Method for preparing copper-based sulfide nanoparticles and its application in iodine capture

Abstract

The application provides a preparation method of copper-based sulfide nanoparticles and application thereof in iodine capture, and relates to the technical field of radioiodine adsorption. The application adopts a one-step method, and by changing the molar ratio of raw materials of Cu and S, CuS nanoparticles, composite nanoparticles of CuS and Cu2S, or Cu2S nanoparticles can be controllably prepared. Through a simple and efficient solution chemical reaction, the copper-based sulfide nanoparticles with controllable composition and mesoporous structure can be prepared. The prepared nanoparticles exhibit excellent performance in adsorbing radioiodine, and can effectively capture gaseous and liquid iodine.

Description

Technical Field

[0001] This invention relates to the field of radioactive iodine adsorption technology, and in particular to a method for preparing copper-based sulfide nanoparticles and their application in iodine capture. Background Technology

[0002] With the development of the nuclear energy industry, the safe disposal of radioactive isotopes, especially iodine isotopes, generated during nuclear power plants and the nuclear fuel cycle has become increasingly prominent. Gaseous and liquid iodine are highly volatile and highly radioactive; if they are not effectively recovered or controlled, they will pose a serious threat to the environment and human health.

[0003] Therefore, developing efficient, safe, and highly operable adsorption materials has always been an important research direction in the field of nuclear waste treatment.

[0004] Traditional adsorbents mainly include activated carbon, metal oxides, zeolites, and organic porous materials. While these materials can adsorb radioactive iodine to some extent, they suffer from drawbacks such as limited adsorption capacity, poor selectivity, insufficient temperature and humidity resistance, and complex preparation processes. Activated carbon has the advantages of large specific surface area and ease of preparation, but its adsorption performance deteriorates significantly under high temperature or high humidity conditions. Zeolites and metal oxide adsorbents have improved thermal stability and selectivity, but their preparation processes are complex, costly, and difficult to implement on a large scale. Furthermore, existing adsorbents lack compatibility with both gaseous and liquid iodine, making it difficult to simultaneously achieve efficient capture of both forms, thus limiting their application in practical nuclear waste treatment.

[0005] In recent years, nanomaterials have attracted widespread attention for their large specific surface area, controllable structure, and high surface activity in the adsorption of environmental pollutants and the treatment of radioactive materials. Porous nanomaterials can provide more active sites, thereby improving adsorption capacity and kinetic performance. Simultaneously, the chemical composition and surface functionalization of nanomaterials offer possibilities for adsorption selectivity and stability. However, the preparation of existing nano-adsorbents typically involves complex processes, stringent reaction conditions, or expensive raw materials, which to some extent limits their widespread application. Furthermore, large-scale preparation of nanomaterials suffers from problems such as agglomeration, uneven particle size distribution, and poor reusability, necessitating the development of new, economical, and controllable preparation methods to meet the demands of industrial applications.

[0006] In practical applications of nuclear waste treatment, adsorbents not only need to possess high adsorption capacity and selectivity, but also need to consider thermal stability, wet stability, and ease of operation to adapt to the complex operating environment of nuclear facilities. Therefore, finding an adsorbent material that can combine high performance, ease of preparation, and wide applicability has become a core research direction in the field of radioactive iodine capture, and is also key to improving nuclear safety management and environmental protection capabilities.

[0007] Therefore, this invention is proposed. Summary of the Invention

[0008] To address the aforementioned technical problems, this invention provides copper-based sulfide nanoparticles and their preparation method. This method, through simple chemical reaction steps, can effectively synthesize high-performance copper-based sulfide nanoparticles. The preparation method is simple to operate, with controllable conditions, and the obtained nanoparticles exhibit excellent performance in adsorbing radioactive iodine.

[0009] In order to achieve the objective of this invention, the following technical solution is adopted: This invention provides a method for preparing copper-based sulfide nanoparticles, characterized by the following steps: dissolving a copper source in a solvent, adding a sulfur source, reacting under stirring, cooling, centrifuging, washing, and drying to obtain the final product.

[0010] Furthermore, the copper source is copper acetate, and the solvent is polyethylene glycol.

[0011] Furthermore, the sulfur source is sublimed sulfur.

[0012] Furthermore, the molar ratio of Cu to S in the copper source and the sulfur source is 1:1, 1:0.75, 1:0.625, 1:0.5, or 1:0.25.

[0013] Furthermore, the reaction temperature is 120°C and the reaction time is 2 hours.

[0014] The present invention also provides copper-based sulfide nanoparticles prepared by the above-mentioned method, wherein the copper-based sulfide nanoparticles are CuS nanoparticles, CuS and Cu2S composite nanoparticles, or Cu2S nanoparticles.

[0015] Furthermore, the nanoparticles possess a mesoporous structure; wherein the average pore sizes of the Cu₂S nanoparticles, CuS nanoparticles, and CuS / Cu₂S composite nanoparticles are 13 nm, 11 nm, and 11-14 nm, respectively; and the pore volumes of the Cu₂S nanoparticles, CuS nanoparticles, and CuS / Cu₂S composite nanoparticles are 0.03 cm³. 3 / g, 0.025cm 3 / g and 0.028-0.041cm 3 / g.

[0016] The present invention also provides the application of the copper-based sulfide nanoparticles described above in capturing radioactive iodine.

[0017] Furthermore, the radioactive iodine is gaseous iodine or liquid iodine.

[0018] Furthermore, the copper-based sulfide nanoparticles capture radioactive iodine at a temperature of 25-150°C.

[0019] Furthermore, the copper-based sulfide nanoparticles capture gaseous iodine at a temperature of 77-150°C; the copper-based sulfide nanoparticles capture liquid iodine at a temperature of 25-45°C.

