A nano-selenium adsorption material and its preparation method using guava and its application in Sb adsorption

Abstract

The present invention relates to the field of wastewater treatment, and more specifically, to a method for preparing a nano-selenium adsorption material from guava. The method comprises extracting guava raw material with an extractant to obtain an extract; mixing the extract with a selenium source and subjecting it to heat treatment, followed by solid-liquid separation, and collecting the nano-selenium adsorption material. The present invention also includes a material obtained by the preparation method and its use in Sb adsorption. The material obtained by the preparation method of the present invention exhibits unexpected results in Sb adsorption.

Description

Technical Field

[0001] The invention belongs to the field of hazardous waste treatment, and in particular relates to the field of treatment of Sb-containing waste. Background Art

[0002] Nanotechnology is a multidisciplinary field encompassing biology, engineering, physics, and chemistry. With the development and application of nanotechnology over the past decade, metallic and non-metallic nanoparticles have garnered increasing attention because selenium nanoparticles (SeNPs) possess unique mechanical, optical, electrical, biological, and chemical properties compared to conventional materials. Numerous methods for synthesizing nanoselenium have been reported, including chemical, biological, and physical methods. However, most of these methods involve tedious and harsh synthesis conditions, expensive and complex instrumentation, toxic reducing agents, and lengthy reaction times.

[0003] Furthermore, water pollution has become a serious issue in recent years, with Sb(III)-containing water pollution becoming a global concern. Nanomaterials, due to their high surface area and unique physicochemical properties, hold broad application prospects in water pollution control. However, existing technologies do not yet utilize nano-selenium for Sb adsorption, nor do they specifically address how to manipulate nano-selenium to improve its Sb adsorption performance. Summary of the Invention

[0004] In order to solve the problem of unsatisfactory Sb(III) adsorption effect, the first purpose of the present invention is to provide a method for preparing nano-selenium adsorption material from guava, aiming to prepare a material with excellent Sb adsorption performance.

[0005] The second purpose of the present invention is to provide a nano-selenium adsorption material prepared by the preparation method and its application in Sb adsorption.

[0006] A method for preparing a nano-selenium adsorption material from guava comprises the following steps: extracting a guava raw material with an extractant to obtain an extract; mixing the extract with a selenium source and subjecting the mixture to heat treatment, followed by solid-liquid separation, and collecting the nano-selenium adsorption material.

[0007] The present invention innovatively utilizes guava extract for the preparation of nano-selenium. This allows the characteristics of the guava extract to be exploited to induce the physical synthesis of nano-selenium, improve its grain size, and modify its surface physicochemical properties. Furthermore, the physicochemical properties imparted by the preparation method unexpectedly facilitate the adsorption of Sb.

[0008] In the present invention, the guava raw material can be any part of the guava, for example, guava leaves.

[0009] In the present invention, the extractant is an aqueous solvent, for example, water or a water-organic solvent mixed solvent, and the organic solvent is, for example, a water-soluble organic solvent, specifically at least one of C1-C4 alcohol, acetone, THF, and acetonitrile.

[0010] In the present invention, the volume content of water in the aqueous solvent is above 5%, preferably above 50%.

[0011] In the present invention, the liquid-to-solid ratio of the extractant to the guava raw material is 5-100 mL / g. Considering the processing cost and effect, it can be further 10-40 mL / g, and further 15-35 mL / g.

[0012] In the present invention, the temperature during the extraction process is above 25°C, preferably above 50°C. Considering the economic value of the treatment process, it can be further 50-150°C, and further 60-80°C.

[0013] In the present invention, in order to improve the extraction efficiency, the extraction stage can be carried out with the assistance of ultrasound. There is no particular requirement for the power of ultrasound, for example, it can be 100 to 1000W.

[0014] In the present invention, the extraction time can be adjusted as needed. For example, the extraction time is more than 30 minutes, and considering the processing efficiency, it can be further adjusted to 1 to 5 hours.

[0015] In the present invention, after the extraction reaction, the extraction system is filtered and / or centrifuged to obtain the extract. For example, the extraction system can be centrifuged to obtain a supernatant, which is then filtered to intercept solid particles therein to obtain the extract.

[0016] In the present invention, the extract can be selectively concentrated or diluted according to preparation requirements.

[0017] In the present invention, the composition characteristics of the guava extract are utilized to unexpectedly facilitate the formation of nano-selenium. Not only that, it is also beneficial to its lattice control and surface physicochemical modification, thus unexpectedly improving its effect in Sb adsorption.

