Application of sodium alginate-copper selenide in heavy metal ion adsorption
By using sodium alginate as a soft template to prepare copper selenide complexes, the problem of heavy metal pollution was solved, efficient adsorption of Pb2+, Cr3+ and Cd2+ was achieved, and a green synthesis path and efficient adsorption materials were provided.
Patent Information
- Application Number
- CN202510957369.X
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-07-11
- Publication Date
- 2025-10-21
AI Technical Summary
In the prior art, there is little research on the use of sodium alginate to prepare copper selenide complexes, and the heavy metal pollution problem is serious, and there is a lack of effective adsorption materials.
Sodium alginate was used as a soft template, and zero-valent elemental selenium was prepared by redox reaction of Vc and Na2SeO3, which was then reacted with CuSO4 to generate copper selenide. The stability of sodium alginate was utilized to synthesize the sodium alginate-copper selenide complex.
The prepared sodium alginate-copper selenide complex has high adsorption performance for Pb2+, Cr3+ and Cd2+, with removal rates reaching 41.3%, 21.2% and 12.0%, respectively, providing a scientific basis for the removal of heavy metals in the environment. The synthesis process has low energy consumption and simple operation, and has the advantages of good biocompatibility, degradability and low cost.
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Abstract
Description
Technical Field
[0001] The invention belongs to the technical field of heavy metal adsorption materials, and particularly relates to application of sodium alginate-copper selenide in heavy metal ion adsorption. Background Art
[0002] Among many metal selenides, copper selenide is an important cation-deficient transition metal selenide. Copper selenide nanomaterials exist in a wide range of compound forms (CuSe, Cu2Se, CuSe2, Cu3Se2, Cu5Se4, Cu7Se4 and Cu 2- x Copper selenide (CopperSe) and crystal structures (orthorhombic, monoclinic, cubic, tetragonal and hexagonal). Copper selenide nanomaterials have attracted widespread attention from researchers due to their many potential applications in optoelectronic devices, medical treatment, gas sensors and catalysts.
[0003] Sodium alginate is a biomass polysaccharide extracted from brown algae. It is a linear polymer composed of β-D-mannuronic acid and α-L-guluronic acid linked by 1-4 glycosidic bonds. Sodium alginate is renewable, abundant, and has good safety and biocompatibility. It exhibits excellent thickening, stability, hydrophilicity, oil resistance, gelation, and film-forming properties, and has been widely used in food, industry, textiles, biomedicine, and other fields. Although research on copper selenide complexes has made some progress, few reports have been published on the preparation of copper selenide complexes using sodium alginate as a soft template.
[0004] Currently, my country faces a severe problem of heavy metal pollution, primarily caused by cadmium, lead, mercury, and chromium, which pose a threat to the health of Chinese residents. This invention uses sodium alginate as a soft template to prepare copper selenide, applying the sodium alginate-copper selenide complex for heavy metal adsorption for the first time, thereby alleviating heavy metal pollution in the environment. Summary of the Invention
[0005] In order to overcome the shortcomings and deficiencies in the prior art, the present invention aims to provide an application of sodium alginate-copper selenide in heavy metal ion adsorption; the sodium alginate-copper selenide is prepared by a soft template method, using sodium alginate as a soft template, utilizing Vc (vitamin C) and Na2SeO3 for oxidation-reduction to prepare zero-valent elemental selenium, adding CuSO4 under the condition of zero-valent elemental selenium to react with it to generate copper selenide, and utilizing the stability of sodium alginate to assist in the synthesis of sodium alginate-copper selenide.
[0006] The purpose of the present invention is achieved through the following technical solutions:
[0007] A method for preparing sodium alginate-copper selenide for heavy metal ion adsorption comprises the following steps:
[0008] (1) Preparation of nano-selenium solution;
[0009] (2) Preparation of copper selenide solution.
