fe 0.96 S nanoparticles with iron vacancies and MoS2 nanosheets with sulfur vacancies; and the double-vacancy Fe0.96 The content of the MoS2 nanosheet in the S@MoS2 nanocomposite is 55-70 wt%.

[0009] Preferably, the double vacancy Fe 0.96 The S@MoS2 nanocomposite is a bird nest-like heterostructure with a particle size of 100-900 nm.

[0010] Fe 0.96 The S@MoS2 nanocomposite forms a special bird nest-like heterostructure. The heterostructure effectively maintains the overall structural integrity and tightness of the composite material, and is also conducive to the uniform dispersion of single components, effectively avoiding the problem of nanoparticle agglomeration caused by the strong magnetism of Fe 0.96 S.

[0011] In addition, due to the significant presence of unsaturated sulfur sites at the edges of the MoS2 nanosheet, Fe 0.96 The S@MoS2 composite material exhibits a significant ability to adsorb H + ions from the solution, improves the Zeta potential of the composite material, thereby generating an acidic microenvironment on the surface of the composite material, promoting the Fe 0.96 S. dissolution, enhancing the homogeneous reaction ability of the system, accelerating the activation of PMS, and further improving the overall catalytic performance of the composite material. 2+

[0012] The present application provides a preparation method of a double vacancy Fe 0.96 S@MoS2 nanocomposite, which comprises: ball-milling iron powder, molybdenum powder, sulfur powder and inert wet grinding medium to obtain a low-crystalline precursor, and then calcining the low-crystalline precursor under an inert atmosphere to obtain a double vacancy Fe 0.96 S@MoS2 nanocomposite.

[0013] In the process of ball-milling molybdenum powder and sulfur powder to prepare MoS2 nanosheet, it is found that it is difficult to generate MoS2 material by directly ball-milling the two, but the generation of MoS2 material can be promoted after introducing iron powder, and Fe 0.96 S material is obtained, and the two can form a heterostructure to further enhance the catalytic activity of the composite material, and when used as a dominant catalyst for a Fenton-like reaction, there is no need to add iron salt to activate the Fenton-like reaction.

[0014] ​The mechanical chemical reaction adopted by the present application does not need to add protective gas, has large system yield and low requirement for equipment, and does not produce secondary pollution. First, in the preparation process, iron powder, molybdenum powder and sulfur powder are used as raw materials, and a small amount of inert wet grinding medium is added, and the co-ball milling reaction is completed. In the co-ball milling stage, the chemical reactions of iron and sulfur and the chemical reactions of molybdenum and sulfur are realized at the same time. On the one hand, the mechanical ball milling process reduces the size of the reaction raw materials by mechanical cutting and crushing of molybdenum particles, while ensuring that the reaction raw materials are fully and uniformly mixed; on the other hand, the ball milling process converts mechanical energy into heat energy to generate a micro-domain high temperature at the reaction interface, which is conducive to promoting the chemical reaction to occur. Second, the mechanical chemical reaction synthesis process of iron powder and sulfur powder belongs to an exothermic reaction process, which further promotes the reaction of molybdenum and sulfur to occur. The above synergistic effect improves the reactivity of the material, effectively reduces the formation energy of MoS2, breaks the reaction barrier between Mo and S that is difficult to prepare MoS2 by mechanical ball milling process, and finally realizes the direct mechanical reaction of molybdenum powder and sulfur powder to generate MoS2 nanomaterials under normal temperature and pressure, without complex equipment and under mild reaction conditions. In addition, the strong collision of the grinding balls makes the powder particles of the raw materials bear repeated extrusion, shearing and impact, and the continuous high-energy collision leads to significant plastic deformation of the internal structure and generates a large number of defects such as vacancies and dislocations inside. Furthermore, the co-ball milling process of the raw materials Fe and Mo promotes the reaction competition of the two with sulfur, improves the unsaturation degree of metal sulfide, and induces the MoS2 nanomaterial to generate abundant sulfur vacancies (Sulfur Vacancies, SVs). Finally, through co-ball milling, the synchronous synthesis of Fe 0.96 S and MoS2 is realized, and the size of the composite material is reduced to the nanoscale, forming a special bird nest-like heterostructure Fe 0.96 S@MoS2 nanocomposite material precursor rich in sulfur vacancies.

[0015] The precursor prepared by co-ball milling has low crystallinity, so further calcination treatment is carried out to accelerate the thermal reaction of the precursor, improve the crystallinity and remove excess sulfur powder impurities, and obtain a Fe 0.96 S@MoS2 nanocomposite material with high crystallinity and uniform mixing.