[0018] In the present invention, the selenium source can be a conventional water-soluble selenium-containing raw material. Considering the processing cost, it can be selenite, preferably sodium selenite.

[0019] The selenium source can be mixed with the extract in the form of an aqueous solution, wherein the concentration of the selenium source in the aqueous solution can be, for example, 5 to 60 mM.

[0020] In the present invention, the amounts of the extract and the selenium source can be adjusted according to needs, such as the preparation scale. Considering the processing economy, the volume ratio of the extract and the selenium source is, for example, 1 to 10:1.

[0021] In the present invention, the solution containing the extract and the selenium source is heat-treated at a temperature of 90° C. or higher, preferably 100° C. or higher, more preferably 100-200° C., and even more preferably 100-130° C. When the heat treatment temperature is 100° C. or higher, it can be performed in a sealed pressure-resistant container.

[0022] In the present invention, the heat treatment time is more than 1 minute, and can further be 4 to 20 minutes;

[0023] Preferably, after the heat treatment, the nano-selenium adsorption material is obtained by centrifugation.

[0024] The present invention also includes a nano-selenium adsorption material prepared from guava prepared by the preparation method.

[0025] Thanks to the preparation method, the present invention can give the prepared material special physical and chemical characteristics. Moreover, the material prepared by the preparation method has unexpected effects in the adsorption of Sb.

[0026] The present invention also provides an application of the guava prepared by the preparation method to prepare a nano-selenium adsorption material, which is used as an adsorption material to remove Sb from Sb-containing pollutants.

[0027] In the application of the present invention, the Sb pollutants are solid waste and wastewater containing Sb;

[0028] Preferably, the valence state of Sb in the Sb contaminant is +3.

[0029] Preferably, the amount of the nano-selenium adsorption material is above 0.3 g / L, preferably above 1.2 g / L, and more preferably 1.5 to 2.5 g / L.

[0030] Preferably, the temperature in the adsorption stage is less than or equal to 60° C., preferably 15 to 50° C., and more preferably 15 to 35° C. Studies have found that at the preferred temperature, better adsorption performance can be unexpectedly obtained.

[0031] Preferably, the pH value in the adsorption stage is 2 to 12, preferably 2 to 3 or 8 to 12. Studies have found that alkaline and acidic conditions are more conducive to improving the adsorption performance of the prepared nano-selenium on Sb.

[0032] Preferably, the adsorption time is greater than or equal to 0.5 h, preferably 1 to 15 h, and more preferably 1 to 10 h.

[0033] Beneficial effects

[0034] The present invention innovatively utilizes guava extract for the preparation of nano-selenium. This allows the characteristics of the guava extract to be exploited to induce the physical synthesis of nano-selenium, improve its grain size, and modify its surface physicochemical properties. Furthermore, the physicochemical properties imparted by the preparation method unexpectedly facilitate the adsorption of Sb.

[0035] The present invention innovatively uses the nano-selenium adsorption material prepared by the preparation method for the adsorption of Sb, which can unexpectedly improve the adsorption performance of Sb by taking advantage of the material characteristics imparted by the preparation process. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 Flow chart of the preparation of nano-selenium in Example 1

[0037] Figure 2 Characterization diagram of nano-selenium in Example 1 (a: UV-visible spectrophotometry; b: X-ray diffraction diagram; c: X-ray photoelectron spectroscopy)

[0038] Figure 3 Laser particle size analysis images (a, b) and scanning electron microscope image (c) of nano-selenium in Example 1

[0039] Figure 4 The removal rate of antimony by nano-selenium under different treatment conditions in Example 1 (treatment conditions a, b and c are different concentrations of nano-selenium, different temperatures and different pH values, respectively)

[0040] Figure 5 This is a scanning electron microscope image of the reaction between nano-selenium and antimony in Example 1

[0041] Figure 6 This is the infrared spectrum of the reaction between nano-selenium and antimony in Example 1

[0042] Figure 7 Figure 1 is the Sb adsorption data of nano-selenium and commercial selenium in Example 1; DETAILED DESCRIPTION

[0043] The following is a detailed description of an embodiment of the present invention. This embodiment is implemented based on the technical solution of the present invention, but the protection scope of the present invention is not limited to the following embodiment.

[0044] In the present invention, guava leaves can be dried leaves or fresh leaves. In the following cases, guava leaves refer to dried leaves unless otherwise stated.

