Photocatalytic material and preparation method and application of gel of photocatalytic material
By preparing O,Sg-C3N4/Bi2O3/TiO2 photocatalytic materials and combining them with gels, the problems of low photocatalytic efficiency and secondary pollution were solved, achieving efficient purification of aquaculture wastewater, reducing costs and promoting resource utilization.
Patent Information
- Application Number
- CN202511250019.6
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-09-03
- Publication Date
- 2025-12-09
AI Technical Summary
Existing photocatalysts are inefficient, costly to prepare, cannot be used stably and continuously in fluid environments, and are prone to secondary pollution, making them difficult to effectively purify aquaculture wastewater.
Using trithiocyanate, oxalic acid, Bi2O3 and TiO2 as raw materials, O, Sg-C3N4/Bi2O3/TiO2 photocatalytic materials were prepared by calcination and combined with a gel matrix to form a porous photocatalytic gel. The photocatalytic degradation of organic pollutants was carried out, and the degradation products were absorbed and utilized by aquatic plants.
It achieves efficient degradation of organic pollutants, improves purification efficiency, reduces secondary pollution, is easy to recycle and reuse, reduces preparation costs, and has industrialization potential.
Smart Images
Figure CN121082306A_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The application relates to a preparation method and application of a photocatalytic material and a gel thereof, and belongs to the technical field of photocatalysis. BACKGROUND
[0002] Aquaculture tail water purification is an important link to ensure water quality and healthy growth of fish. At present, the commonly used treatment method is to improve the physical and chemical factors of the water body by regularly replacing the water, but this method not only pollutes the natural water body due to tail water discharge, but also causes a large amount of water resource waste. Therefore, carrying out purification and recycling of the tail water has become the key to promoting the sustainable development of the aquaculture industry.
[0003] The existing tail water purification methods include: physical treatment technology, which can quickly remove suspended substances in water and part of substances consuming dissolved oxygen in water, has a significant effect on the removal of large particles and suspended substances, and has a low treatment cost. However, the adsorption effect on soluble organic matter and inorganic matter is poor, and the removal effect on nitrogen, phosphorus and other nutrients in the water body is very small. Chemical treatment technology, which can effectively remove heavy metal substances and harmful microorganisms in the water body, has a good killing effect on algae spores; but at the same time, it will kill beneficial microorganisms in the water body and induce pathogenic bacteria and algae spores to produce drug resistance. Long-term use of chemical agents as the main means to improve water quality may be harmful to human health. Biological treatment technology, which can decompose pollutants in the water body, has the effect of inhibiting the growth of pathogenic bacteria, and has the functions of improving water quality and reducing sediment. However, the biological species are relatively single, the application range is small, the technical standards are not unified, and there may be secondary pollution problems, which need to be further improved. SUMMARY
[0004] The application aims to overcome the deficiencies in the prior art, provide a preparation method and application of a photocatalytic material and a gel thereof, and solve the technical problems of low efficiency of the photocatalyst, high preparation cost, and inability to be used stably and continuously in a fluid environment, difficulty in recycling, and easy secondary pollution of water sources.
[0005] To achieve the above-mentioned purpose, the technical solution adopted by the application is: In a first aspect, the application provides a preparation method of a photocatalytic material, comprising: mixing trithiocyanic acid, oxalic acid, Bi2O3 and TiO2 according to a preset mass ratio; calcining the mixed raw materials; cooling the calcined product to obtain an O, S-g-C3N4 / Bi2O3 / TiO2 photocatalytic material.
[0006] In combination with the first aspect, further, the preset mass ratio of the thiocyanic acid, the oxalic acid, the Bi2O3 and the TiO2 is (15-25):(6-10):(1-2):(1-2).
[0007] Further, the preset mass ratio of the thiocyanic acid, the oxalic acid, the Bi2O3 and the TiO2 is 20:8:1:1.
[0008] Further, the temperature of the calcination is at least 550℃, the calcination time is at least 120min, and the temperature rising rate to reach the calcination temperature is 5℃ / min.
