Mercury adsorbent regeneration process and application of regenerated adsorbent

Abstract

This invention provides a mercury adsorbent regeneration process and its application. The process includes: calcining a mercury-loaded adsorbent to remove mercury and condensing and recovering elemental mercury, obtaining mercury-removed slag; then subjecting the slag to sulfidation to obtain the regenerated adsorbent. The mercury adsorbent is prepared from a precursor with a molybdenum-sulfur molar ratio of 1:0.1-1:40. This regeneration process achieves highly efficient adsorbent regeneration, maintaining an adsorption capacity of no less than 3600 mg / g after multiple cycles, while simultaneously recovering mercury resources. It solves the problem of traditional wet regeneration methods that easily damage active sites and is suitable for treating mercury-containing wastewater.

Description

Technical Field

[0001] This invention belongs to the field of mercury-containing wastewater treatment technology, specifically relating to a mercury adsorbent regeneration process and the application of the regenerated adsorbent. Background Technology

[0002] Mercury-containing wastewater (such as waste acid from the non-ferrous smelting industry) is characterized by high acidity, a wide variety of heavy metals, and large concentration fluctuations, posing a serious threat to the ecological environment and human health. Metal sulfide adsorbents (especially sulfur-rich molybdenum-based adsorbents) are effective at removing Hg from waste acid due to their rich surface unsaturated sulfur sites. 2+ It exhibits excellent adsorption capacity and selectivity, and is considered a mercury removal material with great application potential.

[0003] Currently, the regeneration of saturated adsorbents mainly employs wet chemical elution routes, such as using strong complexing agents like thiourea, sodium thiosulfate, or hydrochloric acid, along with acidic solutions, for desorption. However, such wet processes damage the polysulfide framework and core active sites on the surface of sulfur-rich adsorbents, leading to a significant decrease in adsorption capacity after several cycles, making it difficult to meet the requirements for long-term industrial operation. Furthermore, the subsequent treatment of mercury-containing wastewater generated by wet elution is complex, and mercury resource recovery is difficult and costly.

[0004] Therefore, how to achieve efficient regeneration without damaging the microstructure of sulfur-rich adsorbents and simultaneously recover mercury resources during the regeneration process is a technical problem that urgently needs to be solved in this field. Summary of the Invention

[0005] To address the technical problem of achieving efficient regeneration of sulfur-rich adsorbents without damaging their microstructure and simultaneously recovering mercury resources during the regeneration process, this invention provides a mercury adsorbent regeneration process, comprising the following steps: The mercury-loaded adsorbent was calcined to obtain mercury-free slag; The preparation of the mercury-loaded adsorbent includes the following steps: contacting the mercury adsorbent with mercury-containing wastewater to adsorb Hg from the wastewater. 2+ The mercury-loaded adsorbent is obtained by preparing a precursor with a molar ratio of molybdenum to sulfur of 1:0.1-1:40, having a two-dimensional layered structure with an interlayer spacing of 0.85-0.95 nm, which is assembled from two-dimensional nanosheets with lattice defects distributed on the basal surface to form three-dimensional flower-like microspheres. The mercury removal slag is subjected to sulfidation treatment to obtain a regenerated adsorbent.

[0006] Furthermore, the calcination treatment is carried out at a temperature of 150-1000℃ for a duration of 2-36 hours; The calcination process includes: thermally desorbing the mercury-loaded adsorbent in the presence of a stripping carrier gas to obtain mercury-desorbed slag; and condensing and recovering the gaseous mercury generated during desorption.

[0007] Furthermore, during the sulfidation process, the molar ratio of sulfur in the sulfur source to molybdenum in the mercury-removing slag is 2-40:1, and the sulfidation process includes: The mercury-removed slag is mixed with a sulfur source to obtain a mixed system; the mixed system is subjected to a second hydrothermal treatment and solid-liquid separation in sequence to obtain the regenerated adsorbent; wherein, the temperature of the second hydrothermal treatment is 100-250℃ and the duration is 2-15h; Alternatively, the mixture obtained by mixing the mercury removal slag with the sulfur source can be calcined to obtain the regenerated adsorbent; the calcination temperature is 120-400℃ and the duration is 0.5-4h.

[0008] Furthermore, the preparation of the mercury adsorbent includes the following steps: The precursor is obtained by mixing a molybdenum source with a sulfur source; the molar ratio of molybdenum to sulfur in the precursor is 1:0.1-1:40. The precursor is subjected to the first hydrothermal treatment to obtain the mercury adsorbent; the temperature of the first hydrothermal treatment is 120-250℃ and the duration is 4-20h.

[0009] Furthermore, the Mo / S atomic ratio on the surface of the mercury adsorbent is 1:3.4-3.5, and the Mo atoms on the surface contain Mo atoms... 4+ The proportion is 70-80%; S2 in surface sulfur atoms 2- The proportion is 35-50%.

[0010] Furthermore, the elemental atomic percentages on the surface of the mercury adsorbent and the regenerated adsorbent include: S 40-60%, Mo 20%-30%; The elemental atomic percentages on the surface of the mercury-loaded adsorbent include: S 30-40%, Mo 5%-15%, and Hg ≥ 0%.

[0011] Furthermore, the mercury adsorbent has a mercury adsorption capacity ≥3900mg / g, and the regenerated mercury adsorbent has a mercury adsorption capacity ≥3600mg / g.

[0012] The present invention provides a regenerated adsorbent prepared by the mercury adsorbent regeneration process described in any of the preceding claims.

[0013] This invention provides an application of a regenerated adsorbent in mercury adsorption, comprising the following steps: The regenerated adsorbent described above is mixed with mercury-containing wastewater to carry out an adsorption reaction, thereby achieving the adsorption of Hg in the mercury-containing wastewater. 2+ Removal; The dosage of the regenerated adsorbent is 0.05 g / L-1 g / L, and the mercury content in the mercury-containing wastewater is ≤1000 mg.

[0014] Furthermore, the regenerated adsorbent undergoes the regeneration process for adsorption-regeneration cycling, and the number of adsorption-regeneration cycles is ≥2 times; Among them, the regenerated adsorbent obtained after each cycle is effective against Hg. 2+ The adsorption capacity of each is not less than 3600 mg / g.

