A PANIBi2S3 nanocomposite material, its preparation method and application

Abstract

This invention relates to the field of adsorbent technology, and discloses a PANIBi2S3 nanocomposite material, its preparation method, and its application. The composite material is polyaniline-coated bismuth sulfide; the bismuth sulfide has a nanoflower morphology. The nanocomposite material obtained by this invention has good iodine adsorption capacity.

Description

Technical Field

[0001] This invention relates to the field of adsorbent technology, and in particular to a PANIBi2S3 nanocomposite material, its preparation method, and its application. Background Technology

[0002] Since the beginning of the new century, nuclear power has received widespread attention due to its advantages such as safety, efficiency, and economy in addressing energy shortages and environmental pollution. However, the nuclear power generation process inevitably produces large amounts of radioactive pollutants, posing a serious threat to human health and ecosystems. Among these, radioactive iodine (… 129 I and 131 I) It has attracted much attention due to its high environmental migration rate and toxicity. 129 I and 131 I is one of the two main isotopes of radioactive iodine, among which 129 The half-life of I is 1.57 × 10⁻⁶. 7 In 2010, its volatility was extremely high, and once released, it would almost certainly cause permanent damage to the environment and human health. Despite 131 I has a relatively short half-life (8.02 days), but due to its high specific reactivity and high radioactivity, 131 The relative danger of radioactive iodine (I) is far greater than that of other radionuclides. Therefore, the timely and effective capture and preservation of radioactive iodine has become an urgent issue.

[0003] Currently, the main methods for removing radioactive iodine are solution washing and solid adsorption. Solid adsorption is more popular for capturing radioactive iodine due to its high efficiency, low cost, and simple operation. To date, different types of adsorbents have been successfully developed, including activated carbon, silver-exchanged zeolite (AgZ), aerogels, layered double hydroxides (LDH), porous organic polymers (POP), covalent organic frameworks (COF), and metal-organic frameworks (MOF). Among these, activated carbon and silver-exchanged zeolite have been widely used in industrial applications. However, due to their low auto-ignition temperature, low adsorption capacity, and susceptibility to external interference, activated carbon is not the best choice for capturing radioactive iodine in practical applications. Although silver-exchanged zeolite can react with iodine to produce AgI precipitates, the high cost and toxicity of silver further limit its practical application.

[0004] Recently, bismuth-based materials have been considered as alternatives to silver-based materials. Bismuth-based materials are widely used in industrial applications due to their non-toxicity, low cost, chemical stability, ability to handle radioactive iodine at high temperatures, and the formation of thermodynamically stable compounds such as BiI3 or BiOI. Bi2S3 is a simple, non-toxic metal sulfide that has been widely used in catalysis, battery adsorption, and other fields. Some researchers have also used it for iodine adsorption, but its adsorption capacity has not yet been further improved. Summary of the Invention

[0005] To address the aforementioned technical problems, this invention provides a PANIBi2S3 nanocomposite material, its preparation method, and its application. The nanocomposite material obtained by this invention exhibits good iodine adsorption capacity.

[0006] This invention provides a PANIBi2S3 nanocomposite material, wherein the composite material is polyaniline (PANI) coated with bismuth sulfide (Bi2S3).

[0007] Furthermore, the morphology of the bismuth sulfide is that of nanoflowers.

[0008] The present invention also provides a method for preparing the PANIBi2S3 nanocomposite material, the method comprising:

[0009] Bismuth sulfide was mixed with chloroform, aniline was added, and the mixture was stirred until homogeneous. Hydrochloric acid solution and ammonium persulfate solution were added until the solution turned dark green. Solid-liquid separation was performed, followed by washing and drying to obtain the nanocomposite material (PANI / Bi2S3).

[0010] Furthermore, the ratio of aniline to bismuth sulfide is 10%-30% by mass.

[0011] Furthermore, the ratio of aniline to bismuth sulfide is 20% by mass.

[0012] Furthermore, those skilled in the art should understand that chloroform is mainly used to protect bismuth sulfide, and its dosage is not limited; as an example, 100 mL can be added.

[0013] Furthermore, the preparation method of the ammonium persulfate solution specifically involves dissolving and dispersing ammonium persulfate in deionized water.

[0014] Furthermore, the molar ratio of ammonium persulfate to aniline in the ammonium persulfate solution is 1:1.

[0015] Furthermore, the method for preparing the ammonium persulfate solution includes: dispersing ammonium persulfate in deionized water.

[0016] Furthermore, the molar concentration of the hydrochloric acid solution is 1 mol / L.

[0017] Furthermore, the method for preparing the hydrochloric acid solution includes dispersing hydrochloric acid in deionized water.

[0018] Furthermore, the volume ratio of the hydrochloric acid solution to the ammonium persulfate solution is 50:12.5.

[0019] Furthermore, when adding aniline, an ice-water bath is used.

[0020] Furthermore, the specific washing method includes washing with ethanol and deionized water sequentially until the pH value of the precipitate is 7.

[0021] Furthermore, the drying temperature is 55℃-65℃, and the drying time is 23h-25h.

