Preparation method of outdoor natural light response heterojunction photocatalytic material wrapped by calcium alginate gel microspheres
By encapsulating Sv-Cu3SnS4/Bi2WO6 heterojunction photocatalytic material with calcium alginate gel microspheres, the practical application problem of photocatalytic materials in the degradation of antibiotics in the natural environment was solved, and efficient and environmentally friendly catalyst recycling and reuse were achieved.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- JIANGSU OCEAN UNIV
- Filing Date
- 2024-05-16
- Publication Date
- 2026-07-31
AI Technical Summary
Existing photocatalytic materials cannot meet the performance requirements of antibiotic degradation under laboratory conditions, and the catalyst powder is difficult to recover, which can easily cause secondary pollution to water bodies.
A heterojunction photocatalytic material of Sv-Cu3SnS4/Bi2WO6 encapsulated in calcium alginate gel microspheres was designed. The porous structure of the calcium alginate gel microspheres facilitates recycling and reuse, and the photocatalytic performance of the heterojunction enables efficient degradation of antibiotics under natural light.
It achieves good antibiotic degradation performance even under cloudy and overcast conditions, the catalyst is easy to recover, avoids secondary pollution of water bodies, and reduces reaction costs.
Smart Images
Figure CN118491569B_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of photocatalytic materials technology, specifically relating to a method for preparing an outdoor natural light responsive heterojunction photocatalytic material encapsulated in calcium alginate gel microspheres. Background Technology
[0002] Tetracycline, a broad-spectrum antibiotic, is commonly used to treat infectious diseases. However, it is unstable and biodegradable, poorly metabolized or absorbed in animals and humans, and easily excreted into the natural environment, posing a significant threat to human survival and the environment. In recent years, photocatalytic degradation of antibiotics has attracted widespread attention. This technology utilizes abundant, green, and low-cost sunlight as energy and semiconductor materials as catalysts. Under light, the catalytic materials generate highly reactive free radicals (hydroxyl radicals, superoxide radicals, holes, etc.), gradually decomposing the antibiotics into smaller molecules, ultimately degrading them into water, carbon dioxide, and other simple inorganic ions. This method of treating antibiotic wastewater is highly efficient, green, low-cost, and operates under mild reaction conditions, making it one of the most effective ways to solve water pollution problems.
[0003] The core of photocatalysis technology lies in the preparation and research of photocatalytic materials. In photocatalytic degradation reactions, the choice of photocatalyst directly determines the performance of the reaction. Among numerous photocatalytic materials, novel bismuth-based semiconductors possess advantages such as high activity, good stability, greenness, and non-toxicity, showing broad application prospects in fields such as solar energy conversion and environmental remediation. These materials have a unique layered structure and a suitable band gap, allowing them to be excited under visible light. Furthermore, they have wide availability of raw materials, simple synthesis processes, and controllable morphology, demonstrating excellent prospects for industrial application and attracting widespread attention and research. Among these, bismuth tungstate (Bi2WO6) exhibits superior performance in photocatalytic degradation processes due to its stable crystal structure, low price, non-toxicity, wide photoresponse range, high electron transport efficiency, and narrow band gap.
[0004] However, the vast majority of photocatalytic degradation tests are currently conducted in laboratories, typically using xenon lamps as the illumination source to simulate sunlight (light power density 450~500 mW / cm²). 2 This study neglects the unstable weather conditions in the natural environment. These experimental conditions differ significantly from actual environments, and current research cannot meet the needs of practical applications. Furthermore, catalyst powder is difficult to recover from water bodies, hindering recycling and reuse, and can easily cause new pollution to water bodies. Summary of the Invention
[0005] Based on the problems existing in the background technology, this application designs and synthesizes an S with good outdoor natural light response. vA Cu3SnS4 / Bi2WO6 heterojunction photocatalyst material was encapsulated within calcium alginate gel microspheres. The catalyst exhibits a three-dimensional porous spherical structure, facilitating recovery and reuse, reducing reaction costs, solving the problem of difficult catalyst powder recovery, and preventing secondary pollution of water bodies.
[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows: An outdoor natural light-responsive heterojunction photocatalytic material encapsulated in calcium alginate gel microspheres is prepared by means of stannous chloride dihydrate SnCl2•2H2O, copper chloride dihydrate CuCl2•2H2O, thiourea, anhydrous ethanol, sodium hydroxide NaOH, bismuth nitrate pentahydrate Bi(NO3)3•5H2O, sodium tungstate dihydrate Na2WO4•2H2O, hexadecyltrimethylammonium bromide CTAB, deionized water, sodium alginate, sodium bicarbonate NaHCO3, sodium dodecyl sulfate, calcium chloride CaCl2, and acetic acid.