[0015] Compared with the prior art, the present invention has at least the following advantages: This invention employs a regeneration process combining calcination (thermal desorption) and sulfidation to regenerate mercury-loaded adsorbents. Experiments show that after six consecutive adsorption-regeneration cycles, the regenerated adsorbent effectively reduces its resistance to Hg. 2+ The equilibrium adsorption capacity remained above approximately 3600 mg / g without significant decay. This indicates that the present invention can effectively restore the core active sites of the adsorbent, overcoming the technical defect of traditional wet elution processes (such as thiourea and sodium thiosulfate systems) where the adsorption removal rate decreases significantly after three cycles, thus achieving long-term cyclic use of the adsorbent.

[0016] Microstructure analysis shows that the adsorbent regenerated by this invention retains the original mercury adsorbent's petal-shaped molybdenum sulfide structure and 1T-2H mixed-phase composite characteristics; the surface core active sites (Mo 4+ and edge S2 2- The content of S2 is basically stable. 2- The proportion even slightly increases after regeneration. This indicates that the dry regeneration process of this invention can efficiently reconstruct the sulfur-rich surface structure of the adsorbent, rather than destroying its polysulfide framework.

[0017] In the calcination stage, this invention uses thermal desorption to volatilize the mercury loaded on the adsorbent in gaseous form, which is then condensed and recovered as liquid elemental mercury. This process regenerates the adsorbent while simultaneously recovering mercury from waste acid, avoiding the secondary pollution and subsequent treatment challenges caused by mercury-containing wastewater generated by traditional wet regeneration methods. Attached Figure Description

[0018] 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.

[0019] Figure 1 These are scanning electron microscope (SEM) images of adsorbents with different molybdenum-sulfur ratios according to the present invention; wherein, Figure 1 (a) is the SEM image of Mo8S1. Figure 1(b) is a SEM image of Mo2S1. Figure 1 (c) is a SEM image of MoS2. Figure 1 (d) is the SEM image of Mo1S16. Figure 1 (e) is the SEM image of Mo1S24.

[0020] Figure 2 These are transmission electron microscopy (TEM) images of adsorbents with different molybdenum-sulfur ratios according to the present invention; wherein, Figure 2 (a) is a TEM image of Mo8S1. Figure 2 (b) is a TEM image of Mo2S1. Figure 2 (c) is a TEM image of MoS2. Figure 2 (d) is a TEM image of Mo1S16. Figure 2 (e) is a TEM image of Mo1S24.

[0021] Figure 3 The X-ray diffraction (XRD) patterns of the adsorbents with different molybdenum-sulfur ratios of the present invention are shown.

[0022] Figure 4 The present invention relates to different molybdenum-sulfur ratio adsorbents for Hg 2+ The adsorption capacity histogram; where, Figure 4 (a) represents the adsorption capacity of low sulfur-to-molybdenum ratio adsorbents (Mo8S1, Mo4S1, Mo2S1, Mo1S1, MoS2). Figure 4 (b) represents the adsorption capacity of high sulfur-molybdenum ratio adsorbents (Mo1S4, Mo1S8, Mo1S12, Mo1S16, Mo1S20, Mo1S24).

[0023] Figure 5 This invention relates to the effects of different molybdenum-sulfur ratio adsorbents on Hg in a coexisting cation system. 2+ The selective adsorption results are shown in the figure.

[0024] Figure 6 This invention relates to the adsorbents of different molybdenum-sulfur ratios for Hg under different pH conditions. 2+ The effect curve of removal rate.

[0025] Figure 7 This is a diagram showing the equilibrium adsorption capacity of the regenerated adsorbent of the present invention after six consecutive adsorption-regeneration cycles.

[0026] Figure 8 This is a graph showing the desorption efficiency and cyclic adsorption performance of the comparative wet regeneration process of this invention; wherein, Figure 8 (a) Comparison of desorption efficiencies of different types and concentrations of complexing agents. Figure 8 (b) shows the adsorption performance of the 3M sodium thiosulfate system after 5 consecutive cycles.

[0027] Figure 9 These are SEM and EDS elemental distribution diagrams of the adsorbent of this invention in the initial, mercury-loaded, and sulfide regeneration stages; wherein, Figure 9 (ac) is a mercury adsorbent. Figure 9 (df) is a mercury-loaded adsorbent. Figure 9 (gi) is the regenerated adsorbent. Detailed Implementation

[0028] 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.

[0029] 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.

[0030] 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.

[0031] This invention provides a mercury adsorbent regeneration process, comprising the following steps: S1. The mercury-loaded adsorbent is calcined to obtain mercury-free slag; In some embodiments, obtaining the mercury-loaded adsorbent includes the step of contacting the mercury adsorbent with mercury-containing wastewater to adsorb Hg from the wastewater. 2+ The mercury-loaded adsorbent is obtained by first hydrothermal treatment of a precursor with a molar ratio of molybdenum to sulfur of 1:0.1-1:40. It has a two-dimensional layered structure with an interlayer spacing of 0.85-0.95 nm, which is assembled from two-dimensional nanosheets with lattice defects distributed on the basal surface to form three-dimensional flower-like microspheres.

[0032] In some embodiments, the preparation of the mercury adsorbent may include the following steps: S01. Mix the molybdenum source and the sulfur source to obtain the precursor; the molar ratio of molybdenum to sulfur in the precursor is 1:2-1:40.

[0033] In some embodiments, the molybdenum source comprises ammonium heptamolybdate, and the sulfur source comprises thiourea and / or sulfur.

[0034] More specifically, a molybdenum source (such as ammonium heptamolybdate) and a sulfur source (such as thiourea) can be dissolved in deionized water at a set molybdenum-sulfur molar ratio, stirred evenly, and then transferred to a hydrothermal reactor for hydrothermal reaction.

[0035] For example, the molar ratio of molybdenum to sulfur in the precursor can be 1:0.1, 1:0.2, 1:0.3, 1:0.4, 1:0.5, 1:0.6, 1:0.7, 1:0.8, 1:0.9, 1:1.0, 1:1.5, 1:2, 1:5, 1:8, 1:11, 1:14, 1:15, 1:15.5, 1:16, 1:16.5, 1:17, 1:20, 1:25, 1:30, 1:35, 1:40, and any value between such a minimum and maximum, or a range of any two values; for example, the molar ratio of molybdenum to sulfur in the precursor can be 1:15-20.

[0036] S02. The precursor is subjected to the first hydrothermal treatment to obtain the mercury adsorbent; the temperature of the first hydrothermal treatment is 120-250℃ and the duration is 4-20h.

[0037] For example, the temperature of the first hydrothermal treatment can be 120°C, 150°C, 200°C, 220°C, 250°C, and any value between such a minimum and maximum value, or a range of any two values.