[0009] The second aspect provides a photocatalytic material prepared according to any one of the above-mentioned photocatalytic material preparation methods.
[0010] The third aspect provides a photocatalytic gel preparation method, comprising: The O, S-g-C3N4 / Bi2O3 / TiO2 photocatalytic material prepared according to any one of the above-mentioned photocatalytic material preparation methods is dispersed in water, a gel matrix is added, and stirring, aging, freezing, freeze-drying and cross-linking treatment are performed to obtain the O, S-g-C3N4 / Bi2O3 / TiO2 photocatalytic gel.
[0011] In combination with the third aspect, further, the gel matrix comprises sodium carboxymethyl cellulose, alpha-cellulose and polyacrylic acid; and the mass ratio of the photocatalytic material, the sodium carboxymethyl cellulose, the alpha-cellulose and the polyacrylic acid is 1:(2-3):(2-3):(0.5-1.5).
[0012] Further, the temperature of the vacuum freeze-drying is-45℃ to-35℃, and the time is 12 hours; and the temperature of the cross-linking treatment is 80℃-120℃, and the time is 4-8 hours.
[0013] The fourth aspect provides a photocatalytic gel prepared according to any one of the above-mentioned photocatalytic gel preparation methods.
[0014] The fifth aspect provides an application of the photocatalytic material or the photocatalytic gel, which comprises sewage treatment, water purification or photocatalytic degradation of organic matter, and the organic pollutants comprise organic dyes and / or antibiotics.
[0015] Compared with the prior art, the application has the following beneficial effects: The thiocyanic acid and the oxalic acid, which are low-cost and easy to obtain, are used as raw materials, the synthesis of g-C3N4 and O, S co-doping are simultaneously realized by one-step calcination, the process flow is simple and stable in repeatability, and no complex equipment and expensive reagents are needed, so that the industrial large-scale preparation potential is achieved. The O, S-g-C3N4、 The composite of Bi2O3 and TiO2 builds a multi-component heterojunction, which not only widens the absorption range of the photocatalytic material to visible light, but also promotes the effective separation of the photo-generated electron-hole pairs; and then promotes the catalyst to generate more active oxygen species under light, so as to realize the efficient degradation of organic pollutants and improve the removal efficiency.
[0016] The photocatalytic material is combined with a gel matrix, and a porous photocatalytic gel is prepared through freeze-drying and process cross-linking treatment. The porous structure can provide attachment points for the root system of aquatic plants and create a microenvironment for microbial growth. At the same time, the small-molecule organic matter, carbon dioxide, inorganic nitrogen and inorganic phosphorus generated by photocatalytic degradation can be directly absorbed and utilized by aquatic plants as nutrient sources, realizing the combination of purification and resource utilization. In addition, the prepared photocatalytic gel has excellent mechanical strength and structural stability, is easy to separate and recover from water, and effectively avoids the loss of the catalyst and the secondary pollution to the water body.