[0007] A method for preparing an outdoor natural light-responsive heterojunction photocatalytic material encapsulated in calcium alginate gel microspheres, the method being as follows: Step 1: Weigh a certain amount of SnCl2•2H2O, CuCl2•2H2O, and thiourea and dissolve them in anhydrous ethanol. Stir the solution for 1-3 hours under a magnetic stirrer until the materials are completely dissolved. Transfer the solution to a polytetrafluoroethylene stainless steel high-pressure reactor and heat it at 100-200 °C for 6-20 hours. Step 2: After the reaction vessel has cooled to room temperature, collect the precipitate by centrifugation and wash it 3-5 times with anhydrous ethanol and deionized water respectively. Dry the obtained sample in a vacuum drying oven at 60-100 ℃ for 4-20 h to obtain Cu3SnS4 material. Step 3: Add the obtained Cu3SnS4 material to a NaOH solution of a certain concentration, stir at 40-100 °C for 10-60 min, collect the precipitate by centrifugation, wash with deionized water and anhydrous ethanol 3-5 times respectively, and vacuum dry at 60-120 °C for 6-12 h to obtain sulfur-vacancy-rich S. v -Cu3SnS4 material; Step 4: Weigh out a certain amount of Bi(NO3)3•5H2O, Na2WO4•2H2O, and CTAB, dissolve them in deionized water, stir for 30-120 min until the materials are completely dissolved, and add a certain amount of S. v -Cu3SnS4, ultrasonically stirred for 30-60 min until S v -Cu3SnS4 is evenly dispersed, and the solution is completely transferred to a polytetrafluoroethylene stainless steel high-pressure reactor and heated at 100-200 ℃ for 6-20 h. Step 5: After the reaction vessel has cooled naturally to room temperature, collect the precipitate by filtration and wash it 3-5 times with deionized water and anhydrous ethanol, respectively. Dry the obtained sample in a drying oven at 60-100 °C for 4-20 h to obtain Bi2WO6 / S. v -Cu3SnS4 heterojunction catalyst; Step 6: Weigh a certain amount of Bi2WO6 / S v - The Cu3SnS4 catalyst was ultrasonically dispersed in deionized water, and then a certain amount of sodium alginate was added to the dispersion. The mixture was ultrasonically stirred for 1-12 h to form a uniform mixture. A certain amount of NaHCO3 and sodium dodecyl sulfate were added to the mixture, and stirring was continued until the material was completely dissolved. Step 7: Prepare a certain amount of CaCl2 and acetic acid mixture. Use a syringe to draw up the sodium alginate dispersion containing the catalyst and slowly add it dropwise to the CaCl2 and acetic acid mixture. Let it stand for 5-12 hours. After removing the gel balls, dry them to obtain the heterojunction photocatalytic material encapsulated by calcium alginate gel microspheres.
[0008] Furthermore, in step 1, the mass of SnCl2•2H2O weighed is 10-200 mg, the mass of CuCl2•2H2O is 30-500 mg, the mass of thiourea is 5-300 mg, and the volume of anhydrous ethanol used is 50-100 mL.
[0009] Furthermore, in step 3, the mass of Cu3SnS4 added is 0.5-2.0 g, the concentration of NaOH is 0.5-3 mol / L, and the amount used is 50-500 mL.
[0010] Furthermore, in step 4, the mass of Bi(NO3)3•5H2O weighed is 100-500 mg, the mass of Na2WO4•2H2O weighed is 100-300 mg, the mass of CTAB weighed is 10-200 mg, and the mass of S... v The mass of Cu3SnS4 is 0.1-1.0 g, and the amount of deionized water used is 60-100 mL.
[0011] Furthermore, the Bi2WO6 / S weighed in step 6 v The mass of Cu3SnS4 catalyst is 100-500 mg, the mass of sodium alginate is 0.1-1 g, the mass of NaHCO3 is 0.1-0.5 g, and the mass of sodium dodecyl sulfate is 10-200 mg.
[0012] Furthermore, in step 7, the mass fraction of CaCl2 weighed is 5-20%, the volume fraction of acetic acid is 5-30%, and the volume of the mixture of CaCl2 and acetic acid is 100-500 mL.
[0013] Compared with the prior art, the present invention has the following beneficial effects: Compared to traditional photocatalytic materials, this catalyst is less affected by weather changes and exhibits good antibiotic degradation performance even under cloudy and overcast conditions. Calcium alginate gel spheres serve as a carrier; their porous surface facilitates pollutant adsorption, while their interconnected macroporous structure provides channels for pollutant transport, making it easier for the catalytic material to contact tetracycline. In addition to the physical adsorption of calcium alginate, the photocatalytic material encapsulated within generates highly reactive oxidizing substances such as superoxide radicals and hydroxyl radicals under light irradiation, decomposing tetracycline into carbon dioxide and water, without any loss of the catalytic material itself. Attached Figure Description
[0014] Figure 1 The graph shows the photocatalytic tetracycline degradation performance of a heterojunction catalytic material encapsulated in calcium alginate gel spheres versus a single catalytic material (left) and a light intensity variation curve (right).
[0015] Figure 2 It is doped with different proportions of S v -Cu3SnS4 with Ca-alg / Bi2WO6 / S v The tetracycline degradation performance of the Cu3SnS4 heterojunction catalytic material (left) and the light intensity variation curve (right).
[0016] Figure 3 It is Ca-alg / Bi2WO6 / S v -Tetracycline degradation performance of Cu3SnS4 and commercial P25 catalyst under different weather conditions (left) and light intensity variation curve (right).