[0038] For example, the duration of the hydrothermal reaction can be 4h, 8h, 12h, 16h, 20h, or any value between such a minimum and maximum, or a range of any two values.

[0039] The mercury adsorbents in this invention include sulfur-poor adsorbents and sulfur-rich adsorbents. The sulfur-poor mercury adsorbents are prepared by hydrothermal reaction from a precursor with a molybdenum-sulfur molar ratio of 1.5:1 to 2.5:1, and the sulfur-rich mercury adsorbents are prepared by hydrothermal reaction from a precursor with a molybdenum-sulfur molar ratio of 1:15 to 1:17.

[0040] The sulfur-poor mercury adsorbent has an amorphous or short-range ordered structure with sulfur vacancy defects, exhibiting a nanoparticle stacking morphology. The sulfur-rich mercury adsorbent has a two-dimensional layered structure with an interlayer spacing of 0.85-0.95 nm, which is assembled from two-dimensional nanosheets with lattice defects distributed on the basal surface to form three-dimensional flower-like microspheres.

[0041] For example, the interlayer spacing of the mercury adsorbent can be 0.85 nm, 0.86 nm, 0.87 nm, 0.88 nm, 0.89 nm, 0.90 nm, 0.91 nm, 0.92 nm, 0.93 nm, 0.94 nm, 0.95 nm, and any value between such a minimum and maximum value, or a range of any two values.

[0042] This invention provides a sulfur-poor mercury adsorbent that, by reducing the sulfur abundance of the precursor, induces the formation of sulfur vacancy defects and amorphous or short-range ordered structures in the material, resulting in a nanoparticle stacking morphology. This structural feature exposes a large number of unsaturated active sites and edge defects on the material surface.

[0043] During the adsorption process, the sulfur-poor mercury adsorbent passes through the lattice sulfur (S) 2- ) and low-priced molybdenum (Mo 4+ The synergistic effect of ) achieves the effect on Hg 2+ Capture and fixation: On the one hand, S 2- With Hg 2+ Strong chemical coordination occurs to form stable HgS compounds; on the other hand, Mo... 4+ As an electron donor, it participates in redox reactions, transferring some Hg 2+ Reduced to elemental mercury (Hg) 0 ).

[0044] The sulfur-poor mercury adsorbent combines high selectivity, adaptability to acidic environments, and high capacity. High capacity: at pH=2, Hg 2+ Under an initial concentration of 200 mg / L, the equilibrium adsorption capacity of the sulfur-poor mercury adsorbent reaches over 2900 mg / g, with a partition coefficient K. d 2.55×10 6 mL / g, which is much higher than that of conventional adsorption materials.

[0045] Adaptability to acidic environments: Under extremely acidic conditions with pH=0, the sulfur-poor mercury adsorbent can still maintain a removal rate of about 60% and an adsorption capacity of more than 960 mg / g, demonstrating excellent resistance to strong acids.

[0046] High selectivity: Hg in most binary systems 2+ Maintaining a removal rate of over 80%, it is suitable for treating mercury-containing wastewater with few or low concentrations of coexisting interfering ions.

[0047] This invention provides a sulfur-rich mercury adsorbent that, by increasing the sulfur abundance of the precursor, induces the formation of a two-dimensional layered structure with an interlayer spacing of 0.89-0.94 nm. The basal surface of this structure contains lattice-defect-laden two-dimensional nanosheets assembled to form three-dimensional flower-like microspheres. This structural feature exposes a vast number of unsaturated active sulfur sites in the material.

[0048] During the adsorption process, the sulfur-rich mercury adsorbent employs a dual mercury fixation mechanism: on the one hand, highly active S2... 2- Groups and Hg 2+ Strong covalent coordination occurs, forming stable β-HgS (decomposes at 190℃) and α-HgS (decomposes at 305℃); on the other hand, Mo... 4+ Using low-valence sulfur species as electron donors, some Hg 2+ In-situ reduction to elemental mercury (Hg) 0 ).

[0049] Mercury-sulfur-rich adsorbents combine high selectivity, adaptability to acidic environments, and high capacity. High capacity: at pH=2, Hg 2+ Under an initial concentration of 200 mg / L, the equilibrium adsorption capacity of the mercury-rich sulfur adsorbent is as high as 3900 mg / g or more, with a partition coefficient K. d Reaching 1.67×10 8 mL / g.

[0050] Adaptability to acidic environments: Under extremely acidic conditions with pH=0, the sulfur-rich mercury adsorbent can still maintain a removal rate of about 60% and an adsorption capacity of more than 960 mg / g, breaking through the technical bottleneck of traditional adsorbent materials being easily deactivated under strong acid.

[0051] High selectivity: in Cu-containing 2+ Co 2+ Ni 2+ Zn 2+ Cd 2+ Mn 2+ Fe 3+ Cr 3+ As 5+ In a binary or multi-component mixed system containing at least one coexisting cation, the sulfur-rich mercury adsorbent has a positive effect on Hg. 2+ The removal rate remained consistently above 90%, except for Pb, which also exhibits soft acid properties. 2+ There is approximately 20% co-adsorption, exhibiting excellent mercury ion selectivity.

[0052] In some embodiments, the Mo / S atomic ratio on the surface of the sulfur-poor mercury adsorbent is 0.3-0.4:1, wherein Mo... 4+ The proportion is 70-80%, Mo 6+ The proportion is 10-20%, and the surface sulfur species include S2 2- The proportion is 20-30%, S 2- SO4 accounts for 60-70% 2- The proportion is 2-8%.

[0053] In some embodiments, the Mo / S atomic ratio on the surface of the sulfur-rich mercury adsorbent is 1:3.4-3.5, wherein Mo... 4+ The proportion is 70-75%, Mo 6+ The proportion is 10-14%, and S2 is the sulfur species on the surface. 2- The proportion is 36-45%, S 2- The proportion is 45-55%, SO4 2- The proportion is 10-15%.

[0054] In some embodiments, the calcination treatment is carried out at a temperature of 150-1000℃ for a duration of 2-36 hours; The calcination process includes: thermally desorbing the mercury-loaded adsorbent in the presence of a stripping carrier gas to obtain mercury-desorbed slag; and condensing and recovering the gaseous mercury generated during desorption.

[0055] For example, the calcination temperature can be 150°C, 200°C, 250°C, 300°C, 350°C, 400°C, 450°C, 500°C, 650°C, 700°C, 750°C, 800°C, 850°C, 900°C, 950°C, 1000°C, and any value between such a minimum and maximum value, or a range of any two values.