[0020] The present invention has the following technical effects: (1) The method for preparing copper-based sulfide nanoparticles provided by the present invention can synthesize nanoparticles with excellent adsorption properties by precisely controlling the molar ratio of copper source to sulfur source. Compared with the prior art, this method is simple to operate and has mild reaction conditions, avoiding complex equipment and high temperature and high pressure conditions, thereby greatly reducing the preparation cost.

[0021] (2) The copper-based sulfide nanoparticles provided by this invention have a relatively ideal pore volume and pore size distribution, which enables them to exhibit high adsorption capacity and fast adsorption rate during the adsorption process. In particular, in practical applications, these nanoparticles can effectively capture gaseous and liquid radioactive iodine, showing good environmental adaptability. Attached Figure Description

[0022] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0023] Figure 1 The characterization diagram obtained in Experiment Example 1, where Figure 1 -a is a SEM image of Cu2S nanoparticles. Figure 1 -b is a SEM image of C-1 nanoparticles. Figure 1 -c is a SEM image of C-2 nanoparticles. Figure 1 -d is the SEM image of C-3 nanoparticles. Figure 1 -e represents the SEM image of CuS nanoparticles. Figure 1 Figure -f shows the HRTEM image of C-1 nanoparticles, and Figure g shows the SAED image of C-1 nanoparticles. Figure 1 -h is a TEM image of C-1 nanoparticles. Figure 1 -i is the EDS image of C-1 nanoparticles; Figure 2 The characterization diagram obtained in Experiment Example 1, where Figure 2 -a shows EDS images of Cu2S, C-1, C-2, C-3, and CuS nanoparticles. Figure 2 -b represents the Raman spectra of Cu₂S, C⁻¹, and CuS nanoparticles. Figure 2 -c represents the XPS spectrum of Cu2p in Cu2S nanoparticles. Figure 2 -d represents the XPS spectrum of Cu 2p in C-1 nanoparticles. Figure 2 -e represents the XPS spectrum of Cu 2p in CuS nanoparticles. Figure 2 -f represents the XPS spectrum of S 2p in C-1 nanoparticles; Figure 3 The characterization diagram obtained in Experiment Example 1, where Figure 3 -a represents the nitrogen adsorption-desorption isotherms for Cu2S, C-1, C-2, C-3, and CuS materials. Figure 3 -b represents the pore size distribution curves of Cu2S, C-1, C-2, C-3, and Cu-S materials; Figure 4 The graph shows the results obtained from Experiment 2 and Experiment 3, where Figure 4 -a represents the adsorption isotherms of radioactive iodine by Cu₂S, C⁻¹, C⁻², C⁻³, and CuS in iodine / cyclohexane solution. Figure 4 -b represents the kinetic adsorption curves of radioactive iodine by Cu₂S, C₁, C₂, C₃, and CuS in iodine / cyclohexane solution. Figure 4 -c represents the intraparticle diffusion kinetics curves of radioactive iodine to Cu₂S, C₁, C₂, C₃, and CuS in iodine / cyclohexane solution. Figure 4 -d is a graph showing the saturated adsorption capacity of Cu2S, C-1, and CuS for iodine in solution at different temperatures. Figure 4 -e represents the saturated adsorption capacity curves of Cu₂S, C⁻¹, and CuS for gaseous iodine at 77℃. Figure 4 -f is a graph showing the saturated adsorption capacity of C-1 for iodine vapor at different temperatures.

[0024] Figure 5 The figure shows the results obtained in Experiment Example 4, where Figure 5 -a is a graph showing the effect of different time intervals on the release of I2-C-1 iodine from ethanol solution. Figure 5 -b is a graph showing the results of the study on the regeneration performance of iodine by Cu2S, C-1 and CuS; Figure 6 The figure shows the results obtained in Experiment Example 5, where Figure 6 -a is the SEM image of I2-C-1. Figure 6 -b represents the element mapping graph of C-1. Figure 6 -c is the element-mapped image of I2-C-1; Figure 7The figure shows the results obtained in Experiment 5, where 7-a is the XRD pattern of C-1 before and after iodine capture. Figure 7 -b is the Raman spectrum of I2-C-1. Figure 7 -c represents the XPS spectrum of Cu 2p in C-1 after iodine adsorption. Figure 7 -d represents the three-dimensional spectrum; Figure 8 The thermogravimetric analysis (TGA) characterization diagram obtained in Experiment Example 5 is shown. Detailed Implementation

[0025] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of this invention, and not all of them. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0026] In a first aspect, the present invention provides a method for preparing copper-based sulfide nanoparticles, comprising the following steps: dissolving a copper source in a solvent and then adding a sulfur source, reacting under stirring, cooling, centrifuging, washing, and drying to obtain the final product.

[0027] In some embodiments, the copper source is copper acetate and the solvent is polyethylene glycol.

[0028] In some embodiments, the sulfur source is sublimed sulfur.

[0029] In some embodiments, the molar ratio of Cu to S in the copper source and the sulfur source is 1:1, 1:0.75, 1:0.625, 1:0.5, or 1:0.25.

[0030] Specifically, in this invention, when the molar ratio of Cu to S in the copper source and the sulfur source is 1:1, the nanoparticles prepared are CuS nanoparticles; when the molar ratio of Cu to S in the copper source and the sulfur source is 1:0.25, the nanoparticles prepared are Cu2S nanoparticles; and when the molar ratio of Cu to S in the copper source and the sulfur source is 1:0.75, 1:0.625, or 1:0.5, the nanoparticles prepared are all composite nanoparticles of CuS and Cu2S.

[0031] In some embodiments, the reaction temperature is 120°C and the reaction time is 2 hours.

[0032] Secondly, the present invention provides copper-based sulfide nanoparticles prepared by the method described above, wherein the copper-based sulfide nanoparticles are CuS nanoparticles, or composite nanoparticles of CuS and Cu2S, or Cu2S nanoparticles.

