CN113101950A

CN113101950A - Preparation method of surface oxidized tin disulfide nanosheet-coated tellurium nanowire for treating radioactive wastewater

Info

Publication number: CN113101950A
Application number: CN202110394062.5A
Authority: CN
Inventors: 何嵘; 雷佳; 竹文坤; 江新颖; 刘欢欢; 温逢春; 乐昊飏
Original assignee: Southwest University of Science and Technology
Current assignee: Southwest University of Science and Technology
Priority date: 2021-04-13
Filing date: 2021-04-13
Publication date: 2021-07-13
Anticipated expiration: 2041-04-13
Also published as: CN113101950B

Abstract

The invention discloses a preparation method of a tellurium nanowire wrapped by a tin disulfide nanosheet for treating surface oxidation of radioactive wastewater, wherein TeO is added under stirring₂Slowly add to N₂H₄·H₂Stirring and dissolving in O, then dripping the sodium dodecyl sulfate solution, stirring and centrifuging; dispersing the centrifuged product in water to obtain a Te nanowire solution; sodium dodecyl benzene sulfonate and SnCl₄·5H₂Adding O and L-cysteine into a mixed solvent of ethylene glycol and distilled water, stirring, then adding a Te nanowire solution, and stirring to obtain a reaction solution; transferring the reaction solution into a polytetrafluoroethylene high-pressure reaction kettle, heating for reaction, cooling the reaction system to room temperature, centrifuging, collecting precipitate, washing with distilled water and absolute ethyl alcohol, and reacting in a reactorAnd drying in a vacuum oven to obtain the tellurium nanowires wrapped by the tin disulfide nanosheets with oxidized surfaces. The tellurium nanowires wrapped by the surface-oxidized tin disulfide nanosheets prepared by the method can better treat uranium-containing wastewater, and have high photocatalytic reduction capability on hexavalent uranium.

Description

Preparation method of surface oxidized tin disulfide nanosheet-coated tellurium nanowire for treating radioactive wastewater

Technical Field

The invention relates to a preparation method of a heterojunction material, in particular to a preparation method of a tellurium nanowire wrapped by a tin disulfide nanosheet for treating surface oxidation of radioactive wastewater.

Background

With the development of clean nuclear power, large amounts of radioactive waste water are produced. Hexavalent uranium is a key component in radioactive wastewater, has strong chemical toxicity and radioactive toxicity, and therefore needs to be extracted and removed from the radioactive wastewater. Compared with the traditional adsorption method for extracting uranium, the photocatalytic reduction method for extracting soluble uranium has the advantages of high extraction speed, high resistance to non-reductive coexisting ions and the like, and attracts people's attention. In the photocatalytic process, uranium is first confined to the semiconductor surface and then reduced by photoelectrons. Therefore, the uranium confinement of the semiconductor directly affects the utilization of photoelectrons and the uranium reduction efficiency.

In addition to functional groups, coulombic interaction is another factor that affects the strength of the bond between uranium and the confinement site. Given that uranyl ions are the most commonly occurring form of uranium in radioactive wastewater, a negatively charged surface is feasible for extraction of uranium. In the photocatalytic reduction of uranium, the accumulation of electrons on the semiconductor can increase the surface negative charge, which can be achieved by plasma effect injection of hot electrons. Therefore, the semiconductor can be compounded with a plasmonic material to promote confinement of uranium, thereby promoting photocatalytic reduction of uranium.

Disclosure of Invention

An object of the present invention is to solve at least the above problems and/or disadvantages and to provide at least the advantages described hereinafter.

To achieve these objects and other advantages in accordance with the present invention, there is provided a method for preparing surface-oxidized tin disulfide nanosheets-coated tellurium nanowires for treating radioactive wastewater, comprising the steps of:

step one, stirring TeO₂Slowly add to N₂H₄·H₂In O, stirring until TeO₂Completely dissolving, then dripping the sodium dodecyl sulfate solution, stirring for 0.5-1.5 h, and then centrifuging at the speed of 7000-9000 rpm for 8-15 min; dispersing the centrifuged product in distilled water to obtain a Te nanowire solution;

step two, sodium dodecyl benzene sulfonate and SnCl₄·5H₂Adding O and L-cysteine into a mixed solvent of ethylene glycol and distilled water, stirring for 5-15 min, then adding a Te nanowire solution, and stirring for 15-25 min to obtain a reaction solution; and (3) moving the reaction solution into a polytetrafluoroethylene high-pressure reaction kettle, heating at 150-170 ℃ for 8-12 h, cooling the reaction system to room temperature, centrifuging, collecting precipitate, washing with distilled water and absolute ethyl alcohol for 5-8 times, and drying in a vacuum oven at 55-65 ℃ for 8-12 h to obtain the surface oxidized tin disulfide nanosheet-coated tellurium nanowire.