[0056] More specifically, the stripping carrier gas can be a mixture of nitrogen and oxygen; for example, the stripping carrier gas can be a nitrogen-oxygen mixture with a volume ratio of 4:1.

[0057] It should be noted that the calcination treatment time can be 2h, 5h, 10h, 15h, 20h, 25h, 30h, 36h, as well as any value between the minimum and maximum values, or any range of two values.

[0058] In some embodiments, the elemental atomic percentages on the surface of the mercury adsorbent and the regenerated adsorbent include: S 40-60%, Mo 20%-30%; The elemental atomic percentages on the surface of the mercury-loaded adsorbent include: S 30-40%, Mo 5%-15%, and Hg ≥0%.

[0059] In some embodiments, the atomic percentage of mercury atoms in the mercury-loaded adsorbent can be ≥0, such as ≤15%. For example, the mercury-loaded adsorbent can be in a saturated state, where the atomic percentage of mercury atoms is approximately 5%-12% (e.g., 9.73%); or it can be in an unsaturated state, where the atomic percentage of mercury atoms is less than 5% (e.g., 0.1%-5%). Those skilled in the art will understand that as long as the adsorbent is loaded with mercury ions, it constitutes the mercury-loaded adsorbent of the present invention, and its mercury loading depends on the initial mercury concentration, adsorption time, and adsorption conditions, and does not need to be limited to a strictly saturated state.

[0060] In some embodiments, the mercury adsorbent has a mercury adsorption capacity ≥3900 mg / g, and the regenerated mercury adsorbent has a mercury adsorption capacity ≥3600 mg / g.

[0061] S2. The mercury removal slag is subjected to sulfidation treatment to obtain a regenerated adsorbent.

[0062] In some embodiments, the sulfidation treatment includes: mixing the mercury-removing slag with a sulfur source to obtain a mixed system; the mixed system is then subjected to a second hydrothermal treatment and solid-liquid separation to obtain the regenerated adsorbent; The second hydrothermal treatment is performed at a temperature of 120-250℃ for 5-15 hours, and the molar ratio of sulfur in the sulfur source to molybdenum in the mercury-removing slag is 2-40:1 during the sulfidation process.

[0063] In other embodiments, the mixture obtained by mixing the mercury-removing slag and the sulfur source is calcined to obtain the regenerated adsorbent; the calcination temperature is 120-400℃ and the duration is 0.5-4h; during the sulfidation process, the molar ratio of sulfur in the sulfur source to molybdenum in the mercury-removing slag is 2-40:1.

[0064] It should be noted that the vulcanization treatment is carried out under an inert atmosphere.

[0065] For example, the temperature of the second hydrothermal treatment can be arbitrarily selected between 120°C and 250°C. For instance, 120°C, 150°C, 180°C, 200°C, 220°C, or 250°C, or any two of these temperatures as endpoints (e.g., 150-200°C), can be selected. Too low a temperature may result in incomplete sulfidation, while too high a temperature may cause excessive grain growth. Those skilled in the art can determine the specific values ​​through conventional experiments based on the actual phase composition of the mercury-removed slag.

[0066] For example, the duration of the second hydrothermal treatment can be arbitrarily selected between 5 hours and 15 hours. For instance, 5h, 8h, 10h, 12h, or 15h can be selected, or any two of these durations can be used as an endpoint (e.g., 8-12h). The selection of duration should ensure that the sulfur source reacts fully with the mercury removal slag, allowing the sulfur-rich structure of the adsorbent to be reconstructed.

[0067] For example, the calcination temperature can be 150-400℃, 200-400℃, 150-300℃, or 200-300℃.

[0068] For example, the molar ratio of sulfur in the sulfur source to molybdenum in the mercury removal slag can be arbitrarily selected within the range of 2-40:1. For instance, ratios such as 2:1, 5:1, 10:1, 15:1, 18:1, 20:1, 22:1, 25:1, or 30:1, or any two of these ratios as endpoints (e.g., 15:1-25:1), can be selected. A molar ratio that is too low may result in incomplete sulfidation, while a molar ratio that is too high will lead to a waste of the sulfur source. Those skilled in the art can make reasonable adjustments based on the residual sulfur content of the mercury removal slag and the required degree of regeneration.

[0069] In some embodiments, the sulfur source includes at least one of sulfur, thiourea, sodium thiosulfate, and sodium sulfide.

[0070] This invention provides a regenerable adsorbent, prepared by the mercury adsorbent regeneration process described above.

[0071] This invention provides an application of a regenerated adsorbent in mercury adsorption, comprising the following steps: The regenerated adsorbent is mixed with mercury-containing wastewater to carry out an adsorption reaction, thereby achieving the adsorption of Hg in the mercury-containing wastewater. 2+ Removal; The dosage of the regenerated adsorbent is 0.05 g / L-0.1 g / L, and the mercury content in the mercury-containing wastewater is ≤1000 mg.

[0072] In some embodiments, the regenerated adsorbent undergoes the regeneration process for adsorption-regeneration cycling, and the number of adsorption-regeneration cycles is ≥2 times; Among them, the regenerated adsorbent obtained after each cycle is effective against Hg. 2+ The adsorption capacity of each is not less than 3600 mg / g.

[0073] To facilitate a further understanding of the present invention by those skilled in the art, the following examples are provided: Example 1 Preparation of mercury adsorbent Mo1S16: Ammonium heptamolybdate and thiourea were completely dissolved in 50 mL of deionized water and stirred vigorously at 300 r / min to obtain a precursor with a molar ratio of molybdenum to sulfur of 1:16. The precursor 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 an oven at 80 °C for 10 h to obtain Mo1S16.

[0074] Example 2 Preparation of Mo8S1, Mo4S1, Mo2S1, Mo1S1, MoS2, Mo1S4, Mo1S8, Mo1S12, Mo1S20, and Mo1S24: Ammonium heptamolybdate and thiourea were completely dissolved in 50 mL of deionized water and stirred vigorously at 300 r / min to obtain a precursor. The precursor 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 an oven at 80°C for 10 h to obtain the mercury adsorbent sample. Mo8S1 was prepared when the molybdenum-sulfur ratio in the precursor was 8:1. Mo4S1 was prepared when the molybdenum-sulfur ratio in the precursor was 4:1. Mo2S1 was prepared when the molybdenum-sulfur ratio in the precursor was 2:1. Mo1S1 was prepared when the molybdenum-sulfur ratio in the precursor was 1:1. Mo1S2 was prepared when the molybdenum-sulfur ratio in the precursor was 1:2. Mo1S4 was prepared when the molybdenum-sulfur ratio in the precursor was 1:4. Mo1S8 was prepared when the molybdenum-sulfur ratio in the precursor was 1:8. Mo1S12 was prepared when the molybdenum-sulfur ratio in the precursor was 1:12. Mo1S20 was prepared when the molybdenum-sulfur ratio in the precursor was 1:20. Mo1S24 was prepared when the molybdenum-sulfur ratio in the precursor was 1:24.

