PREPARATION METHOD OF IONIC RARE EARTH LEACHING AGENT

Abstract

A preparation method of an ionic rare earth leaching agent includes the following steps: (1) domestication microorganisms with rare earth activated mineral powder culture medium to obtain a microbial suspension; (2) amplifying and culturing the microbial suspension and additives to obtain the amplified culture medium; and (3) mixing the modified sesbania gum with the amplified culture medium to obtain the ionic rare earth leaching agent. The activated mineral powder is the active metal-containing mineral powder in nature, which has excellent cation exchange function after activation, and the activated mineral powder and ionic rare earth mineral powder are used as the medium components to domesticate microorganisms, so that microorganisms can survive in the above-mentioned ionic solution and improve the leaching rate of synergistic leaching ionic rare earth.

Claims

1. A preparation method for ionic rare earth leaching agent, wherein, the method comprises the following steps: (1) domestication microorganisms with rare earth activated mineral powder medium to obtain a microbial suspension; wherein the microorganisms are one or more of actinomycetes and saccharomyces; the rare earth activated mineral powder medium is composed of 2 to 30 g/L carbon source, 5 to 15 g/L nitrogen source, 1 to 10 g/L growth factor, 0.42 to 4.2 g/L inorganic salt, 0.52 to 10 g/L rare earth activated mineral powder and balance water; and the rare earth activated mineral powder is a combination of ionic rare earth mineral powder and activated mineral powder; (2) amplifying and culturing the microbial suspension and an additive to obtain the amplified culture medium; wherein the additive is activated mineral powder; and (3) mixing a modified sesbania gum with the amplified culture medium to obtain the ionic rare earth leaching agent; wherein, the sesbania gum is modified by adding 0.5 to 5.0 g of sesbania gum and 1.0 to 6.5 g of strong alkali solid to the 100 mL of monochloroacetic acid solution, and stirring for 5 to 60 minutes at a temperature of 10 to 35 C., placing the solution in a strong alkaline environment, then vigorously stirring at 40 C. to 80 C. for 1 to 6 h, and separating by suction filtration to obtain alkali metal-modified carboxymethyl sesbania gum; and wherein, the activated mineral powder is prepared by adding an activator to the mineral powder containing active metals according to the weight percentage, and then roasting at 400 C. to 900 C. for 0.5 to 5 h; the activator is one or more of calcium chloride, sodium chloride, potassium carbonate, magnesium carbonate and calcium carbonate; the mineral powder containing active metals is one or more of mica powder, feldspar powder and bentonite; and the amount of the activator is 5% to 40% of the weight of mineral powder containing active metals.

2. The preparation method for ionic rare earth leaching agent according to claim 1, wherein, the domestication in step (1) is to inoculate the microorganisms into the rare earth activated mineral powder medium for cultivation, and the initial microbial inoculation amount is 1.210.sup.7 cells/mL, the inoculation temperature is 15 C. to 60 C., and the domestication time is 36 h to 240 h to obtain a microbial suspension.

3. The preparation method for ionic rare earth leaching agent according to claim 2, wherein the actinomycete is micromonospora, and the saccharomyces is candida or Pichia pastoris, and the carbon source is one or more of fructose, lignin, calcium carbonate and protein; the nitrogen source is one or more of amino acid, protein, nitrate, peptone and urea; the growth factor is one or more of yeast extract, corn steep liquor and wort; and the inorganic salt is a combination of potassium nitrate, sodium chloride, potassium phosphate, magnesium sulfate and iron sulfate.

4. The preparation method for ionic rare earth leaching agent according to claim 3, wherein the amount of the potassium nitrate is 0.1 to 1.2 g/L, and the amount of the sodium chloride is 0.1 to 0.9 g/L, the amount of the potassium phosphate is 0.07 to 0.7 g/L, the amount of the magnesium sulfate is 0.1-0.9 g/L, the amount of the ferric sulfate is 0.05 to 0.5 g/L, and the amount of the ionic rare earth mineral powder is 0.5 to 4 g/L, and the amount of the activated mineral powder is 0.02 to 6 g/L.

5. The preparation method for ionic rare earth leaching agent according to claim 1, wherein, in the amplifying and culturing of step (2), the culture temperature is 15 C. to 60 C., and the culture time is 36 to 240 h, the additive is added by 1% to 6% of the mass of the amplified culture medium, and the volume ratio of the microorganism suspension to the amplified culture medium is 1:10000 to 1:50.