[0017] Figure 4 It is Ca-alg / Bi2WO6 / S v -Cu3SnS4 and Bi2WO6 / S v Photograph of Cu3SnS4 catalyst powder. Detailed Implementation
[0018] Through examples and appendices Figure 1-4 The present invention will be further described in conjunction with the following: This invention designs and synthesizes an outdoor natural light-responsive heterojunction photocatalytic material encapsulated in calcium alginate gel microspheres. The material includes stannous chloride dihydrate SnCl2•2H2O, copper chloride dihydrate CuCl2•2H2O, thiourea, anhydrous ethanol, sodium hydroxide NaOH, bismuth nitrate pentahydrate Bi(NO3)3•5H2O, sodium tungstate dihydrate Na2WO4•2H2O, hexadecyltrimethylammonium bromide CTAB, deionized water, sodium alginate, sodium bicarbonate NaHCO3, sodium dodecyl sulfate, calcium chloride CaCl2, and acetic acid.
[0019] Based on the above material composition, a method for preparing an outdoor natural light-responsive heterojunction photocatalytic material encapsulated in calcium alginate gel microspheres is presented. The specific method is as follows: Weigh 10-200 mg of SnCl2•2H2O, 30-500 mg of CuCl2•2H2O, and 5-300 mg of thiourea and dissolve them in 50-100 mL of anhydrous ethanol. Stir the solution with a magnetic stirrer for 1-3 h until the material is completely dissolved. Transfer the solution completely to a polytetrafluoroethylene stainless steel high-pressure reactor and heat it at 100-200 ℃ for 6-20 h. After the reactor cools naturally to room temperature, collect the precipitate by centrifugation and wash it 3-5 times with anhydrous ethanol and deionized water, respectively. Dry the obtained sample in a vacuum drying oven at 60-100 ℃ for 4-20 h to obtain Cu3SnS4 material. Weigh 0.5-2.0 g of Cu3SnS4 material and add it to a 0.5-3 mol / L NaOH solution. Stir at 40-100 °C for 10-60 min. Collect the precipitate by centrifugation and wash it 3-5 times with deionized water and anhydrous ethanol, respectively. Dry it under vacuum at 60-120 °C for 6-12 h to obtain sulfur-vacancy-rich S. v -Cu3SnS4 material. Weigh 100-500 mg of Bi(NO3)3•5H2O, 100-300 mg of Na2WO4•2H2O, and 10-200 mg of CTAB, and dissolve them in 60-100 mL of deionized water. Stir for 30-120 min until the material is completely dissolved, then add 0.1-1.0 g of S. v -Cu3SnS4, ultrasonically stirred for 30-60 min until S v -Cu3SnS4 was evenly dispersed, and the solution was completely transferred to a polytetrafluoroethylene stainless steel high-pressure reactor. The reactor was heated at 100-200 °C for 6-20 h. After the reactor cooled naturally to room temperature, the precipitate was collected by filtration and washed 3-5 times with deionized water and anhydrous ethanol, respectively. The resulting sample was then dried in a drying oven at 60-100 °C for 4-20 h to obtain Bi2WO6 / S. v -Cu3SnS4 heterojunction catalyst. Weigh 100-500 mg of Bi2WO6 / S vThe Cu3SnS4 catalyst was ultrasonically dispersed in deionized water, and then 0.1-1 g of sodium alginate was added to the dispersion. The mixture was ultrasonically stirred for 1-12 h to form a homogeneous mixture. 0.1-0.5 g of NaHCO3 and 10-200 mg of sodium dodecyl sulfate were added to the mixture, and stirring continued until the material was completely dissolved. A mixture of 5-20% CaCl2 (by mass) and 5-30% acetic acid (by volume) was prepared. The sodium alginate dispersion containing the catalyst was slowly added dropwise to the CaCl2 and acetic acid mixture using a syringe. After standing for 5-12 h, the gel spheres were removed and dried to obtain the heterojunction photocatalytic material encapsulated in calcium alginate gel microspheres. Example 1
[0020] Weigh 50 mg of SnCl₂•2H₂O, 80 mg of CuCl₂•2H₂O, and 30 mg of thiourea and dissolve them in 80 mL of anhydrous ethanol. Stir with a magnetic stirrer for 2 h until the materials are completely dissolved. Transfer the solution completely to a polytetrafluoroethylene stainless steel high-pressure reactor and heat at 180 °C for 12 h. After the reactor cools naturally to room temperature, collect the precipitate by centrifugation and wash it three times each with anhydrous ethanol and deionized water. Dry the obtained sample in a vacuum drying oven at 80 °C for 12 h to obtain Cu₃SnS₄ material. Weigh 1.0 g of Cu₃SnS₄ material and add it to a 2 mol / L NaOH solution. Stir at 60 °C for 60 min. Collect the precipitate by centrifugation and wash it five times each with deionized water and anhydrous ethanol. Dry it under vacuum at 60 °C for 8 h to