[0010] The preparation of the nano-selenium solution in step (1) is specifically carried out as follows: using sodium alginate as a soft template, adding a Vc solution and a Na2SeO3 solution to the sodium alginate solution, and allowing the mixture to react in a water bath at 4-80°C for 15-180 minutes to obtain a nano-selenium solution;
[0011] The preparation of the copper selenide solution in step (2) is specifically carried out according to the following steps:
[0012] Adding CuSO4 solution to the nano-selenium solution obtained in step (1), the resulting mixed solution is allowed to react in a water bath at 4-80°C for 15-180 min, and dialyzed through a dialysis bag with a molecular weight cut-off of 3500 Da for 24 h to obtain a copper selenide solution;
[0013] The concentration of Na2SeO3 in the Na2SeO3 solution in the mixed solution is 10 mmol / L; the concentration of sodium alginate in the sodium alginate solution in the mixed solution is 50-600 μg / mL; the concentration of Vc in the Vc solution in the mixed solution is 40-120 mmol / L; and the concentration of CuSO4 in the CuSO4 solution in the mixed solution is 5-15 mmol / L.
[0014] The concentration of sodium alginate in the sodium alginate solution in the mixed solution is preferably 200 μg / mL; the concentration of Vc in the Vc solution in the mixed solution is preferably 80 mmol / L; the concentration of CuSO4 in the CuSO4 solution in the mixed solution is preferably 10 mmol / L;
[0015] The static reaction time is preferably 15 minutes, and the reaction temperature is preferably 40°C.
[0016] The sodium alginate-copper selenide has an average particle size of 86.5 nm and a Zeta potential of -50.1 mV. The alginate-copper selenide has a spherical shape and is evenly dispersed.
[0017] The sodium alginate-copper selenide is composed of the following elements by mass percentage: 36.9% Se, 15.5% Cu, 21.1% O and 26.5% C.
[0018] The sodium alginate-copper selenide is composed of copper selenide crystals and sodium alginate interacting with each other through hydrogen bonds between -OH groups and copper selenide.
[0019] The heavy metal ion is Pb 2+ Cr 3+ and / or Cd2+ .
[0020] The sodium alginate-copper selenide Pb 2+ The clearance rate of Cr 3+ The clearance rate of Cd 2+ The clearance rate was as high as 12.0%.
[0021] The present invention has the following advantages and beneficial effects compared to the prior art:
[0022] (1) The present invention explores the effects of different reaction times, reaction temperatures, template addition amounts, the molar ratio of Na2SeO3 to CuSO4, and the molar ratio of Vc to Na2SeO3 on the particle size of sodium alginate-copper selenide. Based on the determination of the optimal single factor, the structure of the prepared sodium alginate-copper selenide is characterized by dynamic light scattering (DLS), transmission electron microscopy (TEM), X-ray diffraction (XRD), energy dispersive X-ray spectroscopy (EDX), and Fourier transform infrared spectroscopy (FTIR). Finally, the adsorption of heavy metals by sodium alginate-copper selenide is explored, providing a certain scientific basis for the removal of heavy metals in the environment.
[0023] (2) The present invention uses sodium alginate as a soft template to prepare copper selenide. The linear polysaccharide structure of sodium alginate provides abundant hydroxyl and carboxyl sites, which wrap copper selenide nanoparticles through hydrogen bonds and electrostatic interactions, inhibiting their agglomeration. Compared with the hydrothermal method, sacrificial template method, etc., the soft template method can be prepared at room temperature, has low energy consumption and simple operation, and has the advantages of good biocompatibility, degradability and low cost, which broadens the green synthesis path of copper selenide nanomaterials. BRIEF DESCRIPTION OF THE DRAWINGS
[0024] Figure 1 This is a graph showing the effect of different reaction times on the particle size of sodium alginate-copper selenide.
[0025] Figure 2 This is a graph showing the effect of different reaction temperatures on the particle size of sodium alginate-copper selenide.
[0026] Figure 3 This is a graph showing the effect of different sodium alginate addition amounts on the particle size of sodium alginate-copper selenide.
[0027] Figure 4This is a graph showing the effect of different molar ratios of Na2SeO3 to CuSO4 on the particle size of sodium alginate-copper selenide.