[0045] Example 1

[0046] (1): Grind guava leaves and sieve to obtain guava leaf powder;

[0047] The guava leaves were crushed in a grinder for 3 min and dried through a 40-mesh filter to obtain guava leaf powder of uniform size.

[0048] (2): The guava leaf powder prepared in (1) is mixed with a solvent in a certain proportion, extracted by ultrasonic heating, and filtered multiple times to obtain a clarified guava leaf extract; the specific steps are, for example:

[0049] A1. Mix 20 g of guava leaf powder with 400 mL of distilled water in a beaker, seal with plastic wrap to prevent water evaporation, and sonicate at 400 W and 65°C for 60 min.

[0050] A2. First, centrifuge the guava leaf extract at 10,000 rpm for 15 min two to three times, and retain the supernatant;

[0051] A3. The supernatant collected multiple times was passed through Whatman #1 filter paper to obtain a clarified guava leaf extract, which was then stored in a -4°C refrigerator for later use.

[0052] (3): The extract prepared in (2) is mixed with sodium selenite in a certain proportion, reacted under high temperature conditions, and the obtained reactant particles are centrifuged, washed, frozen, dried, and ground to obtain nano-selenium; the steps are:

[0053] B1. Mix the guava leaf extract with 50 mM sodium selenite in a volume ratio of 4:1, seal the container, and react at 100°C for 5 minutes to obtain a mixture containing nano-selenium particles;

[0054] B2. Centrifuge the nanoparticle mixture at 9000 rpm for 15 min, remove the supernatant, and wash the precipitate with distilled water 3 to 4 times to obtain pure nano-selenium particles;

[0055] B3. Transfer the cleaned nanoselenium particles to a clean centrifuge tube, freeze them at -80°C for 24 hours, and then dry them in a vacuum desiccator for 12 hours. After drying, remove the nanoselenium particles and grind them in agate to obtain evenly dispersed nanoselenium particles (labeled as SeNPs). These particles are then stored in a dry place. Characterization revealed that the nanoselenium particles prepared using guava leaf extract had an average size of approximately 300 nm.

[0056] (4): The nano-selenium prepared in (3) was applied to remove Sb(III) in the solution

[0057] C1. Prepare a 500 μM Sb(III) solution using potassium antimony tartrate as a mother liquor, mix it with the nano-selenium prepared in step (3), and fully react in a shaker at 160 rpm;

[0058] During the adsorption phase, the following screening was conducted on the adsorption conditions. The experimental groups were:

[0059] Group (a): The prepared nanoselenium particles were prepared at concentrations ranging from 0.3 to 2.4 g / L (weight-to-volume ratio relative to the Sb(III) solution, expressed in g / L) and at a temperature of 30°C. The pH during adsorption was not additionally controlled (pH = ~4; the pH here refers to the original pH of the solution, which is close to 4). The test results are shown in Figure 4 a.

[0060] Group (b): The concentration of prepared nano-selenium particles was 1.5 g / L, the temperature was 15-60°C; the pH during the adsorption process was not additionally regulated (pH = ~4); the test results are shown in Figure 4 b;

[0061] Group (c): The concentration of prepared nano-selenium particles was 1.5 g / L, the temperature was 30°C; the pH of the adsorption (i.e., the pH of the adsorption starting solution) was regulated to be 2-12; the test results are shown in Figure 4 c;

[0062] C2. Take out 5 mL of the mixed solution every 1 h. After passing it through a 0.45 μm filter membrane, use an inductively coupled plasma spectrometer (ICP) to measure the concentration change of Sb(Ⅲ) and explore the removal mechanism of Sb(Ⅲ) by nano-selenium. The results show that the maximum removal rate of Sb(Ⅲ) by nano-selenium can reach 98.4% within 60 min.

[0063] The specific process is as follows Figure 1 The synthesis of nano-selenium was verified by ultraviolet-visible spectrophotometry (UV-VIS), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS). The structure, size, and stability of nano-selenium prepared from guava leaf extract were confirmed by laser particle size analyzer (DLS) and scanning electron microscopy (SEM).