obtain sulfur-vacancy-rich S₂S₄. v -Cu3SnS4 material. Weigh 200 mg of Bi(NO3)3•5H2O, 100 mg of Na2WO4•2H2O, and 50 mg of CTAB and dissolve them in 60 mL of deionized water. Stir for 30-120 min until the material is completely dissolved, then add 0.1 g of S. v -Cu3SnS4, ultrasonically stirred for 30 min until S v The Cu3SnS4 was evenly dispersed, and the solution was completely transferred to a polytetrafluoroethylene stainless steel high-pressure reactor. The reactor was heated at 180℃ for 12 h. After the reactor cooled naturally to room temperature, the precipitate was collected by filtration and washed three times each with deionized water and anhydrous ethanol. The resulting sample was then dried in a drying oven at 60℃ for 8 h to obtain Bi2WO6 / S. v -Cu3SnS4 heterojunction catalyst. Weigh 200 mg of Bi2WO6 / S vThe Cu3SnS4 catalyst was ultrasonically dispersed in deionized water, and then 0.5 g of sodium alginate was added to the dispersion. The mixture was ultrasonically stirred for 12 h to form a homogeneous mixture. 0.2 g of NaHCO3 and 50 mg of sodium dodecyl sulfate were added to the mixture, and stirring continued until the material was completely dissolved. A mixture of 20% CaCl2 (by mass) and 10% acetic acid (by volume) was prepared. The sodium alginate dispersion containing the catalyst was slowly added dropwise to the CaCl2 and acetic acid mixture using a syringe. After standing for 10 h, the gel spheres were removed and dried to obtain the heterojunction photocatalytic material (Ca-alg / Bi2WO6 / 0.1S) encapsulated in calcium alginate gel microspheres. v -Cu3SnS4). Example 2
[0021] Weigh 150 mg of SnCl₂•2H₂O, 100 mg of CuCl₂•2H₂O, and 250 mg of thiourea and dissolve them in 80 mL of anhydrous ethanol. Stir with a magnetic stirrer for 2 h until the materials are completely dissolved. Transfer the solution completely to a polytetrafluoroethylene stainless steel high-pressure reactor and heat at 180 °C for 10 h. After the reactor cools naturally to room temperature, collect the precipitate by centrifugation and wash it three times with anhydrous ethanol and deionized water, respectively. Dry the obtained sample in a vacuum drying oven at 60 °C for 8 h to obtain Cu₃SnS₄ material. Weigh 1.5 g of Cu₃SnS₄ material and add it to a 1.0 mol / L NaOH solution. Stir at 60 °C for 30 min. Collect the precipitate by centrifugation and wash it three times with deionized water and anhydrous ethanol, respectively. Dry it under vacuum at 80 °C for 10 h to obtain sulfur-vacancy-rich S₂S₄. v -Cu3SnS4 material. Weigh 300 mg of Bi(NO3)3•5H2O, 100 mg of Na2WO4•2H2O, and 100 mg of CTAB and dissolve them in 100 mL of deionized water. Stir for 60 min until the material is completely dissolved, then add 0.3 g of S. v -Cu3SnS4, ultrasonically stirred for 60 min until S v The Cu3SnS4 was evenly dispersed, and the solution was completely transferred to a polytetrafluoroethylene stainless steel high-pressure reactor and heated at 150 °C for 10 h. After the reactor cooled naturally to room temperature, the precipitate was collected by filtration and washed five times each with deionized water and anhydrous ethanol. The resulting sample was then dried in a drying oven at 80 °C for 10 h to obtain Bi2WO6 / S. v -Cu3SnS4 heterojunction catalyst. Weigh 500 mg of Bi2WO6 / S vThe Cu3SnS4 catalyst was ultrasonically dispersed in deionized water, and then 0.8 g of sodium alginate was added to the dispersion. The mixture was ultrasonically stirred for 6 h to form a homogeneous mixture. 0.3 g of NaHCO3 and 80 mg of sodium dodecyl sulfate were added to the mixture, and stirring continued until the material was completely dissolved. A mixture of 5% (w / w) CaCl2 and 20% (v / v) acetic acid was prepared. The sodium alginate dispersion containing the catalyst was slowly added dropwise to the CaCl2 and acetic acid mixture using a syringe. After standing for 5 h, the gel spheres were removed and dried to obtain the heterojunction photocatalytic material (Ca-alg / Bi2WO6 / 0.3S4) encapsulated in calcium alginate gel microspheres. v -Cu3SnS4). Example 3
