Iron activated sulfide and method of making same, mercury capture method

Abstract

This invention provides an iron-activated sulfide, its preparation method, and a mercury-trapping method; wherein, the preparation method of the iron-activated sulfide includes: obtaining a precursor by hydrothermal reaction of a metal source with thiourea, and then mixing it with a ferric sulfate solution to obtain a product with petal-shaped MoS2 as the matrix and Fe... 3+ Atomic-scale dispersed iron-activated sulfides anchored to the basal plane. The iron-activated sulfides provided by this invention exhibit Hg activity over a wide temperature range of 30-200℃. 0 It has high adsorption capacity and good thermal stability, making it suitable for efficient mercury removal from complex smelting flue gas.

Description

Technical Field

[0001] This invention belongs to the field of flue gas treatment technology, specifically relating to an iron-activated sulfide and its preparation method, and a mercury capture method. Background Technology

[0002] Mercury, as a global pollutant, is extremely toxic, bioaccumulative, and capable of long-distance migration, posing a serious threat to the ecological environment and human health. Mercury in flue gas is mainly in the form of elemental mercury (Hg). 0 ), oxidized mercury (Hg) 2+ Mercury exists in both Mg and particulate forms. Among them, Hg... 0 Due to its high volatility, low water solubility, and chemical inertness, mercury is difficult to remove effectively by existing flue gas purification equipment (such as wet desulfurization and dust removal devices), making it a challenge and key area for mercury pollution control.

[0003] Among numerous mercury removal technologies, adsorption is considered the most promising due to its simple principle, wide applicability, and ability to recover mercury. Developing efficient, stable, and economical adsorbents is the core of this technology. In recent years, metal sulfides (such as MoS2, CuS, and ZnS) have gained attention due to their rich surface content of unsaturated sulfur species, good tolerance to SO2, and ability to react with Hg. 0 The formation of stable HgS and other advantages make it a promising adsorbent for mercury removal. However, most sulfur atoms on the surface of ordinary metal sulfide crystals are in a saturated coordination state, resulting in a limited number of active sites and limiting their effectiveness against Hg. 0 The inherent adsorption activity of these compounds is generally not high.

[0004] A significant bottleneck in existing technologies lies in the difficulty of simultaneously achieving wide temperature range adaptability and high adsorption capacity in mercury adsorbents, which contradicts the need for simple preparation processes. Specifically, many highly active nano-adsorbents (such as nano-CuS) prepared through complex processes exhibit excellent adsorption capacity at low temperatures (<120℃), but their active sites are easily deactivated in high-temperature flue gas environments, leading to a sharp decline in adsorption capacity and limiting their application in real-world industrial scenarios (especially in the medium-high temperature range of 120-150℃). Some materials that maintain structural stability at higher temperatures often have limited intrinsic adsorption capacity, or still require complex modification steps to achieve moderate performance. Existing methods for improving performance often focus on the reconstruction or doping of the material itself, which is cumbersome, lacking a universal and simple post-processing method that can activate common sulfides and significantly improve their wide temperature range (especially the medium-high temperature range) adsorption capacity. Therefore, it is necessary to provide an iron-activated sulfide and its preparation method, as well as a mercury-capturing method, to alleviate or solve the above problems. Summary of the Invention

[0005] To address the technical problem of the difficulty in simultaneously achieving wide temperature range adaptability and high adsorption capacity of mercury adsorbents in commonly used technologies, and the contradiction between this and a simple preparation process, this invention provides a method for preparing iron-activated sulfides, comprising the following steps:

[0006] A metal source and a sulfur source are dispersed in water, and a hydrothermal reaction is carried out to collect the solid and obtain a precursor. The molar ratio of the metal source to the sulfur source is 0.8-1.2:1, and the metal source includes at least one of a molybdenum source and a zinc source.

[0007] The precursor was mixed with an iron agent, and the solid was collected to obtain the iron-activated sulfide; the ratio of the precursor to ferric sulfate was 0.8-1.2 g: 5 × 10⁻⁶ g. -4 -5×10 -3 mol.

[0008] Furthermore, the molybdenum source includes ammonium molybdate, the zinc source includes at least one of zinc sulfate and zinc chloride, the sulfur source includes at least one of thiourea and thioacetamide, and the iron agent includes at least one of ferric sulfate, ferric nitrate, and ferric chloride.

[0009] Furthermore, the hydrothermal reaction is carried out at a temperature of 150-200℃ for a duration of not less than 8 hours.

[0010] Furthermore, the concentration of the iron agent is 1-10 mmol·L⁻¹. -1 The mass-to-volume ratio of the precursor to the iron agent is 0.1-1g:50-100mL.

[0011] The present invention provides an iron-activated sulfide, which is prepared by the preparation method described above, comprising a sulfide matrix having a petal-like structure; and a metal element uniformly anchored on the surface of the sulfide matrix in an atomically dispersed form, wherein the metal element achieves stable immobilization by coordination with the matrix atoms.

[0012] Furthermore, within a temperature range of 30-200℃ and a duration of 80 minutes, the Hg of the iron-activated sulfide... 0 The absorption efficiency is over 90%; the adsorption capacity of the iron-activated sulfide is not less than 40 mg / g.

[0013] Furthermore, based on the XPS peak area, S x 2- The relative atomic percentage content of total sulfur species on the surface of the iron-activated sulfide is not less than 30%.

[0014] This invention provides a method for mercury removal, comprising the steps of: contacting mercury-containing flue gas with an iron-activated sulfide as described above to remove mercury from the mercury-containing flue gas; wherein the mercury concentration in the mercury-containing flue gas is not higher than 500 μg·m³. -3The contact temperature is 30-200℃.

[0015] Furthermore, the mercury-containing flue gas is smelting flue gas, which also contains at least one of SO2, O2, H2O, and HCl.

[0016] Furthermore, the space velocity of the mercury-containing flue gas during the contact process is 2 × 10⁻⁶. 4 m 3 ·h -1 -2.0×10 5 m 3 ·h -1 .