6. The preparation method for ionic rare earth leaching agent according to claim 1, wherein, the mica powder is lepidolite ore powder; and the feldspar powder is one or two of potassium feldspar ore powder and sodium ore powder.

7. The preparation method for ionic rare earth leaching agent according to claim 1, wherein, the amount of the modified sesbania gum is 0.05% to 0.2% of the mass of the ionic rare earth leaching agent.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0064] FIG. 1 is the test report of the ionic rare earth ore used in the present application;

[0065] FIG. 2 is the XRD image of activated mineral powder of Example 3 of the present application;

[0066] FIG. 3 is the SEM image of activated mineral powder of Example 3 of the present application;

[0067] FIG. 4 is the EDS image of activated mineral powder of Example 3 of the present application;

[0068] FIG. 5 is the test report of rare earth leaching concentration after application of the ionic rare earth leaching agent of Example 3 of the present application to rare earth raw ore;

[0069] FIG. 6 is the test report of rare earth leaching concentration after application of (NH.sub.4).sub.2SO.sub.4 leaching agent of Comparative Example 1 to rare earth raw ore;

[0070] FIG. 7 is the test report of rare earth leaching concentration after application of (NH.sub.4).sub.2SO.sub.4 and modified sesbania gum leaching agent of Comparative Example 1 to rare earth raw ore;

[0071] FIG. 8 is the test report of rare earth leaching concentration after application of amplification medium of Comparative Example 3 as leaching agent in rare earth raw ore;

[0072] FIG. 9 is the X-ray diffraction image of the In.sub.2Se.sub.3 nanomaterial prepared by Example 6 of the present application;

[0073] FIG. 10 is the transmission electron microscope low magnification photo of In.sub.2Se.sub.3 nanomaterial prepared by Example 6 of the present application, with a scale of 200 nm;

[0074] FIG. 11 is the transmission electron microscope high magnification photo of In.sub.2Se.sub.3 nanomaterial prepared by Example 6 of the present application, with a scale of 5 nm;

[0075] FIG. 12 is the UV-visible diffuse reflectance image of In.sub.2Se.sub.3 nanomaterial prepared by Example 6 of the present application;

[0076] FIG. 13 shows the degradation rate of tetracycline by photocatalytic degradation of In.sub.2Se.sub.3 nanomaterial prepared in example 6 of the present application;

[0077] FIG. 14 shows the X-ray diffraction image of the tin disulfide nanomaterial prepared by Embodiment 9, where the horizontal coordinate is the 2 diffraction Angle and the vertical coordinate is the diffraction intensity;

[0078] FIG. 15 is the scanning electron microscope (SEM) image of the tin disulfide nanomaterial prepared by Example 9;

[0079] FIG. 16 is the transmission electron microscope (TEM) image of the tin disulfide nanomaterial prepared by Example 9;

[0080] FIG. 17 is the high magnification transmission electron microscope (HRTEM) image of the tin disulfide nanomaterial prepared by Example 9;

[0081] FIG. 18 shows the curve of the ratio of solution concentration and initial concentration with time when the tin disulphide nanomaterial prepared by Example 9 adsorbed organic solvent rhodamine B under dark conditions. The horizontal coordinate is time (min) and the vertical coordinate is C/C.sub.0 (%).

DETAILED DESCRIPTION

[0082] The present application will be further described in detail below in conjunction with the examples, but the embodiments of the present application are not limited to the scope indicated by the examples.

[0083] The ionic rare earth ore and ionic rare earth ore powder mentioned in the examples of the present application are all obtained from ionic rare earth ore in Cenxi City, Wuzhou City, Guangxi Zhuang Autonomous Region. The ore powder is dry powder obtained by grinding ionic rare earth ore to below 200 meshes. The test report is shown in FIG. 1. The rare earth content of the ore sample is 0.12% in the whole phase and 0.062% in the ionic phase.

[0084] The rare earths in ionic rare earth ores can be divided into four phases: water-soluble phase, exchangeable ionic phase, mineral phase and colloidal phase, and the proportion of the four phases in the total rare earth is about <0.0001%, 50% to 90%, 1% to 10% and 5% to 40%. Water-soluble phase rare earth can be free in water that part of rare earth resources, and exchangeable ionic phase rare earth refers to hydroxyl or water and hydroxyl adsorbed on clay rare earth resources. Mineral phase refers to the rare earth ions that compose mineral lattices or disperse and form rock minerals. Colloidal rare earth refers to rare earth oxides or hydroxides that are insoluble in water, especially rare earth resources adsorbed on iron/manganese oxides. Among the above four rare earth resources, colloidal rare earth and mineral rare earth can not be used by direct substitution leaching, but by using strong acids such as sulfuric acid and hydrochloric acid or adding roasting acid leaching, converting them into the form of ions, so that cation substitution leaching which is more active than rare earth can be used. The present application is mainly aimed at leach exchangeable ionic phase of rare earth in mineral samples, and the total phase mentioned in the embodiment refers to the sum of the four phase states of rare earth.

