Metal sulfide adsorbent as well as preparation method and application thereof

Abstract

The invention discloses a metal sulfide adsorbent and a preparation method and application thereof.The preparation method comprises the steps that a tin source, a sulfur source and a polyamine aqueous solution are mixed to be uniform, a mixed solution is obtained, and polyamine is one or a mixture of more of ethylenediamine, diethylenetriamine, triethylene tetramine and o-phenylenediamine; the mixed solution is subjected to a hydrothermal reaction for 4-6 days at the temperature of 120-180 DEG C under the sealing condition of a high-pressure reaction kettle, cooling is conducted to the room temperature, filtering is conducted to obtain a product containing lamellar crystals, washing and drying are conducted, and the metal sulfide adsorbent is obtained. Through double mechanisms of complexing coordination and ion exchange, the metal sulfide adsorbent can still preferentially capture Ni < 2 + > even under the coexistence condition of metal ions such as Cs < + >, Sr < 2 + > and Eu < 3 + >, and is far superior to a traditional adsorbent material.

Description

Technical Field

[0001] This invention belongs to the field of water treatment technology, specifically relating to a metal sulfide adsorbent, its preparation method, and its application. Background Technology

[0002] In modern industrial systems, nickel plays a crucial role in electroplating, new energy batteries, and alloy smelting due to its excellent physicochemical properties. However, the large-scale development and utilization of nickel resources has led to the discharge of large amounts of nickel-containing wastewater, causing irreversible damage to ecosystems and posing significant risks to human safety. Therefore, how to efficiently treat nickel-containing wastewater is an urgent technical problem to be solved.

[0003] While there are various technologies for treating nickel-containing wastewater, most existing methods have limitations. For example, chemical precipitation, though simple to operate, results in high costs for sludge treatment and is prone to secondary pollution; membrane separation, while effective, suffers from high membrane module costs and clogging. Adsorption, however, has become a research hotspot due to its advantages of flexible operation, low energy consumption, and environmental friendliness. Developing high-performance adsorption materials is key to improving the efficiency of adsorption in treating nickel-containing wastewater. In recent years, literature has reported numerous examples of metal chalcogenide ion exchange materials used as high-performance adsorption materials for Ni... 2+ Removal, metal sulfide ion exchange materials rely on the S in their structure 2- and Se 2- Soft basic sites for soft metal ions (such as Cs) + 、Sr 2+ UO2 2+ Ni 2+ ) exhibits high affinity, but the metal chalcogenide ion exchange materials reported in the literature mainly use alkali metal ions (such as Na+). + K + ) or monoamine cations (such as [MeNH3) + [Me2NH2] + And [Me3NH] + As counter cations, alkali metal ions or monoamine cations are used to remove Ni. 2+ The selectivity is poor. For example, the invention patent with publication number CN 105080623A involves monoamine cations [MeNH3]. + [Me2NH2] + Template-constructed metal sulfide adsorbents are used for the separation and extraction of rare earth elements. These metal sulfide ion exchange materials mainly rely on electrostatic interactions, resulting in a single mechanism that makes it difficult to achieve effective separation of Ni. 2+Precise identification and highly selective capture. The invention patent with publication number CN 118681607 A relates to the selective removal of strontium ions using a metal sulfide adsorbent constructed with a macrocyclic molecular template. The macrocyclic molecular interlayer template agent used in its material is effective for Ni… 2+ Limited capture capability, in Ni 2+ It has no significant advantages in removal.

[0004] Furthermore, in multi-ion wastewater systems containing coexisting high-valence cations, metal sulfide adsorbent materials have been developed for Ni... 2+ The adsorption performance is easily affected by high-valence competing ions. For example, the paper (Selective Capture of Ba) 2+ Ni 2+ ,andCo 2+ FJSM-SnS in a Robust Layered Metal Sulfide (Chem. Mater. 2020, 32(5), pp. 1957-1963) for Eu ionization in multi-ion wastewater systems 3+ The selectivity is significantly higher than that of Ni. 2+ , for Ni 2+ The selection is not good.

[0005] Therefore, there is an urgent need to develop novel metal chalcogenide adsorbent materials as Ni 2+ Adsorbents are used to meet the application requirements for the efficient removal of nickel ions from complex water bodies. Summary of the Invention

[0006] In view of the shortcomings of the prior art, the purpose of this invention is to provide a method for preparing a metal sulfide adsorbent.

[0007] Another object of the present invention is to provide a metal sulfide adsorbent obtained by the above preparation method, wherein the metal sulfide adsorbent is a metal sulfide adsorbent constructed with polyamine as a template agent.

[0008] Another objective of this invention is to provide the application of the above-mentioned metal sulfide adsorbent in the efficient separation and extraction of metal ions from wastewater.

[0009] The objective of this invention is achieved through the following technical solution.

[0010] A method for preparing a metal sulfide adsorbent includes the following steps:

[0011] Step 1: Mix the tin source, sulfur source and polyamine aqueous solution until homogeneous to obtain a mixed solution. The ratio of tin in the tin source, sulfur in the sulfur source and polyamine in the polyamine aqueous solution is 1:(2.0-3.5):(8.0-32.0) by molar proportions. The polyamine is one or a mixture of several of ethylenediamine, diethylenetriamine, triethylenetetramine and o-phenylenediamine.

[0012] In step 1, the concentration of polyamine in the polyamine aqueous solution is 60.0–90.0 wt%.

[0013] In step 1, the tin source is a tin chloride compound or elemental tin.

[0014] In the above technical solution, the tin source is tin tetrachloride pentahydrate.

[0015] In step 1, the sulfur source is one or a mixture of several of the following: thiourea, sodium sulfide, potassium sulfide, ammonium sulfide, and elemental sulfur.

[0016] Step 2: The mixed solution obtained in Step 1 is subjected to hydrothermal reaction at 120-180℃ for 4-6 days under sealed conditions in a high-pressure reactor. After cooling to room temperature, the mixture is filtered to obtain a product containing lamellar crystals. The product is then washed and dried to obtain a metal sulfide adsorbent.

[0017] In step 2, the washing process uses deionized water and anhydrous ethanol.

[0018] A metal sulfide adsorbent comprises: layered crystals, the chemical formula of which is (PAH)₂(PA). x Sn3S7·yH2O, where PAH represents a protonated polyamine cation, PA represents a neutral polyamine molecule and a disordered polyamine molecule, x takes values ​​from 0 to 5, and y takes values ​​from 0 to 5.