[0016] Preferably, the molar ratio of the iron powder, molybdenum powder and sulfur powder is 1:(1-6):(5-30).

[0017] Preferably, the purity of the iron powder is ≥98%, the purity of the molybdenum powder is ≥98%, and the purity of the sulfur powder is ≥95%.

[0018] Preferably, the ball milling conditions are: rotation speed 300-600 rpm, time 24-48 h.

[0019] Preferably, the ball milling beads are ceramic ball milling beads.

[0020] Preferably, the ceramic ball milling beads are zirconium oxide milling beads, aluminum oxide milling beads or silicon nitride milling beads.

[0021] Preferably, the mass ratio of the amount of the ball milling beads to the sum of the mass of the iron powder, the molybdenum powder and the sulfur powder is (30-60):1.

[0022] Preferably, the diameter of the ball milling beads is 2-10 mm.

[0023] Preferably, the inert wet milling medium is water or alcohol.

[0024] Preferably, the alcohol is methanol, ethylene glycol or ethanol.

[0025] Preferably, the mass-volume ratio of the amount of the inert wet milling medium to the sum of the mass of the iron powder, the molybdenum powder and the sulfur powder is (0.5-2.5) mL:1 g.

[0026] Preferably, the calcination conditions are: temperature 500-700℃, heating rate 3-15℃ / min, time 2-6h, and protective gas flow rate 0.5-2L / min.

[0027] Preferably, the inert atmosphere is nitrogen and / or argon.

[0028] The present application provides a double vacancy Fe 0.96 The S@MoS2 nanocomposite is used for catalyzing activation of oxidants and promoting Fe 2+ / Fe 3 + The present application provides the use of the double vacancy Fe

[0029] Preferably, the use is performed by sequentially adding the double vacancy Fe 0.96 S@MoS2 nanocomposite, an oxidant into a water body containing organic pollutants, and removing the organic pollutants in the water body by reaction.

[0030] Preferably, the initial pH of the water body containing organic pollutants is 3-9.

[0031] Preferably, the concentration of the organic pollutants in the water body containing organic pollutants is 10-60 mg / L.

[0032] Preferably, the amount of the double vacancy Fe 0.96 S@MoS2 nanocomposite added is 0.1-0.8 g / L, and the amount of the oxidant added is 0.2-1 mM.

[0033] Preferably, the organic pollutants are at least one of bisphenol compounds, antibiotics and organic dyes.

[0034] Preferably, the bisphenol compound is bisphenol A, bisphenol F or bisphenol S.

[0035] Preferably, the antibiotic is sulfadiazine, sulfamethoxazole or sulfisoxazole.

[0036] Preferably, the organic dye is rhodamine B or methylene blue.

[0037] Preferably, the oxidizing agent is at least one of monopersulfate, peroxodisulfate, peroxyacetic acid, ozone, hydrogen peroxide.

[0038] Therefore, the present application has the following beneficial effects:

[0039] (1) The present application uses widely-sourced iron powder, molybdenum powder and sulfur powder as raw materials, and directly prepares Fe 0.96 S@MoS2 nanocomposites with high purity and uniform mixing through a wet mechanical-chemical synthesis method combined with a heat treatment process, which solves the problems of high cost, high equipment requirement, complex method, need for protective gas, small yield and secondary pollution in traditional preparation methods, facilitates large-scale production, improves process controllability, and is suitable for industrial application.

[0040] (2) The present application uses a wet mechanical-chemical synthesis method to obtain low-crystallinity Fe 0.96 S@MoS2 precursors through co-milling, and then performs further calcination treatment to accelerate the thermal reaction of the precursors, improve the crystallinity, and remove excess sulfur powder impurities, thereby obtaining Fe 0.96 S@MoS2 nanocomposites with high crystallinity.

[0041] (3) The present application introduces iron powder in the process of preparing MoS2 nanosheets from molybdenum powder and sulfur powder, uses the heat release characteristics of the ball-milling reaction of iron powder and sulfur powder to improve the reactivity of molybdenum powder and sulfur powder, reduces the formation energy of MoS2, breaks the reaction barrier between Mo and S that makes it difficult to prepare MoS2 through mechanical ball-milling, and promotes the generation of MoS2 nanosheets.

