Photocatalytic material for synchronously removing composite new pollutants in plateau lakes and preparation method of photocatalytic material
By using rare earth metal-doped silica photocatalytic materials, the problem of simultaneous removal of microplastics, antibiotics, and dyes in plateau lakes has been solved, achieving efficient, stable, and low-cost pollutant degradation, which is suitable for pollution control in plateau lakes.
Patent Information
- Application Number
- CN202610494288.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2026-04-15
- Publication Date
- 2026-05-26
AI Technical Summary
Existing technologies are insufficient to simultaneously and efficiently remove three types of complex pollutants—microplastics, antibiotics, and dyes—from plateau lakes. Traditional adsorbents cannot degrade them, advanced oxidation technologies have low capture efficiency for suspended microplastics, and existing photocatalytic materials are expensive and pose a risk of heavy metal leaching, making them difficult to apply in practice.
Rare earth metal-doped silica photocatalytic materials are prepared by a solvothermal method. The surface of the material has both electrostatic adsorption sites and hydrophobic anchoring sites, enabling simultaneous photocatalytic degradation of microplastics, antibiotics and dyes. The material has good stability, is non-toxic and harmless, and has low cost.
It achieves efficient and simultaneous removal of microplastics, antibiotics and dyes, with degradation rates of 92%, 95% and 97.8% respectively. The material has high stability, is environmentally friendly, and is suitable for pollution control of plateau lakes.
Smart Images
Figure CN122076419A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of environmental functional materials technology, specifically to a photocatalytic material for the simultaneous removal of complex new pollutants from plateau lakes, its preparation method, and its application. Background Technology
[0002] High-altitude lakes (such as Dianchi and Erhai Lakes on the Yunnan-Guizhou Plateau, the lake clusters on the Qinghai-Tibet Plateau, and some lakes on the Brazilian Plateau) are important ecological barriers and freshwater reserves, but their ecosystems are fragile and their self-purification capacity is limited. In recent years, with pollution from within their basins and transported over long distances through the atmosphere, high-altitude lakes are facing a severe threat from "complex new pollutants," represented by microplastics, antibiotics, and dyes. Microplastics, as carriers, can adsorb highly toxic antibiotics and dyes, forming complex pollution clusters that pose a long-term risk to aquatic life and drinking water safety.
[0003] Existing water treatment technologies have significant limitations in addressing this type of complex pollution. They are often limited in scope and lack synergistic effects. For example, traditional adsorbents (such as activated carbon) can enrich microplastics and some organic matter, but cannot degrade them, posing risks of saturation and secondary pollution. Advanced oxidation technologies (such as homogeneous Fenton and UV / TiO2) can degrade dissolved organic matter, but their efficiency in capturing suspended microplastics and in interfacial catalysis is extremely low. Therefore, developing an integrated adsorption-catalysis material that can simultaneously achieve efficient microplastic capture and deep degradation of organic pollutants is crucial for controlling this type of complex pollution.
[0004] Currently, most research on the modification of silica (SiO2) materials focuses on its adsorption properties, while research on its use as a photocatalytic matrix is relatively limited. This is mainly because pure SiO2 is an insulator and does not possess photocatalytic activity. Although a few studies have attempted to endow it with catalytic properties by doping with metal elements, they often face the following bottlenecks: (1) The doping process is complex, the elements are unevenly dispersed, and there are few catalytic active sites; (2) The design is mostly aimed at a single pollutant (such as dyes), and there is a lack of design for the simultaneous removal of three types of pollutants with different properties and forms, namely microplastics, antibiotics, and dyes; (3) The environmental friendliness and economic efficiency of the materials are not adequately considered. Many high-performance catalysts contain precious metals or have the risk of heavy metal leaching, and require complex recycling processes, which are costly and difficult to apply in the vast plateau lake environment.
[0005] Therefore, providing a non-toxic, harmless, highly stable, and low-cost photocatalytic material and its preparation method that can simultaneously remove complex pollutants such as microplastics, antibiotics, and dyes is a technical problem that urgently needs to be solved in this field. Summary of the Invention
[0006] To address the aforementioned problems, this invention provides a photocatalytic material for the simultaneous removal of complex new pollutants from plateau lakes, along with its preparation method and applications. The photocatalytic material of this invention can simultaneously and efficiently remove three types of pollutants, and its preparation method is simple, reproducible, and easily scalable.