Example 1

[0085] (1) Preparation of activated mineral powder: 20 g of anhydrous calcium chloride was added to 100 g of 200-mesh potassium feldspar powder, and roasted at 750 C. for 1 hour to obtain activated mineral powder for later use.

[0086] (2) Preparation of potassium-modified carboxymethyl sesbania gum: in a vacuum glove box, 1.0 g of sesbania gum and 1.5 g of potassium hydroxide were added to 100 mL of monochloroacetic acid solution, and stirred for 30 min at 21 C., the solution was placed in a strong alkaline environment, then vigorously stirred at 60 C. for 2.5 h, separated by suction filtration, and washed with alcohol twice to obtain potassium-modified carboxymethyl sesbania gum, which was designated as SG-CH.sub.2COOK for later use.

[0087] (3) Preparation of microbial suspension: candida was inoculated into the medium for domestication, the inoculation amount of microorganisms was 1.510.sup.7/mL, the domestication temperature was 30 C., and the domestication time was 120 h. The medium contained 6.0 g/L peptone, 6.0 g/L amino acid, 22 g/L fructose, 4.5 g/L yeast extract, 0.3 g/L potassium nitrate, 0.4 g/L sodium chloride, 0.4 g/L potassium phosphate, 0.2 g/L magnesium sulfate, 0.1 g/L ferric sulfate, 1.2 g/L ionic rare earth mineral powder, 0.03 g/L activated mineral powder and the balance of water. A microbial suspension was obtained.

[0088] (4) Preparation of amplified culture medium: 27 g of the activated mineral powder obtained in step (1) and 5 mL of the microbial suspension in step (3) were added to 1 L of distilled water at 21 C. for amplification culture for 48 h to obtain the amplified culture medium.

[0089] (5) Preparation of ionic rare earth leaching agent: 0.8 g of SG-CH.sub.2COOK obtained in step (2) was added to 1 L of the amplified culture medium obtained in step (4), and mixed well to obtain an ionic rare earth leaching agent.

[0090] (6) The 90450 mm cylindrical empty pipe was fixed upright, the bottom of the column was fitted with a filter screen, 500 g of ionic rare earth ore was added and 250 g of the above ionic rare earth leaching agent was dripped in. After the leaching agent was dripped, water was slowly added to wash the leaching solution out of the ore body, and 320 mL of the leaching solution was collected. The rare earth leaching rate was 97.12%.

[0091] The pH value of the supernatant after precipitation of rare earths in the leaching solution was 8.2, the COD value was 68.9 mg/L, the ammonia nitrogen was 5.29 mg/L, and other detection indicators were in line with the emission standard of rare earth industry pollutants GB/T 26451-2011.

Example 2

[0092] (1) Preparation of activated mineral powder: 20 g of anhydrous calcium chloride was added to 100 g of 200-mesh lepidolite mineral powder, and roasted at 750 C. for 1 hour to obtain activated mineral powder for later use.

[0093] (2) Preparation of potassium-modified carboxymethyl sesbania gum: in a vacuum glove box, 1.5 g of sesbania gum and 4.2 g of potassium hydroxide were added to 100 mL of monochloroacetic acid solution, and stirred for 30 min at 21 C., the solution was placed in a strong alkaline environment, then vigorously stirred at 60 C. for 2.5 h, separated by suction filtration, and washed with alcohol twice to obtain potassium-modified carboxymethyl sesbania gum, which was designated as SG-CH.sub.2COOK for later use.

[0094] (3) Preparation of microbial suspension: Pichia pastoris was inoculated into the medium for domestication, the inoculation amount of microorganisms was 1.510.sup.7/mL, the domestication temperature was 30 C., and the domestication time was 120 h. The medium contained 6.0 g/L peptone, 6.0 g/L amino acid, 22 g/L fructose, 4.5 g/L yeast extract, 0.3 g/L potassium nitrate, 0.4 g/L sodium chloride, 0.4 g/L potassium phosphate, 0.2 g/L magnesium sulfate, 0.1 g/L ferric sulfate, 1.2 g/L ionic rare earth mineral powder, 0.03 g/L activated mineral powder and the balance of water. Amicrobial suspension was obtained.