[0042] (4) The Fe 0.96 S@MoS2 nanocomposites provided by the present application have iron vacancies and abundant sulfur vacancies and have a heterostructure, the surface of which has a micro-domain acidic environment, which effectively promotes the dissolution of Fe 2+ , and improves the homogeneous catalytic effect of the Fe 0.96 S@MoS2 / PMS system. + The addition of PMS can release H 0.96 , so the Fe 0.96S / PMS system and MoS2 / PMS system, Fe 0.96 The S@MoS2 / PMS system can effectively improve the mineralization effect on pollutants while realizing the adaptation to higher pH.

[0043] (5) The Fe 0.96 The S@MoS2 / PMS system can efficiently degrade various organic pollutants such as bisphenol A, sulfadiazine and rhodamine B, proving that the system has broad applicability; and after multiple cycles, it can still ensure high degradation efficiency, indicating that the system can be widely applied as the treatment of actual organic pollutant wastewater. BRIEF DESCRIPTION OF DRAWINGS

[0044] Figure 1 The XRD results of different nanomaterials prepared, wherein a is Fe 0.96 S@MoS2 nanocomposite (Example 1), Fe 0.96 The comparative graph of S nanomaterial (Comparative Example 1) and MoS2 nanomaterial (Comparative Example 2), and b is the comparative graph of Fe, Mo and S powder after simple physical grinding and wet ball milling, wherein the Fe, Mo, S (Physical grinding product) marked in the graph is the product of Fe, Mo and S powder after simple physical grinding (the same as Example 1 in raw material ratio); MoS2 (Ball mill and heat treatment) is the product of Mo and S powder after wet ball milling and heat treatment (the same as Comparative Example 2 in raw material ratio); Fe, Mo, S (Ball mill product) is the product of Fe, Mo and S powder after wet ball milling (the same as Example 1 in raw material ratio);

[0045] Figure 2 The FESEM graph of Fe 0.96 The electron microscope graph of S@MoS2 nanocomposite, wherein a and b are FESEM graphs under different ratios, and c is an HRTEM graph;

[0046] Figure 3 The Zeta potential graph of different nanomaterials;

[0047] Figure 4 The FESEM graph of Fe 0.96 The XPS spectrum graph of S@MoS2 nanocomposite;

[0048] Figure 5 The BPA degradation performance comparative graph of different nanomaterials prepared;

[0049] Figure 6 The TOC degradation performance comparative graph of different nanomaterials prepared;

[0050] Figure 7 The reduction ability of different nanomaterials to Fe 3+ is shown in the following figure:

[0051] Figure 8 The reduction ability of different nanomaterials to Fe 0.96 S@MoS2 is shown in the following figure:

[0052] Figure 9 The degradation performance of Fe 0.96 S@MoS2 nanocomposites to different organic pollutants is shown in the following figure:

[0053] Figure 10 The degradation performance of Fe 0.96 S@MoS2 nanocomposites to different organic pollutants is shown in the following figure: DETAILED DESCRIPTION

[0054] The present application will be further described below in conjunction with specific examples. Those skilled in the art will be able to implement the present application based on these descriptions. In addition, the examples of the present application involved in the following descriptions are generally only examples of a part of the present application, rather than all examples. Therefore, all other examples obtained by those skilled in the art based on the examples in the present application without making creative efforts should belong to the scope of protection of the present application.

[0055] In this part, the raw materials are as follows: iron powder, purity ≥98%, purchased from Shanghai Maikelin Biotechnology Co., Ltd.; molybdenum powder, purity ≥98%, purchased from Shanghai Maikelin Biotechnology Co., Ltd.; sulfur powder, purity ≥95%, purchased from National Pharmaceutical Group Chemical Reagent Co., Ltd.; ethanol, purchased from National Pharmaceutical Group Chemical Reagent Co., Ltd.

[0056]

EXAMPLE

[0057] Example 1 double vacancy Fe 0.96 S@MoS2 nanocomposite

[0058] (1) 4g of a mixture of iron powder, molybdenum powder and sulfur powder with a molar ratio of 1:1:7 was weighed and placed in a zirconia ball mill jar, and 160g of zirconia balls and 4mL of ethanol were added. The planetary ball mill was set at a parameter of 400r / min and operated for 48h.

[0059] (2) After the planetary ball mill is cooled to room temperature at the end of operation, the ball mill tank is rinsed with anhydrous ethanol, and the mixture in the tank is transferred to a beaker, stirred uniformly, and then transferred to a centrifuge tube and centrifuged at 8000 rpm for 5 min. The obtained solid material is repeatedly washed and centrifuged three times with anhydrous ethanol, and then dried in a glove box for 72 h to obtain a low-crystalline precursor.