[0017] The gel matrix has excellent adsorption performance, which can first quickly enrich the pollutants in water on its surface and in its pores, increase the concentration of pollutants near the catalyst, accelerate the subsequent photocatalytic degradation reaction process, and realize the synergistic effect of "adsorption-photocatalysis". BRIEF DESCRIPTION OF DRAWINGS
[0018] Figure 1 is a flowchart of a photocatalytic material preparation method provided by the embodiments of the present application; Figure 2 is a flowchart of a photocatalytic gel preparation method provided by the embodiments of the present application; Figure 3 is a structural schematic diagram of a device provided by the embodiments of the present application; Figure 4 is a front view of a device provided by the embodiments of the present application; Figure 5 is a top view of a device provided by the embodiments of the present application; Figure 6 is a left side view of a device provided by the embodiments of the present application; Figure 7 is a right side view of a device provided by the embodiments of the present application; Figure 8 is a front view of a photocatalytic gel provided by the embodiments of the present application; Figure 9 is a side view of a photocatalytic gel provided by the embodiments of the present application; Figure 10 is a methylene blue absorbance curve provided by the embodiments of the present application; Figure 11 is an ultraviolet-visible spectrogram of a photocatalytic gel after degrading methylene blue provided by the embodiments of the present application; Figure 12 A methylene blue degradation effect diagram provided for the embodiment of the present application; Figure 13 A methylene blue degradation physical diagram provided for the embodiment of the present application; Figure 14 A terramycin degradation effect diagram of the photocatalytic gel provided for the embodiment of the present application; Figure 15 COD, total nitrogen and total phosphorus effect diagrams of the photocatalytic gel in degrading simulated aquaculture tail water provided for the embodiment of the present application; Figure 16 A SEM diagram of the photocatalytic gel provided for the embodiment of the present application; Figure 17 A mapping diagram of the photocatalytic gel provided for the embodiment of the present application; Figure 18 A mechanism schematic diagram of the photocatalytic gel provided for the embodiment of the present application; The figure mark: 1, support, 2, water inlet pipe, 3, base support, 4, water outlet pipe, 5, light source, 6, reaction tank, 7, fixed grid, 8, photocatalytic gel layer, 9, aquatic plant layer. DETAILED DESCRIPTION
[0019] The present application will be further described below in conjunction with the drawings. The following examples are only used to more clearly illustrate the technical solutions of the present application, and cannot be used to limit the protection scope of the present application.
[0020] Example 1:
[0021] As shown in the figure, a photocatalytic material preparation method provided for the embodiment, comprising the following steps: Figure 1 Step 1: Put thiocyanic acid, oxalic acid, Bi2O3 and TiO2 into a container, stir and mix them evenly; Step 2: Put the materials mixed evenly in the above step into a furnace and calcine; Step 3: After calcination, cool down and collect O, S-g-C3N4 / Bi2O3 / TiO2 photocatalytic material. Among them, the mass ratio of thiocyanic acid, oxalic acid, Bi2O3 and TiO2 in step 1 above is (15-25):(6-10):(1-2):(1-2), and the preferred mass ratio is 20:8:1:1.
[0022] Among them, the container is a 150 mL alumina crucible with a cover.
[0023]
[0024] The step 2 includes the following steps: placing the mixed material in step 1 into a muffle furnace, calcining at 550 DEG C for 120 min, and the heating rate is 5 DEG C / min.
[0025] According to the above method for preparing the photocatalytic material, a first specific implementation process is provided, which includes the following steps: The 20 g of thiocyanic acid, 8 g of oxalic acid, 1 g of Bi2O3 and 1 g of TiO2 are weighed and placed into a 150 mL alumina crucible with a cover, and stirred for 10 min to mix them evenly. The mixed material in the above step is placed into a muffle furnace, calcined at 550 DEG C for 120 min, and the heating rate is 5 DEG C / min. After the calcination is completed, the temperature is lowered, and the O, S-g-C3N4 / Bi2O3 / TiO2 photocatalytic material is collected.
[0026] A second specific implementation process is provided, which includes the following steps: The 25 g of thiocyanic acid, 10 g of oxalic acid, 2 g of Bi2O3 and 2 g of TiO2 are weighed and placed into a 150 mL alumina crucible with a cover, and stirred for 10 min to mix them evenly. The mixed material in the above step is placed into a muffle furnace, calcined at 570 DEG C for 120 min, and the heating rate is 5 DEG C / min. After the calcination is completed, the temperature is lowered, and the O, S-g-C3N4 / Bi2O3 / TiO2 photocatalytic material is collected.
[0027] A third specific implementation process is provided, which includes the following steps: The 15 g of thiocyanic acid, 6 g of oxalic acid, 1 g of Bi2O3 and 2 g of TiO2 are weighed and placed into a 150 mL alumina crucible with a cover, and stirred for 10 min to mix them evenly. The mixed material in the above step is placed into a muffle furnace, calcined at 550 DEG C for 125 min, and the heating rate is 5 DEG C / min. After the calcination is completed, the temperature is lowered, and the O, S-g-C3N4 / Bi2O3 / TiO2 photocatalytic material is collected.