[0017] Compared with the prior art, the present invention has at least the following advantages:

[0018] This invention provides a method for preparing iron-activated sulfides, which effectively solves the core problem of maintaining high adsorption capacity of sulfur-based adsorbents under wide temperature range and complex flue gas conditions through a simplified process. Specifically:

[0019] The iron-activated sulfide provided by this invention has Hg at 150°C 0 Adsorption capacity up to 45 mg·g -1 The efficiency is more than 10 times that of the unmodified sample (P-MoS2); within 100 minutes, the iron-activated sulfide can maintain a high removal efficiency of more than 90% in a wide temperature range of 30-200℃, which breaks through the limitation of most high-performance adsorbents (such as Nano-CuS) that can only perform at their best below 120℃, and makes it adaptable to a wider range of industrial flue gas temperature fluctuations.

[0020] Furthermore, the iron-activated sulfide provided by this invention still achieves an average mercury removal rate of over 90% in simulated complex smelting flue gas containing SO2, O2, H2O, and HCl. This indicates that under conditions of coexistence of typical interfering components, its surface, after being treated with Fe... 3+ The reconstructed active sites exhibit good chemical stability and resistance to poisoning, and are not easily competitively adsorbed or poisoned by acidic components in flue gas (such as SO2 and HCl), thus maintaining excellent mercury removal performance in real smelting flue gas environments. Attached Figure Description

[0021] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.

[0022] Figure 1The image shown is a SEM image of 5Fe / MoS2 in Example 1 of this invention.

[0023] Figure 2 The TEM image of 5Fe / MoS2 in Example 1 of this invention;

[0024] Figure 3 This is a TEM-EDS elemental distribution analysis diagram of 5Fe / MoS2 in Example 1 of this invention;

[0025] Figure 4 The XRD pattern of 5Fe / MoS2 in Example 1 of this invention;

[0026] Figure 5 Raman spectroscopy results for 5Fe / MoS2, 10Fe / MoS2, 2Fe / MoS2, 1Fe / MoS2, and MoS2 in Example 1 of this invention.

[0027] Figure 6 Fe in Example 1 of this invention 3+ Mo 3d XPS spectra of MoS2 before and after activation (MoS2 before activation, 5Fe / MoS2 after activation, referred to as Fe / MoS2 in the figure);

[0028] Figure 7 Fe in Example 1 of this invention 3+ S 2p XPS spectra of MoS2 before and after activation (MoS2 before activation, 5Fe / MoS2 after activation, referred to as Fe / MoS2 in the figure);

[0029] Figure 8 Fe in Example 1 of this invention 3+ The S 2p XPS peak fitting spectra of MoS2 before and after activation (MoS2 before activation, 5Fe / MoS2 after activation, referred to as Fe / MoS2 in the figure), where... Figure 8 (a) is the S 2p XPS peak fitting spectrum of MoS2 before activation. Figure 8 (b) is the S 2p XPS peak fitting spectrum of activated MoS2;

[0030] Figure 9 For the analysis of Hg in 5Fe / MoS2 at different temperatures in Example 2 of this invention 0 Removal efficiency curve;

[0031] Figure 10 In Example 2 of this invention, 5Fe / MoS2 was analyzed at different inlet Hg values. 0 Mercury removal performance at various concentrations;

[0032] Figure 11This is a schematic diagram illustrating the effect of different flue gas components on the mercury removal efficiency of 5Fe / MoS2 in Example 2 of the present invention.

[0033] Figure 12 The Hg of 5Fe / MoS2 at 150℃ in Example 2 of this invention is analyzed. 0 Breakthrough curve and adsorption capacity;

[0034] Figure 13 This is a comparison chart of the adsorption performance of Fe / MoS2 and existing adsorbents over a wide temperature range in Example 2 of this invention.

[0035] Figure 14 In Example 3 of this invention, different sulfur-based adsorbents were subjected to Fe treatment at 50°C and 150°C. 3+ Hg before and after activation 0 Adsorption capacity comparison;

[0036] Figure 15 In Example 3 of this invention, the commercial sulfur-based adsorbent was subjected to Fe treatment at 50°C and 150°C. 3+ Hg before and after activation 0 Adsorption capacity comparison;

[0037] Figure 16 For the analysis of different Fe in Example 3 of this invention 3+ Changes in the mercury removal performance of MoS2 after concentration activation;

[0038] Figure 17 The Hg calculated by DFT in Example 4 of this invention 0 Adsorption energies on different crystal planes of Fe / MoS2;

[0039] Figure 18 Fe in Example 4 of this invention 3+ Electron density difference diagram before and after activation of MoS2 (before activation it is MoS2, after activation it is 5Fe / MoS2, referred to as Fe / MoS2 in the figure);

[0040] Figure 19 For the analysis of Hg in Example 4 of this invention 0 Mo 3d XPS spectra of Fe / MoS2 before and after adsorption;

[0041] Figure 20 For the analysis of Hg in Example 4 of this invention 0 Binding energy shifts in the S 2p XPS spectra of Fe / MoS2 before and after adsorption;

[0042] Figure 21 For the analysis of Hg in Example 4 of this invention 0 S 2p XPS peak patterns of Fe / MoS2 before and after adsorption, where Figure 21 (a) Hg in Example 4 of the present invention0 S 2p XPS peak pattern of Fe / MoS2 before adsorption. Figure 21 (b) Hg in Example 4 of the present invention 0 S 2p XPS peak pattern of Fe / MoS2 after adsorption;

[0043] Figure 22 The Hg-TPD spectrum in Example 4 of this invention is analyzed. Detailed Implementation

[0044] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0045] Furthermore, the technical solutions of the various embodiments of the present invention can be combined with each other, but only if they are based on the ability of those skilled in the art to implement them. When the combination of technical solutions is contradictory or cannot be implemented, it should be considered that such combination of technical solutions does not exist and is not within the scope of protection claimed by the present invention.

[0046] When numerical ranges are given in the embodiments, it should be understood that, unless otherwise stated in the present invention, both endpoints of each numerical range and any value between the two endpoints may be selected. Unless otherwise defined, all technical and scientific terms used in this invention, as well as the prior art known to those skilled in the art and the description of the invention, may be implemented using any prior art methods, devices, and materials similar to or equivalent to the methods, devices, and materials in the embodiments of the present invention.