[0022] Weigh 80 mg of SnCl₂•2H₂O, 350 mg of CuCl₂•2H₂O, and 200 mg of thiourea and dissolve them in 80 mL of anhydrous ethanol. Stir the solution for 3 h with a magnetic stirrer until the materials are completely dissolved. Transfer the solution to a polytetrafluoroethylene stainless steel high-pressure reactor and heat at 120 °C for 8 h. After the reactor cools to room temperature, collect the precipitate by centrifugation and wash it five times each with anhydrous ethanol and deionized water. Dry the resulting sample in a vacuum drying oven at 100 °C for 20 h to obtain Cu₃SnS₄ material. Weigh 1.5 g of Cu₃SnS₄ material and add it to a 3 mol / L NaOH solution. Stir at 60 °C for 30 min. Collect the precipitate by centrifugation and wash it five times each with deionized water and anhydrous ethanol. Dry the sample in a vacuum oven at 100 °C for 8 h to obtain sulfur-vacancy-rich S₂S₄. v -Cu3SnS4 material. Weigh 500 mg of Bi(NO3)3•5H2O, 250 mg of Na2WO4•2H2O, and 150 mg of CTAB and dissolve them in 100 mL of deionized water. Stir for 60 min until the material is completely dissolved, then add 0.5 g of S. v -Cu3SnS4, ultrasonically stirred for 60 min until S v -Cu3SnS4 was evenly dispersed, and the solution was completely transferred to a polytetrafluoroethylene stainless steel high-pressure reactor and heated at 150 °C for 10 h. After the reactor cooled naturally to room temperature, the precipitate was collected by filtration and washed five times each with deionized water and anhydrous ethanol. The resulting sample was then dried in a drying oven at 80 °C for 12 h to obtain Bi2WO6 / S. v -Cu3SnS4 heterojunction catalyst. Weigh 100 mg of Bi2WO6 / S vThe Cu3SnS4 catalyst was ultrasonically dispersed in deionized water, and then 0.6 g of sodium alginate was added to the dispersion. The mixture was ultrasonically stirred for 8 h to form a homogeneous mixture. 0.5 g of NaHCO3 and 150 mg of sodium dodecyl sulfate were added to the mixture, and stirring continued until the material was completely dissolved. A mixture of 15% CaCl2 (by mass) and 20% acetic acid (by volume) was prepared. The sodium alginate dispersion containing the catalyst was slowly added dropwise to the CaCl2 and acetic acid mixture using a syringe. After standing for 10 h, the gel spheres were removed and dried to obtain the heterojunction photocatalytic material (Ca-alg / Bi2WO6 / 0.5S4) encapsulated in calcium alginate gel microspheres. v -Cu3SnS4). Example 4
[0023] Weigh 100 mg of SnCl₂•2H₂O, 360 mg of CuCl₂•2H₂O, and 280 mg of thiourea and dissolve them in 100 mL of anhydrous ethanol. Stir with a magnetic stirrer for 2 h until the materials are completely dissolved. Transfer the solution completely to a polytetrafluoroethylene stainless steel high-pressure reactor and heat at 180 °C for 6 h. After the reactor cools naturally to room temperature, collect the precipitate by centrifugation and wash it three times each with anhydrous ethanol and deionized water. Dry the obtained sample in a vacuum drying oven at 80 °C for 15 h to obtain Cu₃SnS₄ material. Weigh 2.0 g of Cu₃SnS₄ material and add it to a 1.5 mol / L NaOH solution. Stir at 60 °C for 60 min. Collect the precipitate by centrifugation and wash it five times each with deionized water and anhydrous ethanol. Dry it under vacuum at 100 °C for 8 h to obtain sulfur-vacancy-rich S₂S₄. v -Cu3SnS4 material. Weigh 300 mg of Bi(NO3)3•5H2O, 100 mg of Na2WO4•2H2O, and 50 mg of CTAB and dissolve them in 80 mL of deionized water. Stir for 60 min until the material is completely dissolved, then add 1.0 g of S. v -Cu3SnS4, ultrasonically stirred for 50 min until S v The Cu3SnS4 was evenly dispersed, and the solution was completely transferred to a polytetrafluoroethylene stainless steel high-pressure reactor and heated at 200 °C for 8 h. After the reactor cooled naturally to room temperature, the precipitate was collected by filtration and washed five times each with deionized water and anhydrous ethanol. The resulting sample was then dried in a drying oven at 80 °C for 20 h to obtain Bi2WO6 / S. v -Cu3SnS4 heterojunction catalyst. Weigh 500 mg of Bi2WO6 / S vThe Cu3SnS4 catalyst was ultrasonically dispersed in deionized water, and then 1 g of sodium alginate was added to the dispersion. The mixture was ultrasonically stirred for 12 h to form a homogeneous mixture. 0.3 g of NaHCO3 and 150 mg of sodium dodecyl sulfate were added to the mixture, and stirring continued until the material was completely dissolved. A mixture of 20% CaCl2 (by mass) and 25% acetic acid (by volume) was prepared. The sodium alginate dispersion containing the catalyst was slowly added dropwise to the CaCl2 and acetic acid mixture using a syringe. After standing for 10 h, the gel spheres were removed and dried to obtain the heterojunction photocatalytic material (Ca-alg / Bi2WO6 / 1.0S) encapsulated in calcium alginate gel microspheres. v -Cu3SnS4).