[0095] (4) Preparation of amplified culture medium: 27 g of the activated mineral powder obtained in step (1) and 5 mL of the microbial suspension in step (3) were added to 1 L of distilled water at 21 C. for amplification culture for 48 h to obtain the amplified culture medium.

[0096] (5) Preparation of ionic rare earth leaching agent: 0.8 g of SG-CH.sub.2COOK obtained in step (2) was added to 1 L of the amplified culture medium obtained in step (4), and mixed well to obtain the ionic rare earth leaching agent.

[0097] (6) The @90450 mm cylindrical empty pipe was fixed upright, the bottom of the column was fitted with a filter screen, 500 g of ionic rare earth ore was added and 250 g of the above ionic rare earth leaching agent was dripped in. After the leaching agent was dripped, water was slowly added to wash the leaching solution out of the ore body, and 315 mL of the leaching solution was collected. The rare earth leaching rate was 92.41%.

[0098] The pH value of the supernatant after precipitation of rare earths in the leaching solution was 8.5, the COD value was 14.29 mg/L, the ammonia nitrogen was 5.96 mg/L, and other detection indicators were in line with the emission standard of rare earth industry pollutants GB/T 26451-2011.

Example 3

[0099] (1) Preparation of activated mineral powder: 20 g of anhydrous calcium chloride was added to 100 g of 200-mesh bentonite mineral powder, and roasted at 750 C. for 1 hour to obtain activated mineral powder for later use. The obtained activated mineral powder was tested, and the results were shown in FIG. 2 to FIG. 4.

[0100] (2) Preparation of potassium-modified carboxymethyl sesbania gum: in a vacuum glove box, 2.0 g of sesbania gum and 4.2 g of potassium hydroxide were added to 100 mL of monochloroacetic acid solution, and stirred for 30 min at 21 C., the solution was placed in a strong alkaline environment, then vigorously stirred at 60 C. for 2.5 h, separated by suction filtration, and washed with alcohol twice to obtain potassium-modified carboxymethyl sesbania gum, which was designated as SG-CH.sub.2COOK for later use.

[0101] (3) Preparation of microbial suspension: candida was inoculated into the medium for domestication, the inoculation amount of microorganisms was 1.510.sup.7/mL, the domestication temperature was 30 C., and the domestication time was 120 h. The medium contained 6.0 g/L peptone, 6.0 g/L amino acid, 22 g/L fructose, 4.5 g/L yeast extract, 0.3 g/L potassium nitrate, 0.4 g/L sodium chloride, 0.4 g/L potassium phosphate, 0.2 g/L magnesium sulfate, 0.1 g/L ferric sulfate, 1.2 g/L ionic rare earth mineral powder, 0.03 g/L activated mineral powder and the balance of water. A microbial suspension was obtained.

[0102] (4) Preparation of amplified culture medium: 27 g of the activated mineral powder obtained in step (1) and 5 mL of the microbial suspension in step (3) were added to 1 L of distilled water at 21 C. for amplification culture for 48 h to obtain the amplified culture medium.

[0103] (5) Preparation of ionic rare earth leaching agent: 0.3 g of SG-CH.sub.2COOK obtained in step (2) was added to 1 L of the amplified culture medium obtained in step (4), and mixed well to obtain an ionic rare earth leaching agent.

[0104] (6) The 90450 mm cylindrical empty pipe was fixed upright, the bottom of the column was fitted with a filter screen, 500 g of ionic rare earth ore was added and 250 g of the above ionic rare earth leaching agent was dripped in. After the leaching agent was dripped, water was slowly added to wash the leaching solution out of the ore body, and 300 mL of the leaching solution was collected. The rare earth leaching rate was 98.71%.

[0105] The pH value of the supernatant after precipitation of rare earths in the leaching solution was 8.46, the COD value was 36.5 mg/L, the ammonia nitrogen was 6.49 mg/L, and other detection indicators were in line with the emission standard of rare earth industry pollutants GB/T 26451-2011.

Example 4

[0106] (1) Preparation of activated mineral powder: 5 g of anhydrous calcium chloride was added to 100 g of 200-mesh sodium feldspar powder, and roasted at 400 C. for 5 h to obtain activated mineral powder for later use.