[0028] Figure 5 This is a graph showing the effect of different Vc and Na2SeO3 molar ratios on the particle size of sodium alginate-copper selenide.
[0029] Figure 6 This is a graph showing the particle size and zeta potential distribution of sodium alginate-copper selenide (A: particle size; B: zeta potential).
[0030] Figure 7 This is the TEM image of sodium alginate-copper selenide (A: 100 nm; B: 20 nm).
[0031] Figure 8 This is the EDX analysis of sodium alginate-copper selenide; (A: original state; B: C element; C: O oxygen element; D: Se element; E: Cu element; E: O, Se, and Cu element fusion) diagram.
[0032] Figure 9 These are the FT-IR spectra of sodium alginate and sodium alginate-copper selenide.
[0033] Figure 10 This is the XRD pattern of sodium alginate-copper selenide.
[0034] Figure 11 This is the observation diagram of the adsorption of single heavy metal ions by sodium alginate-copper selenide (A: Cd 2+ ;B:Cr 3+ ; C: Pb 2 + )picture.
[0035] Figure 12 Sodium alginate-copper selenide to Pb 2+ Cr 3+ 、Cd 2+ Graph showing the clearance rate of metal ion mixtures. DETAILED DESCRIPTION
[0036] The present invention will be described in further detail below with reference to the embodiments and drawings, but the embodiments of the present invention are not limited thereto.
[0037] Example 1: Effect of different reaction times on the particle size of sodium alginate-copper selenide
[0038] (1) Sodium alginate was dissolved in ultrapure water to obtain a sodium alginate solution with a concentration of 2.5 mg / mL; 2 mL of the above solution was drawn and added to 14 mL of ultrapure water, and magnetically stirred to obtain a uniform mixture. 4 mL of 500 mM Vc solution was added, and magnetically stirred for 5 minutes. After standing for 5 minutes, 2.5 mL of 100 mmol / L Na2SeO3 solution was added, and magnetically stirred for 5 minutes. The mixture was allowed to stand in a 40°C water bath for 15 minutes, 30 minutes, 60 minutes, 120 minutes, and 180 minutes to obtain a sodium alginate-nanoselenium solution;
[0039] (2) 2.5 mL of 100 mM CuSO4 solution was added and magnetically stirred for 5 min. The resulting mixed solution was allowed to stand in a 40°C water bath for the same reaction time as in step (1). The solution was placed in a dialysis bag with a molecular weight cutoff of 3500 Da and dialyzed in ultrapure water for 24 h to remove impurities. The ultrapure water was replaced every 3 h. The result after dialysis was an ammonium alginate-copper selenide solution.
[0040] The average particle size of sodium alginate-copper selenide was measured by DLS technology. The optimal reaction time was determined by comparing the average particle size of sodium alginate-copper selenide at different reaction times. Figure 1 As shown. Figure 1 It can be seen that as the reaction time increases from 15 min to 30 min, the average particle size of sodium alginate-copper selenide increases significantly, and the average particle size increases from 96.96 nm to 102.60 nm. When the reaction time is 30 min and 60 min, there is no significant difference in the average particle size of sodium alginate-copper selenide, and the average particle size is 102.10 nm. It was then found that when the reaction time increases from 60 min to 180 min, the average particle size of sodium alginate-copper selenide increases significantly and gradually, and the average particle size increases significantly from 102.10 nm to 108.55 nm. Figure 1 It can be seen that under different reaction time conditions, the particle size measured when the reaction time of sodium alginate-copper selenide is 15 minutes is the smallest, which is 96.96 nm. Therefore, the reaction time for preparing sodium alginate-copper selenide is determined to be 15 minutes.
[0041] Example 2: Effect of different reaction temperatures on the particle size of sodium alginate-copper selenide
[0042] The other steps are the same as those in Example 1, except that the static reaction time is fixed at 15 min, the water bath reaction temperature is changed, and the water bath reaction temperature is set to 4°C, 25°C, 40°C, 60°C, and 80°C (the water bath reaction temperature of step (1) and step (2) is the same). The average particle size of sodium alginate-copper selenide is determined by DLS technology, and the optimal reaction temperature is determined by comparing the average particle size of sodium alginate-copper selenide at different reaction temperatures. Figure 2 shown.