[0075] Analysis example 1 like Figure 1 As shown, SEM tests were performed on mercury adsorbents with different molybdenum-sulfur ratios. Figure 1 (a) is the SEM image of Mo8S1. Figure 1 (b) is a SEM image of Mo2S1. Figure 1 (c) is a SEM image of MoS2. Figure 1 (d) is the SEM image of Mo1S16. Figure 1 (e) is the SEM image of Mo1S24. As can be seen from the figure, with the increase of sulfur abundance, the morphology of the sample went through an evolution process from dense bulk to loose particles, then to a three-dimensional flower-like network, and finally to agglomeration and densification.

[0076] Under extremely sulfur-deficient conditions (Mo8S1), the product exhibits dense, massive aggregates with smooth surfaces and a lack of pores, indicating that the scarcity of sulfur sources limits the anisotropic growth of crystals. When the molybdenum-sulfur ratio increases to 2:1 (Mo2S1), the massive aggregates disintegrate into smaller nanoparticle stacks, increasing structural porosity. This irregular stacking is often accompanied by abundant grain boundary defects, which facilitates the exposure of unsaturated active sites.

[0077] Normal MoS2 exhibits typical molybdenum disulfide nanoflora characteristics, composed of rolled-up sheets, but the sheets are stacked relatively tightly.

[0078] Mo1S16 mercury adsorbent consists of extremely fluffy, uniformly distributed three-dimensional flower-like microspheres with significantly thinner sheets and increased wrinkles. This highly open, multi-level network structure not only maximizes the exposure area of ​​active sites but also enhances the adsorption capacity for Hg. 2+ The diffusion of sulfur provides abundant mass transfer channels. However, excessive sulfur (Mo1S24) can lead to overgrowth and secondary aggregation of nanoflora, causing partial pore blockage and reducing site accessibility.

[0079] like Figure 2 As shown, TEM tests were performed on mercury adsorbents with different molybdenum-sulfur ratios. Figure 2 (a) is a TEM image of Mo8S1. Figure 2 (b) is a TEM image of Mo2S1. Figure 2 (c) is a TEM image of MoS2. Figure 2 (d) is a TEM image of Mo1S16. Figure 2 (e) is a TEM image of Mo1S24. It can be seen that as the sulfur abundance gradually increases, the morphology of the adsorbent gradually changes from a dense blocky structure to a highly exfoliated two-dimensional sheet structure.

[0080] For sulfur-poor materials with sulfur abundance below the normal stoichiometric ratio (such as Mo8S1 and Mo2S1), their crystallinity is poor, mainly existing in the form of amorphous or short-range ordered short cluster lattices with interlayer spacing of 7.02-7.1 Å. When the normal stoichiometric ratio is reached (MoS2), relatively clear layered molybdenum sulfide lattice fringes appear inside the sample, with an interlayer spacing of approximately 0.64 nm, which conforms to the standard interlayer spacing of typical 2H-MoS2.

[0081] Further increasing the sulfur abundance to a sulfur-rich ratio (Mo1S16) results in significant changes to the material's lattice structure: on the one hand, dense lattice defects on the basal planes break down the previously inert planes, exposing numerous unsaturated, high-energy active sulfur sites; on the other hand, the interlayer spacing widens significantly, extending to 0.89-0.94 nm. This anomalous lattice expansion is due to the embedding of excessive amorphous active sulfur (such as polysulfide species) into the interlayer gaps of molybdenum sulfide during synthesis. The significantly expanded interlayer spacing effectively reduces Hg. 2+ Spatial steric hindrance that diffuses inward creates an efficient physical mass transfer channel.

[0082] From a morphological perspective, sulfur-rich Mo1S16 materials exhibit extremely transparent, wrinkled films, indicating that they possess extremely thin, two-dimensional graphene-like characteristics. However, when sulfur abundance is excessive (Mo1S24), the highly exfoliated ultrathin sheets are affected by surface energy, resulting in secondary agglomeration and re-agglomeration, leading to a decrease in specific surface area and openness.

[0083] Analysis example 2 like Figure 3 As shown, XRD tests were performed on mercury adsorbents with different molybdenum-sulfur ratios. It can be seen that MoS2 matches well with the standard 2H phase MoS2 (JCPDSPDF#37-1492), with the characteristic diffraction peak at 2θ≈14.5° corresponding to a typical (002) crystal plane. According to Bragg's law for crystals, its interlayer spacing is approximately 6.11 Å. Meanwhile, the broadened (100) and (110) diffraction peaks near 33° and 58° indicate that this material has a two-dimensional layered structure but relatively weak overall crystallinity.

[0084] With a significant increase in sulfur abundance, the phase structure of the mercury adsorbent Mo1S16 underwent a significant change. Its characteristic diffraction peak shifted dramatically to a lower angle, moving to 2θ≈9.4°, corresponding to an increase in interlayer spacing of approximately 9.4 Å. This interlayer spacing is about 3.3 Å higher than that of ordinary MoS2. This confirms that the excess sulfur source successfully induced the intercalation of active sulfur species into the lattice, constructing a two-dimensional layered framework with an ultra-large interlayer spacing, thereby providing a suitable adsorbent for Hg. 2+ It provides an extremely wide physical channel for rapid entry and deep diffusion.

[0085] Analysis example 3 As shown in Table 1, the surface elemental composition of adsorbents with different sulfur abundances was analyzed by X-ray photoelectron spectroscopy.

[0086] S2 with high electron cloud polarization 2- The group is related to the soft acid Hg 2+ The core active site undergoes strong covalent coordination, while the low-valence Mo... 4+ It then participates in redox reactions as an electron donor, donating some Hg.2+ It is reduced to elemental mercury. It is evident that an appropriate level of sulfur abundance not only maintains the highly reduced state and stability of the structure, but also promotes the exposure of more polysulfide active terminals on the basal surface and edges.

[0087] Table 1. Elemental valence states (%) on XPS surfaces with different proportions of adsorbents Analysis example 4 Adsorption capacity test.