[0007] To achieve the above objectives, the present invention adopts the following technical solution:
[0008] A photocatalytic material for the simultaneous removal of complex new pollutants from plateau lakes, wherein the photocatalytic material is a composite material of rare earth metal doped with silicon dioxide, and the molar ratio of the rare earth metal to silicon is 3-15%; The composite pollutants include microplastics, antibiotics, and dyes.
[0009] The present invention uses silicon dioxide as a non-toxic and harmless main matrix, doped with rare earth elements. After the reaction, it does not need to be recycled and can naturally settle to the bottom of the water, without causing secondary pollution to the environment, and the raw material cost is low.
[0010] Preferably, the rare earth metal includes at least one of lanthanum, cerium, yttrium, and samarium.
[0011] The preparation method of the photocatalytic material for the simultaneous removal of complex new pollutants in plateau lakes, as described above, specifically includes the following steps: (1) After dissolving the rare earth metal salt in isopropanol and mixing it, solution A is obtained; (2) After mixing tetraethyl silicate and isopropanol evenly, add acid solution and deionized water to obtain solution B; (3) After mixing the solution A and the solution B, a template agent is added, and a solvothermal reaction is carried out; (4) The product obtained by the solvothermal reaction is centrifuged, washed, dried and then calcined to obtain a photocatalytic material for the simultaneous removal of composite new pollutants in plateau lakes.
[0012] Preferably, the rare earth metal salt in step (1) is at least one of lanthanum nitrate hexahydrate, cerium nitrate hexahydrate, yttrium nitrate hexahydrate, and samarium nitrate hexahydrate; The mass-to-volume ratio of the rare earth metal salt to isopropanol is 0.3-1.7 g: 10-20 mL.
[0013] Preferably, the acid solution in step (2) is concentrated nitric acid; The volume ratio of tetraethyl silicate, isopropanol, acid solution and deionized water is 5-7:10-20:0.5-1.0:2-4.
[0014] Preferably, the template agent in step (3) is hexadecyltrimethylammonium bromide; The mass-to-volume ratio of the rare earth metal salt, tetraethyl silicate, and template agent is 0.3-1.7 g: 5-7 mL: 0.1 g; The conditions for the solvothermal reaction are: temperature 140-160℃, time 10-14h; The solvothermal reaction needs to be stirred for 0.5-1.5 hours beforehand.
[0015] Preferably, the calcination temperature in step (4) is 450-550℃ and the time is 1-3h.
[0016] The application of the photocatalytic material or the photocatalytic material prepared by the above-described method in the simultaneous removal of water containing composite new pollutants from plateau lakes is characterized in that the composite new pollutants from plateau lakes include microplastics, antibiotics, and dyes.
[0017] Preferably, the novel pollutants in the plateau lake are polystyrene microplastics, tetracycline hydrochloride, and rhodamine B.
[0018] The photocatalytic material of this invention can achieve a degradation rate of up to 92% for polystyrene microplastics, up to 95% for tetracycline hydrochloride, and up to 97.8% for rhodamine B.
[0019] Preferably, the photocatalytic material is used as follows: after adding the photocatalytic material to water containing composite new pollutants from plateau lakes, the reaction can be carried out under ultraviolet irradiation, wherein the amount of the photocatalytic material added is 0.5-1.5 g / L.
[0020] Preferably, the reaction time is 48 hours.
[0021] Preferably, the photocatalytic material is suitable for purifying lake water in high-altitude areas with strong ultraviolet radiation.
[0022] Preferred, it is suitable for the treatment of shallow lake pollution in regions such as the Yunnan-Guizhou Plateau, the Qinghai-Tibet Plateau, and the Brazilian Plateau.