Preferably, in the first step, TeO₂And N₂H₄·H₂The mass-to-volume ratio of O is 1g: 400-450 mL; the concentration of the sodium dodecyl sulfate solution is 8-12 mmol/L; the TeO₂The mass-volume ratio of the sodium dodecyl sulfate solution to the sodium dodecyl sulfate solution is 1g: 3500-4000 mL.

Preferably, in the second step, sodium dodecyl benzene sulfonate and SnCl₄·5H₂The mass ratio of O to L-cysteine is 2-3: 1: 2.4-3; the volume ratio of the ethylene glycol to the distilled water is 1: 1; the SnCl₄·5H₂The mass volume ratio of the O to the mixed solvent of the glycol and the distilled water is 1g: 300-350 mL; the SnCl₄·5H₂The mass-volume ratio of the O to Te nanowire solution is 1g: 100-120 mL.

Preferably, in the second step, before the reaction liquid is transferred to the high-pressure reaction kettle, an Nd: YAG pulse laser is used for carrying out ultraviolet pulse laser irradiation on the reaction liquid.

Preferably, the irradiation time of the ultraviolet pulse laser is 5-10 min; the wavelength of the ultraviolet pulse laser irradiation is 355nm, the pulse width is 15-25 ns, and the pulse frequency is 20-35 Hz; the single pulse energy is 60-135 mJ.

Preferably, in the second step, the centrifugally collected precipitate is directly put into a supercritical device and soaked in a supercritical acetone-water system with the temperature of 360-370 ℃ and the pressure of 10-18 MPa for 5-10 min; the volume ratio of acetone to water in the supercritical acetone-water system is 2: 1.

The invention provides an application of the surface oxidized tin disulfide nanosheet-coated tellurium nanowire in radioactive wastewater treatment, the surface oxidized tin disulfide nanosheet-coated tellurium nanowire is added into the uranium-containing radioactive wastewater, the uranium-containing radioactive wastewater is stirred for 60min under a dark condition, and then a photocatalytic reaction is carried out under a condition that a xenon lamp simulates sunlight, so that the photocatalytic reduction of hexavalent uranium in the uranium-containing radioactive wastewater is realized.

The invention at least comprises the following beneficial effects:

the tellurium nanowires wrapped by the surface-oxidized tin disulfide nanosheets prepared by the method can better treat uranium-containing wastewater, and the introduction of the Te nanowires provides hot electron injection through a plasma effect under the illumination condition; SnS₂The surface oxidation of the uranium provides abundant surface hydroxyl groups as the limited domain sites of the uranium, so that the uranium has higher photocatalytic reduction capability on hexavalent uranium.

Additional advantages, objects, and features of the invention will be set forth in part in the description which follows and in part will become apparent to those having ordinary skill in the art upon examination of the following or may be learned from practice of the invention.

Description of the drawings:

FIG. 1 shows an embodiment of the invention SnS₂The (a) TEM and (b-c) HRTEM images of (a);

FIG. 2 shows Te @ SnS of the present invention₂The (a) TEM and (b) HRTEM images of (a);

FIG. 3 is Te @ O-SnS of the present invention₂The (a) TEM and (b-c) HRTEM images of (a);

FIG. 4 shows an embodiment of the invention SnS₂、Te@SnS₂And Te @ O-SnS₂XRD spectrum of (1);

FIG. 5 shows an embodiment of the invention₂、Te@SnS₂And Te @ O-SnS₂XPS total spectrum of (a);

FIG. 6 shows an embodiment of the present invention SnS₂、Te@SnS₂And Te @ O-SnS₂Sn 3d (a) and Te 3dXPS high resolution spectra of (1);

FIG. 7(a) is a graph showing the measurement of Te and SnS by UPS spectroscopy₂、Te@SnS₂And Te @ O-SnS₂The secondary electron cut-off edge of (b) is SnS₂、Te@SnS₂And Te @ O-SnS₂The Zeta potential of (c) is Te or SnS₂、Te@SnS₂And Te @ O-Sn _S2 ultraviolet-visible absorption spectrum;