[0060] (3) The low-crystalline precursor is transferred to a vacuum tube furnace, argon is used as the protective gas (gas flow rate is 1 L / min), the temperature rising rate is controlled at 10 ℃ / min, the calcination temperature is 550 ℃, and the calcination time is 2.5 h to prepare a double-vacancy Fe 0.96 S@MoS2 nanocomposite. The content of MoS2 nanosheet in the double-vacancy Fe 0.96 S@MoS2 nanocomposite is about 65 wt%.

[0061] Comparative Example 1 Fe 0.96 S nanomaterial

[0062] (1) 4 g of a mixture of iron powder and sulfur powder in a molar ratio of 1:7 is weighed into a zirconia ball mill tank, and 160 g of zirconia balls and 4 mL of ethanol are added. A planetary ball mill is used with a setting parameter of 400 r / min for 48 h.

[0063] (2) After the planetary ball mill is cooled to room temperature at the end of operation, the ball mill tank is rinsed with anhydrous ethanol, and the mixture in the tank is transferred to a beaker, stirred uniformly, and then transferred to a centrifuge tube and centrifuged at 8000 rpm for 5 min. The obtained solid material is repeatedly washed and centrifuged three times with anhydrous ethanol, and then dried in a glove box for 72 h to obtain a low-crystalline precursor.

[0064] (3) The low-crystalline precursor is transferred to a vacuum tube furnace, argon is used as the protective gas (gas flow rate is 1 L / min), the temperature rising rate is controlled at 10 ℃ / min, the calcination temperature is 550 ℃, and the calcination time is 2.5 h to prepare a double-vacancy Fe 0.96 S nanomaterial.

[0065] Comparative Example 2 MoS2 nanomaterial

[0066] (1) 4 g of a mixture of molybdenum powder and sulfur powder in a molar ratio of 1:7 is weighed into a zirconia ball mill tank, and 160 g of zirconia balls and 4 mL of ethanol are added. A planetary ball mill is used with a setting parameter of 400 r / min for 48 h.

[0067] (2) When the planetary ball mill is cooled to room temperature at the end of operation, the ball mill tank is rinsed with anhydrous ethanol, and the mixture in the tank is transferred to a beaker, stirred uniformly, and then transferred to a centrifuge tube and centrifuged at 8000 rpm for 5 min. The obtained solid material is repeatedly washed and centrifuged three times with anhydrous ethanol, and then dried in a glove box for 72 h to obtain a precursor.

[0068] (3) The precursor is transferred to a vacuum tube furnace, argon is used as a protective gas (the gas flow rate is 1 L / min), the temperature rising rate is controlled to be 10℃ / min, the calcination temperature is 550℃, and the calcination time is 2.5 h to prepare a MoS2 nanomaterial.

[0069] Comparative Example 3

[0070] The FeS nanomaterial prepared in Comparative Example 1 is mixed with the MoS2 nanomaterial obtained in Comparative Example 2 according to a molar ratio of iron to molybdenum of 1:1, 4 g of the mixed mixture is placed in an agate mortar, and grinding is performed for 30 min until the mixture is uniformly mixed, which is denoted as FeS+MoS2. 0.96 S nanomaterial and the MoS2 nanomaterial obtained in Comparative Example 2, 4 g of the mixed mixture is placed in an agate mortar, and grinding is performed for 30 min until the mixture is uniformly mixed, which is denoted as FeS+MoS2. 0.96 S+MoS2.

[0071]

Performance Test

[0072] 1. Structural Characterization

[0073] The nanomaterials prepared in Example 1 and Comparative Examples 1-3 are subjected to XRD and FESEM and TEM tests, and the results are shown in FIGS. 1-3. Figures 1-2