[0107] (2) Preparation of potassium-modified carboxymethyl sesbania gum: in a vacuum glove box, 3.0 g of sesbania gum and 5.0 g of potassium hydroxide were added to 100 mL of monochloroacetic acid solution, and stirred for 60 min at 15 C., the solution was placed in a strong alkaline environment, then vigorously stirred at 40 C. for 6 h, separated by suction filtration, and washed with alcohol twice to obtain potassium-modified carboxymethyl sesbania gum, which was designated as SG-CH.sub.2COONa for later use.

[0108] (3) Preparation of microbial suspension: candida was inoculated into the medium for domestication, the inoculation amount of microorganisms was 1.510.sup.7/mL, the domestication temperature was 15 C., and the domestication time was 240 h. The medium contained 3.0 g/L protein, 2.0 g/L urea, 2 g/L lignin, 1 g/L corn pulp, 0.1 g/L potassium nitrate, 0.1 g/L sodium chloride, 0.07 g/L potassium phosphate, 0.1 g/L magnesium sulfate, 0.05 g/L ferric sulfate, 0.5 g/L ionic rare earth mineral powder, 0.02 g/L activated mineral powder and the balance of water. A microbial suspension was obtained.

[0109] (4) Preparation of amplified culture medium: 2.5 g of the activated mineral powder obtained in step (1) and 5 mL of the microbial suspension in step (3) were added to 250 ml of distilled water at 15 C. for amplification culture for 240 h to obtain the amplified culture medium.

[0110] (5) Preparation of ionic rare earth leaching agent: 0.125 g of SG-CH.sub.2COOK obtained in step (2) was added to 50 ml of the amplified culture medium obtained in step (4), and mixed well to obtain an ionic rare earth leaching agent.

[0111] (6) The 90450 mm cylindrical empty pipe was fixed upright, the bottom of the column was fitted with a filter screen, 500 g of ionic rare earth ore was added and 250 g of the above ionic rare earth leaching agent was dripped in. After the leaching agent was dripped, water was slowly added to wash the leaching solution out of the ore body, and 305 mL of the leaching solution was collected. The rare earth leaching rate was 93.25%.

[0112] The pH value of the supernatant after precipitation of rare earths in the leaching solution was 8.4, the COD value was 27.9 mg/L, the ammonia nitrogen was 7.69 mg/L, and other detection indicators were in line with the emission standard of rare earth industry pollutants GB/T 26451-2011.

Example 5

[0113] (1) Preparation of activated mineral powder: 40 g of anhydrous calcium carbonate was added to 100 g of 200-mesh bentonite, and roasted at 900 C. for 0.5 hour to obtain activated mineral powder for later use. The obtained activated mineral powder was tested.

[0114] (2) Preparation of potassium-modified carboxymethyl sesbania gum: in a vacuum glove box, 2.5 g of sesbania gum and 5.0 g of potassium hydroxide were added to 100 mL of monochloroacetic acid solution, and stirred for 5 min at 35 C., the solution was placed in a strong alkaline environment, then vigorously stirred at 80 C. for 1 h, separated by suction filtration, and washed with alcohol twice to obtain potassium-modified carboxymethyl sesbania gum, which was designated as SG-CH.sub.2COOK for later use.

[0115] (3) Preparation of microbial suspension: candida was inoculated into the medium for domestication, the inoculation amount of microorganisms was 1.510.sup.7/mL, the domestication temperature was 60 C., and the domestication time was 36 h. The medium contained 10.0 g/L peptone, 5.0 g/L amino acid, 30 g/L calcium carbonate, 10 g/L wort, 1.2 g/L potassium nitrate, 0.9 g/L sodium chloride, 0.7 g/L potassium phosphate, 0.9 g/L magnesium sulfate, 0.5 g/L ferric sulfate, 4 g/L ionic rare earth mineral powder, 6 g/L activated mineral powder and the balance of water. A microbial suspension was obtained.

[0116] (4) Preparation of amplified culture medium: 3 kg of the activated mineral powder obtained in step (1) and 5 mL of the microbial suspension in step (3) were added to 50 L of distilled water at 60 C. for amplification culture for 48 h to obtain the amplified culture medium.

[0117] (5) Preparation of ionic rare earth leaching agent: 100 g of SG-CH.sub.2COOK obtained in step (2) was added to 50 L of the amplified culture medium obtained in step (4), and mixed well to obtain an ionic rare earth leaching agent.