[0019] In the above technical solution, the layered crystal is [Sn3S7] with a layered structure. n 2n- As an anionic framework, in [Sn3S7] n 2n- Polyamines are distributed both between and within the layers, existing as protonated polyamine cations, neutral polyamine molecules, and disordered polyamine molecules. Protonated polyamine cations are inserted into [Sn3S7] as counter cations. n 2n- Interlayer, disordered polyamine molecules and neutral polyamine molecules are embedded in [Sn3S7]. n 2n- Interlayer or located in [Sn3S7] n 2n- Within the hexagonal honeycomb-shaped channels of the layer.

[0020] The application of the above-mentioned metal sulfide adsorbents in the extraction of metal ions.

[0021] In the above technical solution, the priority order for metal ion extraction by metal sulfide adsorbents is Ni. 2+ >Co 2+ Eu 3+ >Cd 2+ >Ba 2+ >Sr 2+ >Cs + .

[0022] In the above technical solution, the metal sulfide adsorbent is placed in a container containing Cs + 、Sr 2+ Eu 3+ and Ni 2+ In the solution, Ni 2+ The separation factor relative to other metal ions is greater than 1.

[0023] In the above technical solution, Ni 2+ Compared to Cs + The separation factor is 9.78 × 10⁻⁶. 3 Ni 2+ Compared to Sr 2+ The separation factor is 36.65, Ni 2+ Compared to Eu 3+ The separation factor was 7.92.

[0024] The above-mentioned metal sulfide adsorbents are used in the extraction of Ni 2+ Applications in [the field].

[0025] In the above technical solution, the metal sulfide adsorbent adsorbs Ni for 6 minutes. 2+ The removal rate reached over 90%.

[0026] Compared with the prior art, the present invention has the following beneficial effects:

[0027] (1) Rapid adsorption equilibrium: The metal sulfide adsorbent of the present invention adsorbs Ni at room temperature. 2+ At that time, 6 minutes for Ni 2+ The removal rate exceeds 90%, and adsorption equilibrium is reached within 15 minutes;

[0028] (2) Significantly improve Ni 2+ Selectivity: Through a dual mechanism of complexation coordination and ion exchange, even in Cs + 、Sr 2+ Eu 3+ Under conditions where metal ions coexist, the metal sulfide adsorbent of this invention can still preferentially capture Ni. 2+ It is far superior to traditional adsorbent materials;

[0029] (3) The metal sulfide adsorbent of the present invention can maintain high K values ​​over a wide pH range of 3.99 to 10.84. d The pH value (2645.96~139015.53mL / g) indicates excellent acid and alkali stability.

[0030] (4) This invention solves the problems of difficult preparation and complex process of polyamine modified adsorbent materials. The preparation method of this invention is low in cost, simple in process, can eliminate the problem of separation difficulties caused by by-products, and the yield can reach more than 50% based on Sn in the reactants.

[0031] In summary, the metal sulfide adsorbent provided by this invention achieves an integrated structural and functional design, and is suitable for Ni... 2+ This provides a new material system for the efficient separation and extraction of Ni, suitable for complex aquatic environments such as industrial wastewater and nuclear wastewater. 2+ The need for pollution control. Attached Figure Description

[0032] Figure 1 The metal sulfide adsorbent ((Hen)2(en) prepared in Example 1 1.5 The crystal structure of Sn3S7·3H2O, wherein, Figure 1 The value of a is (Hen)2(en). 1.5 Diagram showing the three forms of ethylenediamine in Sn3S7·3H2O. Figure 1 b is (Hen)2(en) 1.5 Sn3S7·3H2O contains [Sn3S7] n 2n- Layer structure diagram, Figure 1 The value of c is (Hen)2(en). 1.5 Layered stacking structure diagram of Sn3S7·3H2O;

[0033] Figure 2 The metal sulfide adsorbent prepared in Example 1 adsorbs Ni 2+ Comparison of powder X-ray diffraction before and after;

[0034] Figure 3 The adsorption kinetics diagram is shown for the metal sulfide adsorbent prepared in Example 1.

[0035] Figure 4 This is a fitting diagram of the isothermal adsorption model of the metal sulfide adsorbent prepared in Example 1;

[0036] Figure 5 The isothermal adsorption model fitting diagram is shown for the metal sulfide adsorbent prepared in Example 2;

[0037] Figure 6 The metal sulfide adsorbent prepared in Example 1 was used to treat Ni under different pH conditions. 2+ Distribution coefficient (K) d )picture;

[0038] Figure 7 The partition coefficient (K) of the metal sulfide adsorbent prepared in Example 1 under different metal ion species conditions. d Trend charts for removal rate;

[0039] Figure 8 The partition coefficient (K) of the metal sulfide adsorbent obtained in Example 1 for different metal ions in a competing ion solution is given. d )picture;

[0040] Figure 9 The partition coefficient (K) of the metal sulfide adsorbent obtained in Example 2 for different metal ions in a competing ion solution is given. d )picture;

[0041] Figure 10 [(Me2NH2)] 1.25 (Me3NH) 0.75 Sn3S7·0.375(C 12 H 24 The partition coefficient (K) of O6·H2O for different metal ions in competing ion solutions d )picture;

[0042] Figure 11 The partition coefficient (K) of the metal sulfide adsorbent constructed using the monoamine template obtained in Example 3 for different metal ions in a competing ion solution. d )picture. Detailed Implementation

[0043] The technical solution of the present invention will be further described below with reference to specific embodiments.

[0044] This invention uses polyamines as template agents to prepare metal sulfide adsorbents via hydrothermal synthesis. The metal sulfide adsorbents possess a unique two-dimensional porous structure, providing not only rapid diffusion channels for metal ion exchange but also allowing the nitrogen atoms in the neutral polyamine molecules between the layers to act as electron donors for Ni. 2+ Provides selective complexation sites, thereby enabling metal sulfide adsorbents to target Ni 2+ Highly efficient adsorption. Through its ion exchange and complexation coordination mechanisms, it can effectively improve the adsorption efficiency of metal sulfide adsorbents on Ni in complex solution systems. 2+ The adsorption selectivity. In the presence of Cs + Eu 3+ 、Sr 2+Even in competitive ion solutions where metal ions coexist, Ni can still be preferentially captured. 2+ It exhibits excellent Ni 2+ Selectivity demonstrates the use of metal sulfide adsorbents for the selective removal of Ni in complex metal ion environments. 2+ Its potential.

[0045] The formula for calculating the removal rate R (%) is: C0 is the initial concentration of metal ions in the metal ion solution, expressed in mg / L; C t t min represents the concentration of metal ions in the test solution at time t min, expressed in mg / L. t min = 0 min, 6 min, 15 min, 35 min, 60 min, or 1440 min.