[0033] In some embodiments, the nanoparticles have a mesoporous structure; wherein the average pore sizes of the Cu₂S nanoparticles, CuS nanoparticles, and CuS / Cu₂S composite nanoparticles are 13 nm, 11 nm, and 11-14 nm, respectively; and the pore volumes of the Cu₂S nanoparticles, CuS nanoparticles, and CuS / Cu₂S composite nanoparticles are 0.03 cm³. 3 / g, 0.025cm 3 / g and 0.028-0.041cm 3 / g.

[0034] Thirdly, the present invention also provides an application of the above-mentioned copper-based sulfide nanoparticles in capturing radioactive iodine.

[0035] In some embodiments, the radioactive iodine is gaseous iodine or liquid iodine.

[0036] In some embodiments, the copper-based sulfide nanoparticles capture radioactive iodine at a temperature of 25-150°C.

[0037] In some embodiments, the copper-based sulfide nanoparticles capture gaseous iodine at a temperature of 77-150°C; the copper-based sulfide nanoparticles capture liquid iodine at a temperature of 25-45°C.

[0038] The following is a detailed explanation using specific embodiments: Example 1: Dissolve 800 mg of copper acetate in 40 mL of polyethylene glycol; Subsequently, sublimed sulfur was added to the solution containing dissolved copper acetate at concentrations of 128 mg (nCu:nS = 1:1), 32.1 mg (nCu:nS = 1:0.25), 64.2 mg (nCu:nS = 1:0.5), 80.3 mg (nCu:nS = 1:0.625), and 96.4 mg (nCu:nS = 1:0.75), respectively, and the mixture was stirred continuously at 120 °C for 2 hours. Finally, the mixture was cooled to room temperature, centrifuged, and repeatedly washed with ethanol and deionized water to prepare CuS nanoparticles, CuS / Cu2S composite nanoparticles (denoted as C-1, C-2, and C-3, respectively), and Cu2S nanoparticles, respectively. In CuS nanoparticles, nCu:nS = 1:1; in C-1, nCu:nS = 1:0.5; in C-2, nCu:nS = 1:0.625; in C-3, nCu:nS = 1:0.75; and in Cu2S nanoparticles, nCu:nS = 1:0.25.

[0039] Example 1: Characterization of Cu₂S nanoparticles, CuS nanoparticles, or composite nanoparticles of CuS and Cu₂S 1. Characterization by scanning electron microscopy (SEM) Take an appropriate amount of Cu2S nanoparticles, C-1 nanoparticles, C-2 nanoparticles, C-3 nanoparticles and CuS nanoparticles prepared in Example 1 and disperse them in anhydrous ethanol. After ultrasonic dispersion, they are dropped onto the surface of a silicon wafer and allowed to air dry naturally.

[0040] The samples were placed in a scanning electron microscope, and their surface morphology was observed under an accelerating voltage of 5-15 kV. SEM images of each sample were acquired, and the final SEM images are shown below. Figure 1 Figures a, b, c, d, and e are shown in the figure. Figure a is a SEM image of Cu2S nanoparticles, Figure b is a SEM image of C-1 nanoparticles, Figure c is a SEM image of C-2 nanoparticles, Figure d is a SEM image of C-3 nanoparticles, and Figure e is a SEM image of CuS nanoparticles.

[0041] in Figure 1 Figures a and e in the figure show scanning electron microscope (SEM) images of Cu2S, C-1, C-2, C-3 and CuS made from raw materials with different sublimation sulfur contents.

[0042] Figure 1 The results show that Cu₂S exhibits an irregular nanosheet structure, with many spherical particles aggregated on the nanosheets. Meanwhile, the... Figure 1 From -b to 1-d, it can be seen that the number of spherical particles on the irregular nanosheets decreases with increasing sublimated sulfur concentration, and the nanosheet surface gradually becomes smoother. When nCu:nS = 1:1, CuS exhibits a smooth and uniform nanosheet shape. Figure 1 -e).

[0043] 2. Characterization by high-resolution transmission electron microscopy (HRTEM) The C-1 nanoparticles prepared in Example 1 were dispersed in anhydrous ethanol and ultrasonically treated to ensure uniform dispersion.

[0044] The dispersion was dropped onto a carbon film supported by a copper mesh. After natural drying, the sample was observed using a transmission electron microscope (HRTEM) at an accelerating voltage of 200 kV to obtain high-resolution HRTEM images. The lattice spacing was measured and the crystal structure was analyzed. The final HRTEM images are shown below. Figure 1 Figure f in the figure shows an HRTEM image of C-1 nanoparticles.

[0045] Among them, by Figure 1As can be seen from -f, the high-resolution transmission electron microscope (HRTEM) image of C-1 shows lattice spacings of 0.174 nm and 0.273 nm, which correspond to the (311) and (006) crystal planes of Cu2S and CuS, respectively.

[0046] 3. Selected Area Electron Diffraction (SAED) Characterization During HRTEM observation, specific areas of the sample were selected, and SAED patterns were obtained using selected area electron diffraction (SAED). The polycrystalline or single-crystal properties of the C-1 sample were determined by analyzing the positions of diffraction rings or spots. The final HRTEM images are shown below. Figure 1 Figure g shows a SAED image of C-1 nanoparticles.

[0047] Among them, Figure 1 The diffraction rings observed in the selected area electron diffraction (SAED) pattern of -g can also be labeled as the (311) crystal plane of Cu2S and the (006) crystal plane of CuS, confirming the polycrystalline nature of the nanomaterial.

[0048] 4. Transmission electron microscopy (TEM) characterization The C-1 nanoparticles prepared in Example 1 were dispersed in anhydrous ethanol, ultrasonically dispersed, and then dropped onto a carbon film supported by a copper mesh and allowed to dry naturally.

[0049] The morphology and structure of sample C-1 were observed using transmission electron microscopy at an accelerating voltage of 200 kV, and TEM images were obtained. The final TEM images are shown below. Figure 1 Figure h in the figure shows a TEM image of C-1 nanoparticles.