[0047] This invention provides a method for preparing iron-activated sulfides, comprising the following steps:

[0048] S1. Disperse the metal source and the sulfur source in deionized water, and collect the solid after hydrothermal reaction to obtain the precursor; the molar ratio of the metal source to the sulfur source is 0.8-1.2:1, and the metal source includes at least one of molybdenum source and zinc source.

[0049] In some embodiments, the molybdenum source includes ammonium molybdate, the zinc source includes at least one of zinc sulfate and zinc chloride, and the sulfur source includes at least one of thiourea and thioacetamide.

[0050] In some embodiments, the hydrothermal reaction is carried out at a temperature of 150-200°C for a duration of not less than 8 hours.

[0051] The temperature of the hydrothermal reaction can be 150°C, 160°C, 170°C, 180°C, 190°C, 200°C, and any value between such a minimum and maximum, or any range of any two values; the duration of the hydrothermal reaction can be 8h, 9h, 10h, 12h, 15h, 18h, 20h, 24h, and any duration not less than 8h, including any value between these and any range of any two values.

[0052] In some embodiments, the ratio of the metal source to the water added can be 0.5-1.5 mmol: 50 mL.

[0053] S2. The precursor is mixed with an iron agent solution, and the solid is collected to obtain the iron-activated sulfide; the ratio of the precursor to the iron agent is 0.8-1.2 g: 5 × 10 g. -4 -5×10 -3 mol.

[0054] In some embodiments, the ratio of the precursor to ferric sulfate can be 1g:5×10 -3 -3×10 - 3 mol.

[0055] In some embodiments, the iron agent includes ferric sulfate.

[0056] In some embodiments, the concentration of the iron agent may be 1-10 mmol·L⁻¹. -1 The mass-to-volume ratio of the precursor to the iron agent can be 0.1-1g:50-100mL.

[0057] In some embodiments, the ratio of the precursor to the iron agent may be 0.9-1.1 g: 5 × 10⁻⁶ g. -4 -5×10 -3 mol; In some more specific embodiments, the ratio of the precursor to the iron agent may also be 1 g: 5 × 10⁻⁶. -4 -5×10 -3 mol.

[0058] The present invention provides an iron-activated sulfide, which is prepared by the preparation method described above, comprising a sulfide matrix having a petal-like structure; and a metal element uniformly anchored on the surface of the sulfide matrix in an atomically dispersed form, wherein the metal element achieves stable immobilization by coordination with the matrix atoms.

[0059] For example, the sulfide matrix includes a molybdenum disulfide matrix or a zinc sulfide matrix.

[0060] In some embodiments, within a temperature range of 30-200°C and a time range of 80 minutes, the Hg of the iron-activated sulfide... 0 The absorption efficiency reaches over 90%; the adsorption capacity of the iron-activated sulfide is not less than 40 mg·g. -1 For example, the adsorption capacity of the iron-activated sulfide is not less than 45 mg·g. -1 For example, the adsorption capacity of the iron-activated sulfide is 40-80 mg·g. -1 Or 40-60 mg / g -1 Or 45-80 mg / g -1 Or 45-60 mg / g -1 .

[0061] For example, within a temperature range of 30-150℃, 30-120℃, 30-90℃, 50-150℃, 50-120℃, or 50-90℃, and a time range of 80 minutes, the Hg of the iron-activated sulfide... 0 The absorption efficiency is 90%-100%.

[0062] For example, within a temperature range of 30-80℃, 30-70℃, 30-60℃, 30-50℃, 40-80℃, 40-70℃, 40-60℃, 40-50℃, 45-80℃, 45-70℃, 45-60℃, or 45-55℃, and a time interval of 80 minutes, the Hg of the iron-activated sulfide... 0 The absorption efficiency is 98%-100%.

[0063] It should be noted that the Hg of the Fe / MeS sample 0 Capture capability via Hg 0 Removal efficiency (η) a %, and adsorption capacity (q, mg∙g) -1 The evaluation is performed using the following equation:

[0064]

[0065]

[0066] in and The Hg values ​​at the reactor inlet and outlet are respectively. 0 Concentration, t(min) is the reaction duration, m(g) is the mass of mercury adsorbent. and These represent the Hg values ​​at the reactor inlet and outlet within the corresponding time intervals. 0 The total mass.

[0067] In some embodiments, S, measured by XPS peak area x 2- The relative atomic percentage content of total sulfur species on the surface of the iron-activated sulfide is not less than 30%.

[0068] Compared with the prior art, the present invention has at least the following advantages:

[0069] This invention provides a method for preparing iron-activated sulfides, which effectively solves the core problem of maintaining high adsorption capacity of sulfur-based adsorbents under wide temperature range and complex flue gas conditions through a simplified process. Specifically:

[0070] The iron-activated sulfide provided by this invention has Hg at 150°C 0 Adsorption capacity up to 45 mg·g -1 The efficiency is more than 10 times that of the unmodified sample (P-MoS2); within 100 minutes, the iron-activated sulfide can maintain a high removal efficiency of more than 90% in a wide temperature range of 30-200℃, which breaks through the limitation of most high-performance adsorbents (such as Nano-CuS) that can only perform at their best below 120℃, and makes it adaptable to a wider range of industrial flue gas temperature fluctuations.

[0071] Furthermore, the iron-activated sulfide provided by this invention still achieves an average mercury removal rate of over 90% in simulated complex smelting flue gas containing SO2, O2, H2O, and HCl. This indicates that under conditions of coexistence of typical interfering components, its surface, after being treated with Fe... 3+ The reconstructed active sites exhibit good chemical stability and resistance to poisoning, and are not easily competitively adsorbed or poisoned by acidic components in flue gas (such as SO2 and HCl), thus maintaining excellent mercury removal performance in real smelting flue gas environments.