[0046] The formula for calculating adsorption capacity is: Where C0 is the initial concentration of metal ions in the metal ion solution, in mg / L; C e The concentration of metal ions in the test solution at tmin = 1440 min (i.e., when tmin = 1440 min, C) t C e ), where V is the volume of the metal ion solution in mL; and m is the mass of the metal sulfide adsorbent in g.

[0047] Distribution coefficient (K) d The formula for calculating ) is:

[0048] Where C0 is the initial concentration of metal ions in the metal ion solution, in mg / L; C e The concentration of metal ions in the test solution at t min = 1440 min (i.e., when t min = 1440 min, C) t C e ), where V is the volume of the metal ion solution in mL; and m is the mass of the metal sulfide adsorbent in g.

[0049] The raw material information involved in the following examples is as follows:

[0050] reagents Chemical formula purity Tin tetrachloride pentahydrate <![CDATA[SnCl4·5H2O]]> 99％ Sublimed sulfur S Analytical Pure Anhydrous ethylenediamine <![CDATA[C2H8N2]]> Analytical Pure Triethylenetetramine <![CDATA[C6H 18 N4]]> Analytical Pure n-Butylamine <![CDATA[C4H 11 N]]> Analytical Pure

[0051] Example 1

[0052] A method for preparing a metal sulfide adsorbent includes the following steps:

[0053] Step 1: Mix the tin source, sulfur source, and polyamine aqueous solution, and stir until homogeneous at room temperature to obtain a mixed solution. By molar proportions, the ratio of tin in the tin source, sulfur in the sulfur source, and polyamine in the polyamine aqueous solution is 1:3:31. The polyamine is ethylenediamine, the tin source is a tin chloride compound (tin tetrachloride pentahydrate, SnCl4·5H2O), the sulfur source is elemental sulfur (sublimed sulfur), and the concentration of polyamine in the polyamine aqueous solution is 85wt%.

[0054] Step 2: Transfer the mixed solution obtained in Step 1 to a polytetrafluoroethylene-lined autoclave, seal it, and perform a hydrothermal reaction in an oven at 180°C for 5 days. Cool it to room temperature to allow crystals to precipitate. After vacuum filtration, obtain pale yellow lamellar crystals and a small amount of tiny black impurities (according to single-crystal X-ray diffraction testing, the structural formula of the pale yellow lamellar crystals is (Hen)2(en). 1.5 Sn3S7·3H2O was washed three times each with deionized water and anhydrous ethanol, and then air-dried at room temperature for 36 hours. Pale yellow, layered crystals were then picked out to obtain the metal sulfide adsorbent. When the amount of tin source (tin tetrachloride pentahydrate) was 500 mg, the product (Hen)2(en) was obtained. 1.5 The yield of Sn3S7·3H2O can reach 180 mg or more. Based on Sn in the metal sulfide adsorbent, (Hen)2(en) can be calculated. 1.5 The yield of Sn3S7·3H2O is 50% or higher.

[0055] The metal sulfide adsorbent prepared in Example 1 was tested on an XtaLAB Synergy-DW X-ray diffractometer (Cu target, K) α radiation source Single-crystal X-ray diffraction tests were performed on the sample, and the results were as follows: Figure 1 a, Figure 1 b and Figure 1 The crystal structure shown in Figure c is given. Its structural formula is (Hen)₂(en). 1.5 In the structural formula Sn3S7·3H2O, Hen represents a protonated ethylenediamine cation, and en represents a neutral ethylenediamine molecule and a disordered polyamine molecule. The space group of this compound is P21 / n, and its unit cell parameters are... β=92.3950(10)°, Z = 8.

[0056] Figure 1 The value of a is (Hen)2(en). 1.5 The three forms in which ethylenediamine exists in Sn3S7·3H2O are: neutral ethylenediamine molecules ( Figure 1 In the a, “ordered en”), protonated ethylenediamine cation ( Figure 1 "enH" in a +”) and disordered ethylenediamine molecules ( Figure 1 (in the a, "disordered en"); Figure 1 b is (Hen)2(en) 1.5 Sn3S7·3H2O contains [Sn3S7] n 2n- The structure is composed of Figure 1 As can be seen from b, it has a hexagonal honeycomb structure, Sn 4+ All exhibit five coordinations, and S 2- This forms a twisted triangular bipyramidal coordination structure, and the secondary building unit is [Sn3S7]. n 2n- ; Figure 1 The value of c is (Hen)2(en). 1.5 The layered structure of Sn3S7·3H2O. Figure 1 From c, we know that [Sn3S7] n 2n- Through the shared edge ((μ–S)2), it connects with the three surrounding [Sn3S7] respectively. n 2n- They are interconnected, forming a layered anionic framework of 24 atomic rings with a hexagonal honeycomb topology [Sn3S7]. n 2n- Protonated ethylenediamine cation insertion [Sn3S7] n 2n- Between the layers, neutral ethylenediamine molecules and disordered ethylenediamine molecules fill [Sn3S7]. n 2n- In the hexagonal honeycomb pores between and within layers.

[0057] Example 2

[0058] A method for preparing a metal sulfide adsorbent includes the following steps:

[0059] Step 1: Mix the tin source, sulfur source, and polyamine aqueous solution, and stir until homogeneous at room temperature to obtain a mixed solution. By molar percentage, the ratio of tin in the tin source, sulfur in the sulfur source, and polyamine in the polyamine aqueous solution is 1:3.2:8.5. The polyamine is triethylenetetramine (teta), the tin source is a tin chloride compound (tin tetrachloride pentahydrate, SnCl4·5H2O), the sulfur source is elemental sulfur (sublimed sulfur), and the concentration of polyamine in the polyamine aqueous solution is 65wt%.

[0060] Step 2: Transfer the mixed solution obtained in Step 1 to a polytetrafluoroethylene-lined autoclave, seal it, and perform a hydrothermal reaction in an oven at 180°C for 5 days. Cool it to room temperature to allow crystals to precipitate. After vacuum filtration, obtain pale yellow lamellar crystals and a small amount of tiny black impurities (according to single-crystal X-ray diffraction testing, the structural formula of the pale yellow lamellar crystals is (Hteta)2(teta). x Sn3S7·yH2O). It was washed three times each with deionized water and anhydrous ethanol, and then air-dried at room temperature for 36 hours. Pale yellow lamellar crystals were picked out to obtain the metal sulfide adsorbent.

[0061] The metal sulfide adsorbent prepared in Example 2 was tested on an XtaLAB Synergy-DW X-ray diffractometer (Cu target, K) α radiation source Single-crystal X-ray diffraction tests were performed on the compound, and the space group was found to be [space group number missing]. Unit cell parameters are α=90°, β=90°, γ=120°, Z = 3.