[0028] Example 2
[0029] As shown in the following table, the photocatalytic gel is prepared by using the photocatalytic material prepared in Example 1. Figure 2 The preparation method includes the following steps: Step 1: placing the O, S-g-C3N4 / Bi2O3 / TiO2 photocatalytic material into pure water, and ultrasonic dispersion is uniform; Step 2: placing carboxymethyl cellulose sodium, alpha-cellulose and polyacrylic acid into the water, and mechanical stirring is performed to obtain a mixed precursor solution; Step three: after aging the obtained precursor solution, pour the obtained precursor solution into a mold and put it into a refrigerator for freezing; Step four: freeze-dry the frozen precursor solution in a vacuum, and then crosslink it in a vacuum oven to obtain the O, S-g-C3N4 / Bi2O3 / TiO2 photocatalytic gel.
[0030] The step four specifically includes the following processes: the temperature for freeze-drying the frozen precursor solution in a vacuum is -45℃ to -35℃, preferably -40℃, and the time is 12 hours; the temperature for crosslinking is 80℃-120℃, and the time is 4-8 hours, preferably the temperature for crosslinking is 100℃, and the time is 6 hours.
[0031] According to the preparation method of the photocatalytic gel, a first specific implementation process is provided, which includes: Put 1g of the O, S-g-C3N4 / Bi2O3 / TiO2 photocatalytic material described above into a container containing 100mL of pure water, and ultrasonic for 5 minutes to disperse uniformly; Then disperse 2.5g of sodium carboxymethyl cellulose, 2.5g of α-cellulose and 1g of polyacrylic acid in the container, and mechanically stir for 2 hours to obtain a uniformly mixed precursor solution; After aging the obtained precursor solution for 1 hour, use a mold with a size of 20*25cm to pour the precursor solution into the mold, and put it into a refrigerator for freezing for 12 hours; Freeze-dry the frozen precursor solution in a vacuum at -40℃ for 12 hours, and then crosslink it in a vacuum oven at 100℃ for 6 hours to obtain the O, S-g-C3N4 / Bi2O3 / TiO2 photocatalytic gel.
[0032] A second specific implementation process includes: Put 1g of the O, S-g-C3N4 / Bi2O3 / TiO2 photocatalytic material described above into a container containing 100mL of pure water, and ultrasonic for 5 minutes to disperse uniformly; Then disperse 2g of sodium carboxymethyl cellulose, 2g of α-cellulose and 0.5g of polyacrylic acid in the container, and mechanically stir for 2 hours to obtain a uniformly mixed precursor solution; After aging the obtained precursor solution for 1 hour, use a mold with a size of 20*25cm to pour the precursor solution into the mold, and put it into a refrigerator for freezing for 12 hours; Freeze-dry the frozen precursor solution in a vacuum at -35℃ for 12 hours, and then crosslink it in a vacuum oven at 80℃ for 4 hours to obtain the O, S-g-C3N4 / Bi2O3 / TiO2 photocatalytic gel.
[0033] A third specific implementation process includes: Weigh 1 g of the above O, S-g-C3N4 / Bi2O3 / TiO2 photocatalytic material, put it into a container containing 100 mL of pure water, and ultrasonic for 5 minutes, and disperse uniformly; Then 3g of carboxymethyl cellulose sodium, 3g of a-cellulose and 1.5g of polyacrylic acid are dispersed in the container, and mechanically stirred for 2 hours to obtain a uniformly mixed precursor solution; After the obtained precursor solution is aged for 1 hour, a 20*25cm mold is used, the precursor solution is poured into the mold, and placed in a refrigerator for 12 hours; The frozen precursor solution is vacuum freeze-dried at-45℃ for 12 hours, and then placed in a vacuum oven at 120℃ for crosslinking for 8 hours to obtain O, S-g-C3N4 / Bi2O3 / TiO2 photocatalytic gel.