[0072] It should be noted that, to achieve the above-mentioned technical effects, this invention creates highly active and stable trapping sites through surface electronic reconstruction. This is not a simple physical mixing or bulk doping, but rather a reconstruction of the sulfide basal surface achieved through a precisely controlled interfacial chemical process. Specifically:

[0073] Selective anchoring: Intrinsic sulfur vacancies exist on the surface of the hydrothermally prepared precursor (P-MeS) (confirmed by EPR testing). When combined with Fe... 3+ When solutions are mixed, highly electronegative Fe 3+ It will spontaneously and selectively chemisorb onto these sulfur vacancies (EPR signal varies with Fe). 3+ The load increased and then decreased, confirming that the empty space was occupied.

[0074] Atomic-level dispersion and electronic manipulation: Fe 3+Using sulfur vacancies on the precursor surface as anchors, Fe aggregates were stably immobilized in an atomically dispersed manner (no Fe aggregates were observed by TEM / EDS), constructing an "electron-deficient cation-sulfur support" interface. This process triggered significant surface electron rearrangement: XPS analysis showed that Fe... 3+ The introduction of active sulfur species (S2) on the material surface 2- / S n 2- The proportion increased significantly from 28.9% to 32.8%. This is due to Fe 3+ As a strongly electron-deficient center, it pulls electrons from surrounding sulfur atoms, creating more highly active unsaturated sulfur sites rich in delocalized electrons.

[0075] Constructing efficient "capture-fixation" sites: DFT theoretical calculations reveal the root cause of performance improvement at the molecular level. On the unmodified MoS2 basal surface, Hg 0 The adsorption energy is relatively weak (-22.41 kJ·mol⁻¹). -1 Fe 3+ After modification, strong adsorption centers were formed at the anchored basal surface, which is conducive to Hg adsorption. 0 The adsorption energy increases sharply to -103.5 kJ·mol⁻¹ -1 This confirms Fe 3+ The introduction of [a specific substance] "activates" the originally inert basal surface into a highly active one. Simultaneously, the electron density difference (EDD) plot shows that electrons migrate from Hg [a specific location] during adsorption. 0 The Hg-S bonds are transferred to the Fe-S active region on the material surface, eventually forming stable Hg-S bonds (Hg-TPD confirmed that the product is α-HgS with higher thermal stability), thus realizing Hg-S transfer. 0 Efficient oxidation and firm fixation.

[0076] This invention provides a method for mercury capture, comprising the following steps:

[0077] The mercury-containing flue gas is contacted with the iron-activated sulfide as described above to remove mercury from the flue gas; the mercury concentration in the mercury-containing flue gas is not higher than 500 μg·m³. -3 The contact temperature is 30-200℃.

[0078] For example, the mercury concentration in the mercury-containing flue gas can be 10 μg·m³. -3 50 μg·m -3 100 μg·m -3 200 μg·m -3 300 μg·m -3 400 μg·m -3 500 μg·m -3 and 10 μg·m -3 With 500 μg·m-3 Each value between, or a range of any two values.

[0079] For example, the contact temperature can be 30°C, 40°C, 50°C, 60°C, 70°C, 80°C, 90°C, 100°C, 110°C, 120°C, 130°C, 140°C, 150°C, 160°C, 170°C, 180°C, 190°C, 200°C, and any value between 30°C and 200°C, or a range of any two values.

[0080] In some embodiments, the mercury-containing flue gas is smelting flue gas, which also contains at least one of SO2, O2, H2O, and HCl.

[0081] For example, the volume percentage of SO2, O2, or H2O in the mercury-containing flue gas can be greater than 0% and less than 10%; for another example, the volume percentage of SO2, O2, or H2O in the mercury-containing flue gas can be 2-10%, 2%-8%, 2%-6%, 4-10%, 4%-8%, or 5%-6%.

[0082] For example, the concentration of HCl in the mercury-containing flue gas can be greater than 0 and less than 15 ppm; for another example, the concentration of HCl in the mercury-containing flue gas can be 1-15 ppm or 2-15 ppm or 5-15 ppm or 8-15 ppm or 1-12 ppm or 2-12 ppm or 5-12 ppm or 8-12 ppm.

[0083] In some embodiments, the space velocity of the mercury-containing flue gas during the contact process is 2 × 10⁻⁶. 4 m 3 ·h -1 -2.0×10 5 m 3 ·h -1 .

[0084] For example, the space velocity of the mercury-containing flue gas during the contact process can be 2 × 10⁻⁶. 4 m 3 ·h -1 -1.5×10 5 m 3 ·h -1 Or 2×10 4 m 3 ·h -1 -1.2×10 5 m 3 ·h -1 .

[0085] To facilitate a further understanding of the present invention by those skilled in the art, the following examples are provided:

[0086] Example 1

[0087] Preparation of iron-activated sulfides.

[0088] S1. Preparation of MeS: 1 mmol of metal source and 1 mmol of thiourea were completely dissolved in 50 mL of deionized water and stirred vigorously at 300 rpm for 30 min. The mixture was then transferred to a 100 mL Teflon-lined autoclave and kept at 180 °C for 12 h. A black powder was collected by filtration, washed several times with deionized water and ethanol, and then dried in a vacuum drying oven at 80 °C for 10 h to obtain MeS, denoted as P-MeS (precursor). This step also yielded P-MoS and P-ZnS.

[0089] S2. Preparation of Fe / MeS: Disperse 100 mg of P-MeS in 50 mL of deionized water and sonicate for 15 min. Then add 50 mL of ferric sulfate solution of different concentrations (1 mmol·L⁻¹, respectively). -1 2 mmol·L -1 5 mmol·L -1 10 mmol·L -1 After sonication for 5 minutes, the mixture was stirred at room temperature for 1 hour. The sample was collected by filtration, washed several times with deionized water and ethanol, and then dried in a vacuum drying oven at 80°C for 10 hours to obtain Fe / MeS, denoted as XFe / MeS, where X represents the concentration of Fe3(SO4)3 as X mmol·L. -1 .