[0050] Among them, by Figure 1 As can be seen from -h, the transmission electron microscope (TEM) image of C-1 shows a sheet-like structure, similar to the SEM image.

[0051] 5. Energy-dispersive spectroscopy (EDS) characterization While performing TEM observations, elemental analysis of the C-1 sample was conducted using an energy-dispersive X-ray spectrometer equipped with a transmission electron microscope.

[0052] A sample region was selected, and the distribution spectra of Cu and S elements in sample C-1 were acquired to obtain elemental mapping images. The uniformity of elemental distribution was analyzed, and the final EDS image is shown below. Figure 1 Figure i is shown in the figure, where Figure i is an EDS image of C-1 nanoparticles.

[0053] Among them, by Figure 1 As can be seen from -i, energy dispersive spectroscopy (EDS) analysis revealed that Cu and S elements are evenly distributed.

[0054] 6. X-ray diffraction (XRD) characterization Appropriate amounts of Cu2S nanoparticles, C-1 nanoparticles, C-2 nanoparticles, C-3 nanoparticles, and CuS nanoparticles prepared in Example 1 were placed in glass sample troughs, compacted and leveled, and then tested using an X-ray diffractometer.

[0055] The test conditions were: Cu Kα rays (λ=0.15418nm), tube voltage 40kV, tube current 40mA, scanning range 2θ 5°-70°, and scanning speed 5° / min. The obtained diffraction patterns were compared with standard cards (CuS: ​​JCPDS No. 99-0073, Cu2S: JCPDS No. 84-1770) to analyze the phase composition of the samples. The final XRD curves are shown below. Figure 2 Figure a shows the EDS images of Cu2S, C-1, C-2, C-3 and CuS nanoparticles.

[0056] Among them, by Figure 2 As shown in -a, the XRD curves of CuS and Cu2S are consistent with the standard cards for CuS (JCPDS: No. 99-0073) and Cu2S (JCPDS: 84-1770), respectively. Meanwhile, unique peaks for CuS and Cu2S are observed in C-1, C-2, and C-3. As the molar ratio of Cu to S increases, the characteristic peak of CuS becomes more intense, while the characteristic peak of Cu2S weakens.

[0057] 7. Raman spectroscopy characterization Appropriate amounts of Cu2S nanoparticles, C-1 nanoparticles, C-2 nanoparticles, C-3 nanoparticles, and CuS nanoparticles prepared in Example 1 were placed on glass slides and tested using a Raman spectrometer.

[0058] The test conditions were: excitation wavelength 532nm, laser power 50mW, and scanning range 100-1800cm. -1 Record the temperature of each sample at 270cm. -1 and 468cm -1 The characteristic peaks in the vicinity were analyzed to determine the presence of Cu-S and SS bonds. The final Raman spectrum is shown below. Figure 2 Figure b shows the Raman spectra of Cu2S, C-1, and CuS nanoparticles.

[0059] Among them, by Figure 2 -b indicates that at 270cm -1 and 468cm -1 The presence of characteristic peaks at these locations, corresponding to Cu-S and SS bonds respectively, proves the successful fabrication of the material.

[0060] 8. X-ray photoelectron spectroscopy (XPS) characterization The appropriate amounts of Cu2S nanoparticles, C-1 nanoparticles, and CuS nanoparticles prepared in Example 1 were pressed into pellets and then placed in an X-ray photoelectron spectroscopy instrument for testing.

[0061] A monochromatic Al Kα X-ray source (hν=1486.6eV) was used, and the vacuum level in the analysis chamber was better than 5×10⁻⁶. -10 mbar. High-resolution energy dispersive spectroscopy (EDS) spectra of Cu 2p and S 2p were acquired, and charge correction was performed using C1s (284.8 eV). Cu was analyzed by peak fitting. + and Cu² + The valence state distribution and Cu-S bond binding energy were obtained, and the final XPS spectrum is as follows: Figure 2 Figures c-f show the XPS spectra of Cu 2p in Cu2S nanoparticles, Figure d shows the XPS spectra of Cu 2p in C-1 nanoparticles, Figure e shows the XPS spectra of Cu 2p in CuS nanoparticles, and Figure f shows the XPS spectra of S 2p in C-1 nanoparticles.

[0062] in, Figure 2 -c shows the Cu 2p XPS spectrum of Cu₂S, with binding energy peaks at 933.1 and 953.3 eV, likely originating from the partially oxidized Cu₂S phase. Due to its low abundance, no CuS diffraction peaks were observed in the XRD pattern. The two main peaks at 931.2 and 951.0 eV (corresponding to Cu 2p) are... 3 / 2 and Cu 2p 1 / 2 This indicates the presence of Cu. + . Figure 2 -d shows the Cu 2p XPS spectrum of C-1, exhibiting characteristic peaks at 931.9 eV and 951.7 eV, attributed to Cu 2p, respectively. 3 / 2 and Cu 2p 1 / 2 This confirmed the presence of Cu₂S. Meanwhile, characteristic peaks appearing at 933.8 and 954.0 eV (corresponding to Cu 2p, respectively) confirmed the presence of Cu₂S. 3 / 2 and Cu 2p 1 / 2 This indicates the presence of CuS in the composite material, consistent with the XRD pattern. Figure 2 -e shows the Cu 2p XPS spectrum of CuS, attributed to Cu 2p. 3 / 2 The characteristic peaks appear at 932.3 and 934.5 eV. Furthermore, the characteristic peaks at 952.1 and 954.7 eV are attributed to Cu 2p. 1 / 2 These four characteristic peaks all belong to Cu. 2+ Characteristic peaks. Furthermore... Figure 1-f displays the XPS spectrum of S 2p in C-1, showing characteristic peaks at 162.3 and 163.5 eV, both below 164.0 eV, corresponding to Cu-S bonds in metal sulfides. A smaller characteristic signal is observed at 164.9 eV, indicating a lower abundance of S in the negative oxidation state, which may be related to S defects.