[0023] Compared with the prior art, the present invention has the following beneficial effects: (1) Functionalization of the main matrix: This invention uses pure silicon dioxide (intrinsic insulator, no photocatalytic activity) as the only main matrix, and directly endows it with photocatalytic performance through rare earth element doping, realizing a qualitative change from zero activity to high activity; The catalytic principle of this invention is based on the direct regulation of the electronic structure of SiO2 by the 4f electronic layer structure of rare earth elements. Rare earth doping introduces impurity energy levels in the wide bandgap of SiO2, transforming it from an insulator into a semiconductor material with ultraviolet response. This mechanism is fundamentally different from the charge transfer mechanism that relies on multi-metal synergy or multi-phase interface in the prior art. The oxygen vacancies and lattice defects generated by rare earth doping can serve as capture centers for photogenerated electron-hole pairs, significantly suppressing carrier recombination and improving quantum efficiency. These defect sites are also active centers for adsorption and catalytic reactions. (2) Solid-liquid multiphase targeted synergistic degradation: Existing conventional photocatalysts are usually difficult to treat solid phase (macromolecule microplastics) and liquid phase (small molecule antibiotics, dyes) pollutants at the same time because microplastics are hydrophobic solids, while antibiotics / dyes are hydrophilic dissolved states, and the interfacial catalytic conditions required for the two are completely different; This invention uses rare earth-doped SiO2, the surface of which has strong electrostatic adsorption sites (for liquid phase polar molecules) and defect-rich hydrophobic anchoring sites (for solid phase microplastics). In a single reaction system, the polarization defects on the surface of the material not only selectively capture tetracycline and rhodamine B molecules, but also efficiently destroy the inert CC skeleton of polystyrene microplastics; (3) Stable and environmentally friendly materials: The present invention uses SiO2 as the matrix, the material has stable chemical properties, is not easy to dissolve and cause secondary pollution, rare earth elements exist in the form of doping, have good fixation, and have high activity retention rate after recycling, making it an environmentally friendly green material. Attached Figure Description
[0024] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. The drawings in this description are merely embodiments of the present invention.
[0025] Figure 1 The images show the degradation effect of the photocatalytic materials in Examples 1-4 of this invention on polystyrene microplastics. Figure 2 The degradation effects of the photocatalytic materials of Examples 5-7 and Comparative Examples 1-2 on Rhodamine B are shown in the diagram. Figure 3 The graphs show the degradation effects of the photocatalytic materials of Examples 5-7 and Comparative Examples 1-2 on tetracycline hydrochloride. Figure 4 The images show the degradation effects of the photocatalytic materials in Examples 5-7 and Comparative Examples 1-2 on polystyrene microplastics. Detailed Implementation
[0026] Embodiments of the present invention are described below, examples of which are shown in the accompanying drawings. The embodiments described with reference to the drawings are exemplary and intended to explain the present invention, but are not to be construed as limiting the present invention.
[0027] Example 1 This invention provides a method for preparing a photocatalytic material for the simultaneous removal of complex new pollutants from plateau lakes, specifically including the following steps: (1) Weigh 0.349 g of lanthanum nitrate hexahydrate and dissolve it in 15 mL of isopropanol. Stir at 400 r / min for 30 min until completely transparent to obtain solution A; (2) Measure 6 mL of tetraethyl silicate and mix it with 15 mL of isopropanol. Stir at 400 r / min for 15 min, then slowly add 0.6 mL of concentrated nitric acid and 3 mL of deionized water in sequence, and continue stirring for 15 min to obtain solution B; (3) Under stirring at 800 r / min, solution A was slowly added dropwise to solution B, and then 0.1 g of hexadecyltrimethylammonium bromide was added. Stirring was continued for 1 h to form a uniform milky white sol. The sol was transferred to a 100 mL polytetrafluoroethylene-lined high-pressure reactor, sealed, and placed in an oven at 150 °C for 12 h. (4) After the reaction is completed, the product is naturally cooled and centrifuged. It is washed three times with deionized water and anhydrous ethanol respectively. The washed product is dried in a 60℃ forced-air drying oven for 12h. The dried powder is placed in a muffle furnace and heated to 500℃ at 2℃ / min in air atmosphere. It is calcined for 2h and cooled with the furnace to obtain a white powdery 3%La-SiO2 (La to Si molar ratio is 3%) photocatalytic material.
[0028] Example 2 The difference from Example 1 is that 0.349g of lanthanum nitrate hexahydrate was replaced with 0.350g of cerium nitrate hexahydrate. The remaining steps and parameters are the same as in Example 1, and 3% Ce-SiO2 photocatalytic material is obtained.
[0029] Example 3 The difference from Example 1 is that 0.349g of lanthanum nitrate hexahydrate was replaced with 0.329g of yttrium nitrate hexahydrate. The remaining steps and parameters are the same as in Example 1, and 3% Y-SiO2 photocatalytic material is obtained.
[0030] Example 4 The difference from Example 1 is that 0.349g of lanthanum nitrate hexahydrate was replaced with 0.358g of samarium nitrate hexahydrate. The remaining steps and parameters are the same as in Example 1, and 3% Sm-SiO2 photocatalytic material is obtained.