FIG. 8 shows an embodiment of the present invention SnS₂、Te@SnS₂And Te @ O-SnS₂(ii) an infrared spectrum;

FIG. 9 shows an embodiment of the present invention SnS₂、(b)Te@SnS₂And (c) Te @ O-SnS₂Water contact angle of (c);

FIG. 10(a) shows SnS₂、Te@SnS₂And Te @ O-SnS₂Electroreduction potential for uranium (uranium concentration 80. mu.g/L, NaNO)₃The concentration of (a) is 0.5mol/L, the temperature is 293K, and (b) is SnS after the uranium is photocatalytically reduced₂、Te@SnS₂And Te @ O-SnS₂Oxidation potential (NaNO)₃The concentration of (3) is 0.5mol/L and the temperature is 293K);

FIG. 11 shows Te @ O-SnS under different pH conditions₂The photocatalysis removal effect on U (VI) (the concentration of tannic acid is 1mg/L, the concentration of uranium is 8mg/L, the solid-liquid ratio is 0.25g/L, and the temperature is 293K);

FIG. 12 shows Te @ O-SnS under different solid-to-liquid ratios₂The photocatalysis removal effect on U (VI) (the concentration of tannic acid is 1mg/L, the concentration of uranium is 8mg/L, the temperature is 293K, and the pH is 4.8);

FIG. 13 shows Te @ O-SnS at different initial concentrations₂The photocatalysis removal effect on U (VI) (the concentration ratio of uranium to tannic acid is 8:1, the solid-liquid ratio is 0.25g/L, the temperature is 293K, and the pH is 4.8);

FIG. 14 shows SnS₂、Te@SnS₂And Te @ O-SnS₂The photocatalysis removal effect on U (VI) (the concentration of uranium is 8mg/L, the concentration of tannic acid is 1mg/L, the solid-liquid ratio is 0.25g/L, the temperature is 293K, and the pH is 4.8);

FIG. 15 is Te @ O-SnS₂The cycle stability of U (VI) (uranium concentration of 8mg/L, tannic acid concentration of 1mg/L, solid-to-liquid ratio of 0.25g/L, temperature of 293K, pH of 4.8);

FIG. 16 shows SnS₂、Te@SnS₂And Te @ O-SnS₂The removal effect on the tannic acid (the concentration of uranium is 8mg/L, the concentration of the tannic acid is 1mg/L, the solid-liquid ratio is 0.25g/L, the temperature is 293K, and the pH is 4.8);

FIG. 17 is Te @ O-SnS₂And 1-Te @ O-SnS₂The photocatalysis removal effect on U (VI) (the concentration of uranium is 8mg/L, the concentration of tannic acid is 1mg/L, the solid-liquid ratio is 0.25g/L, the temperature is 293K, and the pH is 4.8);

FIG. 18 is Te @ O-SnS₂And 2-Te @ O-SnS₂The photocatalysis removal effect on U (VI) (the concentration of uranium is 8mg/L, the concentration of tannic acid is 1mg/L, the solid-liquid ratio is 0.25g/L, the temperature is 293K, and the pH is 4.8);

FIG. 19 is Te @ O-SnS₂And 3-Te @ O-SnS₂The photocatalytic removal effect on U (VI) (the concentration of uranium is 8mg/L, the concentration of tannic acid is 1mg/L, the solid-liquid ratio is 0.25g/L, the temperature is 293K, and the pH is 4.8).

The specific implementation mode is as follows:

the present invention is further described in detail below with reference to the attached drawings so that those skilled in the art can implement the invention by referring to the description text.

It will be understood that terms such as "having," "including," and "comprising," as used herein, do not preclude the presence or addition of one or more other elements or groups thereof.

Example 1:

a preparation method of a tellurium nanowire wrapped by a tin disulfide nanosheet for treating surface oxidation of radioactive wastewater comprises the following steps:

step one, under stirring, 24mg of TeO₂Addition to 10mL of N₂H₄·H₂In O, stirring until TeO₂Completely dissolving, wherein the color of the solution is changed into blue, then dripping 90mL of 10mmol/L sodium dodecyl sulfate solution, stirring for 1h, and then centrifuging at 8000rpm for 10 min; dispersing the centrifuged product in distilled water to obtain a Te nanowire solution;

step two, 0.2g of sodium dodecyl benzene sulfonate and 0.09g of SnCl₄·5H₂Adding O and 0.24g L-cysteine into a mixed solvent of 30mL of ethylene glycol and distilled water (v/v is 1:1), stirring for 10min, then adding 10mL of Te nanowire solution, and stirring for 20min to obtain a reaction solution; transferring the reaction solution into a polytetrafluoroethylene high-pressure reaction kettle, heating at 160 ℃ for 10h, cooling the reaction system to room temperature, centrifugally collecting precipitate, washing with distilled water and absolute ethyl alcohol for 6 times, and drying in a vacuum oven at 60 ℃ for 10h to obtain surface-oxidized tin disulfide nanosheets wrapped with tellurium nanowires, namely Te @ O-SnS₂。