[0022] Furthermore, the method for preparing bismuth sulfide includes: mixing ethylene glycol containing bismuth nitrate pentahydrate with ethylene glycol containing thiourea, reacting, separating the solid and liquid phases, washing, and drying.

[0023] Furthermore, in the ethylene glycol containing bismuth nitrate pentahydrate, the molar concentration of bismuth nitrate pentahydrate is 0.5 mmol / 10 mL.

[0024] Furthermore, in the ethylene glycol containing thiourea, the mass concentration of thiourea is 3356 mg / 10 mL.

[0025] Furthermore, to promote uniform distribution of thiourea in ethylene glycol, the thiourea is placed in ethylene glycol and then subjected to ultrasonic treatment. As an example, the ultrasonic treatment time is 15 minutes.

[0026] Furthermore, the volume ratio of the ethylene glycol containing bismuth nitrate pentahydrate to the ethylene glycol containing thiourea must be 1:1.

[0027] Furthermore, the reaction temperature is 170℃-190℃, and the reaction time is 11h-13h.

[0028] Furthermore, the specific washing method is as follows: wash at least 3 times with deionized water and ethanol.

[0029] Furthermore, the drying temperature is 55℃-65℃, and the drying time is 23h-25h.

[0030] The present invention also provides the application of the aforementioned PANIBi2S3 nanocomposite material in the adsorption of iodine.

[0031] The embodiments of the present invention have the following technical effects:

[0032] 1. In the nanocomposite material obtained by the present invention, firstly, polyaniline not only enhances the physical adsorption capacity of the adsorbent, but also makes the adsorbent weakly alkaline, which is conducive to the adsorption of iodide ions; secondly, polyaniline also has high electrical conductivity, which is conducive to promoting charge transfer and the adsorption of iodine by bismuth sulfide; thirdly, polyaniline can also reduce the aggregation between bismuth sulfide particles.

[0033] 2. In this invention, in order to improve the adsorption capacity of the composite material, the loading of polyaniline is further limited. When the loading is too low, the modification of bismuth sulfide will be insignificant and its ability to adsorb iodine will be limited. When the loading is too high, the specific surface area and pore size of the composite material will be reduced, which will also lead to a decrease in adsorption capacity. Therefore, in this invention, in order to improve the adsorption capacity of the composite material, the relationship between the amount of polyaniline and bismuth sulfide added is further limited. Attached Figure Description

[0034] 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.

[0035] Figure 1 These are SEM images provided in the embodiments and comparative examples of the present invention, wherein... Figure 1 Image a is the SEM image of scale 2. Figure 1 Image b in the diagram is the SEM image of scale 1. Figure 1 c is the SEM image at low magnification in Example 1. Figure 1 In the middle, d is the SEM image at high magnification in Example 1. Figure 1 In the image, 'e' is the SEM image of Example 1. Figure 1 e1 is the Bi element distribution diagram in Example 1. Figure 1 e2 is the distribution diagram of S element in Example 1. Figure 1 e3 is the distribution diagram of C element in Example 1. Figure 1 e4 is the distribution diagram of N element in Example 1. Figure 1 f is a TEM image of Example 1. Figure 1 g is a TEM image of Example 1. Figure 1 h is the HRTEM image of Example 1. Figure 1 In Figure i, SAED diagram of Example 1 is shown.

[0036] Figure 2 These are test result graphs for the embodiments and comparative examples, where... Figure 2 In Figure a, the XRD plots are for Comparative Example 1 and Comparative Example 2. Figure 2 In Figure b, the XRD patterns of Examples 1-3 are shown. Figure 2 c represents the FT-IR spectra of Examples 1-3. Figure 2 In the image, d represents the Raman spectra of Examples 1-3. Figure 2 In the image, e represents the XPS measurement spectrum of Example 1. Figure 2f is the Bi4f XPS measured spectrum in Example 1. Figure 2 g is the S 2p XPS measured spectrum in Example 1. Figure 2 h is the C 1s XPS measured spectrum in Example 1. Figure 2 In Example 1, i is the N 1s XPS measurement spectrum.

[0037] Figure 3 These are the test results for the examples and comparative examples, where... Figure 3 In Figure 'a', the nitrogen adsorption-desorption isotherm is the one for the examples and comparative examples. Figure 3 In Figure b, the aperture distribution curves of the embodiments and comparative examples are shown.

[0038] Figure 4 These are the test results for the examples and comparative examples, where... Figure 4 Figure a shows the adsorption kinetics test results of gaseous iodine at 77°C for the examples and comparative examples. Figure 4 Image of the sample after iodine adsorption in Example b. Figure 4 In Figure c, the isothermal adsorption test results of the examples and comparative examples are shown. Figure 4 In the figure, d is the fitting curve of the adsorption kinetic model. Figure 4 In the figure, e represents the adsorption capacity of Example 1 at different temperatures. Figure 4 f is the absorption spectrum of Example 1. Detailed Implementation

[0039] 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.

[0040] In a first aspect, some embodiments of the present invention provide a PANIBi2S3 nanocomposite material, wherein the composite material is polyaniline (PANI) coated with bismuth sulfide (Bi2S3).

[0041] In some embodiments, the morphology of the bismuth sulfide is nanoflower-like.