[0074] Figure 1 a is an XRD result graph. As can be observed, the characteristic diffraction peaks of the FeS@MoS2 nanocomposite material are basically consistent with the standard card of FeS (JCPDS: 50-1788) and MoS2 (JCPDS: 37-1492), and no impurity peaks of other substances such as elemental iron, elemental molybdenum and elemental sulfur are observed, indicating that the high-purity FeS@MoS2 composite material is successfully prepared. 0.96 a is an XRD result graph. As can be observed, the characteristic diffraction peaks of the FeS@MoS2 nanocomposite material are basically consistent with the standard card of FeS (JCPDS: 50-1788) and MoS2 (JCPDS: 37-1492), and no impurity peaks of other substances such as elemental iron, elemental molybdenum and elemental sulfur are observed, indicating that the high-purity FeS@MoS2 composite material is successfully prepared. 0.96 a is an XRD result graph. As can be observed, the characteristic diffraction peaks of the FeS@MoS2 nanocomposite material are basically consistent with the standard card of FeS (JCPDS: 50-1788) and MoS2 (JCPDS: 37-1492), and no impurity peaks of other substances such as elemental iron, elemental molybdenum and elemental sulfur are observed, indicating that the high-purity FeS@MoS2 composite material is successfully prepared. 0.96 a is an XRD result graph. As can be observed, the characteristic diffraction peaks of the FeS@MoS2 nanocomposite material are basically consistent with the standard card of FeS (JCPDS: 50-1788) and MoS2 (JCPDS: 37-1492), and no impurity peaks of other substances such as elemental iron, elemental molybdenum and elemental sulfur are observed, indicating that the high-purity FeS@MoS2 composite material is successfully prepared. 0.96 a is an XRD result graph. As can be observed, the characteristic diffraction peaks of the FeS@MoS2 nanocomposite material are basically consistent with the standard card of FeS (JCPDS: 50-1788) and MoS2 (JCPDS: 37-1492), and no impurity peaks of other substances such as elemental iron, elemental molybdenum and elemental sulfur are observed, indicating that the high-purity FeS@MoS2 composite material is successfully prepared. 0.96 a is an XRD result graph. As can be observed, the characteristic diffraction peaks of the FeS@MoS2 nanocomposite material are basically consistent with the standard card of FeS (JCPDS: 50-1788) and MoS2 (JCPDS: 37-1492), and no impurity peaks of other substances such as elemental iron, elemental molybdenum and elemental sulfur are observed, indicating that the high-purity FeS@MoS2 composite material is successfully prepared. 0.96 a is an XRD result graph. As can be observed, the characteristic diffraction peaks of the FeS@MoS2 nanocomposite material are basically consistent with the standard card of FeS (JCPDS: 50-1788) and MoS2 (JCPDS: 37-1492), and no impurity peaks of other substances such as elemental iron, elemental molybdenum and elemental sulfur are observed, indicating that the high-purity FeS@MoS2 composite material is successfully prepared. 0.96 a is an XRD result graph. As can be observed, the characteristic diffraction peaks of the FeS@MoS2 nanocomposite material are basically consistent with the standard card of FeS (JCPDS: 50-1788) and MoS2 (JCPDS: 37-1492), and no impurity peaks of other substances such as elemental iron, elemental molybdenum and elemental sulfur are observed, indicating that the high-purity FeS@MoS2 composite material is successfully prepared. 0.96 a is an XRD result graph. As can be observed, the characteristic diffraction peaks of the FeS@MoS2 nanocomposite material are basically consistent with the standard card of FeS (JCPDS: 50-1788) and MoS2 (JCPDS: 37-1492), and no impurity peaks of other substances such as elemental iron, elemental molybdenum and elemental sulfur are observed, indicating that the high-purity FeS@MoS2 composite material is successfully prepared. 0.96 a is an XRD result graph. As can be observed, the characteristic diffraction peaks of the FeS@MoS2 nanocomposite material are basically consistent with the standard card of FeS (JCPDS: 50-1788) and MoS2 (JCPDS: 37-1492), and no impurity peaks of other substances such as elemental iron, elemental molybdenum and elemental sulfur are observed, indicating that the high-purity FeS@MoS2 composite material is successfully prepared. 0.96 ​S material has good crystallinity.

[0075] In order to fully reflect the effect of wet mechanical ball milling on raw materials, the intermediate product in the preparation process of Example 1 was tested, and the results are as follows: Figure 1 As shown in Figure 2b, it can be observed that the characteristic diffraction peaks of the Mo and S elements are greatly reduced after wet ball milling compared to simple physical grinding. This indicates that a chemical reaction occurred between the molybdenum powder and the sulfur powder during the wet ball milling process. In addition, no characteristic diffraction peaks of the Fe element were observed, indicating that the iron powder was completely reacted during the wet ball milling process.