Example 2:

step two, 0.2g of sodium dodecyl benzene sulfonate and 0.09g of SnCl₄·5H₂Adding O and 0.24g L-cysteine into a mixed solvent of 30mL of ethylene glycol and distilled water (v/v is 1:1), stirring for 10min, then adding 10mL of Te nanowire solution, and stirring for 20min to obtain a reaction solution; performing ultraviolet pulse laser irradiation on the reaction liquid by using an Nd-YAG pulse laser; transferring the reaction solution after irradiation into a polytetrafluoroethylene high-pressure reaction kettle, heating at 160 ℃ for 10h, cooling the reaction system to room temperature, centrifugally collecting precipitate, washing with distilled water and absolute ethyl alcohol for 6 times, and drying in a vacuum oven at 60 ℃ for 10h to obtain the surface oxidized tin disulfide nanosheetWrapping tellurium nanowires; i.e. 1-Te @ O-SnS₂(ii) a The irradiation time of the ultraviolet pulse laser is 5-10 min; the wavelength of the ultraviolet pulse laser irradiation is 355nm, the pulse width is 15-25 ns, and the pulse frequency is 20-35 Hz; the single pulse energy is 60-135 mJ;

FIG. 17 is Te @ O-SnS₂And 1-Te @ O-SnS₂The photocatalysis removal effect on U (VI) (the concentration of uranium is 8mg/L, the concentration of tannic acid is 1mg/L, the solid-liquid ratio is 0.25g/L, the temperature is 293K, and the pH is 4.8); YAG pulse laser is used for carrying out ultraviolet pulse laser irradiation on reaction liquid, and the surface oxidized tin disulfide nanosheet prepared by coating tellurium nano-wires on the surface has better photocatalysis effect on uranium.

Example 3:

step two, 0.2g of sodium dodecyl benzene sulfonate and 0.09g of SnCl₄·5H₂Adding O and 0.24g L-cysteine into a mixed solvent of 30mL of ethylene glycol and distilled water (v/v is 1:1), stirring for 10min, then adding 10mL of Te nanowire solution, and stirring for 20min to obtain a reaction solution; transferring the reaction solution into a polytetrafluoroethylene high-pressure reaction kettle, heating at 160 ℃ for 10h, cooling the reaction system to room temperature, centrifuging, collecting precipitate, directly putting the centrifugally collected precipitate into a supercritical device, and soaking for 6min in a supercritical acetone-water system at 365 ℃ and 15 MPa; then washing the substrate for 6 times by using distilled water and absolute ethyl alcohol, and drying the substrate for 10 hours in a vacuum oven at the temperature of 60 ℃ to obtain surface oxidized tin disulfide nanosheets wrapped with tellurium nanowires; i.e. 2-Te @ O-SnS₂(ii) a The volume ratio of acetone to water in the supercritical acetone-water systemIs 2: 1.

FIG. 18 is Te @ O-SnS₂And 2-Te @ O-SnS₂The photocatalysis removal effect on U (VI) (the concentration of uranium is 8mg/L, the concentration of tannic acid is 1mg/L, the solid-liquid ratio is 0.25g/L, the temperature is 293K, and the pH is 4.8); as can be seen from the figure, the photocatalytic effect of the tellurium nano-wires wrapped by the tin disulfide nano-sheets with oxidized surfaces on uranium is better through soaking and precipitating in a supercritical acetone-water system.