[0088] The adsorption experiment was conducted at pH=2, Hg 2+ The initial concentration was 200 mg·L. -1 The mercury adsorbent dosage was 10 mg, and the solution volume was 100 mL. The mixture was stirred at 380 rpm for 12 h at room temperature to ensure the adsorption process was complete, thus obtaining the mercury-loaded adsorbent. After the reaction, the solution was filtered through a 20 μm filter, and the mercury concentration in the solution before and after adsorption was determined using a LUMEX-RA-915 liquid mercury analyzer.

[0089] Mercury adsorption capacity of adsorbents with different molybdenum-sulfur ratios, such as Figure 4 As shown, where Figure 4 (a) Bar chart of adsorption capacity of low sulfur-molybdenum-mercury ratio adsorbent materials (Mo8S1, Mo4S1, Mo2S1, Mo1S1, MoS2), Figure 4 (b) Bar chart of adsorption capacity of high sulfur-molybdenum-mercury adsorbent materials (Mo1S4, Mo1S8, Mo1S12, Mo1S16, Mo1S20, Mo1S24).

[0090] As can be seen, the adsorption capacity of the adsorbent reaches its highest value of 3956 mg / g (denoted as Mo1S16) when Mo:S = 1:16. The above results indicate that sulfur abundance has a significant impact on the adsorption performance of MoS2, and appropriate sulfur regulation can effectively optimize the structure of active sites, thereby constructing a high-performance mercury adsorbent.

[0091] Analysis example 5 The effect of different sulfur abundances on the selective mercury removal performance of molybdenum disulfide adsorbents was investigated.

[0092] like Figure 5 As shown, the study investigated the effects of Mo2S1, normal MoS2, and Mo1S16 in binary and multi-component mixed systems (Pb). 2+ Cu 2+ Co 2+ Ni 2+ Zn 2+ Cd 2+ Mn 2+ Fe 3+ Cr 3+As 5+ Mercury selectivity under [specific conditions]. The experiment was conducted at room temperature, with 10 mg of mercury adsorbent added to 100 mL of solution containing 200 mg·L⁻¹ mercury. -1 Hg 2+ The removal rate of each ion was measured after reacting in a mixed solution of ions and interfering ions of equal concentration for 12 hours.

[0093] The results show that sulfur abundance plays a decisive role in the material's resistance to interference. For example... Figure 5 As shown in (b), firstly, normal MoS2 exhibits extreme susceptibility to disturbances in binary systems. Compared to single-component systems, it is more susceptible to disturbances related to Hg. 2+ The adsorption capacity decreased significantly; especially when combined with Pb. 2+ When coexisting, this adsorbent is effective against Pb. 2+ The removal rate was 68%, surpassing that of Hg. 2+ The removal rate was 39%; while compared with Ni 2+ Fe 3+ and As 5+ Coexistence or in a multi-component mixture system, its effect on Hg 2+ The removal rate drops to almost 10% or even approaches 0. This indicates that the surface active sites of molybdenum sulfide in conventional proportions are limited and easily occupied by other cations or lose activity due to competition.

[0094] like Figure 5 As shown in (c), Mo1S16 exhibits excellent Hg. 2+ High selectivity. Whether in a binary system with ten single interfering ions or in an extremely demanding eleven-ion mixture, this material exhibits high selectivity for Hg. 2+ The removal rates consistently remained above 90%. Except for Pb... 2+ Aside from about 20% co-adsorption, the adsorption of other interfering ions is extremely low.

[0095] The effects of the mercury adsorbent Mo1S16 on binary and multi-component mixed systems (Cl) were also investigated. - F - HCO3 - and PO4 3- Mercury selectivity under different anions. 2+ The effects of adsorption vary significantly. For F - HCO3 - and PO4 3- Mo1S16 exhibits excellent anti-interference ability. In binary systems where these three anions are present respectively, Mo1S16 shows good resistance to Hg. 2+ The removal rate remained close to 100%.

[0096] Further quantitative studies were conducted to investigate the selectivity of the adsorbent for Hg and its competitiveness in practical applications.

[0097] The allocation coefficient K was introduced. d This key parameter is used to evaluate the adsorbent's effect on Hg. 2+ Its capture ability and affinity. It is generally believed that when K... d >10 5 mL·g -1 At this time, the adsorbent exhibits excellent affinity for this ion. The K2 of normal MoS2... d The value is 9.33 × 10 4 mL·g -1 K of Mo2S1 d The value was increased to 2.55 × 10. 6 mL·g -1 ;and the K of Mo1S16 d The value is as high as 1.67 × 10 8 mL·g -1 It far surpasses other adsorbents and can react with Hg. 2+ It generates extremely strong specific binding force, thus achieving efficient enrichment of mercury even at extremely low concentrations.

[0098] Analysis example 6 The effect of pH on mercury adsorption performance was investigated.

[0099] The effects of strongly acidic conditions (pH 0-2.0) on the mercury removal performance of three adsorbents with different sulfur abundances were investigated. Figure 6 As shown. 10 mg of mercury adsorbent (Mo2S1, normal MoS2, and Mo1S16) was weighed and added to 100 mL of Hg solution with an initial concentration of 200 mg / L. 2+ In the solution, the pH values ​​were adjusted to 0, 1.0, 1.5 and 2.0 respectively with sulfuric acid and sodium hydroxide. The solution was stirred at 380 rpm for 12 hours at room temperature (25℃) to ensure that the adsorption process was fully carried out.

[0100] from Figure 6 It can be seen that all three materials exhibit excellent mercury removal performance within a pH range of 1.0-2.0, and are effective in removing Hg. 2+ The removal rate remained stable at over 98%, even approaching 100%, with a corresponding saturated adsorption capacity as high as 2000 mg / g. This indicates that the active sites on the material surface are highly active in weakly acidic to moderately strong acidic environments. When the solution acidity further increases to extreme conditions of pH < 1.0, the adsorption efficiency decreases to varying degrees. In an extremely acidic environment of pH=0, the removal rate of normal MoS2 adsorbent drops to about 42%; while Mo1S16 adsorbent exhibits relatively stronger acid resistance, still maintaining a removal rate of about 60% and an adsorption capacity of over 960 mg / g.

[0101] Analysis example 7 Study on the adsorption mechanism of mercury adsorbent.

[0102] 10 mg of adsorbent Mo1S16 was added to 100 mL, resulting in an initial concentration of 200 mg·L⁻¹. -1 Hg 2+ In solution, samples were collected before and after the reaction to study the mercury adsorption mechanism.

