TWO-DIMENSIONAL CHALCOGENIDE, AND PREPARATION METHOD AND USE THEREOF

Abstract

The invention provides a two-dimensional chalcogenide, which is a crystalline material, and has a chemical formula of (NH.sub.4).sub.2[Sn.sub.3S.sub.7].Math.(C.sub.4H.sub.13N.sub.3).sub.1.41, cell parameters of a=b=13.2307(10) Å, c=19.335(2) Å, α=β=90°, and γ=120°, and space group of P6.sub.3/mmc. The invention further provides a method for preparing the two-dimensional chalcogenide and use thereof in the adsorption of iodine vapor. The two-dimensional chalcogenide of the present invention is capable of removing iodine vapor of various concentrations (as low as 400 ppm) over a wide range of temperatures (25° C.-75° C.), without desorption of iodine after standing for a long time.

Claims

1. A two-dimensional chalcogenide, which is a crystalline material, and has a chemical formula of (NH.sub.4).sub.2[Sn.sub.3S.sub.7].Math.(C.sub.4H.sub.13N.sub.3).sub.1.41, cell parameters of a=b=13.2307(10) Å, c=19.335(2) Å, α=β=90°, and γ=120°, and space group of P6.sub.3/mmc.

2. A method for preparing a two-dimensional chalcogenide according to claim 1, comprising: reacting a tin source and elemental sulfur in diethylenetriamine at 150° C. to 180° C., to obtain the two-dimensional chalcogenide, wherein a molar ratio of the tin source to the elemental sulfur is 1:1 to 1:5.

3. The method for preparing a two-dimensional chalcogenide according to claim 2, wherein the reaction is carried out in a sealed environment.

4. The method for preparing a two-dimensional chalcogenide according to claim 2, wherein the tin source is a tin powder or tin tetrachloride.

5. The method for preparing a two-dimensional chalcogenide according to claim 2, wherein the elemental sulfur is sublimed sulfur.

6. The method for preparing a two-dimensional chalcogenide according to claim 2, wherein the molar ratio of the tin source to the elemental sulfur is 3:7.

7. The method for preparing a two-dimensional chalcogenide according to claim 2, wherein the reaction time is 3 to 7 days.

8. Use of the two-dimensional chalcogenide according to claim 1 in adsorption of iodine vapor.

9. The use according to claim 8, wherein the iodine vapor is radioactive iodine vapor.

10. The use according to claim 8, wherein the two-dimensional chalcogenide has an adsorption capacity of up to 1.66 g/g for iodine vapor with a concentration of 400 ppm at 25° C., and an adsorption capacity of up to 2.12 g/g for iodine vapor with a concentration of 400 ppm at 75° C.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0025] FIG. 1 is a schematic view of (NH.sub.4).sub.2[Sn.sub.3S.sub.7].Math.(C.sub.4H.sub.13N.sub.3).sub.1.41;

[0026] FIG. 2 shows a triangular node composed of a Sn atom and a S atom in the structure of (NH.sub.4).sub.2[Sn.sub.3S.sub.7].Math.(C.sub.4H.sub.13N.sub.3).sub.1.41;

[0027] FIG. 3 shows a curve of thermogravimetric analysis of (NH.sub.4).sub.2[Sn.sub.3S.sub.7].Math.(C.sub.4H.sub.13N.sub.3).sub.1.41;

[0028] FIG. 4(a) shows the adsorption amount of (NH.sub.4).sub.2[Sn.sub.3S.sub.7].Math.(C.sub.4H.sub.13N.sub.3).sub.1.41 for a high concentration of iodine vapor at 75° C. as a function of time;

[0029] FIG. 4(b) shows the change in the amount of iodine adsorbed on (NH.sub.4).sub.2[Sn.sub.3S.sub.7].Math.(C.sub.4H.sub.13N.sub.3).sub.1.41 after long-time standing; and

[0030] FIG. 5 shows the equilibrium adsorption capacity of (NH.sub.4).sub.2[Sn.sub.3S.sub.7].Math.(C.sub.4H.sub.13N.sub.3).sub.1.41 for a low concentration of iodine vapor at 25° C. and 75° C.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0031] The present invention will be further described below with reference to the accompanying drawings and specific examples, so that those skilled in the art can better understand and implement the present invention; however, the present invention is not limited thereto.

[0032] Unless otherwise stated, all technical and scientific terms used herein have the same meaning as commonly understood by persons skilled in the art to which the present invention pertains. The terms used in the descriptions of the present invention are for the purpose of describing specific embodiments only and are not intended to limit the present invention. The term “and/or” as used herein includes any and all combinations of one or more of the listed related items.

[0033] Unless otherwise stated, the experimental methods given in examples below are all conventional methods. The materials and reagents involved in the examples are commercially available, unless otherwise specified.

EXAMPLE 1

Synthesis of Two-Dimensional Chalcogenide (NH.SUB.4.).SUB.2.[Sn.SUB.3.S.SUB.7.].Math.(C.SUB.4.H.SUB.13.N.SUB.3.).SUB.1.41

[0034] 3 mmol of tin powder and 7 mmol of sulfur powder were added to the reaction vessel, and then 4 mL of diethylenetriamine was added. The reaction vessel was sealed, and the reaction temperature was set to 180° C. The reaction was continued for 4 days, followed by programmed cooling for 12 hrs to room temperature. After the reaction, the product was washed with water to obtain a yellow crystal designated as SCU-SnS.