[0062] Example 3

[0063] A method for preparing a metal sulfide adsorbent constructed using a monoamine template includes the following steps:

[0064] Step 1: Mix the tin source, sulfur source, and n-butylamine aqueous solution, and stir at room temperature until homogeneous to obtain a mixed solution. By molar amount, the ratio of tin in the tin source, sulfur in the sulfur source, and n-butylamine in the n-butylamine aqueous solution is 1:3:26. The tin source is a tin chloride compound (tin tetrachloride pentahydrate, SnCl4·5H2O), the sulfur source is elemental sulfur (sublimed sulfur), and the concentration of n-butylamine in the n-butylamine aqueous solution is 69wt%.

[0065] Step 2: Transfer the mixed solution obtained in Step 1 to a polytetrafluoroethylene-lined autoclave, seal it, and perform a hydrothermal reaction in an oven at 180°C for 5 days. Cool to room temperature to allow crystals to precipitate. After vacuum filtration, obtain pale yellow layered crystals and a small amount of tiny black impurities. Wash the pale yellow layered crystals three times each with deionized water and anhydrous ethanol, and air dry at room temperature for 36 hours to obtain a metal sulfide adsorbent constructed with a monoamine template.

[0066] Example 4

[0067] Metal sulfide adsorbents and Ni adsorbents 2+ The changes in the crystal structure of the subsequent metal sulfide adsorbent were analyzed, including the following steps:

[0068] Step 1, Sample Preparation: The metal sulfide adsorbent prepared in Example 1 was manually ground for 5 minutes using an agate mortar and pestle to obtain a fine powder, which was then used as the sample. 50 mg of this sample was added to 100 mL of NiCl2 aqueous solution (NiCl2 aqueous solution contains Ni...). 2+ The concentration of NiCl2 was 1000 ppm, and the pH of the NiCl2 aqueous solution was 7.89. The solution was placed in a shaker at 298 K and shaken thoroughly at 160 rpm for 24 h. Then, it was centrifuged at 7000 rpm for 5 min to obtain the precipitate. The precipitate was filtered and washed three times each with deionized water, anhydrous ethanol, and acetone, and then dried (air-dried) at room temperature for 36 hours to obtain NiCl2. 2+ The product of the exchange (EN-SnS-Ni).

[0069] The second step is analysis and testing: The metal sulfide adsorbent (EN-SnS) prepared in Example 1 and the Ni obtained after adsorption were analyzed. 2+ The exchanged product (EN-SnS-Ni) was subjected to X-ray powder diffraction phase analysis, yielding the following results: Figure 2 The XRD pattern is shown. X-ray powder diffraction phase analysis (XRD) was performed on a Rigaku Ultima IV X-ray diffractometer at 40 kV, 40 mA, with a Cu target and K. α radiation source Depend on Figure 2 It can be seen that Ni 2+ The products of the exchange ( Figure 2 The Bragg peak of EN-SnS-Ni shifts to a higher 2θ, indicating a decrease in interlayer spacing, suggesting that the large polyamines in the interlayer may be replaced by smaller nickel ions. Furthermore, EN-SnS and EN-SnS-Ni exhibit the same characteristic peaks, indicating that EN-SnS-Ni and EN-SnS have an isomorphic structure.

[0070] Example 5

[0071] Metal sulfide adsorbents for Ni 2+ Exchange kinetics experiment:

[0072] The metal sulfide adsorbent prepared in Example 1 was manually ground for 5 minutes using an agate mortar and pestle to obtain a fine powder, which was then used as a sample. 30 mg of this sample was added to 30 mL of a metal ion solution and placed in a shaker at 298 K with a rotation speed of 160 r / min for 1440 minutes. The mixture was then centrifuged at 7000 r / min for 5 minutes to separate the supernatant and precipitate. During these 1440 minutes, 1 mL of the supernatant was taken at each minute t as the test solution. The concentration of metal ions in the test solution was determined using inductively coupled plasma mass spectrometry (ICP-MS) and denoted as C. t(mg / L), t min = 0 min, 6 min, 15 min, 35 min, 60 min or 1440 min. The metal ion solution is a NiCl2 aqueous solution with pH = 7, and NiCl2 aqueous solution contains Ni 2+ The concentration was 6.31 ppm (i.e., 6.31 mg / L). To ensure more accurate calculation of the removal rate, inductively coupled plasma mass spectrometry (ICP-MS) was used to precisely measure the NiCl2 concentration in the aqueous solution. 2+ The concentration of metal ions, i.e. the initial concentration of metal ions in the metal ion solution, is denoted as C0 (mg / L).

[0073] C0, C at t min = 6 min, 15 min, 35 min, 60 min and 1440 min t The removal rates R are shown in Table 1.

[0074] Table 1

[0075] Time t (min) <![CDATA[C0(mg / L)]]> <![CDATA[C t (mg / L)]]> R(％) 6 6.31169 0.601655 90.47 15 6.31169 0.23495 96.28 35 6.31169 0.2619 95.85 60 6.31169 0.25475 95.96 1440 6.31169 0.12942 97.95

[0076] Plotting t min as the x-axis and C as the y-axis t (mg / L) and removal rate R are used as the ordinates, respectively, to obtain Figure 3 The adsorption kinetics diagram shown ( Figure 3 The 80-1420 minute segment on the horizontal axis is displayed compressed using " / / ", while the actual time is continuous. Figure 3 It can be seen that the metal sulfide adsorbent prepared in Example 1 exhibits good performance on Ni under room temperature conditions. 2+ The adsorption reached equilibrium within 15 minutes. Compared to several typical chalcogenide ion exchange materials reported so far, the metal sulfide adsorbent prepared in Example 1 significantly shortened the time required for adsorption equilibrium. For example, CTS-1 required 40 minutes to reach adsorption equilibrium (described in Highly Selective Capture of Ni). 2+ from complex environments by asandwichlikelayered metal sulfide ion exchanger J.Hazard.Mater.2024, page 136562), [CH3NH3]4Ga4SbS9S 0.28 O 0.72 H requires 1440 minutes to reach adsorption equilibrium (as documented in A Three-Dimensionally Open Framework Heterometallic Chalcogenidoantimonate Exhibiting Ni). 2+Ion-ExchangeProperty Chem.-Asian J. 2018, 13, pp. 672-678. Furthermore, the metal sulfide adsorbent prepared in Example 1 exhibits a high removal rate, achieving a removal rate of Ni within 6 minutes. 2+ The removal rate reached 90.5%.