[0090] Based on the above steps S1 and S2, with molybdenum as the metal source (ammonium molybdate) and ferric sulfate solution concentration of 1 mmol / L (i.e., the ratio of precursor to ferric sulfate added is 1 g: 5 × 10⁻⁶), -4 In the case of mol), the iron-activated sulfide prepared is denoted as 1Fe / MoS;

[0091] When the metal source is molybdenum (ammonium molybdate) and the concentration of the ferric sulfate solution is 2 mmol·L⁻¹ -1 (That is, the ratio of the precursor to ferric sulfate added is 1g: 1×10) -3 In the case of (mol), the iron-activated sulfide prepared is denoted as 2Fe / MoS;

[0092] When the metal source is molybdenum (ammonium molybdate) and the ferric sulfate solution concentration is 5 mmol·L⁻¹ -1 (That is, the ratio of the precursor to ferric sulfate is 1g: 2.5×10) -3 The iron-activated sulfide prepared under the condition of (mol) is denoted as 5Fe / MoS;

[0093] With molybdenum as the metal source (ammonium molybdate) and a ferric sulfate solution concentration of 10 mmol·L⁻¹, -1 (That is, the ratio of the precursor to ferric sulfate is 1g: 5×10) -3 In the case of mol), the iron-activated sulfide prepared is denoted as 10Fe / MoS;

[0094] When the metal source is zinc (zinc sulfate), the concentration of the ferric sulfate solution is 5 mmol·L⁻¹. -1 (That is, the ratio of the precursor to ferric sulfate is 1g: 2.5×10) -3 The iron-activated sulfide prepared under the condition of (mol) is denoted as 5Fe / ZnS.

[0095] Comparative Example 1

[0096] 1. Compared to Example 1, only step S1 is adjusted, and the rest remains unchanged:

[0097] S1. Preparation of MeS: 1 mmol copper sulfate and 1 mmol thiourea were completely dissolved in 50 mL deionized water and stirred vigorously at 300 rpm for 30 min. The mixture was then transferred to a 100 mL Teflon-lined autoclave and kept at 180 °C for 12 h. A black powder was collected by filtration, washed several times with deionized water and ethanol, and then dried in a vacuum drying oven at 80 °C for 10 h to obtain P-CuS.

[0098] S2. Preparation of Fe / MeS: Disperse 100 mg P-CuS in 50 mL of deionized water and sonicate for 15 min. Then add 50 mL of 5 mmol·L⁻¹ water. -1 The ferric sulfate solution was sonicated for 5 minutes and stirred at room temperature for 1 hour. The sample was collected by filtration, washed several times with deionized water and ethanol, and then dried in a vacuum drying oven at 80°C for 10 hours to obtain 5Fe / CuS.

[0099] That is, with copper as the metal source (copper sulfate) and the ferric sulfate solution concentration being 5 mmol·L⁻¹ -1 (That is, the ratio of the precursor to ferric sulfate is 1g: 2.5×10) -3 In the case of mol), the iron-activated sulfide prepared is denoted as 5Fe / CuS, wherein the precursor prepared in step S1 is denoted as P-CuS.

[0100] 2. Compared to Example 1, only step S1 is adjusted, and the rest remains unchanged:

[0101] S1. Preparation of MeS: 1 mmol lead acetate and 1 mmol thiourea were completely dissolved in 50 mL of deionized water and stirred vigorously at 300 rpm for 30 min. The mixture was then transferred to a 100 mL Teflon-lined autoclave and kept at 180 °C for 12 h. A black powder was collected by filtration, washed several times with deionized water and ethanol, and then dried in a vacuum drying oven at 80 °C for 10 h to obtain P-PbS.

[0102] S2. Preparation of Fe / MeS: 100 mg of P-PbS was dispersed in 50 mL of deionized water and sonicated for 15 min. Then, 50 mL of 5 mmol / L ferric sulfate solution was added, and the mixture was sonicated for 5 min and stirred at room temperature for 1 h. The sample was collected by filtration, washed several times with deionized water and ethanol, and then dried in a vacuum drying oven at 80°C for 10 h to obtain 5Fe / PbS.

[0103] That is, with lead as the metal source (lead acetate) and the ferric sulfate solution concentration being 5 mmol·L⁻¹ -1 (That is, the ratio of the precursor to ferric sulfate is 1g: 2.5×10) -3 In the case of mol), the iron-activated sulfide prepared is denoted as 5Fe / PbS, wherein the precursor prepared in step S1 is denoted as P-PbS.

[0104] Comparative Example 2

[0105] Compared to Example 1, all other conditions remain unchanged in this comparative example, except for step S1.

[0106] S1. Obtain commercial sulfur-based adsorbents MeS, namely CuS, ZnS, PbS and MoS2, all purchased from Aladdin.

[0107] S2. Preparation of Fe / commercial-MeS: Disperse 100 mg of commercial sulfur-based adsorbent in 50 mL of deionized water and sonicate for 15 min. Then add 50 mL of 5 mmol·L⁻¹ adsorbent. -1 The ferric sulfate solution was sonicated for 5 minutes and stirred at room temperature for 1 hour. The sample was collected by filtration, washed several times with deionized water and ethanol, and then dried in a vacuum drying oven at 80°C for 10 hours to obtain Fe / commercial-MeS, which were denoted as Fe / commercial-CuS, Fe / commercial-ZnS, Fe / commercial-PbS, and Fe / commercial-MoS2, respectively.

[0108] It should be noted that 1Fe / MoS, 2Fe / MoS, 5Fe / MoS, 10Fe / MoS, and 5Fe / ZnS mentioned in the following analytical examples 1-4 are derived from Example 1 of the present invention; 5Fe / CuS and P-PbS are derived from Comparative Example 1 of the present invention; and Fe / commercial-MoS2, Fe / commercial-ZnS, Fe / commercial-PbS, and Fe / commercial-CuS mentioned in the following analytical examples 1-4 are derived from Comparative Example 2 of the present invention.

[0109] Analysis example 1

[0110] Characterization analysis.

[0111] Fe was analyzed using SEM and TEM. 3+ Microstructures on the surface of MoS2, such as Figure 1 SEM images show that Fe 3+ The activated MoS2 sample (5Fe / MoS2) exhibited a typical petal-like structure with no surface aggregation. Figure 2 As shown, TEM images confirm that 5Fe / MoS₂ has a thin, layered structure, and no obvious aggregation occurred after activation, indicating that Fe is dispersed on the surface of the MoS₂ substrate. In the high-resolution TEM images, Fe… 3+ The highly dispersed bright spots on the surface of MoS2 after activation indicate that iron atoms exist in the form of dispersed small clusters or single atoms.