[0103] To clarify the effect of mercury adsorbents on Hg 2+ The capture mechanism of Hg was characterized by X-ray photoelectron spectroscopy (XPS) before and after adsorption, indicating that Hg... 2+ Successfully loaded onto the material surface. Further analysis of the Hg 4f spectrum confirmed the interaction between the active sulfur sites on the adsorbent surface and Hg. 2+ A strong chemical coordination occurred, resulting in a stable compound dominated by Hg-S covalent bonds.

[0104] Analysis of the adsorbed sample using mercury temperature-programmed desorption (Hg-TPD) revealed that some Hg... 2+ It is reduced in situ to Hg by the reducing sites on the material surface. 0 This reveals the existence of an adsorption-reduction synergistic mechanism.

[0105] The subsequent temperature-induced desorption curves further revealed the form in which chemisorbed mercury existed. This indicates that Hg... 2+ Not only are conventional surface coordination complexes formed on the surface of sulfur-rich materials, but they are also further transformed into crystalline mercury sulfide with extremely high thermal stability through lattice rearrangement.

[0106] In summary, based on XPS and Hg-TPD, it is inferred that the Mo1S16 mercury adsorbent has a significant effect on Hg. 2+ The capture of Hg follows a unique dual mercury-fixing mechanism: a portion of Hg 2+ Reduced to elemental Hg 0 One portion is physically enriched, while the other portion undergoes strong chemical bonding with reactive sulfur to form stable β-HgS and α-HgS. This synergistic effect of "electron transfer + Hg-S coordination" may be the fundamental reason why this material achieves ultra-high adsorption capacity and excellent environmental stability.

[0107] Example 3 Mercury adsorbent regeneration process.

[0108] The adsorption experiment was conducted at pH=2, Hg 2+ The initial concentration was 200 mg·L. -1The amount of mercury adsorbent (Mo1S16 prepared in Example 1) was 10 mg, the solution volume was 100 mL, and the mixture was shaken and stirred at 380 rpm for 12 h at room temperature to ensure that the adsorption process was fully carried out, thus obtaining the mercury-loaded adsorbent.

[0109] The obtained mercury-loaded adsorbent was placed in a tube furnace for high-temperature calcination. A nitrogen-oxygen mixture with a volume ratio of 4:1 was used as the stripping carrier gas. In this embodiment, the calcination temperature was 260°C and the calcination time was 8 hours.

[0110] The mercury removal residue, initially a black powder containing mercury adsorbent, turned into a pure white solid after calcination, presumably molybdenum oxide crystals, indicating a phase transformation of the adsorbent after thermal desorption. The recovered product in the tail gas condenser was liquid elemental mercury, a silvery-white metallic droplet.

[0111] The calcined adsorbent was then regenerated by adding the mercury-removing slag to a mixture of thiourea and deionized water and stirring vigorously at 300 rpm for 30 min to obtain a mixed system. The mixed system was then transferred to a 100 mL Teflon-lined autoclave for hydrothermal treatment. The resulting 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 the regenerated adsorbent sample. The molar ratio of sulfur source to molybdenum in the mercury-removing slag was 20:1, the hydrothermal treatment temperature was 240 °C, and the treatment time was 12 h.

[0112] Example 4 This embodiment evaluates the long-term cyclic adsorption performance of the mercury adsorbent prepared in Example 1. In each cyclic adsorption experiment, 5 mg of the regenerated adsorbent was weighed and added to 100 mL of an initial Hg(II) concentration of 200 mg·L⁻¹. -1 The adsorption was carried out in a solution with stirring. After 12 hours, the change in Hg(II) concentration in the solution before and after adsorption was measured, and the equilibrium adsorption capacity of the regenerated adsorbent in this cycle was calculated.

[0113] Experimental results are as follows Figure 7 As shown, after six consecutive adsorption-regeneration cycles, the adsorption capacity of the adsorbent did not show significant decline, remaining stable at approximately 3600 mg / g. This indicates that the hydrothermal sulfidation regeneration method can restore the effective adsorption sites of the adsorbent, ensuring that the adsorbent possesses excellent regeneration capability and structural stability.

[0114] Comparative Example 2 The mercury-loaded adsorbent prepared in Example 4 was regenerated using a wet regeneration process. Weigh 100 mg of MoS16 adsorbent (mercury-loaded adsorbent) in its saturated state and place it in a clean beaker. Add 50 mL of chemical leaching solution, including thiourea solution or sodium thiosulfate solution, to the beaker and stir continuously for 3 hours to desorb and regenerate the adsorbent. The desorbed adsorbent is then filtered, washed multiple times with deionized water, and dried before being re-added to mercury-containing wastewater for a circulating adsorption performance test. The mercury-containing filtrate is transferred to a closed oil bath heating system for high-temperature evaporation. The vaporized mercury enters a condenser and, after thorough cooling, is converted into liquid elemental mercury and collected.

[0115] like Figure 8 As shown in (a), the desorption effects of both eluents were unsatisfactory. The mercury desorption rate of the thiourea system was extremely low. The desorption rates corresponding to 1% and 10% concentrations of thiourea solution were only 1% and 10%, respectively. The desorption capacity of the sodium thiosulfate system was slightly improved. The desorption rates of 0.5 M, 1 M, and 3 M sodium thiosulfate solutions were 27%, 29%, and 32%, respectively. Increasing the eluent concentration did not improve the mercury desorption efficiency. Wet complexation leaching could not effectively dissociate strongly coordinated mercury ions on the material framework.

[0116] In this comparative example, a 3 M sodium thiosulfate solution with relatively good desorption performance was selected for adsorbent cyclic regeneration experiments. In a single cycle, 100 mg of the eluted and regenerated adsorbent was added to 100 ml of an initial concentration of 200 mg·L⁻¹. -1 Mercury-containing wastewater, such as Figure 8 As shown in (b), the performance of the regenerated adsorbent degrades significantly after three cycles.

[0117] Analysis example 8 The microstructure of the regenerated adsorbent in Example 2 was analyzed using SEM, such as... Figure 9 As shown in (ac), the original adsorbent has a typical petal-like structure of molybdenum sulfide. Even after adsorbing a large amount of mercury, the adsorbent still maintains its complete petal-like structure. Figure 9 (d, f) No obvious densification or collapse occurred. Furthermore, the adsorbed mercury was uniformly loaded onto the adsorbent. Figure 9 e), EDS quantitative analysis showed that the relative proportion of mercury atoms reached 9.73% (as shown in Table 2). The microstructure of the regenerated adsorbent was consistent with that of the original adsorbent, exhibiting the same petal-like structure. Figure 9 g, i), and EDS quantitative analysis showed that the mercury in the adsorbent completely disappeared (Table 2), indicating that the adsorbent was effectively regenerated and its structure was completely restored.