[0042] Secondly, some embodiments of the present invention also provide a method for preparing the PANIBi2S3 nanocomposite material, the method comprising:

[0043] Bismuth sulfide was mixed with chloroform, aniline was added, and the mixture was stirred until homogeneous. Hydrochloric acid and ammonium persulfate solution were added until the solution turned dark green. Solid-liquid separation was performed, followed by washing and drying to obtain the nanocomposite material (PANI / Bi2S3).

[0044] In some embodiments, the ratio of aniline to bismuth sulfide is 10%-30% by weight.

[0045] In this invention, when the loading of polyaniline is too low, the modification of bismuth sulfide will be insignificant and its ability to adsorb iodine will be limited. When the loading is too high, the specific surface area and pore size of the composite material will be reduced, which will also lead to a decrease in adsorption capacity. Therefore, in order to improve the adsorption capacity of the composite material, the addition ratio of aniline and bismuth sulfide is further limited to 10%-30%.

[0046] In some embodiments, the ratio of aniline to bismuth sulfide is 20% by weight.

[0047] When the mass ratio of aniline to bismuth sulfide is 20%, the resulting adsorbent exhibits better adsorption performance.

[0048] In some embodiments, the preparation method of the ammonium persulfate solution specifically involves dissolving and dispersing ammonium persulfate in deionized water.

[0049] In some embodiments, the molar ratio of ammonium persulfate to aniline in the ammonium persulfate solution is 1:1.

[0050] In some embodiments, the preparation method of the ammonium persulfate solution includes: dispersing ammonium persulfate in deionized water.

[0051] In some embodiments, the molar concentration of the hydrochloric acid solution is 1 mol / L.

[0052] In some embodiments, the method for preparing the hydrochloric acid solution includes dispersing hydrochloric acid in deionized water.

[0053] In some embodiments, the volume ratio of the hydrochloric acid solution to the ammonium persulfate solution is 50:12.5.

[0054] In some embodiments, the addition of aniline is performed under ice-water bath conditions.

[0055] In some embodiments, the washing method includes washing with ethanol and deionized water sequentially until the pH of the precipitate is 7.

[0056] In some embodiments, the drying temperature is 55°C-65°C, and the drying time is 23h-25h.

[0057] In some embodiments, the method for preparing bismuth sulfide includes: mixing ethylene glycol containing bismuth nitrate pentahydrate with ethylene glycol containing thiourea, reacting, separating the solid and liquid phases, washing, and drying.

[0058] In some embodiments, the molar concentration of bismuth nitrate pentahydrate in the ethylene glycol containing bismuth nitrate pentahydrate is 0.5 mmol / 10 mL.

[0059] In some embodiments, the thiourea-containing ethylene glycol has a thiourea mass concentration of 3356 mg / 10 mL.

[0060] In some embodiments, to promote uniform distribution of thiourea in ethylene glycol, the thiourea is placed in ethylene glycol and then subjected to ultrasonic treatment. As an example, the ultrasonic treatment time is 15 minutes.

[0061] In some embodiments, the volume ratio of the ethylene glycol containing bismuth nitrate pentahydrate to the ethylene glycol containing thiourea must be 1:1.

[0062] In some embodiments, the reaction temperature is 170°C-190°C and the reaction time is 11h-13h.

[0063] In some embodiments, the specific washing method is as follows: wash at least 3 times with deionized water and ethanol.

[0064] In some embodiments, the drying temperature is 55°C-65°C, and the drying time is 23h-25h.

[0065] Thirdly, some embodiments of the present invention also provide the application of the PANIBi2S3 nanocomposite material in the adsorption of iodine.

[0066] The following description uses specific examples and comparative models to illustrate the points:

[0067] Example 1:

[0068] 242.5 mg (0.5 mmol) of bismuth nitrate pentahydrate was dissolved in 10 mL of ethylene glycol, recorded as solution A; simultaneously, 335.6 mg of thiourea was added to 10 mL of ethylene glycol and sonicated for 15 minutes, recorded as solution B. The solutions were then thoroughly mixed and reacted in an oven at 180 °C for 12 hours. Solid-liquid separation was performed, and the mixture was washed repeatedly with water and ethanol 10 times, then dried at 60 °C for 24 hours to obtain nanoflower bismuth sulfide.

[0069] 23.5 g of nano-flower bismuth sulfide was thoroughly mixed with 100 mL of chloroform, and then 2.3 mL of aniline was added under ice-water bath conditions with continuous stirring for 30 minutes. Subsequently, 50 mL of 1 mol / L hydrochloric acid solution was added to the dispersion. Finally, 12.5 mL of ammonium persulfate solution (where the molar ratio of ammonium persulfate to aniline in the ammonium persulfate solution was 1:1) was added dropwise to the above solution until the color turned dark green. The solution was then washed with ethanol and deionized water. The precipitate was filtered until pH=7. The filtered precipitate was dried at 60 °C for 24 hours and labeled as 10%-PANI / Bi₂S₃.

[0070] Example 2:

[0071] The preparation method is the same as in Example 1, but in Example 2, the mass ratio of aniline to bismuth sulfide is 20%, and other parameters are the same as in Example 1.