[0064] Figure 2 (a) is the UV-visible spectrogram of Example 1 after 5 minutes of reaction. From the results, it can be seen that the generated nanomaterial has an obvious characteristic peak at 356.77, proving the formation of nano-selenium. Figure 2 The characteristic peaks of nano-Se in (b) are consistent with the peaks of nano-Se specified in the document JCPDS card#06-0362. XPS is a powerful analytical technique used to study the elemental and chemical composition of surfaces, such as Figure 2(c) shows X-ray photoelectron spectroscopy (XPS) analysis of Se nanoparticles. Core-level spectra of C1s, O1s, and Se3d were recorded, and a distinct peak at 55.16 eV, corresponding to Se3d, was observed. This peak is characteristic of elemental selenium and confirms that the chemical valence of selenium in the Se nanoparticles is zero, indicating that the Se nanoparticles are composed of elemental selenium.

[0065] Figure 3 (a, b) Laser scattering (DLS) analysis shows that the average size of the prepared nanoparticles is 300 nm, and the zeta potential of the nanoselenium is -30.1 mV. The high zeta potential indicates that the prepared nanomaterial is very stable. Figure 3 (c) Scanning electron microscopy (SEM) and other characterizations revealed that the nano-selenium prepared using guava leaf extract was a spherical structure with an average size of approximately 300 nm. These particles were well distributed after aggregation, which was consistent with the results of DLS analysis.

[0066] The present invention further explores the effect of adsorbent dosage, temperature, and pH on the removal of Sb(III) to illustrate the influence of different conditions on the removal effect of Sb(III), and analyzes nano-selenium after reaction with Sb(III) by scanning electron microscopy (SEM) and infrared spectroscopy (FTIR) to explore its mechanism of removing Sb(III).

[0067] like Figure 4 As shown, at different initial nano-selenium concentrations, the Sb(III) removal rate increased with increasing nano-selenium concentration. When the nano-selenium concentration was 1.5 g / L, the maximum removal rate reached 91.8%. With further increases in nano-selenium concentration, the Sb(III) removal rate remained almost unchanged. At different temperatures, the Sb(III) removal rate first increased and then decreased with increasing temperature, with the maximum removal rate exceeding 90%. Under different pH conditions, the Sb(III) removal effect was optimal at slightly acidic or slightly alkaline conditions, with a maximum removal rate of 98.4%. In all of the above, a 500 μM Sb(III) solution was prepared using potassium antimony tartrate as the mother liquor, mixed with 1.5 g / L nano-selenium, and fully reacted on a shaker at 160 rpm. Every hour, 5 mL of the mixture was removed and, after passing through a 0.45 μm filter membrane, the Sb(III) concentration change was measured using ICP.

[0068] After the adsorption reaction, the nano-selenium particles were collected by centrifugation, freeze-dried and characterized. Figure 5 As shown in the scanning electron microscope image, it can be seen that the surface structure of the nano-selenium has changed, which may be due to the adsorption of Sb (III) on the surface of the nano-selenium, causing the spherical structure of the nano-selenium to bulge and deform. Figure 6 The infrared spectrum of nano-selenium shows that after reacting with Sb(Ⅲ), the spectrum of nano-selenium has an intensity of 3632 cm-1 、3350cm -1 and 2360cm -1 The generation of new peaks for OH, NH, and CC nearby is likely due to the addition of nano-selenium, which triggers chemical adsorption and leads to the expansion and contraction of functional groups. Simultaneously, the peak positions of CO, C=O, NH, COC, and CH show slight shifts and expansions, indicating that these groups participate in the adsorption of Sb(III). In summary, green synthesized nano-selenium has promising practical applications in combating Sb(III) contamination in aquatic environments.

[0069] Example 2

[0070] Compared with Example 1, the only difference is that the steps and parameters of (3) are changed:

[0071] Guava leaf extract and 30 mM sodium selenite were mixed in a 4:1 ratio, sealed, and reacted at 120°C for 5 minutes to produce a mixture containing selenium nanoparticles. The color of the reaction solution changed from brown to red. The nanoparticle mixture was centrifuged at 9000 rpm for 15 minutes, the supernatant removed, and the precipitate washed 3-4 times with distilled water to obtain pure selenium nanoparticles. The cleaned nanoparticles were transferred to a clean centrifuge tube, frozen at -80°C for 24 hours, and then dried in a vacuum desiccator for 12 hours. After drying, the nanoselenium nanoparticles were removed and ground in agate to obtain uniformly dispersed nanoparticles, which were then stored in a dry place. Laser sizing (DLS) and scanning electron microscopy (SEM) revealed that the nanoselenium nanoparticles prepared from guava leaf extract had a structure of 300-400 nm in size and good stability.