Example 4:

step two, 0.2g of sodium dodecyl benzene sulfonate and 0.09g of SnCl₄·5H₂Adding O and 0.24g L-cysteine into a mixed solvent of 30mL of ethylene glycol and distilled water (v/v is 1:1), stirring for 10min, then adding 10mL of Te nanowire solution, and stirring for 20min to obtain a reaction solution; performing ultraviolet pulse laser irradiation on the reaction liquid by using an Nd-YAG pulse laser; transferring the irradiated reaction solution into a polytetrafluoroethylene high-pressure reaction kettle, heating at 160 ℃ for 10h, cooling the reaction system to room temperature, centrifugally collecting precipitates, directly putting the centrifugally collected precipitates into a supercritical device, and soaking for 6min in a supercritical acetone-water system at 365 ℃ and 15 MPa; then washing the substrate for 6 times by using distilled water and absolute ethyl alcohol, and drying the substrate for 10 hours in a vacuum oven at the temperature of 60 ℃ to obtain surface oxidized tin disulfide nanosheets wrapped with tellurium nanowires; i.e. 3-Te @ O-SnS₂(ii) a The volume ratio of acetone to water in the supercritical acetone-water system is 2: 1;the irradiation time of the ultraviolet pulse laser is 5-10 min; the wavelength of the ultraviolet pulse laser irradiation is 355nm, the pulse width is 15-25 ns, and the pulse frequency is 20-35 Hz; the single pulse energy is 60-135 mJ.

Comparative example 1:

step two, 0.2g of sodium dodecyl benzene sulfonate and 0.09g of SnCl₄·5H₂Adding O and 0.24g L-cysteine into 30mL of distilled water, stirring for 10min, then adding 10mL of Te nanowire solution, and stirring for 20min to obtain a reaction solution; transferring the reaction solution into a polytetrafluoroethylene high-pressure reaction kettle, heating at 160 ℃ for 10h, cooling the reaction system to room temperature, centrifugally collecting precipitate, washing with distilled water and absolute ethyl alcohol for 6 times, and drying in a vacuum oven at 60 ℃ for 10h to obtain Te @ -SnS₂。

Comparative example 2:

mixing 0.2g sodium dodecylbenzenesulfonate and 0.09g SnCl₄·5H₂Adding O and 0.24g L-cysteine into 30mL of distilled water, and stirring for 10min to obtain a reaction solution; transferring the reaction solution into a polytetrafluoroethylene high-pressure reaction kettle, heating at 160 ℃ for 10h, cooling the reaction system to room temperature, centrifuging, collecting precipitate, washing with distilled water and absolute ethyl alcohol for 6 times, and drying in a vacuum oven at 60 ℃ for 10h to obtain SnS₂。

FIG. 1 shows an embodiment of the invention SnS₂The (a) TEM and (b-c) HRTEM images of (a); FIG. 2 shows Te @ SnS of the present invention₂The (a) TEM and (b) HRTEM images of (a); FIG. 3 is Te @ O-SnS of the present invention₂The (a) TEM and (b-c) HRTEM images of (a); TEM imageImage display Te @ O-SnS₂And Te @ SnS₂A typical 1D-2D hybrid structure is presented. On the (101) face of the Te nanowire, a plane pitch of

The lattice fringes of (2). At Te @ SnS₂Similar results were also observed in the samples. Te @ O-SnS₂The HRTEM images of (g) show that in the nanoplatelet region most of the phases exhibit two closest lattice fringes with an orientation angle of 60 ° and a face-to-face spacing of

This corresponds to a hexagonal SnS₂The (100) and (010) planes of (1). Another set of the plane spacing is

And

the orthogonal lattice stripes of (A) respectively correspond to square SnO₂The (110) plane and the (002) plane of (A), verified that SnS₂And oxidizing the surface of the nano sheet. Furthermore, SnS₂Leads to a variety of defects including dislocations and faults.

FIG. 4 shows an embodiment of the invention SnS₂、Te@SnS₂And Te @ O-SnS₂XRD spectrum of (1); from XRD of the material, Te @ O-SnS₂And Te @ SnS₂SnS with two hexagons₂And the characteristic peak of the Te nanowire proves that Te @ O-SnS₂The successful synthesis of the compound.

X-ray photoelectron Spectroscopy (XPS) analysis was performed using a Kratos Axis Ultra photoelectron Spectroscopy (Thermo escalab 250Xi, Thermo Fisher, USA) using monochromatic AlK_αAs an X-ray source. FIG. 5 shows an embodiment of the invention₂、Te@SnS₂And Te @ O-SnS₂XPS total spectrum of (a); FIG. 6 shows an embodiment of the present invention SnS₂、Te@SnS₂And Te @ O-SnS₂Sn 3d (a) and Te 3dXPS high resolution spectra of (1); in XPS spectra, all SnS₂The main elements of the substrate are S and Sn, and Te @ SnS₂And Te @ O-SnS₂Showing an additional Te element, Te @ O-SnS₂Additional O elements are shown. Further, the positions of the Sn 3d peak and Te 3d peak correspond to Sn in an oxidized state⁴⁺And Te⁰And is at Te @ O-SnS₂Is dominant.