[0076] As a comparison, we ball-milled a mixture of Mo and S (without adding iron powder) and then heat-treated it (Comparative Example 2). The XRD pattern of the corresponding product is shown in Figure 2. Figure 1 (a, b). XRD shows that the characteristic diffraction peak of the MoS2 nanomaterial obtained in Comparative Example 2 is only partially consistent with the standard card of MoS2 (JCPDS: 29-0723), and an obvious impurity peak of elemental molybdenum is observed (JCPDS: 42-1120), indicating that when only molybdenum powder and sulfur powder are co-ball milled, it is difficult for the two to directly react chemically to completely generate MoS2. Moreover, in the MoS2 nanomaterial obtained in Comparative Example 2, the characteristic diffraction peak of the Mo element is higher than the characteristic diffraction peak of the Mo element in the group "Fe, Mo, S (Ball mill product) is the product of Fe, Mo, and S powders after wet ball milling". This also shows that iron powder can promote the ball milling of molybdenum powder and sulfur powder to generate MoS2. The specific mechanism is: the mechanochemical reaction synthesis process of iron powder and sulfur powder is an exothermic reaction process, which further promotes the reaction of molybdenum and sulfur, effectively reduces the formation energy of MoS2, and ultimately promotes the reaction synthesis of MoS2.

[0077] Furthermore, the Fe 0.96 The S@MoS2 nanocomposite material was tested by electron microscopy, and the results are as follows Figure 2 Observation Figure 2 It can be seen that Fe 0.96 The S@MoS2 nanocomposite material forms a special bird's nest-like heterogeneous structure, which effectively maintains the overall structural integrity and tightness of the composite material. This structure is conducive to the uniform dispersion of material components and effectively avoids Fe 0.96 SThe particle agglomeration problem caused by strong magnetism.

[0078] 2. Zeta potential and XPS

[0079] Fe 0.96 S@MoS2 nanocomposites, Fe 0.96 The Zeta potential test results of S nanomaterials and MoS2 nanomaterials are shown in Figure 2. Figure 3 Observation Figure 3 It can be seen that Fe 0.96 The Zeta potential of S@MoS2 nanocomposites is higher than that of Fe 0.96 S nanomaterials, which is due to the significant presence of unsaturated sulfur sites at the edges of MoS2 nanosheets, Fe 0.96 S@MoS2 nanocomposites exhibit H adsorption from solution + The significant ability of Fe ions improves the Zeta potential of the composite material, thereby generating a surface acidic microenvironment on the surface of the composite material and promoting the 0.96 Fe in S 2+ dissolution, enhancing homogeneous reaction, is beneficial to the activation of PMS and further improves the catalytic performance of the material.

[0080] Fe 0.96 The S@MoS2 nanocomposite material was subjected to XPS test, and the results are as follows Figure 4 Observation Figure 4 It can be seen that the composite material synthesized by the co-ball milling reaction of iron powder, molybdenum powder and sulfur powder has abundant S vacancies. Due to the strong collision of the grinding balls, the powder particles are subjected to repeated extrusion, shearing and impact. The continuous high-energy collision leads to significant plastic deformation of the internal structure and many defects (vacancies and dislocations) inside the material, which makes the material rich in sulfur vacancies (Sulfur Vacancies, SVs), increases the electron transfer ability of the composite material, and has strong adsorption and catalytic ability for PMS, which is conducive to the generation of various active species, thereby further improving the catalytic performance of the material.

[0081] 3. Degradation ability

[0082] ①Degradation ability of different nanomaterials

[0083] The Fe prepared in Example 1 0.96 S@MoS2 nanocomposite material, Fe 0.96 S nanomaterials, MoS2 nanomaterials in Comparative Example 2, and Fe 0.96 The S+MoS2 physical composite material was used as a catalyst to activate PMS to degrade bisphenol A (BPA) in organic wastewater. PMS alone was used as a blank control.

[0084] The degradation conditions are specifically: the target degradation substance is a 20 mg / L BPA solution, the initial pH of the pollutant is 6.05, and the catalyst dosage is 0.25 g / L; after the catalyst is added and adsorption-desorption equilibrium is reached (30 min), 0.6 mM PMS is added, and the stirring continuous reaction is carried out.

[0085] The concentration of BPA corresponding to different reaction times is determined by high performance liquid chromatography (HPLC), and the degradation rate of BPA is calculated.

[0086] The above degradation results are shown in Figure 5 Fe 0.96 S+PMS, MoS2+PMS and PMS alone all exhibit weak degradation effect on BPA; Fe 0.96 S+MoS2+PMS system exhibits enhanced degradation effect compared with Fe 0.96 S+PMS or MoS2+PMS alone, and the degradation efficiency within 30 min is close to 50%. Fe 0.96 S@MoS2+PMS system has much higher degradation performance than other materials, and 100% degradation can be completed in 20 min. The above results can prove that the Fe 0.96 S@MoS2 nanocomposite provided by the application has excellent organic pollutant removal efficiency.