[0072] Comparative Example 1

[0073] Compared with Example 1, the only difference is that commercial nano-Se (commercial selenium, Shanghai McLean Biochemical Technology Co., Ltd., S817647-25g) is used to replace the nano-Se material prepared by the preparation method. The adsorption effect of the nano-Se (commercial selenium, Shanghai McLean Biochemical Technology Co., Ltd., S817647-25g) is compared with the SeNPs prepared in Example 1. Figure 7 It shows that the nano-selenium prepared by the preparation method of the present invention can unexpectedly exhibit excellent Sb adsorption performance.

[0074] The above embodiments are preferred implementations of the present invention. Any other changes, substitutions, simplifications, modifications, and combinations 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 guava in preparing nano-selenium adsorption materials, characterized in that: It is used as an adsorption material to remove Sb from Sb-containing pollutants; the Sb pollutants are solid waste and wastewater containing Sb; The method for preparing nano-selenium adsorption material from guava comprises: extracting guava raw material with an extractant to obtain an extract; mixing the extract with a selenium source and performing heat treatment, followed by solid-liquid separation, and collecting to obtain the nano-selenium adsorption material; The guava raw material is guava leaves; The extractant is water; The temperature of the heat treatment is 100-200°C.

2. The use of guava for preparing a nano-selenium adsorption material as claimed in claim 1, wherein the liquid-to-solid ratio of the extractant to the guava raw material is 5-100 mL / g.

3. The use of guava for preparing nano-selenium adsorption material as claimed in claim 1, wherein the temperature during the extraction process is above 25°C.

4. The use of guava for preparing nano-selenium adsorption material as claimed in claim 3, wherein the temperature during the extraction process is above 50°C.

5. The use of guava for preparing nano-selenium adsorption material as claimed in claim 4, wherein the temperature during the extraction process is 50-150°C.

6. The use of guava for preparing nano-selenium adsorption material as claimed in claim 1, wherein the extraction stage is carried out with the assistance of ultrasound.

7. The use of guava for preparing nano-selenium adsorption material as claimed in claim 1, wherein the power of the ultrasound is 100-1000W.

8. The use of guava for preparing nano-selenium adsorption material according to claim 1, wherein the extraction time is more than 30 minutes.

9. The use of guava for preparing nano-selenium adsorption material according to claim 8, wherein the extraction time is 1 to 5 hours.

10. The use of guava for preparing nano-selenium adsorption material according to claim 1, wherein the extract is filtered and / or centrifuged after extraction to obtain the extract.

11. The use of guava for preparing nano-selenium adsorption material according to claim 1, wherein the selenium source is selenite.

12. The use of guava for preparing nano-selenium adsorption material according to claim 11, wherein the selenium source is sodium selenite.

13. The use of guava for preparing nano-selenium adsorption material according to claim 1, wherein the heat treatment temperature is 100-130°C.

14. The use of guava for preparing nano-selenium adsorption material according to claim 1, wherein the heat treatment time is more than 1 minute.

15. The use of guava for preparing nano-selenium adsorption material according to claim 1, wherein the nano-selenium adsorption material is obtained by heat treatment and then centrifugation.

16. The use of guava for preparing nano-selenium adsorption materials according to claim 1, wherein the Sb in the Sb pollutant has a valence state of +3.

17. The use of guava for preparing nano-selenium adsorption material according to claim 1, wherein the amount of the nano-selenium adsorption material is above 0.3 g / L.

18. The use of guava for preparing nano-selenium adsorption material according to claim 1, wherein the amount of the nano-selenium adsorption material is above 1.2 g / L.

19. The use of guava for preparing nano-selenium adsorption material according to claim 1, wherein the amount of the nano-selenium adsorption material is 1.5-2.5 g / L.

20. The use of guava for preparing nano-selenium adsorption material according to claim 1, wherein the temperature in the adsorption stage is less than or equal to 60°C.

21. The use of guava for preparing nano-selenium adsorption material according to claim 20, wherein the temperature in the adsorption stage is 15-50°C.

22. The use of guava for preparing nano-selenium adsorption material according to claim 20, wherein the temperature in the adsorption stage is 15-35°C.

23. The use of guava for preparing nano-selenium adsorption material according to claim 1, wherein the pH value in the adsorption stage is 2-12.

24. The use of guava for preparing nano-selenium adsorption material according to claim 1, wherein the pH value in the adsorption stage is 2-3 or 8-12.

25. The use of guava for preparing nano-selenium adsorption material according to claim 1, wherein the adsorption time is 1 to 15 hours.

Images