The charge change of the surface of the material is analyzed by a Zeta potentiometer (zetaPALS); ultraviolet photoelectron spectroscopy was performed on an X-ray photoelectron spectrometer (UPS, Thermo escalab 250Xi, Thermo Fisher, US) with a monochromatic He I source (21.22 eV). To verify Te @ O-SnS₂We analyzed the UPS spectrum and zeta potential of the sample. FIG. 7(a) is a graph showing the measurement of Te and SnS by UPS spectroscopy₂、Te@SnS₂And Te @ O-SnS₂The secondary electron cut-off edge of (b) is SnS₂、Te@SnS₂And Te @ O-SnS₂The Zeta potential of (c) is Te or SnS₂、Te@SnS₂And Te @ O-Sn _S2 ultraviolet-visible absorption spectrum; as shown, Te nanowire, SnS₂Nanosheet, Te @ SnS₂And Te @ O-SnS₂Respectively 15.87eV, 18.69eV, 18.79eV and 19.19eV, corresponding to work functions of 5.35eV, 2.53eV, 2.43eV and 2.03eV, respectively. SnS₂The lower work function of the base sample relative to the Te nanowire is due to SnS₂The delocalized electrons caused by the surface defects of the nanosheets. In particular, Te @ O-SnS is due to the abundance of free electrons and oxidation-induced surface defects in conductive Te nanowires₂Has the lowest work function. The result shows that Te @ O-SnS₂Tends to transfer electrons outward, which may facilitate the reduction of u (vi). Likewise, Te @ O-SnS₂Zeta potential ratio SnS₂And Te @ SnS₂The zeta potential of (a) is more negative, which is also a defect due to integration of free electrons provided by the Te nanowires and surface oxidation. Thus, the introduction of Te nanowires and surface oxidation increases SnS₂The negative surface charge of the nano sheet enhances the positive valence UO₂ ²⁺Coulomb interaction of ions. The plasmon effect of Te prompted us to further explore SnS caused by the injection of thermal electrons under light irradiation₂The electrons at the nanosheet surface accumulate. FIG. 7c shows Te nanowire, SnS₂、Te@SnS₂And Te @ O-SnS₂Ultraviolet-visible spectrum of (a). Plasma adsorption of Te nanowire to ensure Te @ SnS₂And Te @ O-SnS₂The photoresponse range of (a) is extended to the visible/near infrared region.

To verify SnS₂Surface oxidation of (2), we studied O-SnS₂Functional groups present on the surface. FIG. 8 shows an embodiment of the present invention SnS₂、Te@SnS₂And Te @ O-SnS₂(ii) an infrared spectrum; FIG. 9 shows an embodiment of the present invention SnS₂、(b)Te@SnS₂And (c) Te @ O-SnS₂Water contact angle of (c); as shown, 3436cm^-1And 1631cm^-1The adsorption bands are respectively related to the stretching vibration and the bending vibration of isolated hydroxyl groups. Te @ O-SnS₂Is stronger than SnS₂And Te @ SnS₂Indicating that surface oxidation results in the formation of-OH groups. The water contact angle of the material is shown in FIG. 9, SnS₂Has a water contact angle of 81 degrees, Te @ SnS₂The water contact angle of the film is 77 degrees, Te @ O-SnS₂Has a water contact angle of 68 DEG, Te @ O-SnS₂The lower water contact angle further validates this result. The above results show that the surface oxidation of the added-OH groups provides additional confinement sites for U (VI).

Electrochemical characterization of the materials prepared in the examples and comparative examples was done on a chi760d workstation, with Ag/AgCl (3.5M KCl) and Pt wire as reference and counter electrodes, respectively. The working electrode was prepared as follows: first, 3mg of catalyst powder (materials prepared in example 1 and comparative examples 1 to 2) was mixed with 9mg of carbon black, 30. mu.L of Nafion solution (0.5 wt%), and 2mL of ethanol to obtain a carbon-based catalyst ink. Then, carbon-based catalyst ink was uniformly brushed on 1 × 2cm of carbon paper. At 80. mu.g/LU (VI) +0.5M NaNO₃In the electrolyte of (2 mV s)^-1Speed of U (VI) reduction LSV curve test, potential window from 0V to-1.6V vs Ag/AgCl. For oxidation of U (IV), at 0.5MNaNO₃In solution at 2mV s^-1LSV measurements were performed with a potential window of-1.6V to 0V vs Ag/AgCl.