[0024] Comparative Example 1: 200 mg of SnCl₂•2H₂O, 400 mg of CuCl₂•2H₂O, and 250 mg of thiourea were dissolved in 80 mL of anhydrous ethanol. The mixture was stirred with a magnetic stirrer for 2 h until the materials were completely dissolved. The solution was then completely transferred to a polytetrafluoroethylene stainless steel high-pressure reactor and heated at 150 °C for 6 h. After the reactor cooled naturally to room temperature, the precipitate was collected by centrifugation and washed three times each with anhydrous ethanol and deionized water. The resulting sample was dried in a vacuum drying oven at 80 °C for 12 h to obtain Cu₃SnS₄ material. 1.5 g of Cu₃SnS₄ material was added to a 2 mol / L NaOH solution and stirred at 60 °C for 60 min. The precipitate was collected by centrifugation and washed five times each with deionized water and anhydrous ethanol. The sample was then vacuum dried at 80 °C for 8 h to obtain sulfur-vacancy-rich S₂S₄. v -Cu3SnS4 material. Weigh 300 mg of S. v The Cu3SnS4 catalyst was ultrasonically dispersed in deionized water, and then 0.5 g of sodium alginate was added to the dispersion. The mixture was ultrasonically stirred for 12 h to form a homogeneous mixture. 0.3 g of NaHCO3 and 100 mg of sodium dodecyl sulfate were added to the mixture, and stirring continued until the material was completely dissolved. A mixture of 15% CaCl2 (by mass) and 20% acetic acid (by volume) was prepared. The sodium alginate dispersion containing the catalyst was slowly added dropwise to the CaCl2 and acetic acid mixture using a syringe. After standing for 10 h, the gel spheres were removed and dried to obtain the heterojunction photocatalytic material (Ca-alg / S) encapsulated in calcium alginate gel microspheres. v -Cu3SnS4).
[0025] Comparative Example 2: 150 mg of Bi(NO3)3•5H2O, 80 mg of Na2WO4•2H2O, and 80 mg of CTAB were weighed and dissolved in 100 mL of deionized water. The solution was stirred for 60 min until completely dissolved. The solution was completely transferred to a polytetrafluoroethylene stainless steel high-pressure reactor and heated at 150 °C for 8 h. After the reactor cooled naturally to room temperature, the precipitate was collected by filtration and washed five times each with deionized water and anhydrous ethanol. The resulting sample was dried in a drying oven at 80 °C for 12 h to obtain Bi2WO6 powder catalyst. 300 mg of Bi2WO6 catalyst was ultrasonically dispersed in deionized water. Then, 0.5 g of sodium alginate was added to the dispersion, and the mixture was ultrasonically stirred for 12 h to form a homogeneous mixture. 0.5 g of NaHCO3 and 200 mg of sodium dodecyl sulfate were added to the mixture, and stirring was continued until the materials were completely dissolved. Prepare a mixture of 20% CaCl2 by mass and 25% acetic acid by volume. Use a syringe to draw up a sodium alginate dispersion containing the catalyst and slowly add it dropwise to the mixture of CaCl2 and acetic acid. Let it stand for 10 h, remove the gel balls and dry them to obtain the Bi2WO6 photocatalytic material (Ca-alg / Bi2WO6) encapsulated in calcium alginate gel microspheres.
[0026] Comparative Example 3: 300 mg of P25 catalyst was ultrasonically dispersed in deionized water. Then, 0.8 g of sodium alginate was added to the dispersion, and the mixture was ultrasonically stirred for 12 h to form a homogeneous mixture. 0.5 g of NaHCO3 and 120 mg of sodium dodecyl sulfate were added to the mixture, and stirring continued until the material was completely dissolved. A mixture of 10% CaCl2 (by mass) and 20% acetic acid (by volume) was prepared. The sodium alginate dispersion containing the catalyst was slowly added dropwise to the CaCl2 and acetic acid mixture using a syringe. After standing for 10 h, the gel spheres were removed and dried to obtain the heterojunction photocatalytic material (Ca-alg / P25) encapsulated in calcium alginate gel microspheres.
[0027] Comparative Example 4: 200 mg of SnCl₂•2H₂O, 360 mg of CuCl₂•2H₂O, and 250 mg of thiourea were dissolved in 100 mL of anhydrous ethanol. The solution was stirred for 2 h with a magnetic stirrer until completely dissolved. The solution was then transferred to a polytetrafluoroethylene stainless steel high-pressure reactor and heated at 150 °C for 6 h. After the reactor cooled to room temperature, the precipitate was collected by centrifugation and washed three times each with anhydrous ethanol and deionized water. The resulting sample was dried in a vacuum drying oven at 80 °C for 12 h to obtain Cu₃SnS₄ material. 1.0 g of Cu₃SnS₄ material was added to a 1.5 mol / L NaOH solution and stirred at 60 °C for 60 min. The precipitate was collected by centrifugation and washed five times each with deionized water and anhydrous ethanol. The sample was then vacuum dried at 80 °C for 8 h to obtain sulfur-vacancy-rich S₂S₄. v -Cu3SnS4 material. Weigh 300 mg of Bi(NO3)3•5H2O, 200 mg of Na2WO4•2H2O, and 100 mg of CTAB and dissolve them in 100 mL of deionized water. Stir for 60 min until the material is completely dissolved, then add 0.5 g of S. v -Cu3SnS4, ultrasonically stirred for 50 min until S v The Cu3SnS4 was evenly dispersed, and the solution was completely transferred to a polytetrafluoroethylene stainless steel high-pressure reactor and heated at 200 °C for 8 h. After the reactor cooled naturally to room temperature, the precipitate was collected by vacuum filtration and washed five times each with deionized water and anhydrous ethanol. The resulting sample was then dried in a drying oven at 80 °C for 20 h to obtain Bi2WO6 / 0.5S. v -Cu3SnS4 heterojunction catalyst powder.