[0118] (6) The 90450 mm cylindrical empty pipe was fixed upright, the bottom of the column was fitted with a filter screen, 500 g of ionic rare earth ore was added and 250 g of the above ionic rare earth leaching agent was dripped in. After the leaching agent was dripped, water was slowly added to wash the leaching solution out of the ore body, and 300 mL of the leaching solution was collected. The rare earth leaching rate was 92.76%.

[0119] The pH value of the supernatant after precipitation of rare earths in the leaching solution was 8.51, the COD value was 41.7 mg/L, the ammonia nitrogen was 11.22 mg/L, and other detection indicators were in line with the emission standard of rare earth industry pollutants GB/T 26451-2011.

Comparative Experiment

[0120] Comparative Example 1:0.15 mol/L (NH.sub.4).sub.2SO.sub.4 was added to 500 mL of distilled water and stirred evenly to obtain leaching agent B; 325 mL of leaching solution was collected.

[0121] Comparative Example 2:0.15 mol/L (NH.sub.4).sub.2SO.sub.4 and 0.15 g of the potassium-modified carboxymethyl sesbania gum of Example 3 were added to 500 mL of distilled water, and stirred evenly to obtain leaching agent C. 340 mL of leaching solution was collected.

[0122] Comparative Example 3: the amplified culture medium of Example 3 was used as the leaching agent D. 325 mL of leaching solution was collected.

[0123] Adopt the same leaching process as in Example 3: The 90450 mm cylindrical empty pipe was fixed upright, the bottom of the column was fitted with a filter screen, 500 g of 0.062% ionic rare earth ore was added and 250 g of the above-mentioned rare earths from Comparative Examples 1 to 10 rare earth leaching agent was dripped, water was added slowly after the leaching agent was dripped, so that the leaching solution can be washed out from the ore body, and stop collecting when the quality of the leaching solution exceeds 250 mL. The resulting leaching solution was sent to testing, and the results are shown in Table 1, and the testing originals are shown in FIGS. 5 to 8.

TABLE-US-00001 TABLE 1 Rare earth content of the ore sample Full phase Ionic phase 0.12 0.062 Rare earth Leaching rate /% Ionic rare earth ore Original concentration in Full Ionic Leaching agent composition number leaching solution /mg/L phase phase Example 3 Amplified +SG-CH.sub.2COOK GX-11 1020.00 51.00 98.71 culture medium Comparative (NH.sub.4).sub.2SO.sub.4 GX-13 754.18 40.85 79.07 Example 1 Comparative (NH.sub.4).sub.2SO.sub.4 + SG-CH.sub.2COOK GX-14 775.52 43.95 85.06 Example 2 Comparative Amplified culture medium GX-23 828.62 44.88 86.87 Example 3

[0124] It can be seen from Table 1: [0125] (1) Comparative example 1 and Comparative example 2 illustrate that when the traditional (NH.sub.4).sub.2SO.sub.4 was used as the leaching agent, the modified sesbania gum after modification helps to increase the leaching rate of ionic rare earths; [0126] (2) Example 3 and Comparative Example 3 illustrate that the microbial suspension amplified culture medium and the modified sesbania gum have the effect of synergistically leaching ionic rare earths. [0127] (3) Example 3 and Comparative Example 2, Comparative Example 1 and Comparative Example 3 all show that when the microbial suspension amplified culture medium was used as a leaching agent, the effect of leaching ionic rare earths is better than that of the traditional (NH.sub.4).sub.2SO.sub.4 leaching agent. The leaching rate of ionic rare earths is the highest in Example 3 of the present application in which the microbial suspension amplified culture medium synergistically modifies the sesbania gum.

Example 6

[0128] This example is an example of a method for preparing In.sub.2Se.sub.3 nanomaterials for photocatalytic degradation of tetracycline described in the present application, as follows:

[0129] 2 mmol of indium chloride and 2 mmol of selenium powder were weighted, the above substances were added into 100 ml three-neckflask at room temperature, and then 16 ml of oleamine was injected into the three-neck flask; the three-neck flask was put in the electric heating jacket, heated to 60 C. and kept for 10 min, so that the sample was mixed well; then heated to 290 C. and held for 1 h to make it fully react. The whole reaction was stirred under the protection of argon. At the end of the procedure, the sample was naturally cooled to room temperature. After that, 12 ml of n-hexane was mixed with 4 ml of ethanol and washed repeatedly for 3 times. It was then vacuum dried and grinded into a powder. The obtained powder was again put into a three-neck flask, and a mixed solution of 10 ml toluene+10 ml 10% 3-mercaptopropionic acid aqueous solution was injected into the three-neck flask, and the mixture were stirred for 5 h. After that, they were washed with ethanol for 3 times, vacuum dried, and grinded to obtain a black indium selenide product. FIG. 9 shows the X-ray diffraction image of the product, and the obtained product is In.sub.2Se.sub.3. FIG. 10 shows the transmission electron microscope image of the product, and it can be observed that In.sub.2Se.sub.3 has the shape of both nanosheets and nanoparticles. FIG. 11 shows a high-resolution electron microscopic image of the In.sub.2Se.sub.3 nanometer photocatalyst. FIG. 12 shows the UV-visible absorption spectrum of In.sub.2Se.sub.3 nanometer photocatalyst.

[0130] 20 mg/L of tetracycline (80 ml) was decomposed by 50 mg of indium selenide photocatalyst at normal temperature and pressure. The concentration of tetracycline was determined by UV-visible spectrophotometry, and the degradation rate was calculated according to the concentration. FIG. 13 shows the curve of tetracycline degradation rate and light time, and the degradation rate reached 53% in 20 min.

Example 7

[0131] This example is another example of a method for preparing In.sub.2Se.sub.3 nanomaterials for photocatalytic degradation of tetracycline described in the present application, as follows:

[0132] 2 mmol of indium acetate and 3 mmol of selenium powder were weighted, the above substances were added into 100 ml three-neck flask at room temperature, and then 16 ml of dodecylamine was injected into the three-neck flask; the three-neck flask was put in the electric heating jacket, heated to 50 C. and kept for 20 min, so that the sample was mixed well; then heated to 280 C. and held for 1 h to make it fully react. The whole reaction was stirred under the protection of argon. At the end of the procedure, the sample was naturally cooled to room temperature. After that, 12 ml of n-hexane was mixed with 4 ml of ethanol and washed repeatedly for 3 times. It was then vacuum dried and grinded into a powder. The obtained powder was again put into a three-neck flask, and a mixed solution of 10 ml toluene+10 ml 10% 3-mercaptopropionic acid aqueous solution was injected into the three-neck flask, and the mixture were stirred for 8 h. After that, they were washed with ethanol for 3 times, vacuum dried, and grinded to obtain a black indium selenide product.

[0133] 20 mg/L of tetracycline (80 ml) was decomposed by 50 mg of indium selenide photocatalyst at normal temperature and pressure. The concentration of tetracycline was determined by UV-visible spectrophotometry, and the degradation rate was calculated according to the concentration.

Example 8

[0134] This example is another example of a method for preparing In.sub.2Se.sub.3 nanomaterials for photocatalytic degradation of tetracycline described in the present application, as follows:

[0135] 2 mmol of indium chloride and 4 mmol of selenium powder were weighted, the above substances were added into 100 ml three-neck flask at room temperature, and then 16 ml of cetylamine was injected into the three-neck flask; the three-neck flask was put in the electric heating jacket, heated to 70 C. and kept for 10 min, so that the sample was mixed well; then heated to 300 C. and held for 1 h to make it fully react. The whole reaction was stirred under the protection of argon. At the end of the procedure, the sample was naturally cooled to room temperature. After that, 12 ml of n-hexane was mixed with 4 ml of ethanol and washed repeatedly for 3 times. It was then vacuum dried and grinded into a powder. The obtained powder was again put into a three-neck flask, and a mixed solution of 10 ml toluene+10 ml 10% 3-mercaptopropionic acid aqueous solution was injected into the three-neck flask, and the mixture were stirred for 5 h. After that, they were washed with ethanol for 3 times, vacuum dried, and grinded to obtain a black indium selenide product.

[0136] 20 mg/L of tetracycline (80 ml) was decomposed by 50 mg of indium selenide photocatalyst at normal temperature and pressure. The concentration of tetracycline was determined by UV-visible spectrophotometry, and the degradation rate was calculated according to the concentration.

[0137] The evaluation method of photocatalytic tetracycline degradation performance of the catalyst is as follows: 50 mg of In.sub.2Se.sub.3 is dispersed in tetracycline (80 ml) aqueous solution with a concentration of 20 mg/L. Before the photocatalytic experiment, the solution is adsorbed in the dark for 20 min, so that the photocatalyst and tetracycline aqueous solution reach adsorption-desorption equilibrium. Then the solution was irradiated by 300W xenon lamp. The concentration of tetracycline was measured by UV-visible spectrophotometry at intervals of 2 ml to 5 ml solution, and the photocatalytic degradation efficiency of tetracycline by In.sub.2Se.sub.3 catalyst was calculated.