[0063] 9. Characterization by nitrogen adsorption-desorption isotherms A suitable amount of Cu2S nanoparticles, C-1 nanoparticles, C-2 nanoparticles, C-3 nanoparticles and CuS nanoparticles prepared in Example 1 were degassed at 120°C for more than 6 hours to remove the moisture and gas adsorbed on the sample surface.

[0064] Nitrogen adsorption-desorption isotherms were tested at -196℃ (liquid nitrogen temperature) using a specific surface area and pore size analyzer. The final nitrogen adsorption-desorption isotherms are as follows: Figure 3 As shown, where Figure 3 -a represents the nitrogen adsorption-desorption isotherms for Cu2S, C-1, C-2, C-3, and CuS materials. Figure 3 -b represents the pore size distribution curves of Cu2S, C-1, C-2, C-3, and Cu-S materials.

[0065] Among them, Cu₂S, C₁, C₂, C₃, and CuS all exhibit type IV isotherms and have obvious hysteresis loops, such as... Figure 3 As shown in -a, it indicates the presence of a mesoporous structure. Figure 3 The pore size distribution in -b indicates that the pores are mainly concentrated below 20 nm, verifying the mesoporous nature of the material.

[0066] The specific surface area of ​​the sample was calculated using the BET method, and the pore size distribution and pore volume were calculated using the BJH method. The final results are shown in Table 1 below.

[0067] Table 1. Specific surface area, average pore size, and pore volume of Cu2S, CX, and CuS materials.

[0068] Experimental Example 2: Iodine Adsorption Performance Test in Solution 2.1 Adsorption Isotherm Experiment A certain amount of elemental iodine was dissolved in cyclohexane to prepare a series of iodine-cyclohexane solutions with different concentration gradients. 20 mg of the test samples (Cu2S, C-1, C-2, C-3, CuS) were weighed and placed in stoppered centrifuge tubes, and 20 mL of the above-mentioned iodine-cyclohexane solutions of different concentrations were added to each.

[0069] Place the centrifuge tubes in a constant-temperature shaker and shake at 180 rpm for 24 hours at 25°C to ensure that the adsorption reaches equilibrium.

[0070] After adsorption, the mixture was centrifuged and the supernatant was collected. The absorbance of the residual iodine in the supernatant was measured at a wavelength of 523 nm using a UV-Vis spectrophotometer. The concentration of iodine in the solution after adsorption was calculated based on the pre-established iodine standard curve, and the adsorption capacity of each sample was calculated.

[0071] The Langmuir and Freundlich isotherm adsorption models were used to fit the experimental data and analyze the adsorption behavior of the material.

[0072] The final result is as follows Figure 4 As shown, where Figure 4 -a represents the adsorption isotherms of radioactive iodine by Cu₂S, C₁, C₂, C₃ and CuS in iodine / cyclohexane solution.

[0073] Among them, such as Figure 4 As shown in Figure -a, the adsorption capacity of Cu₂S, C₁, C₂, C₃, and CuS in cyclohexane solution was tested. With increasing iodine cyclohexane solution concentration, the adsorption capacity of the materials gradually increased until equilibrium was reached. The saturated adsorption capacities of Cu₂S, C₁, C₂, C₃, and CuS at equilibrium were 995.0, 803.9, 673.7, 519.0, and 130.8 mg / g, respectively. -1 Due to Cu + It has a greater affinity for I2 than Cu. 2+ Therefore, Cu2S exhibits the highest adsorption capacity among these materials.

[0074] The adsorption performance of Cu₂S, C₁, C₂, C₃, and CuS for I₂ was also determined by fitting the isothermal adsorption curves using Langmuir and Freundlich isothermal adsorption models. The Langmuir model showed a stronger correlation coefficient (R²). 2 ),like Figure 4 As shown in -a, the material uses a monolayer adsorption mechanism to adsorb radioactive iodine.

[0075] 2.2 Adsorption Kinetics Experiment Weigh 20 mg of the test sample (Cu2S, C-1, C-2, C-3, CuS) and place it in a stoppered centrifuge tube. Add 20 mL of iodine-cyclohexane solution with an initial concentration of 1200 mg / L to each tube.

[0076] Centrifuge tubes were placed in a constant-temperature shaker and shaken at 180 rpm at 25°C. Centrifuge tubes were removed at different time points (0.5, 1, 3, 5, 10, 15, 30, 45, 60, 90, 120, 180, 240, and 300 minutes). After centrifugation, the supernatant was collected, and the absorbance of iodine was measured at 523 nm using a UV-Vis spectrophotometer. The adsorption capacity at each time point was calculated.

[0077] The adsorption data were fitted using pseudo-first-order and pseudo-second-order kinetic models, respectively, and the rate-controlling steps of the adsorption process were analyzed using the Weber-Morris intraparticle diffusion model.

[0078] The final result is as follows Figure 4 As shown, where Figure 4 -b represents the kinetic adsorption curves of radioactive iodine by Cu₂S, C₁, C₂, C₃, and CuS in iodine / cyclohexane solution. Figure 4 -c represents the intraparticle diffusion kinetics curves of radioactive iodine to Cu2S, C-1, C-2, C-3, and CuS in iodine / cyclohexane solution.

[0079] Among them, such as Figure 4 As shown in -b and 4-c, the adsorption rates of I2 by Cu2S, C-1, C-2, C-3, and CuS increase rapidly within the first 15 minutes. However, as the number of surface adsorption sites decreases, the materials reach adsorption equilibrium after approximately 90 minutes.

[0080] The saturated adsorption capacities of Cu2S, C-1, C-2, C-3, and CuS were 958.7, 769.6, 608.9, 487.1, and 116.0 mg g, respectively. -1 It is slightly higher than that of previously published adsorbent materials.