[0028] In Examples 1-4, the outdoor natural light-responsive recyclable photocatalytic material obtained by the technical solution of the present invention is calcium alginate gel microspheres, Bi2WO6 / S. v The synergistic effect of the Cu3SnS4 heterojunction catalyst is analyzed in detail below: Figure 1 (Left) This image shows the photocatalytic tetracycline degradation performance of a heterojunction catalytic material encapsulated in calcium alginate gel spheres compared to a single catalytic material. The image shows the difference in Ca-alg / S content between the single component obtained using the methods and components of Comparative Examples 1 and 2. v The tetracycline degradation performance of Cu3SnS4 and Ca-alg / Bi2WO6 catalytic materials was low, with degradation efficiencies of 31.81% and 23.46% respectively after 150 min of reaction under outdoor natural light conditions. In contrast, the Ca-alg / Bi2WO6 / 0.5Ca-alg / S catalyst obtained in Example 3... vThe catalytic performance of the Cu3SnS4 heterojunction material was significantly improved. After 150 min of illumination under the same lighting conditions, the decomposition efficiency of tetracycline reached 47.46%, indicating that the construction of the heterojunction can reduce the recombination efficiency of photogenerated electrons and holes in the catalytic material, thereby accelerating the carrier transport efficiency and improving photocatalytic performance. The changes in light intensity throughout the testing process are as follows: Figure 1 As shown on the right.
[0029] Figure 2 (Left) shows S doping in different proportions v -Cu3SnS4 with Ca-alg / Bi2WO6 / S v The graph shows the tetracycline degradation performance of the Cu3SnS4 heterojunction catalytic material. As can be seen from the graph, the Ca-alg / Bi2WO6 / S obtained using the methods and components in Examples 1-4... v The degradation efficiency of tetracycline by Cu3SnS4 increases with the concentration of S. v The doping concentration of Cu3SnS4 initially increases and then decreases with increasing concentration. After reacting for 150 min under natural outdoor light, the Ca-alg / Bi2WO6 / 0.1S... v -Cu3SnS4、Ca-alg / Bi2WO6 / 0.3S v -Cu3SnS4、Ca-alg / Bi2WO6 / 0.5S v -Cu3SnS4, Ca-alg / Bi2WO6 / 1.0S v The tetracycline degradation efficiencies of Cu3SnS4 were 57.11%, 61.57%, 65.45%, and 46.35%, respectively. The Ca-alg / Bi2WO6 / 0.5S obtained using the method and components of Example 3... v -Cu3SnS4 exhibited the highest photocatalytic performance, therefore this sample was chosen for performance comparison with the commercially available P25 catalyst. The light intensity changes throughout the testing process are as follows: Figure 2 As shown on the right.
[0030] Figure 3 (Left) is Ca-alg / Bi2WO6 / S v -Graph showing the tetracycline degradation performance of Cu3SnS4 and commercial P25 catalyst under different weather conditions. As can be seen from the graph, the commercial P25 catalyst Ca-alg / P25 encapsulated with calcium alginate obtained in Comparative Example 3 exhibits poor tetracycline degradation performance under outdoor sunny and cloudy weather conditions, with degradation efficiencies of only 17.63% and 12.35% after 150 min of illumination, respectively. In contrast, the Ca-alg / Bi2WO6 / 0.5S catalyst obtained using the method and components of Example 3 shows significantly better performance. v-Cu3SnS4 significantly improved catalytic performance, with tetracycline degradation efficiencies of 57.61% and 46.35% after 150 min of illumination, respectively, demonstrating the effectiveness of the Bi2WO6 / 0.5S4 synthesized in this column. v The Cu3SnS4 heterojunction catalytic material exhibits excellent tetracycline degradation performance under outdoor natural light conditions, regardless of whether it is sunny or cloudy. The changes in light intensity during the entire testing process under sunny and cloudy conditions are shown below. Figure 3 As shown on the right.
[0031] Figure 4 Ca-alg / Bi2WO6 / S v -Cu3SnS4 and Bi2WO6 / S v A comparison of photographs of Cu3SnS4 catalyst powder. The images show the catalyst encapsulated within calcium alginate gel microspheres, forming a three-dimensional porous spherical structure that facilitates recovery and reuse, reduces reaction costs, solves the problem of difficult catalyst powder recovery, and avoids secondary pollution of water bodies. The calcium alginate gel spheres serve as a carrier; their porous surface facilitates pollutant adsorption, while their interconnected macroporous structure provides channels for pollutant transport, making it easier for the catalytic material to contact tetracycline. In addition to the physical adsorption by calcium alginate, the photocatalytic material encapsulated within generates highly oxidizing active substances such as superoxide radicals and hydroxyl radicals under light irradiation, decomposing tetracycline into carbon dioxide and water, without any loss of the catalytic material itself.
[0032] Based on the above examples and comparative analyses, it is clear that most current photocatalytic degradation tests are conducted in laboratories, ignoring unstable weather conditions in the natural environment. These experimental conditions differ significantly from real-world conditions, and current research cannot meet the needs of practical applications. Furthermore, catalyst powder is difficult to recover from water bodies, hindering recycling and reuse, and easily causing new pollution to water bodies. This patent designs and synthesizes S... v The Cu3SnS4 / Bi2WO6 heterojunction photocatalyst exhibits excellent outdoor natural light response performance, demonstrating good tetracycline degradation performance under both sunny and cloudy conditions. Furthermore, the catalyst is encapsulated in calcium alginate gel microspheres. The catalyst's overall three-dimensional porous spherical structure facilitates recovery and reuse, reduces reaction costs, solves the problem of difficult catalyst powder recovery, and avoids secondary pollution of water bodies.