The increase in negative charge and-OH groups is associated with an increase in U (VI) binding strength. FIG. 10(a) shows SnS₂、Te@SnS₂And Te @ O-SnS₂Para-uraniumElectrical reduction potential of (uranium concentration 80. mu.g/L, NaNO)₃At a concentration of 0.5mol/L and a temperature of 293K), and FIG. 10(b) shows SnS after photocatalytic reduction of uranium₂、Te@SnS₂And Te @ O-SnS₂Oxidation potential (NaNO)₃At a concentration of 0.5mol/L and at a temperature of 293K). Two peaks appear at-0.36 to-0.44V (vs Ag/AgCl) and-0.88 to-1.13V (vs Ag/AgCl), respectively the peak for U (VI) to U (V) and the peak for U (V) to U (IV). Te @ O-SnS₂Peak position ratio SnS₂And Te @ SnS₂The peak position of (A) is more negative, indicating that Te @ O-SnS₂Is the easiest to reduce U (VI) in the three samples. In addition, we have also investigated the SnS after U (VI) reduction deposition₂LSV curve of u (iv) oxidation of base material (fig. 10 b). Of the three samples, Te @ O-SnS₂The upper deposited u (iv) exhibits the most positive potential. The results demonstrate that Te incorporation and surface oxidation increase uranium in SnS₂The binding strength on the surface, which is attributed to the negative charge and the enhanced uranium confinement effect of the surface-OH groups.

In the photocatalytic process, 5mg of the prepared photocatalyst (materials prepared in examples 1 to 4 and comparative examples 1 to 2) was dispersed in 20mL of a dispersion having various concentrations (C)_U(VI)Concentrations of 8ppm, 50ppm, 100ppm, 150ppm and 200ppm, respectively, C_TA1ppm) in u (vi) solution. The pH was then adjusted with 0.1mol/L NaOH and HCl solution. Before the reaction, the photocatalyst was added under protection from light and stirred for 60 minutes to ensure adsorption-desorption equilibrium. Then, a 300W xenon lamp (BL-GHX-V, China) with an am1.5G filter was used as a light source. The concentrations of U (VI) and TA were determined in a UV spectrophotometer at 651.8nm and 273nm, respectively, over time. After each u (vi) photocatalytic cycle, the photocatalyst was further treated with 0.1M HCl solution under ultrasonic conditions for 4h, washed twice with ultrapure water and twice with alcohol, respectively, to remove uranium. The removal rates (Ads,%) for u (vi) and TA were calculated by the following formula:

Ads＝(C₀-C_t)/C₀×100％；

the enhancement of the u (vi) binding strength prompted us to study the photocatalytic reduction of u (vi) under am1.5g filter xenon lamp conditions (simulated sunlight). TA is prevalent as a true radioactive wastewaterCoexisting organic materials are used as sacrificial agents. FIG. 14 shows SnS in a solution of 1mg/L TA in 8mg/L U (VI)₂、Te@SnS₂And Te @ O-SnS₂Plots are removed for U (VI) as a function of reaction time. In the absence of illumination, Te @ O-SnS₂The removal rate of (2) is 13% which is higher than that of SnS₂(19.8%) and Te @ SnS₂(25%). After the introduction of the simulated sunlight, Te @ SnS₂And Te @ O-SnS₂The removal rate of U (VI) is obviously improved, and the removal rate in 60min is 82.3 percent and 97.3 percent respectively. Furthermore, Te @ O-SnS₂U (VI) was almost completely removed within 90min, with a removal of 98.6%. At the same time, Te @ O-SnS₂Degradation ratio of TA to SnS₂And Te @ SnS₂Respectively 1.66 times and 1.04 times higher (fig. 16).

As an important factor for evaluating the utility of the photocatalyst, we further evaluated Te @ O-SnS by repeating the photoreduction U (VI) 5 times₂Reusability of (2). As shown in FIG. 15, Te @ O-SnS₂After 5 cycles, the U (VI) removal rate is kept above 92.4 percent, which means the feasibility of applying the U (VI) extraction in industrial wastewater.