[0081] By fitting pseudo-first-order and pseudo-second-order kinetic models, we can better understand the I2 adsorption behavior of materials. For example... Figure 4 As shown in -b, the pseudo-second-order kinetic model is more suitable for describing the adsorption behavior of I2, indicating that the adsorption of I2 by the material is mainly dominated by chemisorption.

[0082] like Figure 4 As shown in -c, the kinetic adsorption results were further investigated using the Weber-Morris intraparticle diffusion model equation. The adsorption of I2 by Cu2S, C-1, C-2, C-3, and CuS mainly consists of three steps.

[0083] Surface adsorption is the first step (0-15 minutes). This stage is particularly important for the entire adsorption process due to its maximum slope.

[0084] In the second stage, I2 diffuses into the interior of the particles, lasting from 15 to 90 minutes. The number of active sites inside the material steadily decreases with increasing adsorption time, which reduces the adsorption rate until the process reaches equilibrium.

[0085] In the third stage, the reaction reaches adsorption equilibrium.

[0086] 2.3 Adsorption Thermodynamics Experiment Weigh 20 mg of the test samples (Cu2S, C-1, CuS) and place them in stoppered centrifuge tubes. Add 20 mL of iodine-cyclohexane solution with an initial concentration of 1200 mg / L to each tube.

[0087] The adsorption was allowed to reach equilibrium by oscillating at 180 rpm for 24 hours at different temperatures (25°C, 35°C, 45°C).

[0088] After adsorption is complete, centrifuge the sample, take the supernatant to determine the iodine concentration, and calculate the equilibrium adsorption capacity at each temperature.

[0089] The final result is as follows Figure 4 As shown, Figure 4 -d is a graph showing the saturated adsorption capacity of Cu2S, C-1 and CuS for iodine in solution at different temperatures.

[0090] Among them, such as Figure 4 As shown in Figure d, the adsorption thermodynamics of Cu2S, C-1 and CuS were studied at 25℃, 35℃ and 45℃.

[0091] With increasing temperature, the iodine adsorption capacity of Cu₂S, C₁, and CuS decreased from 956.8, 772.9, and 115.5 mg g, respectively. -1 Decreased to 809.5, 685.4 and 93.0 mg g -1 This indicates that the mechanism of iodine adsorption in the material is exothermic.

[0092] Experiment Example 3: Iodine Vapor Capture Experiment 3.1 Iodine vapor adsorption experiments on different materials at 77°C Weigh approximately 20 mg of the sample to be tested (Cu2S, C-1, CuS) and place them in glass dishes respectively, and accurately record the initial mass of the sample.

[0093] Place an excess of elemental iodine at the bottom of a sealed glass container, and suspend the glass dish containing the sample above the container to ensure that the sample does not come into direct contact with the iodine solid.

[0094] The sealed container is heated in a constant temperature oven at 77°C to sublimate iodine and produce iodine vapor.

[0095] Remove the sample dish at different time points (0, 5, 15, 30, 60, 90, 120, 180, 300 minutes), weigh it quickly, and record the sample mass.

[0096] The adsorption is considered to have reached equilibrium when the mass no longer changes after two consecutive weighings, and the iodine vapor adsorption capacity of the sample is then calculated.

[0097] The final result is as follows Figure 4 As shown, where Figure 4 -e is a graph showing the saturated adsorption capacity of Cu2S, C-1 and CuS for gaseous iodine at 77℃.

[0098] Among them, such as Figure 4 As shown in -e, the obtained adsorption capacities were 1421.3, 1277.5, and 853.5 mg g, respectively. -1 .

[0099] 3.2 Iodine vapor adsorption experiment of C-1 material at different temperatures Weigh approximately 20 mg of C-1 sample into a glass dish and accurately record the initial mass.

[0100] Using the same experimental setup described above, iodine vapor adsorption experiments were conducted at different temperatures (77°C, 100°C, and 150°C).

[0101] The sample dish was removed and weighed at different time points until adsorption reached equilibrium. The saturated adsorption capacity of C-1 material at each temperature was recorded, and the effect of temperature on adsorption performance was analyzed.

[0102] The final result is as follows Figure 4 As shown, where Figure 4 -f is a graph showing the saturated adsorption capacity of C-1 for iodine vapor at different temperatures.

[0103] To better understand how temperature affects iodine adsorption capacity through physical and chemical adsorption, the iodine adsorption performance of C-1 material was investigated at 77℃, 100℃, and 150℃. Figure 4 As shown in -f, the contribution of physisorption decreases with increasing temperature due to the weakening of van der Waals interactions. Although higher temperatures may promote chemical reactions, the overall adsorption capacity decreases because physisorption plays a crucial role in the initial capture and diffusion of iodine molecules to reaction sites.

[0104] Experiment Example 4: Iodine Release and Regeneration Experiment 4.1 Iodine Release Test Take about 20 mg of the C-1 sample after iodine adsorption and place it in a stoppered centrifuge tube, then add anhydrous ethanol.

[0105] Place the centrifuge tubes in a thermostatic shaker and shake at 180 rpm at 25°C.

[0106] Centrifuge tubes were removed at different time points (1, 2, 3, 5, 7, 10, and 24 hours). After centrifugation, the supernatant was collected, and the absorbance of the released iodine in the solution was measured at a wavelength of 523 nm using a UV-Vis spectrophotometer. The concentration of released iodine and the iodine release rate were calculated based on the pre-established iodine standard curve.

[0107] The final result is as follows Figure 5 As shown, where Figure 5 -a is a graph showing the effect of different time intervals on the release of I2-C-1 iodine from ethanol solution.

[0108] Among them, by Figure 5 As shown in -a, the iodine release rate gradually increases over time, reaching 72.4% after 24 hours.

[0109] 4.2 Adsorption-Regeneration Performance Experiment Weigh 20 mg of the test samples (Cu2S, C-1, CuS) and place them in stoppered centrifuge tubes. Add 20 mL of iodine-cyclohexane solution with an initial concentration of 1200 mg / L to each tube.