[0031] 50 mg of each of the four photocatalytic materials prepared in Examples 1-4 and 50 mg of polystyrene microplastics were weighed and dissolved in 50 mL of deionized water. The solutions were placed on a magnetic stirrer and stirred for 30 min in the dark until homogeneous. The mixture was then irradiated under a 100 W ultraviolet mercury lamp for 48 h. The resulting solution was filtered, the residue was collected, dried, and weighed. The degradation rate of the polystyrene microplastics in Examples 1-4 was calculated as follows: Figure 1 As shown, by Figure 1 It is known that 3% La-SiO2 has the best degradation effect on polystyrene, reaching 78%.
[0032] Example 5 The difference from Example 1 is that 0.349g of lanthanum nitrate hexahydrate was replaced with 0.582g of lanthanum nitrate hexahydrate. The remaining steps and parameters are the same as in Example 1, and 5% La-SiO2 photocatalytic material is obtained. Example 6 The difference from Example 1 is that 0.349g of lanthanum nitrate hexahydrate was replaced with 1.164g of lanthanum nitrate hexahydrate. The remaining steps and parameters are the same as in Example 1, and 10% La-SiO2 photocatalytic material is obtained.
[0033] Example 7 The difference from Example 1 is that 0.349g of lanthanum nitrate hexahydrate was replaced with 1.745g of lanthanum nitrate hexahydrate. The remaining steps and parameters are the same as in Example 1, and 15% La-SiO2 photocatalytic material is obtained.
[0034] Comparative Example 1 The difference from Example 1 is that lanthanum nitrate hexahydrate is not added, and 15 mL of isopropanol is used directly as solution A. The remaining steps and parameters are the same as in Example 1, and pure SiO2 catalyst material is obtained.
[0035] Comparative Example 2 The difference between this comparative example and Example 6 is that the ultraviolet mercury lamp was not turned on during the degradation experiment, and the entire process was carried out in darkness. The remaining steps and parameters were the same as in Example 1.
[0036] Weigh out 50 mg of each of the five photocatalytic materials prepared in Examples 5-7 and Comparative Examples 1-2, and 50 mg of polystyrene microplastics, respectively, and dissolve them in 50 mL of deionized water. Add rhodamine B and tetracycline hydrochloride, with a concentration of 10 mg / L for rhodamine B and 20 mg / L for tetracycline hydrochloride. Place the mixture on a magnetic stirrer and stir for 30 min in the dark to ensure homogeneity. Then irradiate under a 100 W ultraviolet mercury lamp for 48 hours. Take samples at regular intervals, centrifuge, and measure the absorbance of the supernatant at 553 nm and 357 nm using a UV-Vis spectrophotometer. Calculate the degradation rates of rhodamine B and tetracycline hydrochloride. The results are as follows: Figure 2 and Figure 3 As shown; the solution after the reaction was filtered, the filter residue was collected, dried and weighed, and the degradation rate of polystyrene microplastics was calculated, as shown in the figure. Figure 4 As shown.
[0037] Depend on Figure 2 It can be seen that after 30 minutes of illumination, the degradation rate of Rhodamine B by 10% La-SiO2 reached over 97.8%; Figure 3 It is known that after 60 minutes of illumination, 10% La-SiO2 achieved a degradation rate of over 95% for tetracycline hydrochloride, while pure SiO2 in Comparative Example 1 had almost no degradation effect on tetracycline hydrochloride and rhodamine B; from Figure 4 It can be seen that the microplastics in Example 6 have the highest weight loss rate, reaching 92%, indicating that the photocatalytic material and preparation method for the simultaneous removal of composite new pollutants in plateau lakes provided by the present invention have a good degradation effect on microplastics and are better than the microplastic degradation effects reported in the current literature.
[0038] Comparing the data of Example 6 and Comparative Examples 1-2, it can be seen that the weight loss rate of Comparative Example 1 is much lower than that of Example 6, indicating that the 10% La-SiO2 composite semiconductor material provided by the present invention, as a catalyst for photocatalytic degradation of microplastics, significantly improves the degradation of microplastics. Under no-light conditions, the removal rate of 10% La-SiO2 for the three types of pollutants is less than 10%, while the removal rate under light conditions (92-97.8%) is much higher than that under dark conditions (5.8-9%). This removal mainly comes from the physical adsorption of the material surface. The above results confirm that the removal of microplastics, antibiotics, and dyes by the material of the present invention is a photocatalytic degradation process, rather than a simple adsorption process. The active oxygen species generated by light excitation are the key to achieving pollutant degradation.