[0112] like Figure 3 As shown, TEM-EDS elemental distribution analysis of 5Fe / MoS2 revealed that Fe elements were uniformly distributed in the MoS2 matrix without obvious agglomeration, indicating that Fe... 3+ Activation is essentially a process of surface chemical adsorption and atomic-level dispersion, without phase deposition.

[0113] like Figure 4 As shown, Fe was analyzed by XRD. 3+ The effect of modification on the crystal structure of MoS2. P-MoS2 (the Fe-free precursor obtained in step S1 of Example 1) 3+ The XRD pattern of activated hydrothermal synthesized molybdenum sulfide (MoS2) agrees well with the standard PDF 77-1716 MoS2, showing a distinct characteristic peak belonging to the 002 crystal plane at a 2θ angle of 12.6°. The corresponding interlayer spacing, calculated using the Bragg equation (d = 0.5λ / sin(θ)), is 6.6 Å. After being treated with different concentrations of Fe... 3+ After activation, the intensity and width of the sample diffraction peaks did not change significantly, which proves that Fe 3+ Activation did not change the phase structure of MoS2, and no Fe-related phases appeared. 3+ The characteristic peaks indicate that Fe 3+ No crystals formed.

[0114] like Figure 5 As shown, the effect of Fe activation on the layered structure of MoS2 was analyzed using Raman spectroscopy. The Fe / MoS ratios at 148, 236, and 337 cm⁻¹ were [data missing]. -1 Characteristic peaks belonging to modes J1, J2, and J3 appear at 283, 377, and 405 cm⁻¹. -1 Appearance belongs to E 1g E 2g A 1g The characteristic peaks of the model indicate that it has a mixed phase structure of 1T and 2H. (Fermentation / Fermentation / Fermentation) 3+ After activation, none of the characteristic peaks showed significant shifts or broadening, indicating that the mixed-phase structure of MoS2 remained unchanged after activation. Furthermore, no Fe-S bonding vibrational modes were found in the Raman spectroscopy. Combining the XRD, TEM, and Raman spectroscopy results, it can be inferred that Fe... 3+ It is adsorbed on the MoS2 surface in a highly dispersed atomic form, and anchored to the basal surface of MoS2 through coordination with surface atoms. Fe 3+ Activation mainly involves surface atoms and failed to alter the crystal and layered structure of MoS2.

[0115] like Figure 6 As shown, Fe 3+ Mo 3d before and after activation 3 / 2 and 3D 5 / 2 The ratio of peak position to peak intensity did not change significantly. For example... Figure 7 As shown, Fe 3+ S 2p before and after activation 1 / 2 and 2p 3 / 2 The peak intensity changed significantly, as can be seen from the peak division of the S 2p spectrum. Figure 8 ), Fe 3+ S after activation x 2- The proportion increased from 28.9% to 32.8%, confirming that Fe... 3+ This can alter the surface charge structure of sulfur, affecting the distribution of sulfur valence states. Since sulfur is primarily located on the MoS2 basal plane, it is speculated that Fe... 3+ It is more likely to adsorb onto the MoS2 substrate.

[0116] Analysis example 2

[0117] Hg 0 Adsorption capacity test.

[0118] Thermal stability test (using 5Fe / MoS2, mercury concentration of 200 μg·m) -3 The background atmosphere is pure N2, and the airspeed is 1.2 × 10⁻⁶. 5 m 3 ·h -1).like Figure 9 As shown, the thermal stability of the adsorbent was evaluated through a temperature gradient experiment. It was found that within 80 min, the Hg of 5Fe / MoS2 remained stable within the range of 50-150 °C. 0 With an absorption efficiency exceeding 80%, it is evident that iron-activated sulfides possess excellent Hg absorption capacity across a wide temperature range. 0 Adsorption stability.

[0119] Experiment on mercury concentration gradient in mercury-containing flue gas. (Using 5Fe / MoS2, temperature 150℃, background atmosphere pure N2, space velocity 1.2×10⁻⁶) 5 m 3 ·h -1 )like Figure 10 As shown, its adaptability to dynamic changes in flue gas mercury concentration was evaluated through a flue gas mercury concentration gradient experiment. The initial mercury concentration in the flue gas was 100 μg·m³. -3 The airspeed is 1.2 × 10⁻⁶. 5 m 3 / h (corresponding to an initial mercury concentration of 100 μg·m -3 ), export Hg 0 The concentration was consistently maintained at 0 μg·m -3 When the initial mercury concentration was 200 μg·m -3 300 μg·m -3 500 μg·m -3 At that time, after a 60-minute test, Hg 0 The adsorption efficiency decreased by 7%, 25%, and 30%, respectively; while when the space velocity decreased to 2×10 4 m 3 ·h -1 At that time, it can be completely adsorbed under high concentration of flue gas, indicating that the material still has good adsorption stability under high concentration of flue gas mercury.

[0120] The effect of different flue gas components on the performance of mercury adsorbents. (Using 5Fe / MoS2, temperature 150℃, mercury concentration 200 μg·m³) -3 The airspeed is 1.2 × 10⁻⁶. 5 m 3 ·h -1 )like Figure 11 As shown, the effects of O2, SO2, H2O, and HCl alone on the activated sample Hg 0 The removal efficiency was minimally affected, and an average mercury removal rate of 94.3% could still be achieved in a complex atmosphere of simulated non-ferrous metallurgical flue gas (N2+6%H2O+6%O2+6%SO2+100ppmHCl), demonstrating excellent resistance to poisoning.

[0121] Mercury adsorption capacity determination. (Using 5Fe / MoS2, temperature 150℃, flue gas pure N2, mercury concentration 200 μg·m ... -3 The airspeed is 1.2 × 10⁻⁶. 5 m 3 ·h -1 )like Figure 12 As shown, the Hg content of 5Fe / MoS2 was measured through a continuous mercury removal experiment lasting 2000 min. 0 The adsorption capacity reached 46.03 mg·g -1 The value was significantly higher than that of unmodified MoS2, indicating that Fe... 3+ Activation can significantly enhance the mercury adsorption capacity of MoS2.