[0087] Further, the TOC removal performance of the Fe 0.96 S@MoS2 nanocomposite prepared in Example 1, the Fe 0.96 S nanomaterial in Comparative Example 1 and the MoS2 nanomaterial in Comparative Example 2 on pollutants is tested.

[0088] Figure 6 is a TOC removal effect diagram. It can be observed that the Fe 0.96 S@MoS2 nanocomposite exhibits more excellent TOC removal effect than the Fe 0.96 S nanomaterial and the MoS2 nanomaterial.

[0089] ②Fe 3+ reduction capacity

[0090] The Fe 0.96 S@MoS2 nanocomposite prepared in Example 1, the Fe 0.96 S nanomaterial in Comparative Example 1 and the MoS2 nanomaterial in Comparative Example 2 are tested for Fe 3+ reduction capacity.

[0091] At room temperature, 100 mg / L Fe 3+The FeCl3 solution with a concentration of 1.5-2.0 was used as the simulated reduction reaction solution. 0.25 g / L of catalyst was added to the reaction solution and stirred for continuous reaction. The FeCl3 solution with different reaction times was determined by o-phenanthroline spectrophotometry. 2+ Ion concentration reflects the different materials' Fe 3+ restoration ability.

[0092] The above results are as follows Figure 7 As shown, the results show that: Fe 0.96 S+100mg / L Fe 3+ System for Fe 3+ Basically no reducing effect; MoS2+100mg / L Fe 3+ System for Fe 3+ The reduction of Fe 3+ The reduction effect can reach nearly 30% within 30 minutes; while Fe 0.96 S@MoS2+100mg / L Fe 3+ System Fe 3+ The reduction capacity is much higher than other materials, nearly 75% of Fe 3+ It can be reduced within 30 minutes. 0.96 S@MoS2 nanocomposites have excellent Fe 3+ Restoration ability.

[0093] ③The influence of pH

[0094] The specific degradation conditions are as follows: the target degradation product is 20 mg / L BPA solution, and the initial pH of the pollutant solution is adjusted to 3, 5, 7, and 9 using sodium hydroxide and sulfuric acid. 0.96 The dosage of S@MoS2 nanocomposite was 0.25 g / L. After reaching adsorption-desorption equilibrium (30 min), 0.6 mM PMS was added and the reaction was continued with stirring.

[0095] The concentrations of BPA corresponding to different reaction times were determined by high performance liquid chromatography (HPLC), and the degradation rates of BPA were calculated.

[0096] Under different initial pH conditions, Fe 0.96 The degradation results of BPA by S@MoS2 nanocomposites are shown in Figure 8 ,Depend on Figure 8 It can be seen that Fe 0.96 The S@MoS2 nanocomposite material maintained excellent degradation performance over a wide pH range, especially at high pH (pH = 9), achieving nearly 100% BPA degradation within 30 minutes.

[0097] ④Degradation of different organic pollutants

[0098] The degradation conditions are as follows: the initial pH of the pollutants is 6.05, the Fe 0.96 The dosage of the S@MoS2 nanocomposite is 0.25 g / L; after reaching the adsorption-desorption equilibrium (30 min), 0.6 mM of PMS is added, and the continuous reaction is stirred. The target degradation substance is a 20 mg / L sulfadiazine (SDZ) solution and a 20 mg / L rhodamine B (RhB) solution.

[0099] The concentration of the pollutants corresponding to different reaction times is determined by high performance liquid chromatography (HPLC) and ultraviolet-visible spectrophotometry, and the degradation rate of each pollutant is calculated.

[0100] Observation Figure 9 It can be seen that the Fe 0.96 The S@MoS2 nanocomposite can degrade 100% of SDZ within 10 min; observation Figure 10 It can be seen that the Fe 0.96 The S@MoS2 nanocomposite can degrade 100% of RhB within 5 min.

[0101] ⑤Cyclic ability

[0102] Step one: under room temperature conditions, a 20 mg / L BPA solution (initial pH is 6.05) is prepared and used as simulated organic wastewater. In the scaled-up system, Fe 0.96 S@MoS2 nanocomposite (catalyst dosage is 0.25 g / L) is added to the organic wastewater, and after reaching the adsorption-desorption equilibrium (30 min), 0.6 mM of PMS is added, and the continuous reaction is stirred. The BPA concentration corresponding to different reaction times is determined by high performance liquid chromatography (HPLC), and the degradation rate of BPA in the first cycle is calculated.

[0103] Step two: the liquid after the reaction of the scaled-up system is suction filtered, the catalyst after suction filtration is dried in a vacuum oven for 4 h, and is ground into powder.