[0072] Example 3: The preparation method is the same as in Example 1, but the mass ratio of aniline to bismuth sulfide in Example 3 is 30%, and other parameters are the same as in Example 1.

[0073] Comparative Example 1:

[0074] 242.5 mg (0.5 mmol) of bismuth nitrate pentahydrate was dissolved in 10 mL of ethylene glycol, recorded as solution A; simultaneously, 335.6 mg of thiourea was added to 10 mL of ethylene glycol and sonicated for 15 minutes, recorded as solution B. The solutions were then thoroughly mixed and reacted in an oven at 180 °C for 12 hours. Solid-liquid separation was performed, and the mixture was washed repeatedly with water and ethanol 10 times, then dried at 60 °C for 24 hours to obtain nanoflower bismuth sulfide, denoted as Bi₂S₃.

[0075] Comparative Example 2:

[0076] 2.3 mL of aniline was added under ice-water bath conditions and stirred continuously for 30 minutes. Then, 50 mL of 1 mol / L hydrochloric acid solution was added to the dispersion. Finally, 12.5 mL of ammonium persulfate solution (where the molar ratio of ammonium persulfate to aniline in the ammonium persulfate solution was 1:1) was added dropwise to the above solution until the color turned dark green. The solution was then washed with ethanol and deionized water. The precipitate was filtered until pH=7. The filtered precipitate was dried at 60°C for 24 hours and denoted as PANI.

[0077] The present invention will also obtain embodiments and comparative examples for testing, and the testing process is as follows:

[0078] (1) Sample characteristics:

[0079] The crystal structure of the x%-PANI / Bi₂S₃ composite material was characterized by X-ray diffraction (XRD, XRD-6100, Shimadzu, Japan) under Cu Kα radiation at 40 kV and 40 mA, with a scanning range of 5° to 70°. To determine the elemental composition and elucidate the valence states in x%-PANI / Bi₂S₃, an X-ray photoelectron spectrometer (XPS, Qantera II, PHI, Japan) with a monochromatic Al Kα X-ray source was used. Fourier transform infrared (FTIR) spectra were obtained using a Fourier transform infrared spectrometer (FTIR, iS5, Nicolet, USA). The morphology and elemental distribution of the PANI, Bi₂S₃, and x%-PANI / Bi₂S₃ samples were characterized using a field emission scanning electron microscope (SEM, JSM-IT500HR, JEOL, Japan) equipped with an energy-dispersive X-ray spectrometer (EDS). The microstructure and crystal structure of the material were observed using a transmission scanning electron microscope (TEM, TECNAI G2 20 LaB6, FEI, USA). The BET method was used to obtain the specific surface area at liquid nitrogen temperature (77 K) using a gas adsorption analyzer (Belsorp max, MicrotracBEL, Japan). Thermogravimetric analysis (TGA) was performed on the material using a thermogravimetric analyzer (TGA, TGA55, TA, USA). The concentration of iodine was determined using a UV-Vis spectrophotometer (UV-3600, Shimadzu, Japan).

[0080] (2) Iodine vapor adsorption:

[0081] Because scientific isotopes of iodine have the same electronic configuration and potential energy surface, and they generally exhibit nearly identical chemical properties, stable non-radioactive iodine was used instead of radioactive iodine to determine the iodine-capturing capacity of the material in iodine vapor and iodine / cyclohexane solution. In a typical experimental procedure, excess solid iodine was placed in an open glass Pyrex beaker, followed by 20 mg of adsorbent in an airtight container, which was then sealed. The glass flask was heated in an oven at 350 K and 1 bar. After capturing iodine vapor for a period of time, the container was cooled to room temperature and weighed. The amount of iodine adsorbed, Q (wt%), was calculated based on the change in mass, using the following equation:

[0082] ;

[0083] Where m1 and m2 represent the mass (mg) of x%-PANI / Bi2S3 composite material before and after iodine vapor adsorption.

[0084] (3) Adsorption of iodine in the liquid phase:

[0085] The adsorption performance of x%-PANI / Bi2S3 nanocomposite for iodine in solution was evaluated using an iodine / cyclohexane solution. 20 mg of x%-PANI / Bi2S3 sample was dispersed in 20 mL of iodine / cyclohexane solution, and the residual iodine content in the solution was measured at certain time points. The iodine concentration in the supernatant was measured using a UV-Vis spectrophotometer. The equilibrium adsorption capacity (Q) of x%-PANI / Bi2S3 was determined. e (mg / g) is calculated using the following equation:

[0086] ;

[0087] Where C0 and C e The values ​​represent the iodine concentration (mg / L) before and after adsorption, respectively; V represents the volume (L) of the iodine / cyclohexane solution; and m represents the mass (mg) of the PANI / Bi2S3 sample used.

[0088] Results and Analysis:

[0089] Table 1. Specific surface area, average pore diameter, and pore volume of the examples and comparative examples.