[0122] like Figure 13 As shown, 5Fe / MoS2 exhibits unique advantages in wide-temperature adsorption. The maximum adsorption capacity of existing mercury adsorbents is typically below 120℃, limiting their applicability in high-temperature industrial environments. In contrast, Fe / MoS2 maintains excellent Hg adsorption capacity at both low and high temperatures. 0 Capture performance: even at 150°C, the adsorption capacity exceeds 46 mg·g. -1 This high-temperature elasticity, combined with strong Hg 0 The adsorption capacity makes Fe / MoS2 an effective adsorbent for mercury removal under harsh flue gas conditions.

[0123] Analysis example 3

[0124] like Figure 14 As shown, (contact temperature is 150℃ or 50℃, background atmosphere is pure N2, mercury concentration is 200 μg·m⁻²) -3 The airspeed is 1.2 × 10⁻⁶. 5 m 3 ·h -1 ) after Fe 3+ After activation, the Hg of all hydrothermally synthesized sulfides under flue gas at 50℃ and 150℃ was measured. 0 The adsorption performance of all three types of MoS2 was significantly improved. Specifically, the Hg adsorption capacity of MoS2 after Fe activation was significantly enhanced. 0 The adsorption performance showed the greatest improvement, with adsorption capacities increasing by 52% and 61% within 180 min at 50℃ and 150℃, respectively. Meanwhile, the Hg content of Fe / MoS2 also increased. 0 The adsorption performance remained high across a wide temperature range. It should be noted that the CuS in the figure is the P-CuS obtained in step S1 of Comparative Example 1 of this invention, and the 50℃ figure corresponds to the Hg of P-CuS at a contact temperature of 50℃. 0 Adsorption capacity, 50℃-Fe diagram corresponding to Hg of 5Fe / CuS prepared in Example 1 at a contact temperature of 50℃. 0Adsorption capacity, with the graph showing Hg of P-CuS at a contact temperature of 150℃. 0 Adsorption capacity, 150℃-Fe diagram corresponding to Hg of 5Fe / CuS at a contact temperature of 150℃ 0 Adsorption capacity.

[0125] In the figure, PbS corresponds to P-PbS obtained in step S1 of Comparative Example 1 of this invention. Its legend is consistent with that of CuS, representing the Hg of P-PbS and 5Fe / PbS at 50℃ and 150℃, respectively. 0 Adsorption capacity. The ZnS in the figure corresponds to the P-ZnS obtained in step S1 of Example 1 of this invention. The legend has the same meaning as above, representing the Hg values ​​of P-ZnS and 5Fe / ZnS at 50℃ and 150℃, respectively. 0 Adsorption capacity. In the figure, MoS corresponds to P-MoS2 obtained in step S1 of Example 1 of this invention. The legend has the same meaning as above, representing the Hg values ​​of P-MoS2 and 5Fe / MoS2 at 50℃ and 150℃, respectively. 0 Adsorption capacity.

[0126] To further verify Fe 3+ The universality of activation was also tested on sulfide chemicals, such as... Figure 15 As shown. The CuS in the figure is the commercial CuS used in Comparative Example 2 of this invention, and the 50°C figure corresponds to the Hg of the commercial CuS at a contact temperature of 50°C. 0 Adsorption capacity, 50℃-Fe legend corresponds to Hg of Fe / commercial-CuS at a contact temperature of 50℃. 0 Adsorption capacity, legend for Hg of commercial CuS at 150℃ (corresponding to a contact temperature of 150℃) 0 Adsorption capacity, 150℃-Fe. Legend: Hg of Fe / commercial-CuS at a contact temperature of 150℃. 0 Adsorption capacity.

[0127] In the figure, PbS corresponds to the commercial PbS obtained in step S1 of Comparative Example 1 of this invention. Its legend is consistent with that of CuS, representing Hg at 50°C and 150°C for commercial PbS and Fe / commercial-PbS, respectively. 0 Adsorption capacity. The ZnS in the figure corresponds to the commercial ZnS in Comparative Example 2 of this invention. The legend has the same meaning as above, representing the Hg values ​​of commercial ZnS and Fe / commercial ZnS at 50℃ and 150℃, respectively. 0 Adsorption capacity. In the figure, MoS corresponds to the commercial MoS in Comparative Example 2 of this invention, and the legend has the same meaning as above, representing the Hg values ​​of commercial MoS2 and Fe / commercial-MoS2 at 50℃ and 150℃, respectively. 0 Adsorption capacity.

[0128] Fe was studied 3+The effect of activation parameters on mercury removal from sulfides was investigated. First, the Fe... 3+ The effect of concentration on the mercury removal performance of sulfides. For example... Figure 16 As shown, (temperature is 150℃, flue gas is pure N2, mercury concentration is 200 μg·m³) -3 The airspeed is 1.2 × 10⁻⁶. 5 m 3 ·h -1 ) through different concentrations of Fe 3+ The mercury removal performance of MoS2 was significantly improved after activation, with the increase of Fe 3+ The concentration increases initially, then decreases, when Fe... 3+ Concentration of 5 mmol·L -1 At the optimal concentration, the activated sample exhibits the best mercury removal performance. At a suitable concentration, Fe... 3+ It can form active sites of suitable density and uniform distribution, thereby significantly enhancing surface adsorption activity. Too low an Fe concentration may be detrimental to the formation of sufficient active sites, while too high an Fe concentration may lead to Fe aggregation on the surface, thus weakening the activation effect. Fe was analyzed... 3+ The relationship between activation effect and sulfide substrate structure.

[0129] Analysis example 4

[0130] Analysis of the mercury adsorption mechanism.