[0077] Example 6

[0078] The metal sulfide adsorbent obtained in Example 1 for Ni 2+ Adsorption model experiment:

[0079] The metal sulfide adsorbent prepared in Example 1 was manually ground for 5 min using an agate mortar to obtain a fine powder. m (g) of the ground metal sulfide adsorbent was added to V (mL) of metal ion solution, with 1 g of metal sulfide adsorbent added to every 1000 mL of metal ion solution. The mixture was placed in a shaker at 298 K and shaken thoroughly at 160 r / min for t min, t min = 1440 min (24 hours). Then, it was centrifuged at 7000 r / min for 5 min to separate the supernatant and precipitate. 7 mL of the supernatant was then taken as the test solution, and the concentration of metal ions in the test solution was determined using inductively coupled plasma mass spectrometry (ICP-MS), denoted as C. e (mg / L). The metal ion solution is an aqueous solution of NiCl2 with pH=7. The NiCl2 aqueous solution contains Ni... 2+ The concentrations of NiCl2 in the aqueous solution were selected from 6.31 mg / L, 14.30 mg / L, 33.92 mg / L, 95.09 mg / L, and 995.95 mg / L. To ensure more accurate calculation results, inductively coupled plasma mass spectrometry (ICP-MS) was used to precisely determine the NiCl2 concentration in the aqueous solution. 2+ The concentration of metal ions, i.e. the initial concentration of metal ions in the metal ion solution, is denoted as C0 (mg / L).

[0080] C0, C e V, m, removal rate R and adsorption capacity q are shown in Table 2.

[0081] Table 2

[0082] <![CDATA[C0(mg / L)]]> <![CDATA[C e (mg / L)]]> V(mL) m(g) R(％) q(mg / g) 6.31169 0.12942 30 0.0322 97.95 5.8 14.30112478 0.351103277 9 0.0091 97.54 13.8 33.91833428 0.271927166 9 0.0091 99.2 33.28 95.08914489 55.16913633 9 0.0091 41.98 39.48 995.95 953.65 8 0.0083 4.25 40.77

[0083] C in Table 2 e The value is the x-coordinate (C) e C e1 C e2 C e3 C e4 C e5 C e1 The concentration was 0.12942 mg / L, and the concentration was C. e2The concentration was 0.351103277 mg / L, and the concentration was C. e3 The concentration was 0.271927166 mg / L, C e4 The concentration was 55.16913633 mg / L, and C e5 The adsorption capacity (q) in Table 2 was 953.65 mg / L. Using this value as the ordinate, the Langmuir isothermal adsorption model in Origin software was used to perform nonlinear fitting on the obtained coordinate points, resulting in a fitting curve (isothermal adsorption curve). This led to the determination of the adsorption capacity. Figure 4 The isothermal adsorption model diagram shown has the following fitting formula: Where, q m (mg / g) represents the maximum adsorption capacity, and b (L / mg) represents the adsorption equilibrium constant. After fitting, the corresponding isothermal adsorption curve and q can be obtained. m (mg / g) and b (L / mg) values. Figure 4 This indicates that the metal sulfide adsorbent prepared in Example 1 contains (Hen)2(en). 1.5 Sn3S7·3H2O on Ni 2+ The adsorption conforms to the Langmuir model. According to the Langmuir model fitting results, (Hen)2(en) 1.5 Sn3S7·3H2O on Ni 2+ The maximum adsorption capacity is 40.31 mg / g.

[0084] According to the above "Metal sulfide adsorbent obtained in Example 1 for Ni 2+ The adsorption model experiment was conducted on the metal sulfide adsorbent obtained in Example 2 to perform adsorption on Ni. 2+ Adsorption model experiment, C0 and C corresponding to Example 2 e The values ​​of V, m, removal rate R, and adsorption capacity q are shown in Table 3.

[0085] Table 3

[0086] <![CDATA[C0(mg / L)]]> <![CDATA[C e (mg / L)]]> V(mL) m(g) R(％) q(mg / g) 14.301125 0.001425 10 0.0101 99.99 14.16 33.918335 2.71222 10 0.0103 92 30.3 66.21921 35.23459 10 0.0103 46.79 30.08 95.089145 61.97315 10 0.0104 34.83 31.84

[0087] C in Table 3 e The value is the x-coordinate (C) e C e1 C e2 C e3 C e4 C e1 The concentration was 0.001425 mg / L, and the concentration was C. e2 The concentration was 2.71222 mg / L, and the concentration was C. e3 The concentration was 35.23459 mg / L, and the concentration was C. e4 The concentration was 61.97315 mg / L. Using the adsorption capacity q in Table 3 as the ordinate, and with... Figure 4Similarly, the results were obtained by fitting the Langmuir isotherm adsorption model in Origin software. Figure 5 The diagram shows the isothermal adsorption model. Figure 5 Show that, (Hteta)2(teta) x Sn3S7·yH2O on Ni 2+ The adsorption conforms to the Langmuir model. Based on the Langmuir model fitting results, its adsorption on Ni... 2+ The maximum adsorption capacity is 30.75 mg / g.

[0088] Example 7

[0089] Verification of the effect of the metal sulfide adsorbent obtained in Example 1 on Ni under different pH conditions 2+ Adsorption effect:

[0090] The metal sulfide adsorbent prepared in Example 1 was manually ground for 5 min using an agate mortar to obtain a fine powder. m (g) of the ground metal sulfide adsorbent was added to V (mL) of metal ion solution and placed in a shaker at 298 K at 160 r / min for t min, t min = 1440 min (24 hours). Then, it was centrifuged at 7000 r / min for 5 min to separate the supernatant and precipitate. 7 mL of the supernatant was then taken as the test solution, and the concentration of metal ions in the test solution was determined using inductively coupled plasma mass spectrometry (ICP-MS), denoted as C. e (mg / L). The metal ion solution is an aqueous solution of NiCl2. The NiCl2 aqueous solution contains Ni... 2+ The concentration of NiCl2 was 6 mg / L. To ensure more accurate calculation results, inductively coupled plasma optical emission spectroscopy (ICP-OES) was used to precisely measure the NiCl2 concentration in the aqueous solution. 2+ The concentration of the metal ions, i.e., the initial concentration of the metal ions in the metal ion solution, is denoted as C0 (mg / L). The pH of the NiCl2 aqueous solution is one of 2.47, 3.09, 3.99, 5.00, 6.2, 7.67, and 10.84. In this test, the pH is adjusted by adding hydrochloric acid or NaOH aqueous solution. The concentration of HCl in the hydrochloric acid is 0.1 mol / L, and the concentration of the NaOH aqueous solution is 0.1 mol / L. Based on V, m, C0, and C... e The allocation coefficient (K) is calculated. d K d The higher the value, the stronger the adsorbent's adsorption capacity for that ion.