[0090]

[0091] Table 2 Comparison of the embodiments of the present invention with the prior art

[0092]

[0093] Table 3. Parameters of the fitted pseudo-first-order and pseudo-second-order dynamic models

[0094]

[0095] Table 4. Thermodynamic parameters of iodine adsorption in the examples

[0096]

[0097] The microstructure and morphology of the product were observed using SEM. For example... Figure 1 As shown in (a), the formed PANI exhibits a typical rod-like structure with an average diameter of 50 nm; Figure 1 As shown in (b), the SEM image of Bi2S3 reveals a layered nanoflower structure with a smooth surface and good crystallinity, consisting of many interconnected nanorods with an average diameter of 3 μm. Figure 1 (c)- Figure 1 (d) shows low-magnification and high-magnification SEM images of 10%-PANI / Bi2S3, where the composite material inherits the hierarchical nanoflower structure of Bi2S3, and its surface is covered with PANI. Figure 1 (e) and Figure 1 (e1)- Figure 1 The elemental mapping in (e4) shows that elements C and N are uniformly dispersed on the surface of Bi2S3 nanoflowers, confirming the successful synthesis of PANI / Bi2S3 materials.

[0098] To further reveal the microstructure of the prepared product, the PANI / Bi2S3 nanomaterials were analyzed by TEM and HRTEM. Figure 1 (f)- Figure 1 TEM in (g) shows that PANI is loaded on the surface of Bi2S3 nanoflowers, and the PANI / Bi2S3 composite grows in the form of nanoflowers, which is consistent with the SEM results. Figure 1 (h) shows the HRTEM image of PANI / Bi2S3. PANI / Bi2S3 corresponds to a (220) interplanar spacing of 0.391 nm, which matches the (220) interplanar spacing of Bi2S3. Figure 1 (i) shows the selected area electron diffraction (SAED) pattern, confirming the polycrystalline nature of the material.

[0099] The structures of Bi₂S₃, PANI, and PANI / Bi₂S₃ were confirmed by X-ray diffraction (XRD). Figure 2 As shown in (a), the typical diffraction peaks of PANI appear at 2θ = 21.1° and 25.6°, which belong to the (020) and (200) crystal planes of polyaniline adamantane-adamantaldehyde (ES), respectively. In the XRD pattern of the synthesized Bi2S3, the peaks at 2θ = 15.9°, 17.8°, 22.6°, 23.9°, 25.1°, 28.8°, 32.0°, 33.1°, 35.8°, 40.1°, 42.8°, 45.7°, 46.7°, 49.3°, 52.9°, 59.4°, 62.8°, 65.3°, 67.9°, and 69.6° correspond to the (200) and (120) crystal planes, respectively. The lattice planes of (220), (101), (310), (211), (221), (410), (240), (430), (421), (440), (501), (160), (312), (640), (152), (721), (532), and (651) are consistent (JCPDS NO.17-0320). The synthesized PANI / Bi2S3, such as... Figure 2 As shown in (b), diffraction peaks of Bi2S3 and PANI are present, which confirms the successful preparation of the PANI / Bi2S3 material in this invention.

[0100] To further verify the chemical bonding and vibrational bands of the PANI / Bi2S3 nanomaterials, FTIR vibrational spectroscopy was performed. Figure 2 As shown in (c), 795cm -1 948cm -1 1297cm -1 1475cm -1 and 1588cm -1 The absorption peaks at these locations correspond to the CH bonding mode of the aromatic ring and the NH in the PANI chain, respectively. + CN stretching of groups, benzene rings, quinone groups, and C=C stretching of benzene and quinone rings. 1109cm -1 and 1375cm -1 The peak at that location belongs to the stretching vibration of the Bi-S bond in Bi2S3, further proving the successful preparation of the composite material.

[0101] The PANI / Bi2S3 heterostructure was further characterized by Raman spectroscopy, such as... Figure 2 (d) shows the obtained Raman spectrum at 128 cm⁻¹. -1 437cm -1 and 965cm -1 Characteristic peaks are observed at this location, which are attributed to the vibrational modes of the Bi-S bonds in Bi₂S₃. Furthermore, at 1162 cm⁻¹... -1 1379cm -1 1497cm -1 and 1579cm -1 The peaks at these locations are characteristic peaks of PANI, attributed to the bending vibrations of the CH ring in PANI's quinone ring, the stretching vibrations of the Ar-N aromatic amine, the stretching vibrations of C=N, and the stretching vibrations of C=C, respectively. The quinone and hydroquinone structures of PANI exhibit redox activity; they can accept and release electrons, thus promoting electron transfer between materials and enhancing the adsorption capacity of Bi₂S₃ for iodide ions.