The pH stability is another important index for evaluating the photocatalytic reduction U (VI) performance of the material. Therefore, we studied Te @ O-SnS₂The removal rate of U (VI) when the pH of the solution is 2.8-9.8. Te @ O-SnS₂Over 88.4% removal was maintained over a wide pH range, with Te @ O-SnS2 reaching 98.6% removal of U (VI) at pH 4.8 (FIG. 11). FIG. 12 is Te @ O-SnS₂The removal rate of U (VI) and U (VI) is reduced under different solid-to-liquid ratios of 0.10g/L to 0.40 g/L. When the solid-liquid ratio is more than 0.25g/L, the removal rate can reach more than 98.6 percent. We further tested the initial concentration pair Te @ O-SnS₂Influence of photocatalytic reduction of U (VI). Te @ O-SnS at an initial concentration of between 8mg/L and 200mg/L₂Both showed higher u (vi) removal (fig. 13). At an initial concentration of 200mg/L, Te @ O-SnS₂The extraction of U (VI) reaches 704.8 mg/g. These results show that Te @ O-SnS₂Has good application prospect in the complex uranium-bearing actual wastewater treatment environment.

While embodiments of the invention have been described above, it is not limited to the applications set forth in the description and the embodiments, which are fully applicable in various fields of endeavor to which the invention pertains, and further modifications may readily be made by those skilled in the art, it being understood that the invention is not limited to the details shown and described herein without departing from the general concept defined by the appended claims and their equivalents.

Claims

1. A preparation method of a tellurium nanowire wrapped by a tin disulfide nanosheet for treating surface oxidation of radioactive wastewater is characterized by comprising the following steps:

2. The method for preparing surface-oxidized tin disulfide nanosheets-coated tellurium nanowires for treating radioactive wastewater as claimed in claim 1, wherein in the first step, TeO₂And N₂H₄·H₂The mass-to-volume ratio of O is 1g: 400-450 mL; the concentration of the sodium dodecyl sulfate solution is 8-12 mmol/L; the TeO₂The mass-volume ratio of the sodium dodecyl sulfate solution to the sodium dodecyl sulfate solution is 1g: 3500-4000 mL.

3. The method for preparing surface-oxidized tin disulfide nanosheets-coated tellurium nanowires for treating radioactive wastewater as claimed in claim 1, wherein in step two, sodium dodecylbenzenesulfonate, SnCl₄·5H₂The mass ratio of O to L-cysteine is 2-3: 1: 2.4-3; the volume ratio of the ethylene glycol to the distilled water is 1: 1; the SnCl₄·5H₂The mass volume ratio of the O to the mixed solvent of the glycol and the distilled water is 1g: 300-350 mL; the SnCl₄·5H₂The mass-volume ratio of the O to Te nanowire solution is 1g: 100-120 mL.

4. The method for preparing surface-oxidized tin disulfide nanosheets wrapped tellurium nanowires for treating radioactive wastewater according to claim 1, wherein in the second step, ultraviolet pulse laser irradiation is performed on the reaction liquid by using an Nd: YAG pulse laser before the reaction liquid is transferred into the high-pressure reaction kettle.

5. The method for preparing the tellurium nanowire-coated tin disulfide nanosheet for surface oxidation in the treatment of radioactive wastewater as claimed in claim 4, wherein the irradiation time of the ultraviolet pulsed laser is 5-10 min; the wavelength of the ultraviolet pulse laser irradiation is 355nm, the pulse width is 15-25 ns, and the pulse frequency is 20-35 Hz; the single pulse energy is 60-135 mJ.

6. The method for preparing surface-oxidized tin disulfide nanosheets wrapped with tellurium nanowires for treating radioactive wastewater as claimed in claim 1, wherein in the second step, the centrifugally collected precipitates are directly placed into a supercritical device, and immersed for 5-10 min in a supercritical acetone-water system at a temperature of 360-370 ℃ and a pressure of 10-18 MPa; the volume ratio of acetone to water in the supercritical acetone-water system is 2: 1.

7. The application of the surface oxidized tin disulfide nanosheet-coated tellurium nanowires as defined in any one of claims 1 to 6 in treating radioactive wastewater, wherein the surface oxidized tin disulfide nanosheet-coated tellurium nanowires is added into the uranium-containing radioactive wastewater, the uranium-containing radioactive wastewater is stirred for 60min under dark conditions, and then photocatalytic reaction is carried out under the condition that a xenon lamp simulates sunlight, so that the photocatalytic reduction of hexavalent uranium in the uranium-containing radioactive wastewater is realized.