[0091] pH value, CO, C e V, m and distribution coefficient (K) d As shown in Table 4.

[0092] Table 4

[0093] pH value <![CDATA[C0(mg / L)]]> <![CDATA[C e (mg / L)]]> V(mL) m(g) <![CDATA[K d (mL / g)]]> pH = 2.47 6.251473169 0.02468 15 0.0150 8.40 pH = 3.09 6.251473169 0.130455 15 0.0153 593.18 pH = 3.99 6.251473169 0.063835562 15 0.0153 95030.28 pH = 5.00 6.251473169 0.0437791 15 0.0153 139015.53 pH = 6.2 6.31169 0.12942 30 0.0302 44783.48 pH = 7.67 5.896285 0.297965 10 0.0101 18602.49 pH = 10.84 5.896285 1.560585 10 0.0105 2645.96

[0094] Partition coefficient (K) at different pH values d )like Figure 6 As shown. By Figure 6 It can be seen that within the pH range of 3.99 to 10.84, the partition coefficient (K) d The value ranged from 2645.96 to 139015.53 mL / g, indicating that (Hen)2(en) 1.5 Sn3S7·3H2O adsorbs Ni 2+ High K can be maintained over a wide pH range. d Value, that is, to maintain a strong adsorption capacity.

[0095] Example 8

[0096] Comparison of the adsorption capacity of metal sulfide adsorbents for different metal ions in a single environment:

[0097] The metal sulfide adsorbent prepared in Example 1 was manually ground for 5 min using an agate mortar to obtain a fine powder. m (g) of this fine powder was added to V (mL) of metal ion solution and placed in a shaker at 298 K at 160 r / min for t min, t min = 1440 min (24 h). Then, it was centrifuged at 7000 r / min for 5 min. 9 mL of the supernatant was taken as the test solution, and Cs in the test solution was determined using inductively coupled plasma mass spectrometry (ICP-MS). + 、Sr 2+ Eu 3+ Ni 2+ Co 2+ Cd 2+ Ba 2+ The concentration of metal ions in the test solution is denoted as C. e (mg / L).

[0098] The metal ion solution is one of the following: NiCl2 aqueous solution, CoCl2 aqueous solution, EuCl3 aqueous solution, CdCl2 aqueous solution, BaCl2 aqueous solution, SrCl2 aqueous solution, and CsCl aqueous solution. In the NiCl2 aqueous solution, Ni... 2+ The concentration of CoCl2 in the aqueous solution was 6.31 ppm. 2+ The concentration was 5.37 ppm. EuCl3 aqueous solution contained Eu 3+ The concentration of CdCl2 in the aqueous solution was 4.94 ppm. 2+ The concentration of BaCl2 in the aqueous solution was 7.56 ppm. 2+The concentration of SrCl2 in the aqueous solution was 5.44 ppm. 2+ The concentration was 5.55 ppm. The CsCl aqueous solution contained Cs... + The concentration was 3.98 ppm. To ensure more accurate calculation results, inductively coupled plasma mass spectrometry (ICP-MS) was used to precisely determine the Cs concentration in the CsCl aqueous solution. + NiCl2 aqueous solution Ni 2+ Concentration of CoCl2 in aqueous solution 2+ Concentration of EuCl3 in aqueous solution 3+ Concentration of Cd in CdCl2 aqueous solution 2+ The concentration of BaCl2 in aqueous solution 2+ The concentration of SrCl2 in aqueous solution and Sr 2+ The concentration of is denoted as C0.

[0099] Types of metal ions, CO, C e V, m, K d R and q are shown in Table 5.

[0100] Table 5

[0101]

[0102] The K values ​​corresponding to different metal ions in Table 5 are... d The value and removal rate R are plotted as a trend graph, such as Figure 7 As shown, in metal sulfide adsorbents, (Hen)₂(en) 1.5 Sn3S7·3H2O on Ni 2+ It has optimal selectivity, and (Hen)2(en) 1.5 The ion selectivity order of Sn3S7·3H2O is Ni 2+ >Co 2+ Eu 3+ >Cd 2+ >Ba 2+ >Sr 2+ >Cs + .

[0103] Example 9

[0104] Determining the effect of metal sulfide adsorbents on Ni under complex conditions with multiple competing ions. 2+ Selective adsorption properties:

[0105] Four different metal sulfide adsorbents were placed in metal ion solutions (competitive ion solutions) to determine whether these four different metal sulfide adsorbents, under interference from other ions, could improve Ni... 2+It exhibits good adsorption performance and preferential adsorption capability. Specifically, 10 mg of adsorbent and 10 mL of competing ion solution were mixed and placed in a shaker at 298 K with a rotation speed of 160 r / min for t min, t min = 1440 min (24 h). Then, it was centrifuged at 7000 r / min for 5 min, and 7 mL of the supernatant was taken as the test solution. The Cs in the test solution were determined by inductively coupled plasma mass spectrometry (ICP-MS). + 、Sr 2+ Eu 3+ Ni 2+ The concentration of metal ions in the test solution is denoted as C. e (Measured Cs) + The concentration is denoted as C. e Cs The measured Sr 2+ The concentration is denoted as C. e Sr The measured Eu 3+ The concentration is denoted as C. e Eu The measured Ni 2+ The concentration is denoted as C. e Ni Among them, competing ion solutions include: Cs + 、Sr 2+ Eu 3+ Ni 2+ and deionized water (Cs) + Introduced by CsCl, Sr 2+ Introduced by SrCl2, Eu 3+ Introduced by EuCl3, Ni 2+ (Introduced by NiCl2), to obtain more accurate results, inductively coupled plasma mass spectrometry (ICP-MS) was used to determine Cs in the competing ion solution. + 、Sr 2+ Eu 3+ Ni 2+ The concentration of Cs is denoted as C0 (the measured Cs). + The concentration is denoted as C0. Cs The measured Sr 2+ The concentration is denoted as C0. Sr The measured Eu 3+ The concentration is denoted as C0. Eu The measured Ni 2+ The concentration is denoted as C0. Ni The adsorbents are the metal sulfide adsorbents prepared in Example 1, the metal sulfide adsorbents prepared in Example 2, and the [(Me2NH2)] obtained in Example 1 of the invention patent CN 118681607 A. 1.25 (Me3NH)0.75 Sn3S7·0.375(C 12 H 24 One of the metal sulfide adsorbents constructed from the monoamine template obtained in Example 3 (O6)·H2O.