[0131] like Figure 17 As shown, Hg was studied. 0 Adsorption at different sites in the Fe / MoS2(002) and (100) planes. Hg 0 It is strongly adsorbed at the Fe edge of the Fe / MoS2(100) plane, with the highest adsorption energy being -78.15 kJ·mol⁻¹. -1 , and Fe 3+ There was no significant difference compared to before activation. Hg was studied. 0 Adsorption of Hg at different sites in the Fe / MoS2(002) plane 0 It is strongly adsorbed at the Fe edge of the P-MoS2(002) plane, with the highest adsorption energy being -103.5 kJ·mol⁻¹. -1 The adsorption energy of Hg on the P-MoS2(002) basal surface was significantly improved compared to the original active sites on the basal surface (the adsorption of Hg on the P-MoS2(002) basal surface was analyzed, and the adsorption energy of Hg was calculated). 0 The adsorption energy at the S site on the basal surface is -22.41 kJ·mol⁻¹. -1 The interaction is weak, belonging to physical adsorption. Calculation results confirm that Fe 3+ Activation primarily acts on the S-defect sites on the MoS2 basal plane, causing the basal plane to face Hg. 0 The adsorption is more active, which is conducive to the capture of Hg at high temperatures.0 The main sites.

[0132] like Figure 18 As shown, in order to analyze Hg 0 The electron transfer process during adsorption was analyzed in Fe. 3+ EDD plots before and after MoS2 activation. Red and blue regions represent electron accumulation and consumption, respectively. Significant electron density accumulation was observed between adsorbed Fe atoms and adjacent surface Mo atoms, indicating strong orbital overlap and charge transfer. Furthermore, a marked charge redistribution was observed near the Fe sites, with electron depletion occurring around Fe and accumulation observed in the surface S adsorption region. This suggests that Fe may promote electron donation and enhance surface sulfur activation, leading to Hg... 0 Strong chemical adsorption.

[0133] like Figure 19 As shown, this is to clarify the participation of gaseous Hg on the Fe / MoS2 surface. 0 The active sites for oxidative adsorption were analyzed using XPS to compare the Fe / MoS2 ratio in Hg. 0 Changes in surface chemical state before and after adsorption (Fresh) and after adsorption (Used). The Mo3d peak area and intensity of Fe / MoS2 showed no significant change before and after Hg adsorption at 50℃ and 150℃, proving that the surface Mo is not Hg. 0 Oxidation active sites.

[0134] like Figure 20 As shown, after adsorption at 150℃, the binding energy of the S2p orbital in the sample showed a negative shift of approximately 0.10 eV, indicating an increase in the electron density around the sulfur species and its affinity for Hg. 0 It is related to electron transfer in chemisorption. For example... Figure 21 As shown, in the S2p spectrum, the peaks of the fresh sample at 162.8 eV, 163.5 eV, 164.4 eV, and 165.9 eV are respectively S x 2- 2p 1 / 2 and S x 2- 2p 3 / 2 Species. Hg 0 After adsorption, the S of Fe / MoS2 x 2- The percentage decreased from 32.13% to 28.33%, indicating that S x 2- In Hg 0 It is consumed during adsorption, that is, it participates in the oxidation of Hg. For example... Figure 22 As shown, a mercury-programmed temperature desorption (Hg-TPD) experiment was conducted on the mercury-adsorbed sample to determine the adsorption morphology of mercury on the material surface. The results indicate that Fe... 3+Activating MoS2 effectively increases the number of strong adsorption sites, thereby enhancing the capture of Hg by Fe / MoS2. 0 Stability. S x 2- It is Hg 0 The key active sites for oxidation and adsorption, the reaction process from Hg 0 It gains electrons and eventually converts Hg 0 It is converted into stable α-HgS.

[0135] The above technical solutions of the present invention are merely preferred embodiments of the present invention and do not limit the patent scope of the present invention. All equivalent structural transformations made under the technical concept of the present invention using the contents of the present invention specification and drawings, or direct / indirect applications in other related technical fields, are included in the patent protection scope of the present invention.

Claims

1. A method for capturing mercury, characterized in that, Mercury-containing flue gas is contacted with iron-activated sulfides to remove mercury from the flue gas; the contact temperature is 30-200°C. The preparation of the iron-activated sulfide includes the following steps: A metal source and a sulfur source are dispersed in water, and a hydrothermal reaction is carried out to collect the solid, thereby obtaining a precursor; the molar ratio of the metal source to the sulfur source is 0.8-1.2:1, and the metal source includes a molybdenum source; The precursor was mixed with an iron agent, and the solid was collected to obtain the iron-activated sulfide; the ratio of the precursor to the iron agent was 0.8-1.2 g: 5 × 10 g. -4 -5×10 -3 mol; the iron agent is ferric sulfate; the iron-activated sulfide comprises a sulfide matrix with a petal-like structure, the phase structure of the iron-activated sulfide is the same as that of the precursor, and the iron agent provides Fe 3+ The sulfide matrix is ​​uniformly anchored in an atomically dispersed manner, and stable immobilization is achieved through coordination with the matrix atoms, thus constructing a highly active MoS2 matrix.

2. The method for capturing mercury from iron-activated sulfides according to claim 1, characterized in that, The molybdenum source includes ammonium molybdate, and the sulfur source includes at least one of thiourea and thioacetamide.

3. The mercury-collecting method according to claim 1, characterized in that, The hydrothermal reaction is carried out at a temperature of 150-200℃ for a duration of not less than 8 hours.

4. The mercury-collecting method according to claim 1, characterized in that, The concentration of the iron agent is 1-10 mmol·L. -1 .

5. The mercury-collecting method according to claim 1, characterized in that, Within a temperature range of 30-200℃ and a duration of 80 minutes, the Hg of the iron-activated sulfide... 0 The absorption efficiency reaches over 90%; the adsorption capacity of the iron-activated sulfide is not less than 40 mg·g. -1 .

6. The mercury-collecting method according to claim 1, characterized in that, Based on XPS peak area, S x 2- The relative atomic percentage content of total sulfur species on the surface of the iron-activated sulfide is not less than 30%.

7. The mercury-collecting method according to claim 1, characterized in that, The mercury concentration in the mercury-containing flue gas is not higher than 500 μg·m³. -3 .

8. The mercury-collecting method according to claim 1, characterized in that, The mercury-containing flue gas is smelting flue gas, which also contains at least one of SO2, O2, H2O, and HCl.

9. The mercury-collecting method according to claim 1, characterized in that, The space velocity of the mercury-containing flue gas during the contact process is 2 × 10⁻⁶. 4 m 3 ·h -1 -2.0×10 5 m 3 ·h -1 .

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