[0043] Depend on Figure 2 It can be seen that as the reaction temperature increases from 4°C to 25°C, the average particle size of sodium alginate-copper selenide decreases from 115.50nm to 111.06nm. When the reaction temperature is set at 40°C, the average particle size is 93.17nm, which is significantly smaller than that at 4°C and 25°C. Subsequently, when the reaction temperature is set at 60°C and 80°C, the average particle size is 129.43nm and 145.73nm respectively. On the contrary, it is found that the average particle size is significantly larger than that at 40°C. Figure 2 It can be seen that under different reaction temperature conditions, the average particle size of sodium alginate-copper selenide is the smallest when the reaction temperature is 40°C. Therefore, the reaction temperature for preparing sodium alginate-copper selenide is determined to be 40°C.
[0044] Example 3: Effect of different sodium alginate addition amounts on the particle size of sodium alginate-copper selenide
[0045] The other steps were the same as those in Example 1, except that the static reaction time was fixed at 15 min, the amount of sodium alginate added was controlled, and the amount of sodium alginate added was set to 50 μg / mL, 100 μg / mL, 200 μg / mL, 400 μg / mL, and 600 μg / mL. The average particle size of sodium alginate-copper selenide was determined by DLS technology, and the optimal amount of sodium alginate added was determined by comparing the particle size differences of sodium alginate-copper selenide under different sodium alginate addition amounts. Figure 3 shown.
[0046] Depend on Figure 3 It can be seen that as the amount of sodium alginate added increased from 50μg / mL to 100μg / mL, the average particle size of sodium alginate-copper selenide was found to decrease significantly, and the average particle size decreased from 106.36nm to 92.12nm. When the amount of sodium alginate added was controlled at 200μg / mL, the average particle size was significantly smaller than that of 50μg / mL and 100μg / mL, and the average particle size was 87.00nm. Subsequently, when the amount of sodium alginate added was controlled to 400μg / mL and 600μg / mL, it was found that the average particle size was significantly larger than that of 200μg / mL, and the average particle sizes were 92.30nm and 104.46nm respectively. Figure 3 It can be seen that when the addition amount of sodium alginate is 200 μg / mL, the average particle size of sodium alginate-copper selenide is the smallest, so the addition amount of sodium alginate is selected to be 200 μg / mL.
[0047] Example 4: Effect of different molar ratios of Na2SeO3 to CuSO4 on the particle size of sodium alginate-copper selenide
[0048] The other steps are the same as those in Example 1, except that the static reaction time is fixed at 15 min, and the Na2SeO3:CuSO4 molar ratio is set to 10:5, 10:7.5, 10:10, 10:12.5, and 10:15; because the molar concentration of Na2SeO3 in the mixed solution is 10 mmol / L, that is, the concentration of CuSO4 is 5 mmol / L, 7.5 mmol / L, 10 mmol / L, 12.5 mmol / L, or 15 mmol / L. The average particle size of sodium alginate-copper selenide is determined by DLS technology, and the particle size of sodium alginate-copper selenide at different Na2SeO3:CuSO4 molar ratios is compared to determine the optimal Na2SeO3:CuSO4 molar ratio. Figure 4 shown.
[0049] Depend on Figure 4 It can be seen that as the CuSO4 concentration changes from 5mmol / L to 7.5mmol / L, the average particle size of sodium alginate-copper selenide is found to decrease significantly, from 102.20nm to 99.04nm. When the CuSO4 concentration is controlled at 10mmol / L, the average particle size is smaller than that of 7.5mmol / L and also smaller than that of 5mmol / L, with an average particle size of 87.51nm. Subsequently, when the CuSO4 concentration is controlled at 12.5mmol / L and 15mmol / L, the average particle size gradually increases, with average particle sizes of 92.31nm and 115.10nm respectively. Figure 4 It can be seen that under different molar ratios of Na2SeO3 and CuSO4, the average particle size of sodium alginate-copper selenide CuSO4 reaction concentration is 10mmol / L with the smallest average particle size. Therefore, the molar ratio of Na2SeO3 and CuSO4 is selected as 10:10 to prepare sodium alginate-copper selenide.