[0110] Place the centrifuge tubes in a constant-temperature shaker and shake at 180 rpm at 25°C until adsorption reaches equilibrium.

[0111] After adsorption is complete, centrifuge the sample, take the supernatant to determine the iodine concentration, and calculate the adsorption capacity.

[0112] After the adsorption was performed, the sample was immersed in anhydrous ethanol for 10 hours and then vacuum dried at 60°C for 12 hours.

[0113] The regenerated sample was subjected to the above adsorption experiment again, and the operation was repeated 5 times. The adsorption capacity after each cycle was recorded to evaluate the regeneration performance of the sample.

[0114] The final result is as follows Figure 5 As shown, where Figure 5 -b is a graph showing the results of the study on the regeneration performance of iodine by Cu2S, C-1 and CuS.

[0115] Among them, by Figure 5 -b indicates that when the concentration of the iodocyclohexane solution is 1200 ppm, after five adsorption cycles, the adsorption capacities of Cu₂S, C₁, and CuS decrease to 168.2, 88.8, and 56.3 mg g, respectively. -1 .

[0116] 4.3 Morphology and Phase Characterization of Regenerated Samples Take the regenerated I2-C-1 sample and observe it using a scanning electron microscope (SEM) according to the method in Experiment Example 1 to analyze the morphological changes of the regenerated sample.

[0117] Meanwhile, X-ray diffraction (XRD) was used to analyze the phase composition of the regenerated sample under the same test conditions as in Experiment 1. The obtained diffraction pattern was compared with the CuI standard card (JCPDS No. 06-0246) to analyze the presence of residual CuI in the regenerated sample.

[0118] The final result is as follows Figure 5 As shown, where Figure 5 -c is the SEM image of I2-C-1 after iodine release. Figure 5 -d is the XRD pattern of I2-C-1 after iodine release.

[0119] Among them, such as Figure 5 -c, elemental iodine still exists after I₂-C₁ regeneration. XRD pattern of regenerated I₂-C₁ ( Figure 5 -d) also clearly shows the presence of CuI, supporting the earlier findings. This further explains why the adsorption capacity decreased after five adsorption cycles. The strong chemical affinity between C-1 and I2 prevented the complete decomposition of CuI, resulting in residual CuI being trapped within the pore channels.

[0120] Experiment Example 5: Analysis of Iodine Capture Mechanism 5.1 Scanning electron microscopy (SEM) and energy dispersive spectroscopy analysis of the adsorbed sample The C-1 sample (I2-C-1) after iodine adsorption was dispersed in anhydrous ethanol, ultrasonically dispersed evenly, and then dropped onto the surface of a silicon wafer and allowed to air dry naturally.

[0121] The surface morphology of the samples after adsorption was observed using a scanning electron microscope at an accelerating voltage of 5-15 kV, and compared with the morphology before adsorption.

[0122] Meanwhile, elemental analysis was performed on the C-1 sample and the adsorbed C-1 sample using an energy-dispersive X-ray spectrometer (EDS) equipped with a scanning electron microscope. Distribution spectra of Cu, S and I were collected to analyze the uniformity of iodine distribution in the sample.

[0123] The final result is as follows Figure 6 As shown, where Figure 6 -a is the SEM image of I2-C-1. Figure 6 -b represents the element mapping graph of C-1. Figure 6 -c is the element-mapped image of I2-C-1.

[0124] in, Figure 6-a shows a SEM image of C-1 after iodine adsorption. The image shows a change in the appearance of C-1 after iodine adsorption, which is likely due to the chemical interaction between C-1 and I2 to produce CuI. Figure 6 -b and Figure 6 As can be seen from -c, the EDS spectrum further confirms the presence of element I.

[0125] 5.2 X-ray diffraction (XRD) characterization of the adsorbed sample The C-1 sample (I2-C-1) after iodine adsorption was placed in a glass sample cell, compacted and leveled, and then tested using an X-ray diffractometer.

[0126] The test conditions were: Cu Kα rays (λ=0.15418nm), tube voltage 40kV, tube current 40mA, scanning range 2θ 5°-70°, and scanning speed 5° / min.

[0127] The obtained diffraction pattern was compared with the CuI standard card (JCPDS No. 06-0246) to confirm the formation of the reaction product CuI. Simultaneously, the XRD patterns before and after adsorption were compared to analyze the phase transition.

[0128] The final result is as follows Figure 7 As shown, where Figure 7 -a is the XRD pattern of C-1 before and after iodine capture.

[0129] XRD measurements are used to examine the phase composition and crystal structure of I₂-C₁, such as... Figure 7 As shown in -a, characteristic peaks appeared at 2θ values ​​of 25.5°, 29.5°, 42.2°, 50.0°, 52.3°, 61.2°, and 67.4°. These values ​​are related to the (111), (200), (220), (311), (222), (400), and (331) crystal planes of CuI, respectively (JCPDS No. 06-0246). Furthermore, by comparing the XRD patterns before and after the reaction, it can be seen that the unique peaks of CuI after adsorption replaced the characteristic peaks of Cu2S and CuS. This indicates that I2 can react with Cu... + or Cu 2+ A chemical reaction occurs, producing CuI.

[0130] 5.3 Raman spectral characterization of the sample after adsorption The C-1 sample (I2-C-1) after iodine adsorption was placed on a glass slide and tested using a Raman spectrometer.

[0131] The test conditions were: excitation wavelength 532nm, laser power 50mW, and scanning range 100-1800cm. -1 The sample was recorded at 116.5 cm.-1 and 148.6cm -1 The nearby characteristic peaks are respectively attributed to I3 - The symmetric stretching vibrations of I₂ and the inherent vibrations of I₂ were used to analyze the coexistence characteristics of physical adsorption and chemical adsorption.

[0132] The final Raman spectrum is as follows Figure 7 As shown in 7-b, where Figure 7 -b is the Raman spectrum of I2-C-1.