[0102] Furthermore, XPS analysis was used to determine the surface composition and chemical state of elements in the PANI / Bi2S3 nanomaterials. Figure 2 (e) Spectroscopic studies show that, taking 10%-PANI / Bi₂S₃ as an example, 10%-PANI / Bi₂S₃ involves C, N, S, and Bi elements. Figure 2 In (f), the two strong peaks at 160 eV and 165.3 eV are attributed to Bi 4f, respectively. 7 / 2 and Bi4f 5 / 2 This is due to the formation of Bi₂S₃; in addition, the Bi₄f spectrum also contains another set of weak peaks (158.9 eV and 164.3 eV, corresponding to Bi₄f). 7 / 2 and Bi 4f 5 / 2This confirms the coexistence of two different chemical allotropes of bismuth. For example... Figure 2 As shown in (g), the peak values ​​at 164.1 eV and 165.3 eV are attributed to S 2p 3 / 2 and S 2p 5 / 2 .exist Figure 2 The high-resolution C 1s spectra at 284.8 eV, 285.9 eV, and 287.7 eV in (h) can be decomposed into three peaks, attributed to C / C, CO, and C=O bonds, respectively. Figure 2 In the high-resolution N 1s spectrum of (i), the two peaks with binding energies of 399.9 eV and 400.7 eV, respectively, are associated with different nitrogen forms corresponding to pyridine-N (=N-) and pyrrole-N (-NH-). These results further demonstrate the successful synthesis of the PANI / Bi2S3 composite material.

[0103] like Figure 3 As shown in (a), the specific surface area and pore structure of the materials were analyzed using nitrogen adsorption-desorption isotherms. All samples exhibited a hysteresis loop of type H3 hysteresis, which is related to the typical type IV adsorption isotherm characteristics of mesoporous materials, indicating that they possess a typical mesoporous structure. Corresponding pore size distribution analysis further validated this conclusion, such as... Figure 3 As shown in (b), the specific surface area of ​​the composite material increases significantly with increasing PANI content, and the pore volume of the embodiment of the present invention also increases to 0.142 cm³ compared to Bi₂S₃. 3 / g, 0.164cm 3 / g and 0.134cm 3 / g (Table 1). The increased surface area and pore volume of the PANI / Bi2S3 composite material can provide more adsorption sites and space for reactant molecules.

[0104] PANI contains numerous free amino (-N) groups and π-π conjugated structures, providing abundant active sites and excellent iodine adsorption. Bi₂S₃ contains low-electron-weight Bi-S bonds, which are more easily broken and form new chemical bonds with iodine. Therefore, PANI / Bi₂S₃ composites may be a potentially effective material for radioactive iodine capture. Iodine capture capability was tested by exposing the material to iodine vapor at 75°C and ambient pressure. Figure 4 (a)- Figure 4As shown in (b), the iodine uptake capacity of samples at different time intervals was determined by gravimetric analysis. All samples exhibited rapid iodine uptake within the first 10 minutes, which remained constant after 4.5 hours, indicating that adsorption equilibrium had been reached. With PANI loadings of 10%, 20%, and 30%, the iodine uptake of the PANI / Bi₂S₃ composites increased to 321.0 wt%, 330.7 wt%, and 291.3 wt% after 4.5 hours, respectively, significantly higher than that of PANI (93.9 wt%) and Bi₂S₃ (140.6 wt%). This is likely due to the increased specific surface area and pore volume of the composite material caused by PANI loading, thus providing more active sites for iodine. Simultaneously, PANI's high conductivity allows it to directly promote iodine capture by Bi₂S₃ through electron transfer; furthermore, the interaction between the present invention and iodine is further enhanced because PANI contains a large number of free amino groups.

[0105] Compared with reported bismuth-based materials, silver-based materials, MOFs and COFs, the optimal iodine adsorption capacity of PANI / Bi2S3 nanoflowers at 77 °C (10%-PANI / Bi2S3 is 3307 mg g) is [missing value]. -1 It showed better adsorption performance (as shown in Table 2).

[0106] Isothermal adsorption experiments were conducted to compare the adsorption capacity of I2 by PANI, Bi2S3, 10%-PANI / Bi2S3, 20%-PANI / Bi2S3, and 30%-PANI / Bi2S3 in cyclohexane solutions with different initial I2 concentrations. Figure 4As shown in (c), the curves indicate that the iodine adsorption capacity of each adsorbent increases rapidly with increasing initial iodine concentration in the solution until equilibrium is reached. Finally, in the embodiments of the present invention, due to PANI loading, the maximum equilibrium adsorption capacities of 10%-PANI / Bi2S3, 20%-PANI / Bi2S3, and 30%-PANI / Bi2S3 for I2 are 1235.8 mg / g, 1361.3 mg / g, and 1110.3 mg / g, respectively. The loading of PANI nanorods effectively improves the iodine adsorption performance of Bi2S3 nanoflowers, mainly due to the increase in specific surface area and pore volume, which effectively prevents the aggregation of Bi2S3 during the reaction process. Furthermore, the saturated adsorption capacity of the composite material first increases and then decreases with increasing PANI content. When the PANI doping amount is 10% to 20%, the introduction of PANI leads to an increase in the active sites of the composite material, thereby increasing their adsorption capacity. When the PANI doping amount increases to 30%, the adsorption performance decreases due to the decrease in specific surface area and pore size. Therefore, it can be concluded that introducing an appropriate amount of PANI can effectively increase the active sites of the composite material, thereby further improving the adsorption performance of the material. More preferably, the mass ratio of aniline to bismuth sulfide is 20%.