[0050] Example 5: Effect of different molar ratios of Vc to Na2SeO3 on the particle size of sodium alginate-copper selenide
[0051] The other steps are the same as those in Example 1, except that the static reaction time is fixed at 15 min, and the molar ratio of Vc:Na2SeO3 is set to 40:10, 60:10, 80:10, 100:10, and 120:10; because the molar concentration of Na2SeO3 in the mixed solution is 10 mmol / L, the amount of Vc added is changed so that the concentration of Vc in the mixed solution is 40 mmol / L, 60 mmol / L, 80 mmol / L, 100 mmol / L, and 120 mmol / L, and the average particle size of sodium alginate-copper selenide is determined by DLS technology. By comparing the particle size of sodium alginate-copper selenide at different molar ratios of Vc to Na2SeO3, the optimal Vc reaction concentration ratio is determined, as shown in FIG. Figure 5 shown.
[0052] Depend on Figure 5 It can be seen that as the concentration of Vc changes from 40mmol / L to 60mmol / L, the average particle size of sodium alginate-copper selenide decreases significantly, and the average particle size decreases from 109.20nm to 91.1nm. When the Vc concentration is set to 80mmol / L, the average particle size is significantly smaller than that of 60mmol / L, and the average particle size is 88.88nm. Then when the Vc concentration is set to 100mmol / L and 120mmol / L, the average particle size gradually increases, and the average particle size is 94.17nm and 95.12nm respectively. Figure 5 It can be seen that when the molar concentration of Vc is 80 mmol / L, the average particle size of sodium alginate-copper selenide measured under this condition is the smallest, so the molar ratio of Vc to Na2SeO3 is selected as 80:10 to prepare sodium alginate-copper selenide.
[0053] Example 6: Sodium alginate-copper selenide structure characterization
[0054] (1) Particle size and Zeta potential analysis of sodium alginate-copper selenide
[0055] Based on the single-factor experiment, the optimal conditions were selected to prepare sodium alginate-copper selenide: using sodium alginate as a template, Na2SeO3 solution and Vc solution were added to the sodium alginate solution to cause a reduction reaction; then CuSO4 solution was added to obtain a mixed solution (relative to the mixed solution, the concentration of sodium alginate was 200 μg / mL, the concentration of Na2SeO3 was 10 mmol / L, the concentration of Vc was 80 mmol / L, and the concentration of CuSO4 was 10 mmol / L), and the sodium alginate-copper selenide solution was prepared by reaction; the reaction time was 15 min and the reaction temperature was 40°C.
[0056] The particle size and Zeta potential of the sodium alginate-copper selenide obtained in this example were measured by DLS. Figure 6 shown.
[0057] according to Figure 6 From A, we can see that the particle size distribution of sodium alginate-copper selenide nanoparticles is 43.8~220nm. Among them, the particle size at 91.3nm has the highest intensity, reaching 16.1%, while the particle size at 220nm has the lowest intensity, only 0.3%. The average particle size of sodium alginate-copper selenide is 86.5nm. Figure 6 As can be seen from B, the average Zeta potential of sodium alginate-copper selenide is -50.1 mV, indicating that the copper selenide prepared by using sodium alginate in the present invention has strong stability.
[0058] (2) Observation of the morphology of sodium alginate-copper selenide
[0059] The sodium alginate-copper selenide obtained in this example was observed under an electron microscope. Figure 7 As can be seen from A and B, the sodium alginate-copper selenide particle spheres observed at different magnifications are larger than 20 nm and smaller than 100 nm, which is consistent with the particle size measured by DLS technology. The sodium alginate-copper selenide nanoparticles prepared by the present invention have a monodisperse uniform spherical structure under TEM.