[0106] C e Cs C e Sr C e Eu C e Ni C0 Cs C0 Sr C0 Eu and C0 Ni The values ​​are shown in Table 6.

[0107] Table 6

[0108]

[0109] According to C e Cs The calculated allocation coefficient is denoted as K. d Cs According to C e Sr The calculated allocation coefficient is denoted as K. d Sr According to C e Eu The calculated allocation coefficient is denoted as K. d Eu According to C e Ni The calculated allocation coefficient is denoted as K. d Ni The allocation coefficient (K) is calculated based on the data in Table 6. d The values ​​of ) are shown in Table 7.

[0110] Table 7

[0111]

[0112] The separation factor (SF) was calculated using the formula and the data in Table 7. The formula for calculating the separation factor (SF) is as follows:

[0113] in, (mL / g) represents the partition coefficient of metal ion A, where A is Ni 2+ , (mL / g) represents the partition coefficient of metal ion B, where B is Cs + 、Sr 2+ Or Eu3+ When SF > 1, the adsorbent tends to adsorb metal ion A; when SF < 1, the adsorbent tends to adsorb metal ion B; and when SF = 1, the adsorbent has the same adsorption capacity for metal ions A and B, showing no selectivity. A larger SF indicates that the adsorbent preferentially adsorbs Ni. 2+ .

[0114] The values ​​of the separation factor (SF) are shown in Table 8. Ni / Cs Represents Ni 2+ Compared to Cs + Separation factor, SF Ni / Sr Represents Ni 2+ Compared to Sr 2+ Separation factor, SF Ni / Eu Represents Ni 2+ Compared to Eu 3+ (Separation factor).

[0115] Table 8

[0116] Adsorbent <![CDATA[SF Ni / Cs ]]> <![CDATA[SF Ni / Sr ]]> <![CDATA[SF Ni / Eu ]]> Embodiment 1 of the present invention <![CDATA[9.78×10 3 ]]> 36.65 7.92 Embodiment 2 of the present invention <![CDATA[1.95×10 2 ]]> 80.04 4.97 <![CDATA[[(Me2NH2) 1.25 (Me3NH) 0.75 ]Sn3S7·0.375(C 12 H 24 O6)·H2O]]> 23.26 0.03 0.136 Embodiment 3 of the present invention 3.14 0.51 0.0001

[0117] Figure 8 When the metal sulfide adsorbent prepared in Example 1 is used as an adsorbent, the partition coefficient (K) of different metal ions in the competing ion solution is... d (Image) By Figure 8 It can be seen that, under the condition of multiple competing ions coexisting, the metal sulfide adsorbent prepared in Example 1 contains (Hen)2(en). 1.5 Sn3S7·3H2O on Ni 2+ It has a strong adsorption capacity, K d The value can reach 23759.64 mL / g. Meanwhile, Ni... 2+ Compared to Cs + Separation factor SF Ni / Cs It is 9.78×10 3 Ni 2+ Compared to Sr 2+ Separation factor SF Ni / Sr 36.65; Ni 2+ Compared to Eu 3+ Separation factor SF Ni / Eu The value is 7.92. This indicates that although Cs is present in the solution... + 、Sr 2 + Eu 3+ Equal competing ions, (Hen)₂(en) 1.5 Sn3S7·3H2O on Ni 2+ It still has a very strong preferential adsorption capacity, that is, it has high selectivity.

[0118] Figure 9 When the metal sulfide adsorbent prepared in Example 2 is used as an adsorbent, the partition coefficient (K) of different metal ions in the competing ion solution is... d (Image) By Figure 9 It can be seen that in an environment where multiple competing ions coexist, the metal sulfide adsorbent prepared in Example 2 contains (Hteta)2(teta). x Sn3S7·yH2O on Ni 2+ K has the best adsorption capacity. d The value can reach 51732.01 mL / g. Meanwhile, Ni... 2+ Compared to Cs + Separation factor SF Ni / Cs 1.95×10 2 Ni 2+ Compared to Sr 2+ Separation factor SF Ni / Sr 80.04; Ni 2+ Compared to Eu 3+ Separation factor SF Ni / Eu The value is 4.97. (Hteta)2(teta) x Sn3S7·yH2O in Cs + 、Sr 2+ Eu 3+ In complex solution environments where competing ions coexist, it also exhibits resistance to Ni. 2+ Priority selection.

[0119] Figure 10 [(Me2NH2)] 1.25 (Me3NH) 0.75 Sn3S7·0.375(C 12 H 24 When O6·H2O is used as an adsorbent, the partition coefficient (K) of different metal ions in a competing ion solution is... d (Figure). [(Me2NH2) 1.25 (Me3NH) 0.75 Sn3S7·0.375(C 12 H 24 O6)·H2O on Sr 2+ K has the best adsorption capacity. d The value can reach 641711.74 mL / g, but for Ni... 2+ The adsorption capacity is poor, K d The value was only 16105.68 mL / g. Meanwhile, Ni... 2+ Compared to Cs + Separation factor SF Ni / Cs It is 23.26; Ni 2+Compared to Sr 2+ Separation factor SF Ni / Sr Only 0.03; Ni 2+ Compared to Eu 3+ Separation factor SF Ni / Eu Only 0.136. This indicates that with Sr 2+ Eu 3+ When ion interference occurs, the adsorbent cannot achieve Ni 2+ It preferentially adsorbs, but lacks selectivity.

[0120] Figure 11 When the metal sulfide adsorbent constructed using the monoamine template prepared in Example 3 is used as an adsorbent, the partition coefficient (K) of different metal ions in the competing ion solution is... d Figure 3. The metal sulfide adsorbent constructed using the monoamine template prepared in Example 3 for Eu... 3+ K has the best adsorption capacity. d The value can reach 32010530.27 mL / g, for Ni 2+ The adsorption capacity is poor, K d The value was only 1971.70 mL / g. Meanwhile, Ni... 2+ Compared to Cs + Separation factor SF Ni / Cs It is 3.14; Ni 2+ Compared to Sr 2+ Separation factor SF Ni / Sr Only 0.51; Ni 2+ Compared to Eu 3+ Separation factor SF Ni / Eu The value is only 0.0001. This indicates that the adsorbent also lacks the ability to adsorb Ni. 2+ Selectivity of preferential adsorption.