[0107] To better study the iodine adsorption process and the corresponding rate-controlling steps, pseudo-first-order and pseudo-second-order kinetic models were used to fit the kinetic data, as shown in the following formulas:

[0108] ;

[0109] ;

[0110] Where q t (mg g -1 ) is the adsorption capacity at time t (min), q e (mg g -1 () refers to the adsorption capacity at equilibrium. k1 and k2 (g mg) -1 min -1 ) are the adsorption rate constants of the pseudo-first-order kinetic model and the pseudo-second-order kinetic model, respectively.

[0111] Model fitting curves and corresponding parameters are as follows Figure 4 (d) and Table 3 show the correlation coefficients (R) obtained using the pseudo-second-order dynamic model. 2 The values ​​of PANI / Bi2S3 on I2 are higher than those of the pseudo-first-order kinetic model, indicating that the pseudo-second-order kinetic model is more suitable for describing the adsorption process of composite materials on I2. The adsorption process of PANI / Bi2S3 on I2 belongs to rate-controlled chemisorption.

[0112] To investigate the effect of PANI / Bi₂S₃ composites on I₂ adsorption performance at different solution temperatures, a 10%-PANI / Bi₂S₃ composite was used as an example for further study, testing its adsorption capacity and equilibrium time at temperatures ranging from 298 K to 328 K. The results are as follows: Figure 4 As shown in (e), the adsorption capacity of 10%-PANI / Bi2S3 for I2 increases with increasing solution temperature, from 1228.4 mg / g. -1 It rose to 1301.1 mg g -1 This indicates that the adsorption of iodine monomer by the composite material is an endothermic process. To further understand the change in internal energy during adsorption, the thermodynamic parameters (ΔG) were calculated using thermodynamic equations. 0 , △H 0 , △S 0 ), as shown in the following formula:

[0113]

[0114]

[0115] Where △G 0 (kJ·mol -1 ), △H 0 (kJ.mol -1 ) and △S 0 (J·mol -1 ·K -1 These represent the Gibbs free energy, enthalpy, and entropy change, respectively; K is the thermodynamic equilibrium constant; R(8.314 J mol) -1 K -1 ) is the universal gas constant; T(K) is the solution temperature. A linear graph of 1 / T was plotted using lnK to obtain the slope and intercept, and the calculated thermodynamic parameters are shown in Table 4. At solution temperatures of 298K, 308K, and 318K, ΔG... 0 A value <0 indicates that the adsorption process of the composite material on I2 is spontaneous. △H 0 >0 indicates that heat was absorbed during the adsorption process, suggesting that increased temperature promotes the adsorption of radioactive iodine. △S 0 A value >0 indicates that the internal degrees of freedom of the system increase as the adsorption process proceeds. This further verifies that the adsorption of iodine monomers by the composite material is an exothermic process.

[0116] Furthermore, we found that the adsorption of I₂ by the PANI / Bi₂S₃ composite material is reversible. Therefore, using 10%-PANI / Bi₂S₃ as an example, 5 mg of the adsorbed iodine was added to 10 ml of ethanol solution. The absorption spectra of the composite material in the ethanol solution at different time intervals were studied using UV-Vis spectroscopy to investigate its release process. Figure 4 As shown in (f), the spectrum exhibits characteristic peaks at 288 nm and 360 nm, which is attributed to I3. - and I5 - The presence of this also indicates that Bi2S3 and I2 react chemically to form polyiodide ions.

[0117] In summary, the results of this study demonstrate that the PANI / Bi₂S₃ nanocomposite material can effectively remove radioactive iodine. Compared with pure Bi₂S₃ nanoflowers, the iodine absorption capacity and equilibrium rate of the PANI / Bi₂S₃ composite material are significantly improved. This can be attributed to the presence of numerous nitrogen-containing groups in PANI with high affinity for soft Lewis acidic I₂, which facilitates the uptake of large amounts of I₂. Simultaneously, PANI exhibits high conductivity, which further promotes iodine capture via electron transfer. The synthesized PANI / Bi₂S₃ composite material exhibits high iodine absorption capacities of 330.7 wt% and 1361.3 mg g / g in the gas and liquid phases, respectively. -1 The high adsorption capacity of PANI / Bi2S3 demonstrates its significant potential for iodine absorption. In conclusion, the excellent iodine absorption capacity of PANI / Bi2S3 indicates its enormous application potential in iodine absorption.

[0118] It should be noted that the terminology used in this invention is for describing specific embodiments only and is not intended to limit the scope of this application. As shown in this specification, unless the context clearly indicates otherwise, words such as "a," "an," "an," and / or "the" do not specifically refer to the singular and may include the plural. The terms "comprising," "including," or any other variations thereof are intended to cover a non-exclusive inclusion, such that a process, method, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, or apparatus that includes said element.

[0119] It should also be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the present invention. Unless otherwise expressly specified and limited, the terms "installed," "connected," "linked," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components. For those skilled in the art, the specific meaning of the above terms in the present invention can be understood according to the specific circumstances.

[0120] 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.

[0121] References:

[0122] [1]Y. Nan, LL Tavlarides, DW DePaoli, Adsorption of iodine onhydrogen‐reduced silver‐exchanged mordenite: Experiments and modeling, AIChEJournal 63 (2017).