[0060] (3) Analysis of elemental composition on the surface of sodium alginate-copper selenide particles
[0061] In order to determine the elemental composition of the sodium alginate-copper selenide obtained in this example, TEM-EDX was used to perform elemental composition analysis. Figure 8 It can be seen that the surface of sodium alginate-copper selenide contains Se, Cu, O, and C elements, among which the mass percentages of Se, Cu, O, and C are 36.9%, 15.5%, 21.1%, and 26.5%, respectively; the ratio of Se and Cu on the surface of sodium alginate-copper selenide is 2.4:1.0; the O element mainly comes from sodium alginate. From the observation with F of 8, it can be seen that sodium alginate is successfully combined with the surface of copper selenide particles, and sodium alginate is likely to play a stabilizing role on copper selenide.
[0062] (4) Analysis of the interaction between sodium alginate and copper selenide
[0063] according to Figure 9 It can be seen that the characteristic peaks of the sodium alginate-copper selenide obtained in this embodiment are similar to those of sodium alginate, indicating that sodium alginate exists in the sodium alginate-copper selenide. FT-IR analysis shows that the infrared spectrum of sodium alginate has a peak at 3378 cm -1 The characteristic peak of hydroxyl group is at 3432 cm, which represents the stretching vibration of -OH. In the infrared spectrum of sodium alginate-copper selenide, the stretching vibration of -OH changes to 3432 cm -1 , indicating that there is a hydrogen bond interaction between the -OH group of sodium alginate and copper selenide, and that sodium alginate can stabilize copper selenide.
[0064] (5) Crystal form analysis of sodium alginate-copper selenide
[0065] Depend on Figure 10 It can be seen that the sodium alginate-copper selenide obtained in this example has diffraction peaks at 2θ angles of 27°, 31°, 45°, 53°, 65°, 72°, 83°, and 89°, which correspond to the diffraction peaks of the copper selenide standard card PDF#06-0680 and are consistent with the standard spectrum of copper selenide crystals.
[0066] Example 7: Adsorption of heavy metals by sodium alginate-copper selenide
[0067] (1) Using the sodium alginate-copper selenide obtained in Example 6 as a sample, the sodium alginate-copper selenide was tested for the effect of Pb 2+ Cr 3+ 、Cd 2+ Adsorption
[0068] according to Figure 11 It can be seen from A that the Cd 2+ The solution was mixed with sodium alginate-copper selenide solution, and the effect of sodium alginate-copper selenide on Cd 2+ There is some adsorption at 1000 μmol / L, but the effect is not obvious at 31.25-500 μmol / L. Figure 11 It can be seen from B that at different concentrations of Cr 3+ The solution was mixed with sodium alginate-copper selenide solution, and the effect of sodium alginate-copper selenide on Cr 3+ The adsorption effect is stronger at 1000 μmol / L, but weaker at 500 μmol / L; Figure 11 It can be seen from C that Pb at different concentrations 2+ The solution was mixed with sodium alginate-copper selenide solution. It can be seen that sodium alginate-copper selenide has a strong effect on Pb at the concentrations of 1000 μmol / L and 500 μmol / L. 2+ The adsorption effect is strong at 250 μmol / L, but it is relatively weak at 250 μmol / L. Figure 11 It can be seen that the adsorption effect of sodium alginate-copper selenide on the three metal ion solutions, Pb 2+ The adsorption effect is relatively strong, Cr 3+ Adsorption is second, Cd 2+ The adsorption effect is the weakest.
[0069] (2) Using the sodium alginate-copper selenide obtained in Example 6 as a sample, the sodium alginate-copper selenide was tested for the effect of Pb 2+ Cr 3 + 、Cd 2+ The clearing effect
[0070] Pb 2+ Cr 3+ 、Cd 2+ The three heavy metal ions were prepared into a mixed solution, and then an equal volume of sodium alginate-copper selenide solution was added and mixed. The supernatant was taken after centrifugation to measure the clearance rate. Figure 12 It can be seen that sodium alginate-copper selenide has a great influence on Pb 2+ Strong adsorption, Cr 3+ Next, Cd 2+ The removal rates of the three heavy metal ions were relatively weak, which was consistent with the adsorption effect of a single heavy metal ion, and were 41.3%, 21.2%, and 12.0%, respectively.