[0121] In summary, in competitive ion solutions, the metal sulfide adsorbent prepared in Example 1 is the most suitable adsorbent for Ni... 2+ Distribution coefficient (K) d Ni ) is [(Me2NH2) 1.25 (Me3NH) 0.75 Sn3S7·0.375(C 12 H 24 The Ni content of O6·H2O is 1.48 times that of the monoamine template-constructed metal sulfide adsorbent prepared in Example 3, and 12 times that of the adsorbent prepared in Example 2. 2+ Distribution coefficient (K) d Ni ) is [(Me2NH2) 1.25 (Me3NH)0.75 Sn3S7·0.375(C 12 H 24 It is 3.2 times that of O6)·H2O and 26.2 times that of the metal sulfide adsorbent constructed with the monoamine template prepared in Example 3.

[0122] In Cs + 、Sr 2+ Eu 3+ In solutions with interference from coexisting ions, when the metal sulfide adsorbents constructed from the polyamine templates prepared in Examples 1-2 of this invention are used as adsorbents, their SF6 content is low. Ni / Cs SF Ni / Sr SF Ni / Eu Both are greater than 1. Therefore, (Hen)²(en) 1.5 Sn3S7·3H2O and (Hteta)2(teta) x Sn3S7·yH2O on Ni 2+ It exhibits optimal adsorption performance and the best selectivity. The metal sulfide adsorbents prepared in Examples 1-2 of this invention, and [(Me₂NH₂] in CN 118681607 A]... 1.25 (Me3NH) 0.75 Sn3S7·0.375(C 12 H 24 SF6·H2O and the metal sulfide adsorbent constructed using the monoamine template prepared in Example 3 Ni / Cs The values ​​are all greater than 1, but the SF of the metal sulfide adsorbents constructed with polyamine templates prepared in Examples 1-2 is higher. Ni / Cs The value is much greater than [(Me2NH2)]. 1.25 (Me3NH) 0.75 Sn3S7·0.375(C 12 H 24 The metal sulfide adsorbent constructed using the monoamine template prepared in Example 3 (O6)·H2O and [(Me2NH2)] was also used. 1.25 (Me3NH) 0.75 Sn3S7·0.375(C 12 H 24 When adsorbing metal sulfide adsorbents constructed using the monoamine template prepared in Example 3 and O6·H2O, SF Ni / Sr SF Ni / Eu Both are less than 1, making it impossible to achieve Ni 2+ Preferred selection and effective separation. Even in complex solutions with competing ions, the metal sulfide adsorbent constructed with the polyamine template of this invention can achieve Ni... 2+ Good separation.

[0123] It has the general formula (PAH)2(PA). x The Sn3S7·yH2O metal sulfide adsorbent uses polyamines as templates to synthesize crystals through precise control of the reaction process, achieving co-intercalation of polyamine molecules and protonated polyamine cations. The abundant amino functional groups in the polyamine molecules not only guide crystal growth but also facilitate ion exchange and specific complexation with target toxic metal ions. Based on this characteristic, polyamine molecules adapted to the properties of the target toxic metal ions can be selected to directionally optimize the physicochemical properties of the adsorbent, thereby significantly improving the material's selectivity for target nickel ions. This enables efficient separation and extraction of nickel ions from wastewater, addressing the shortcomings of existing adsorbent technologies and holding significant importance for the treatment of toxic metal ion pollution in aquatic environments.

[0124] The present invention has been described above by way of example. It should be noted that any simple modifications, alterations or other equivalent substitutions that can be made by those skilled in the art without creative effort without departing from the core of the present invention fall within the protection scope of the present invention.

Claims

1. A metal sulfide adsorbent, characterized in that, include: Layered crystals, the general chemical formula of which is: (PAH)₂(PA) x Sn3S7·yH2O, where PAH represents a protonated polyamine cation, PA represents a neutral polyamine molecule and a disordered polyamine molecule, x takes values ​​of 0 to 5, and y takes values ​​of 0 to 5.

2. The metal sulfide adsorbent according to claim 1, characterized in that, Layered crystals with a layered structure [Sn3S7] n 2n- As an anionic framework, in [Sn3S7] n 2n- Polyamines are distributed both between and within the layers, existing as protonated polyamine cations, neutral polyamine molecules, and disordered polyamine molecules. Protonated polyamine cations are inserted into [Sn3S7] as counter cations. n 2n- Interlayer, disordered polyamine molecules and neutral polyamine molecules are embedded in [Sn3S7]. n 2n- Interlayer or located in [Sn3S7] n 2n- Within the hexagonal honeycomb-shaped channels of the layer.

3. A method for preparing a metal sulfide adsorbent, characterized in that, Includes the following steps: Step 1: Mix the tin source, sulfur source and polyamine aqueous solution until homogeneous to obtain a mixed solution. The ratio of tin in the tin source, sulfur in the sulfur source and polyamine in the polyamine aqueous solution is 1:(2.0-3.5):(8.0-32.0) by molar proportions. The polyamine is one or a mixture of several of ethylenediamine, diethylenetriamine, triethylenetetramine and o-phenylenediamine. Step 2: The mixed solution obtained in Step 1 is subjected to a hydrothermal reaction at 120-180°C for 4-6 days under sealed conditions. After cooling to room temperature, the mixture is filtered to obtain a product containing layered crystals. The product is then washed and dried to obtain a metal sulfide adsorbent.

4. The preparation method according to claim 3, characterized in that, In step 1, the concentration of polyamine in the polyamine aqueous solution is 60.0–90.0 wt%.

5. The application of metal sulfide adsorbents in the extraction of metal ions, characterized in that, The metal sulfide adsorbent is the metal sulfide adsorbent of claim 1 or the metal sulfide adsorbent obtained by the preparation method of claim 3.

6. The application according to claim 5, characterized in that, The priority order for metal ion extraction by metal sulfide adsorbents is Ni. 2+ >Co 2+ >Eu 3+ >Cd 2+ >Ba 2+ >Sr 2+ >Cs + .

7. The application according to claim 5, characterized in that, Place the metal sulfide adsorbent in a container containing Cs + 、Sr 2+ Eu 3 + and Ni 2+ In the solution, Ni 2+ The separation factor relative to other metal ions is greater than 1.

8. The application according to claim 7, characterized in that, Ni 2+ Compared to Cs + The separation factor is 9.78 × 10⁻⁶. 3 Ni 2 + Compared to Sr 2+ The separation factor is 36.65, Ni 2+ Compared to Eu 3+ The separation factor was 7.

92.

9. Metal sulfide adsorbents in the extraction of Ni 2+ The application of [the technology] is characterized by, The metal sulfide adsorbent is the metal sulfide adsorbent of claim 1 or the metal sulfide adsorbent obtained by the preparation method of claim 3.

10. The application according to claim 9, characterized in that, The metal sulfide adsorbent for Ni after 6 minutes of adsorption 2+ The removal rate reached over 90%.

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