[0033] The above description is merely a specific embodiment of the present invention, but the scope of protection of the invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the invention.
Claims
1. A method for preparing an outdoor natural light-responsive heterojunction photocatalytic material encapsulated in calcium alginate gel microspheres, characterized in that: The material was prepared by reacting stannous chloride dihydrate (SnCl2•2H2O), copper chloride dihydrate (CuCl2•2H2O), thiourea, anhydrous ethanol, sodium hydroxide (NaOH), bismuth nitrate pentahydrate (Bi(NO3)3•5H2O), sodium tungstate dihydrate (Na2WO4•2H2O), hexadecyltrimethylammonium bromide (CTAB), deionized water, sodium alginate, sodium bicarbonate (NaHCO3), sodium dodecyl sulfate, calcium chloride (CaCl2), and acetic acid. The preparation method is as follows: Step 1: Weigh a certain amount of SnCl2•2H2O, CuCl2•2H2O, and thiourea and dissolve them in anhydrous ethanol. Stir the solution for 1-3 hours under a magnetic stirrer until the materials are completely dissolved. Transfer the solution to a polytetrafluoroethylene stainless steel high-pressure reactor and heat it at 100-200 °C for 6-20 hours. Step 2: After the reaction vessel has cooled to room temperature, collect the precipitate by centrifugation and wash it 3-5 times with anhydrous ethanol and deionized water respectively. Dry the obtained sample in a vacuum drying oven at 60-100 ℃ for 4-20 h to obtain Cu3SnS4 material. Step 3: Add the obtained Cu3SnS4 material to a NaOH solution of a certain concentration, stir at 40-100 °C for 10-60 min, collect the precipitate by centrifugation, wash with deionized water and anhydrous ethanol 3-5 times respectively, and vacuum dry at 60-120 °C for 6-12 h to obtain sulfur-vacancy-rich S. v -Cu3SnS4 material; Step 4: Weigh out a certain amount of Bi(NO3)3•5H2O, Na2WO4•2H2O, and CTAB, dissolve them in deionized water, stir for 30-120 minutes until the materials are completely dissolved, and add a certain amount of S. v -Cu3SnS4, ultrasonically stirred for 30-60 min until S v -Cu3SnS4 is evenly dispersed, and the solution is completely transferred to a polytetrafluoroethylene stainless steel high-pressure reactor and heated at 100-200 ℃ for 6-20 h. Step 5: After the reaction vessel has cooled naturally to room temperature, collect the precipitate by filtration and wash it 3-5 times with deionized water and anhydrous ethanol, respectively. Dry the obtained sample in a drying oven at 60-100 °C for 4-20 h to obtain Bi2WO6 / S. v -Cu3SnS4 heterojunction catalyst; Step 6: Weigh a certain amount of Bi2WO6 / S v - The Cu3SnS4 catalyst was ultrasonically dispersed in deionized water, and then a certain amount of sodium alginate was added to the dispersion. The mixture was ultrasonically stirred for 1-12 h to form a uniform mixture. A certain amount of NaHCO3 and sodium dodecyl sulfate were added to the mixture, and stirring was continued until the material was completely dissolved. Step 7: Prepare a certain amount of CaCl2 and acetic acid mixture. Use a syringe to draw up the sodium alginate dispersion containing the catalyst and slowly add it dropwise to the CaCl2 and acetic acid mixture. Let it stand for 5-12 hours. After removing the gel balls, dry them to obtain the heterojunction photocatalytic material encapsulated by calcium alginate gel microspheres.
2. The method of claim 1, wherein: In step 1, the mass of SnCl2•2H2O weighed is 10-200 mg, the mass of CuCl2•2H2O is 30-500 mg, the mass of thiourea is 5-300 mg, and the volume of anhydrous ethanol used is 50-100 mL.
3. The method of claim 1, wherein: In step 3, the mass of Cu3SnS4 added is 0.5-2.0 g, the concentration of NaOH is 0.5-3 mol / L, and the amount used is 50-500 mL.
4. The method of claim 1, wherein: In step 4, the weighed amounts of Bi(NO3)3•5H2O are 100-500 mg, Na2WO4•2H2O are 100-300 mg, CTAB is 10-200 mg, and S... v The mass of Cu3SnS4 is 0.1-1.0 g, and the amount of deionized water used is 60-100 mL.
5. The method of claim 1, wherein: Bi2WO6 / S v The mass of the Cu3SnS4 catalyst was 100-500 mg, the mass of the sodium alginate was 0.1-1 g, the mass of the NaHCO3 was 0.1-0.5 g, and the mass of the sodium dodecyl sulfate was 10-200 mg.
6. The method of claim 1, wherein: In step 7, the mass fraction of CaCl2 weighed is 5-20%, the volume fraction of acetic acid is 5-30%, and the volume of the mixture of CaCl2 and acetic acid is 100-500 mL.