[0071] The above embodiments are preferred implementation modes of the present invention, but the implementation modes of the present invention are not limited to the above embodiments. Any other changes, modifications, substitutions, combinations, and simplifications that do not deviate from the spirit and principles of the present invention should be considered as equivalent replacement methods and are included in the scope of protection of the present invention.
Claims
1. An application of sodium alginate-copper selenide in heavy metal ion adsorption, characterized in that: The sodium alginate-copper selenide is prepared by using sodium alginate as a template, reducing Na2SeO3 with Vc, and adding CuSO4.
2. The use of sodium alginate-copper selenide in heavy metal ion adsorption according to claim 1, characterized in that: The preparation of the sodium alginate-copper selenide comprises the following steps: (1) Preparation of nano-selenium solution; (2) Preparation of copper selenide solution; The preparation of the nano-selenium solution in step (1) is specifically carried out as follows: using sodium alginate as a soft template, adding a Vc solution and a Na2SeO3 solution to the sodium alginate solution, and allowing the mixture to react in a water bath at 4-80°C for 15-180 minutes to obtain a nano-selenium solution; The preparation of the copper selenide solution in step (2) is specifically carried out according to the following steps: Adding CuSO4 solution to the nano-selenium solution obtained in step (1), the resulting mixed solution is allowed to react in a water bath at 4-80°C for 15-180 min, and dialyzed through a dialysis bag with a molecular weight cut-off of 3500 Da for 24 h to obtain a copper selenide solution; The concentration of Na2SeO3 in the Na2SeO3 solution in the mixed solution is 10 mmol / L; the concentration of sodium alginate in the sodium alginate solution in the mixed solution is 50-600 μg / mL; the concentration of Vc in the Vc solution in the mixed solution is 40-120 mmol / L; and the concentration of CuSO4 in the CuSO4 solution in the mixed solution is 5-15 mmol / L.
3. The use of sodium alginate-copper selenide in heavy metal ion adsorption according to claim 2, characterized in that: The concentration of sodium alginate in the sodium alginate solution in the mixed solution is 200 μg / mL; the concentration of Vc in the Vc solution in the mixed solution is 80 mmol / L; and the concentration of CuSO4 in the CuSO4 solution in the mixed solution is 10 mmol / L.
4. The use of sodium alginate-copper selenide in heavy metal ion adsorption according to claim 2, characterized in that: The static reaction time was 15 min and the reaction temperature was 40°C.
5. The use of sodium alginate-copper selenide in heavy metal ion adsorption according to claim 1 or 2, characterized in that: The sodium alginate-copper selenide has an average particle size of 86.5 nm and a Zeta potential of -50.1 mV. The alginate-copper selenide has a spherical shape and is evenly dispersed.
6. Use of sodium alginate-copper selenide in heavy metal ion adsorption according to claim 1 or 2, characterized in that: The sodium alginate-copper selenide is composed of the following elements in percentage by mass: Composition: Se 36.9%, Cu 15.5%, O 21.1% and C 26.5%.
7. Use of sodium alginate-copper selenide in heavy metal ion adsorption according to claim 1 or 2, characterized in that: The sodium alginate-copper selenide is composed of copper selenide crystals and sodium alginate interacting with each other through hydrogen bonds between -OH groups and copper selenide.
8. Use of sodium alginate-copper selenide in heavy metal ion adsorption according to claim 1 or 2, characterized in that: The heavy metal ion is Pb 2+ Cr 3+ and / or Cd 2+ .
9. Use of sodium alginate-copper selenide in heavy metal ion adsorption according to claim 1 or 2, characterized in that: The sodium alginate-copper selenide Pb 2+ The clearance rate of Cr 3+ The clearance rate of Cd 2+ The clearance rate was as high as 12.0%.