[0035] The obtained yellow crystal was tested by single-crystal X-ray diffraction. The crystallographic parameters are listed in Table 1.

TABLE-US-00001 TABLE 1 Crystallographic parameters of two-dimensional chalcogenide (NH.sub.4).sub.2[Sn.sub.3S.sub.7]•(C.sub.4H.sub.13N.sub.3).sub.1.41 Materials SCU—SnS Molecular formula (NH.sub.4).sub.2[Sn.sub.3S.sub.7]•(C.sub.4H.sub.13N.sub.3).sub.1.41 Mr [g .Math. mol.sup.−1] 762.08   Crystal system Hexagonal system Space group P6.sub.3/mmc a (Å) 13.2307(10) b (Å) 13.2307(10) c (Å) 19.335(2) α 90    β 90    γ 120     V (Å.sup.3) 2931.2(5) Z 1    D.sub.c (g cm.sup.−3) 1.420 μ (mm.sup.−1) 3.016 F (000) 1176     T(K)   173(2) GOF on F.sup.2 1.102 R.sub.1,.sup.a wR.sub.2.sup.b (I > 2σ(I)) 0.0344, 0.0462 R.sub.1,.sup.a wR.sub.2.sup.b (all data) 0.0876, 0.0917 .sup.aR.sub.1 = Σ||F.sub.o| − |F.sub.c||/Σ|F.sub.o|. .sup.bwR.sub.2 = [Σw(F.sub.o.sup.2 − F.sub.c.sup.2).sup.2/Σw(F.sub.o.sup.2).sup.2].sup.1/2

[0036] FIGS. 1 and 2 schematically show the structure of the two-dimensional chalcogenide. As can be seen, the Sn atom and S atom form a triangle-like node, and the nodes are connected to each other through S atoms to form a layered structure. The layers are stacked with each other to form a negatively charged frame structure, and ammonium ions are present in the pores of (NH.sub.4).sub.2[Sn.sub.3S.sub.7].Math.(C.sub.4H.sub.13N.sub.3).sub.1.41, to balance the charges.

[0037] The obtained two-dimensional chalcogenide was tested by thermogravimetric analysis (TG) under a nitrogen atmosphere, at a temperature ramping from 30° C. to 900° C. at a heating rate of 10° C./min. The results are shown in FIG. 3.

[0038] It can be seen from FIG. 3 that under a nitrogen atmosphere, the two-dimensional chalcogenide is stable at 200° C., indicating that the material has good thermal stability. The weight reduction between 30° C. and 100° C. is mainly caused by the volatilization of water molecules on the surface of SCU-SnS, and the structure is disintegrated at around 200° C.

EXAMPLE 2

[0039] At 75° C., the two-dimensional chalcogenide material was placed in an atmosphere with a high concentration of iodine vapor (16000 ppm), and the adsorption amount of the material for iodine vapor was tested periodically. The result obtained is shown in FIG. 4(a).

[0040] It can be seen from FIG. 4(a) that as the reaction time elapses, the amount of iodine adsorbed on the material initially increases rapidly, then gradually becomes stable, and finally reaches equilibrium. The adsorption capacity is as high as 6.12 g/g. The two-dimensional chalcogenide material is an inorganic material with the highest adsorption capacity reported so far.

EXAMPLE 3

[0041] The iodine-adsorbed two-dimensional chalcogenide material was left to stand, and the amount of iodine adsorbed on the material was tested periodically. The result is shown in FIG. 4(b).

[0042] It can be seen from FIG. 4(b) that after the iodine-adsorbed two-dimensional chalcogenide material is left to stand for 6 days, the retention rate of iodine on the material is still close to 100%. This indicates that the two-dimensional chalcogenide material has no desorption of iodine due to long-term standing, and thus has good adsorption stability.

EXAMPLE 4

[0043] The two-dimensional chalcogenide material was allowed to stand in an atmosphere with iodine vapor of 400 ppm (close to the concentration of iodine vapor in the post-treatment process of spent nuclear fuel), at 25° C. and 75° C. respectively. The equilibrium adsorption capacity of the material for iodine vapor was tested. The result is shown in FIG. 5.

[0044] The result shows that the material has an adsorption capacity of up to 1.66 g/g for iodine vapor with a concentration of 400 ppm at 25° C., and an adsorption capacity of up to 2.12 g/g for iodine vapor with a concentration of 400 ppm at 75° C. (close to the temperature of the tail gas at the tail end of the device for post-treatment of the spent nuclear fuel).

[0045] Therefore, the new two-dimensional chalcogenide (NH.sub.4).sub.2[Sn.sub.3S.sub.7].Math.(C.sub.4H.sub.13N.sub.3).sub.1.41 provided in the present invention has a good absorption effect for iodine vapor, and has no desorption of iodine after standing for a long time, thus being applicable to the removal of radioactive iodine vapor during the post-treatment of spent nuclear fuel.

[0046] The above-described embodiments are merely preferred embodiments for the purpose of fully illustrating the present invention, and the scope of the present invention is not limited thereto. Equivalent substitutions or modifications can be made by those skilled in the art based on the present invention, which are within the scope of the present invention as defined by the claims. The scope of the present invention is defined by the appended claims.