[0133] in, Figure 7 b shows the Raman spectrum of material C-1 after iodine adsorption. I3 - The symmetrical stretching vibration and the natural vibration of I2 are at 116.5 and 148.6 cm, respectively. -1 A characteristic peak appears at this location. This supports the earlier finding that the iodine adsorption process on C-1 materials involves both physico- and chemisorption.

[0134] 5.4 X-ray photoelectron spectroscopy (XPS) characterization of the adsorbed sample After the C-1 sample adsorbed with iodine was pressed into a pellet, it was tested using an X-ray photoelectron spectrometer.

[0135] A monochromatic Al Kα X-ray source (hν=1486.6eV) was used, and the vacuum level in the analysis chamber was better than 5×10⁻⁶. -10 mbar.

[0136] High-resolution energy spectra of Cu 2p and I 3d were acquired, and charge correction was performed using C 1s (284.8 eV).

[0137] Peak fitting was performed on the Cu 2p energy spectrum to analyze Cu. + Price state changes; Peak fitting was performed on the I 3d energy spectrum to distinguish I3 - (or I) - The presence forms of I₂ and I₂. The ratio of chemisorbed iodine to physisorbed iodine is calculated based on the convolution peak area.

[0138] The final XPS spectrum is as follows Figure 7 As shown in 7-c and 7-d, where Figure 7 -c represents the XPS spectrum of Cu 2p in C-1 after iodine adsorption. Figure 7 -d represents the three-dimensional spectrum.

[0139] The Cu 2p XPS spectrum of I2-C-1 shows two convolution peaks at 932.0 and 951.9 eV (corresponding to Cu 2p, respectively). 3 / 2 and Cu 2p 1 / 2 This indicates the presence of Cu. + ,like Figure 7 -c is shown. Meanwhile, the I3d XPS spectra show 619.5 and 631.1 eV (corresponding to I3d5 / 2 and I3d, respectively). 3 / 2 The unique peak of I3 indicates that - (or I) - The presence of I2 is responsible for the convolution peaks at 620.7 and 632.3 eV. Figure 7 -d). This means that the adsorption of radioactive iodine includes both chemisorption and physisorption. Based on the calculation of the convolution peak area, I3 - (or I) - The peak area accounts for 88% of the total area. This means that chemisorption plays a dominant role in the adsorption of radioactive iodine.

[0140] 5.5 Thermogravimetric analysis (TGA) characterization Take an appropriate amount of the sample to be tested (C-1 and I2-C-1 after iodine adsorption) and place it in a thermogravimetric analyzer. Heat it from room temperature to 800°C at a heating rate of 10°C / min under a nitrogen atmosphere, and record the thermogravimetric curve (TG curve) of the sample mass change with temperature.

[0141] The mass loss of the sample after iodine adsorption was analyzed in different temperature ranges: the mass loss in the 100-200°C range was attributed to the release of physically adsorbed iodine and the evaporation of water molecules captured during synthesis; the mass loss above 200°C was attributed to the decomposition of CuI. Thermogravimetric analysis (TGA) curves were used to evaluate the thermal stability of the material and the thermal behavior after iodine capture.

[0142] The final result is as follows Figure 8 As shown, C-1 exhibits good thermal stability below 800℃. After iodine adsorption, a 5.2% weight loss occurs within the temperature range of 100-200℃. This can be explained by the release of iodine molecules (physical adsorption) and the evaporation of water molecules captured during synthesis. When the temperature rises above 200℃, a 77.5% weight change occurs, primarily due to the decomposition of CuI.

[0143] Overall, the capture mechanism of radioactive iodine involves the interaction between chemical and physical adsorption. (1) Cu + and Cu 2+ Both can react chemically with I2 to produce stable CuI complexes, Cu + Its chemical affinity for iodine is greater than that for Cu. 2+ (2) Physical interactions can adsorb a small amount of I2.

[0144] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the technical solutions of the embodiments of the present invention.

Claims

1. A method for preparing copper-based sulfide nanoparticles, characterized in that, Includes the following steps: The copper source is dissolved in a solvent, and then the sulfur source is added. The mixture is stirred and reacted. After cooling, the mixture is centrifuged, washed, and dried to obtain the final product.

2. The preparation method according to claim 1, characterized in that, The copper source is copper acetate, and the solvent is polyethylene glycol.

3. The preparation method according to claim 1, characterized in that, The sulfur source is sublimed sulfur.

4. The preparation method according to claim 3, characterized in that, The molar ratio of Cu to S in the copper source and the sulfur source is 1:1, 1:0.75, 1:0.625, 1:0.5, or 1:0.

25.

5. The preparation method according to claim 1, characterized in that, The reaction temperature was 120°C and the reaction time was 2 hours.

6. A method for preparing copper-based sulfide nanoparticles according to any one of claims 1-5, characterized in that, The copper-based sulfide nanoparticles are CuS nanoparticles, CuS and Cu2S composite nanoparticles, or Cu2S nanoparticles.

7. The copper-based sulfide nanoparticles according to claim 6, characterized in that, The nanoparticles possess a mesoporous structure; the average pore sizes of the Cu₂S nanoparticles, CuS nanoparticles, and CuS / Cu₂S composite nanoparticles are 13 nm, 11 nm, and 11-14 nm, respectively; the pore volumes of the Cu₂S nanoparticles, CuS nanoparticles, and CuS / Cu₂S composite nanoparticles are 0.03 cm³. 3 / g, 0.025cm 3 / g and 0.028-0.041cm 3 / g.

8. The application of copper-based sulfide nanoparticles prepared by the preparation method according to any one of claims 1-5 in capturing radioactive iodine.

9. The application according to claim 8, characterized in that, The radioactive iodine is either gaseous or liquid.

10. The application according to claim 8, characterized in that, The copper-based sulfide nanoparticles capture radioactive iodine at temperatures ranging from 25 to 150°C.

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