[0118] Table 2. Atomic percentage of EDS elements at different stages of the adsorbent (%) Further Raman spectroscopy was used to study the evolution of the crystal phase structure of the adsorbent before and after regeneration, and the E of the regenerated sample was analyzed. 2g 1 and A 1g The peak spacing did not shift significantly, and the peak morphology and relative intensity did not change significantly. This indicates that the dry regeneration process did not cause irreversible damage to the intrinsic lattice characteristics of the material. The hydrothermal sulfur replenishment process successfully restored the microstructure of the adsorbent.

[0119] Analysis example 9 The peaks of Mo 3d and S 2p were separated, and the changes in the content of active sites before and after adsorbent regeneration were further analyzed, as shown in Table 3.

[0120] Table 3. Surface element valence ratios before and after adsorbent regeneration Mo 4+ With edge unsaturation S2 2- It adsorbs Hg 2+ The core active sites were found. The content of active sites did not change significantly before and after regeneration. This indicates that the dry regeneration process can achieve efficient reconstruction of the core active sites on the surface. The regenerated adsorbent maintains the Mo... 4+ In addition to increasing the abundance, it further enriched the surface polysulfide binding sites.

[0121] Analysis example 10 The specific surface area and pore structure of MoS16 adsorbent before and after pyrolysis-hydrothermal sulfidation regeneration were analyzed. The pore size of the samples before and after regeneration was mainly concentrated in the range of 2-50 nm.

[0122] Table 4 shows the specific surface area, pore volume, and average pore size of the samples before and after regeneration. The specific surface area of ​​the original MoS16 was 13 m². 2 ·g -1 The pore volume is 0.1180 cm³. 3 ·g -1 The average pore size was 13.83 nm. After pyrolysis-hydrothermal sulfidation regeneration, the specific surface area of ​​the sample decreased to 6 m². 2 ·g -1 The decrease was approximately 50%; the pore volume decreased to 0.0529 cm³. 3 ·g -1 The decrease was approximately 55%; however, the average aperture increased to 16.47 nm.

[0123] Table 4. Specific surface area, pore volume, and average pore size of the adsorbent before and after regeneration. The above results indicate that the regeneration process has a certain impact on the pore structure of the adsorbent. The decrease in specific surface area and pore volume may be related to the collapse of some pores during pyrolysis, while the increase in average pore size may be due to the preferential destruction or blockage of small-sized pores.

[0124] 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 mercury adsorbent regeneration process, characterized in that, Including the following steps: The mercury-loaded adsorbent was calcined to obtain mercury-free slag; The preparation of the mercury-loaded adsorbent includes the following steps: contacting the mercury adsorbent with mercury-containing wastewater to adsorb Hg from the wastewater. 2+ The mercury-loaded adsorbent was obtained by preparing a precursor with a molar ratio of molybdenum to sulfur of 1:0.1-1:

40. The mercury removal slag is subjected to sulfidation treatment to obtain a regenerated adsorbent.

2. The mercury adsorbent regeneration process according to claim 1, characterized in that, The calcination treatment is carried out at a temperature of 150-1000℃ for a duration of 2-36 hours. The calcination process includes: thermally desorbing the mercury-loaded adsorbent in the presence of a stripping carrier gas to obtain mercury-desorbed slag; and condensing and recovering the gaseous mercury generated during desorption.

3. The mercury adsorbent regeneration process according to claim 1, characterized in that, During the sulfidation process, the molar ratio of sulfur in the sulfur source to molybdenum in the mercury-removing slag is 2-40:1, and the sulfidation process includes: The mercury-removed slag is mixed with a sulfur source to obtain a mixed system; the mixed system is subjected to a second hydrothermal treatment and solid-liquid separation in sequence to obtain the regenerated adsorbent; wherein, the temperature of the second hydrothermal treatment is 100-250℃ and the duration is 2-15h; Alternatively, the mixture obtained by mixing the mercury removal slag and the sulfur source is calcined to obtain the regenerated adsorbent; the calcination temperature is 120-400℃ and the duration is 0.5-4h.

4. The mercury adsorbent regeneration process according to claim 1, characterized in that, The preparation of the mercury adsorbent includes the following steps: The precursor is obtained by mixing a molybdenum source with a sulfur source; the molar ratio of molybdenum to sulfur in the precursor is 1:0.1-1:

40. The precursor is subjected to a first hydrothermal treatment to obtain the mercury adsorbent.

5. The mercury adsorbent regeneration process according to claim 4, characterized in that, The temperature of the first hydrothermal treatment is 120-250℃, and the duration is 4-20h; the sulfur source includes at least one of sulfur, thiourea, sodium thiosulfate, and sodium sulfide.

6. The mercury adsorbent regeneration process according to claim 4, characterized in that, The elemental atomic percentages on the surfaces of the mercury adsorbent and the regenerated adsorbent include: S 40-60%, Mo 20%-30%; The elemental atomic percentages on the surface of the mercury-loaded adsorbent include: S 30-40%, Mo 5%-15%, and Hg ≥0%.

7. The mercury adsorbent regeneration process according to claim 4, characterized in that, The mercury adsorbent has a mercury adsorption capacity ≥3900mg / g, and the regenerated mercury adsorbent has a mercury adsorption capacity ≥3600mg / g.

8. A regenerable adsorbent, characterized in that, It is prepared by the mercury adsorbent regeneration process according to any one of claims 1-7.

9. The application of a regenerated adsorbent in mercury adsorption, characterized in that, Including the following steps: The regenerated adsorbent according to claim 8 is mixed with mercury-containing wastewater to carry out an adsorption reaction, thereby achieving the adsorption of Hg in the mercury-containing wastewater. 2+ Removal; The dosage of the regenerated adsorbent is 0.05 g / L-1 g / L, and the mercury content in the mercury-containing wastewater is ≤1000 mg.

10. The application of the regenerated adsorbent according to claim 9 in mercury adsorption, characterized in that, The regenerated adsorbent undergoes adsorption-regeneration cycle using the regeneration process, and the number of adsorption-regeneration cycles is ≥2 times. Among them, the regenerated adsorbent obtained after each cycle is effective against Hg. 2+ The adsorption capacity of each is not less than 3600 mg / g.

Images