[0123] [2]Y. Tan, R. Wang, Q. Zhao, T. Duan, L. Zhu, One-step synthesis ofAg@polyaniline core–shell particles for efficient removal of radioactiveiodine, J Radioanal Nucl Chem 333 (2024) 2105–2114. https: / / doi.org / 10.1007 / s10967-024-09444-3.

[0124] [3]X. Wang, M. Li, J. Zhang, X. He, J.C. Crittenden, W. Zhang, SilverIon-Exchanged Anionic Metal–Organic Frameworks for Iodine Adsorption: SilverSpecies Evolution from Ions to Nanoparticles, ACS Appl. Nano Mater. 6 (2023)7206–7217. https: / / doi.org / 10.1021 / acsanm.3c00264.

[0125] [4]T. Assaad, B. Assfour, Metal organic framework MIL-101 forradioiodine capture and storage, Journal of Nuclear Materials 493 (2017) 6–11. https: / / doi.org / 10.1016 / j.jnucmat.2017.05.036.

[0126] [5]C. Wang, H. Yao, J. Sun, T. Tong, Z. Ye, H. Dong, C. Li, S. Ma,Nanoscale assembly of MoS2 / CoS2 / Ni3S2 grown on Ni foam for synergisticcapture of iodine, Chemical Engineering Journal 493 (2024) 152514. https: / / doi.org / 10.1016 / j.cej.2024.152514.

[0127] [6]L. Zhang, M. Li, X. Liu, J. Feng, Y. Liu, Y. Tu, S. Li, T. Duan,Fabrication of amidoxime grafted polyacrylonitrile for iodine vapor capturefrom off-gas, Chemical Engineering Journal 493 (2024) 152618. https: / / doi.org / 10.1016 / j.cej.2024.152618.

[0128] [7]Y. Xiong, Y. Ai, H. Wang, Y. Zhang, X. He, H. Dan, Y. Ding, Facilesynthesis of novel Cu0@SiO2 adsorbents derived from rice husk for highlyefficient capture iodine gas, J Sol-Gel Sci Technol 107 (2023) 503–511.https: / / doi.org / 10.1007 / s10971-023-06100-2.

[0129] [8]M.M. Khan, K.-W. Chen, Y.-T. Chen, H.-Y. Liu, M. Xia, F. Ni, C.-H.Gong, P. Wang, Y. Yang, A highly efficient composite of Cu-BTC and g-C3N4with bismuth doped for the adsorption of radioactive iodine, Separation andPurification Technology 354 (2025) 128746. https: / / doi.org / 10.1016 / j.seppur.2024.128746.

[0130] [9]M.A.S. Salem, A.M. Khan, Y.K. Manea, M.T.A. Qashqoosh, F.A.M.Alahdal, Highly efficient iodine capture and ultrafast fluorescent detectionof heavy metals using PANI / LDH@CNT nanocomposite, Journal of HazardousMaterials 447 (2023) 130732. https: / / doi.org / 10.1016 / j.jhazmat.2023.130732.

[0131]

[10] K. Chen, A. Gu, X. Zhou, P. Wang, C. Gong, P. Mao, Y. Jiao, K.Chen, Y. Yang, In-situ growth of zeolitic imidazolate framework-8 onpolypyrrole nanotubes for highly efficient and reversible capture ofradioiodine, Colloids and Surfaces A: Physicochemical and Engineering Aspects658 (2023) 130751. https: / / doi.org / 10.1016 / j.colsurfa.2022.130751.

[0132]

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Claims

1. An application of a PANIBi2S3 nanocomposite material in iodine adsorption, characterized in that, The composite material is polyaniline-coated bismuth sulfide; The preparation method of the PANIBi2S3 nanocomposite material includes: Bismuth sulfide was mixed with chloroform, aniline was added, and the mixture was stirred until homogeneous. Hydrochloric acid and ammonium persulfate solution were added until the solution turned dark green. Solid-liquid separation was performed, followed by washing and drying to obtain the nanocomposite material. The ratio of aniline to bismuth sulfide by mass is 10%-30%.

2. The application of the nanocomposite material according to claim 1 in iodine adsorption, characterized in that, The morphology of the bismuth sulfide is nanoflower.

3. The application of the PANIBi2S3 nanocomposite material according to claim 1 in the adsorption of iodine, characterized in that, The molar ratio of ammonium persulfate to aniline in the ammonium persulfate solution is 1:1; The molar concentration of hydrochloric acid is 1 mol / L.

4. The application of the PANIBi2S3 nanocomposite material according to claim 1 in the adsorption of iodine, characterized in that, The volume ratio of the hydrochloric acid to the ammonium persulfate solution is 50:12.

5.

5. The application of the PANIBi2S3 nanocomposite material according to claim 1 in the adsorption of iodine, characterized in that, When adding aniline, an ice-water bath is used.

6. The application of the PANIBi2S3 nanocomposite material according to claim 1 in iodine adsorption, characterized in that, The specific washing method includes washing with ethanol and deionized water sequentially until the pH value of the precipitate is 7.

7. The application of the PANIBi2S3 nanocomposite material according to claim 1 in the adsorption of iodine, characterized in that, The drying temperature is 55℃-65℃, and the drying time is 23h-25h.

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