Example 9

[0138] The present embodiment is an example of the preparation method of sheet tin disulfide nanomaterial for efficient adsorption of organic dyes described in the present application, with the following steps:

[0139] 2 mmol of stannous chloride dihydrate and 10 mmol of thiourea were added to 100 ml beaker, 35 mL of triethylene glycol was added to the beaker, followed by magnetic stirring at room temperature for 1 h to mix well. After the mixture was uniform, the solution in the beaker was transferred to a 50 mL of stainless steel reaction kettle lined with PTFE, and the reaction kettle was placed in a constant temperature blast drying oven, and the reaction temperature was set at 200 C. and the reaction time was 10 h. After the reactor was cooled to room temperature, the resulting product was centrifuged and repeatedly washed with deionized water and ethanol three times. Finally, the solid was dried in a vacuum oven at 60 C. for 8 h to obtain the tin disulfide nanomaterial. FIG. 14 shows the X-ray diffraction image of the product, which confirms that the prepared product is mainly tin disulfide, while containing a small amount of tin sulfide (SnS), and the crystallization of the material is good. FIG. 15 shows the scanning electron microscope image of tin disulfide. The obtained samples are homogeneous in morphology and size, and all of them are nanoflower-like structures self-assembled by two-dimensional nanosheets. FIG. 16 is the transmission electron microscope image of the prepared sample. FIG. 17 shows the HRTEM image of the prepared sample. FIG. 18 shows the adsorption performance of the prepared sample for organic solvent rhodamine B under dark conditions, with time (min) as the horizontal coordinate and C/C0 (%) as the ratio of solution concentration to initial concentration.

Example 10

[0140] The present embodiment is another example of the preparation method of sheet tin disulfide nanomaterial for efficient adsorption of organic dyes described in the present application, with the following steps:

[0141] 2 mmol stannous chloride dihydrate and 15 mmol thiourea were added to 100 ml beaker, 35 mL triethylene glycol was added to the beaker, followed by magnetic stirring at room temperature for 1 h to mix well. After the mixture was uniform, the solution in the beaker was transferred to a 50 mL stainless steel reaction kettle lined with PTFE, and the reaction kettle was placed in a constant temperature blast drying oven, and the reaction temperature was set at 200 C. and the reaction time was 10 h. After the reactor was cooled to room temperature, the resulting product was centrifuged and repeatedly washed with deionized water and ethanol three times. Finally, the solid was dried in a vacuum oven at 60 C. for 8 h to obtain the tin disulfide nanomaterial.

Example 11

[0142] The present embodiment is another example of the preparation method of sheet tin disulfide nanomaterial for efficient adsorption of organic dyes described in the present application, with the following steps:

[0143] 2 mmol of stannous chloride dihydrate and 15 mmol of thiourea were added to 100 mL beaker, 35 mL of triethylene glycol was added to the beaker, followed by magnetic stirring at room temperature for 1 h to mix well. After the mixture was uniform, the solution in the beaker was transferred to a 50 mL of stainless steel reaction kettle lined with PTFE, and the reaction kettle was placed in a constant temperature blast drying oven, and the reaction temperature was set at 220 C. and the reaction time was 8 h. After the reactor was cooled to room temperature, the resulting product was centrifuged and repeatedly washed with deionized water and ethanol three times. Finally, the solid was dried in a vacuum oven at 60 C. for 8 h to obtain the tin disulfide nanomaterial.

[0144] The evaluation method of organic dye adsorption performance of adsorbent is as follows: at room temperature (about 25 C.), 40 mg of the prepared tin disulfide adsorbent was placed in the reactor and 100 mL of rhodamine B solution with a concentration of 20 mg/L was injected, and the tin disulfide was fully dispersed in the rhodamine B solution under dark conditions, and 3 ml of supernatant was taken at regular intervals. The concentration of rhodamine B was determined by UV-visible spectrophotometry, and the adsorption rate of rhodamine B was calculated according to the concentration of tin disulfide adsorbent.

[0145] The above embodiments are only specific examples of the purpose, technical solution and beneficial effects of the present application in further detail, and the present application is not limited herein. Any modification, equivalent replacement, improvement, etc. made within the scope of disclosure of the present application shall be included in the scope of protection of the present application.