[0104] Step three: the recovered and dried Fe 0.96 S@MoS2 nanocomposite is used for the second, third, fourth, and fifth cycle degradation experiments, which are consistent with steps one and two.

[0105] The cycle results are shown in Figure 10 After 5 cycles, the degradation rate of BPA by the Fe 0.96 S@MoS2 nanocomposite is still close to 100%, which shows that the long-term stability of the catalytic activity of the Fe 0.96 S@MoS2 nanocomposite can be recycled for degradation of organic pollutants.

Claims

1. A divacancy Fe 0.96 S@MoS2 nanocomposite material, characterized in that The divacancy Fe 0.96 S@MoS2 nanocomposites include Fe 0.96 S nanoparticles and MoS2 nanosheets with sulfur vacancies; the divacancy Fe 0.96 Based on the mass of the S@MoS2 nanocomposite material, the content of MoS2 nanosheets is 55 to 70 wt%.

2. The divacancy Fe as claimed in claim 1 0.96 S@MoS2 nanocomposite material, characterized in that The divacancy Fe 0.96 The S@MoS2 nanocomposite material has a bird's nest-like heterogeneous structure and its particle size is 100 to 900 nm.

3. The divacancy Fe according to claim 1 or 2 0.96 The preparation method of S@MoS2 nanocomposite material is characterized in that: include: Iron powder, molybdenum powder, sulfur powder and inert wet grinding medium are ball-milled to obtain a low crystalline precursor, which is then calcined under an inert atmosphere to obtain divacancy Fe 0.96 S@MoS2 nanocomposite materials.

4. The preparation method according to claim 3, wherein The molar ratio of the iron powder, molybdenum powder and sulfur powder is 1:(1-6):(5-30); Preferably, the purity of the iron powder is ≥98%, the purity of the molybdenum powder is ≥98%, and the purity of the sulfur powder is ≥95%.

5. The preparation method according to claim 3, wherein The ball milling conditions are: rotation speed 300-600 rpm, time 24-48 h; Preferably, the ball milling beads are ceramic ball milling beads; Preferably, the ceramic ball milling beads are zirconium oxide grinding beads, aluminum oxide grinding beads or silicon nitride grinding beads; Preferably, the mass ratio of the amount of the ball milling beads to the sum of the mass of the iron powder, molybdenum powder and sulfur powder is (30-60):1; Preferably, the diameter of the ball milling beads is 2 to 10 mm; Preferably, the inert wet grinding medium is water or alcohol; Preferably, the alcohol is methanol, ethylene glycol or ethanol; Preferably, the mass volume ratio of the amount of the inert wet grinding medium to the sum of the masses of the iron powder, molybdenum powder and sulfur powder is (0.5-2.5) mL:1 g.

6. The preparation method according to claim 3, wherein The calcination conditions are: temperature 500-700°C, heating rate 3-15°C / min, time 2-6h, protective gas flow rate 0.5-2L / min; Preferably, the inert atmosphere is nitrogen and / or argon.

7. The divacancy Fe according to claim 1 or 2 0.96 S@MoS2 nanocomposite material or divacancy Fe prepared by the preparation method according to any one of claims 3 to 6 0.96 S@MoS2 nanocomposites have the potential to catalyze the activation of oxidants and promote Fe 2+ / Fe 3+ Application of redox cycles in water treatment for degradation of organic pollutants.

8. The use according to claim 7, characterized in that The application method is: adding the divacancy Fe 0.96 S@MoS2 nanocomposite materials and oxidants react to remove organic pollutants from water bodies; Preferably, the initial pH of the water containing organic pollutants is 3 to 9; Preferably, the concentration of organic pollutants in the water containing organic pollutants is 10 to 60 mg / L; Preferably, the divacancy Fe 0.96 The added amount of the S@MoS2 nanocomposite material is 0.1-0.8 g / L, and the added amount of the oxidant is 0.2-1 mM.

9. The use according to claim 7 or 8, characterized in that The organic pollutant is at least one of bisphenol compounds, antibiotics, and organic dyes; Preferably, the bisphenol compound is bisphenol A, bisphenol F or bisphenol S; Preferably, the antibiotic is sulfadiazine, sulfamethoxazole or sulfamethazine; Preferably, the organic dye is rhodamine B or methylene blue.

10. The use according to claim 7 or 8, characterized in that The oxidant is at least one of peroxymonosulfate, peroxydisulfate, peracetic acid, ozone, and hydrogen peroxide.

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