[0039] Depend on Figure 2 and Figure 3 It is known that 10% La-SiO2 has the best degradation effect on rhodamine B and tetracycline hydrochloride. The degradation rate of rhodamine B can reach up to 97.8% within 30 minutes, and the degradation rate of tetracycline hydrochloride can reach up to 95% within 60 minutes. That is, the photocatalytic material and preparation method for the simultaneous removal of compound new pollutants in plateau lakes provided by this invention can simultaneously degrade microplastics (polystyrene microplastics), antibiotics (tetracycline hydrochloride) and dyes (rhodamine B) in water with very good results. This invention effectively broadens the photoresponse range of silica by rare earth doping, significantly promoting the separation and migration efficiency of photogenerated electron-hole pairs. This enables the simultaneous and efficient removal of three types of composite pollutants—microplastics, antibiotics, and dyes—from water at room temperature and pressure. The prepared 10% La-SiO2 and other rare earth doped silica materials exhibit superior photocatalytic activity under high-altitude and strong ultraviolet environments, and also possess comprehensive advantages such as low raw material cost, environmental friendliness, and no need for complex recycling after use.
[0040] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.
Claims
1. A photocatalytic material for the simultaneous removal of complex new pollutants from plateau lakes, characterized in that, The photocatalytic material is a composite material of rare earth metal-doped silicon dioxide, wherein the molar ratio of the rare earth metal to silicon is 3-15%. The new composite pollutants include microplastics, antibiotics, and dyes.
2. The photocatalytic material for the simultaneous removal of composite new pollutants in plateau lakes according to claim 1, characterized in that, The rare earth metals include at least one of lanthanum, cerium, yttrium, and samarium.
3. The method for preparing a photocatalytic material for the simultaneous removal of composite new pollutants in plateau lakes according to any one of claims 1-2, characterized in that, Specifically, the following steps are included: (1) After dissolving the rare earth metal salt in isopropanol and mixing it, solution A is obtained; (2) After mixing tetraethyl silicate and isopropanol evenly, add acid solution and deionized water to obtain solution B; (3) After mixing the solution A and the solution B, a template agent is added, and a solvothermal reaction is carried out; (4) The product obtained by the solvothermal reaction is centrifuged, washed, dried and then calcined to obtain a photocatalytic material for the simultaneous removal of composite new pollutants in plateau lakes.
4. The method for preparing a photocatalytic material for the simultaneous removal of composite new pollutants in plateau lakes according to claim 3, characterized in that, The rare earth metal salt mentioned in step (1) is at least one of lanthanum nitrate hexahydrate, cerium nitrate hexahydrate, yttrium nitrate hexahydrate, and samarium nitrate hexahydrate; The mass-to-volume ratio of the rare earth metal salt to isopropanol is 0.3-1.7 g: 10-20 mL.
5. The method for preparing a photocatalytic material for the simultaneous removal of composite new pollutants in plateau lakes according to claim 3, characterized in that, The acid solution mentioned in step (2) is concentrated nitric acid; The volume ratio of tetraethyl silicate, isopropanol, acid solution and deionized water is 5-7:10-20:0.5-1.0:2-4.
6. The method for preparing a photocatalytic material for the simultaneous removal of composite new pollutants in plateau lakes according to claim 3, characterized in that, The template agent mentioned in step (3) is hexadecyltrimethylammonium bromide; The mass-to-volume ratio of the rare earth metal salt, tetraethyl silicate, and template agent is 0.3-1.7 g: 5-7 mL: 0.1 g; The conditions for the solvothermal reaction are: temperature 140-160℃, time 10-14h; The solvothermal reaction needs to be stirred for 0.5-1.5 hours beforehand.
7. The method for preparing a photocatalytic material for the simultaneous removal of composite new pollutants in plateau lakes according to claim 3, characterized in that, The calcination temperature in step (4) is 450-550℃ and the time is 1-3h.
8. The application of the photocatalytic material according to any one of claims 1-2 or the photocatalytic material obtained by the preparation method according to any one of claims 3-7 in the simultaneous removal of water containing complex new pollutants from plateau lakes, characterized in that, The new pollutants in the plateau lakes include microplastics, antibiotics, and dyes.
9. The application according to claim 8, characterized in that, The specific method of using the photocatalytic material is as follows: after adding the photocatalytic material to water containing composite new pollutants from plateau lakes, the reaction can be carried out under ultraviolet irradiation, wherein the amount of the photocatalytic material added is 0.5-1.5 g / L.
10. The application according to claim 8, characterized in that, The photocatalytic material is suitable for purifying lake water in high-altitude areas with strong ultraviolet radiation.