[0034] The experimental process of the O, S-g-C3N4 / Bi2O3 / TiO2 photocatalytic gel obtained by the first specific implementation process is as follows: First, the O, S-g-C3N4 / Bi2O3 / TiO2 photocatalytic gel is cut into 2*2*0.5cm cubes, as shown in Figure 8 and Figure 9 Then put it into 100mL of 20ppm methylene blue solution, then turn on the light source, and carry out photocatalytic degradation under 1 solar equivalent light. The sampling time interval is 0, 1, 5, 10, 15, 20, 25, 30 minutes. Then measure the absorbance of the solution at a wavelength of 664nm, as shown in Figures 10 to 13 .
[0035] According to Figure 10 , methylene blue shows good absorbance curve at a concentration of 0.5mg / L-15mg / L, which meets the test interval of the standard curve; according to Figure 11 , the photocatalytic gel shows good adsorption and degradation of 15mg / L methylene blue within 10 minutes, and basically removes the methylene blue; within 30 minutes, the methylene blue is completely removed; according to Figure 12 , the photocatalytic gel is quantified for the degradation effect of methylene blue, which further highlights the degradation efficiency of the photocatalytic gel to 15mg / L methylene blue; according to Figure 13 , the degradation of the photocatalytic gel to the dye is intuitively shown, which further highlights the high adsorption and degradation performance of the photocatalytic gel to the dye.
[0036] As shown in Figure 14 , it is the effect diagram of the photocatalytic gel degrading terramycin, according to Figure 14As can be seen from the comparison chart of the degradation efficiency of different photocatalytic gel precursors (TiO2, Bi2O3 and O, S-g-C3N4) on terramycin (3.7%, 17.2%, 38.4% and 93.7%), the photocatalytic gel has high efficiency in degrading terramycin antibiotics, which proves that the photocatalytic gel has high efficiency in degrading antibiotics in aquaculture tail water.
[0037] As shown in Figure 15 , the effect diagram of photocatalytic gel degrading COD, total nitrogen and total phosphorus in simulated aquaculture tail water, wherein the simulated concentrations of COD, total nitrogen and total phosphorus are 50 mg / L, 8 mg / L and 1.5 mg / L respectively. According to Figure 15 , it can be seen that when the original concentrations of COD, total nitrogen and total phosphorus are 50 mg / L, 8 mg / L and 1.5 mg / L respectively, the removal degradation rates of COD, total nitrogen and total phosphorus by photocatalytic gel after 12 h of photocatalytic reaction are 68.9%, 42.5% and 28.7% respectively, which reflects the removal of pollutants in simulated aquaculture tail water by photocatalytic gel.
[0038] The SEM diagram of photocatalytic gel can be referred to Figure 16 , the mapping diagram of photocatalytic gel can be referred to Figure 17 , and the degradation mechanism diagram of photocatalytic gel can be referred to Figure 18 , according to Figure 18 , it can be seen that under the irradiation of photocatalytic gel, a large amount of reactive oxygen species (ROS) is generated, which can oxidize and reduce the pollutants in the aquaculture tail water, so that the macromolecular pollutants are gradually mineralized into small molecular harmless products.
[0039] Example three:
[0040] As shown in Figure 3 and Figure 4 , the embodiment provides a device of O, S-g-C3N4 / Bi2O3 / TiO2 photocatalytic gel, which comprises a reaction tank 6, a water inlet pipe 2, a plurality of water outlet pipes 4, a light source 5, a photocatalytic gel layer 8 and an aquatic plant layer 9. One side of the reaction tank 6 is provided with the water inlet pipe 2 which is in communication with the inside of the reaction tank 6. The other side of the reaction tank 6 is provided with a plurality of water outlet pipes 4 which are in communication with the inside of the reaction tank 6. The inner bottom of the reaction tank 6 is provided with the photocatalytic gel layer 8 which is paved by O, S-g-C3N4 / Bi2O3 / TiO2 photocatalytic gel. The aquatic plant layer 9 is arranged above the photocatalytic gel layer 8. The light source 5 is arranged at the bottom of the reaction tank 6.
[0041] In the embodiment, the water inlet pipe 2 and the plurality of water outlet pipes 4 are respectively provided with valves, so that the water inlet pipe 2 and the plurality of water outlet pipes 4 can be controlled to be opened or closed as needed during use. The aquatic plant layer 9 can be planted with ecological-friendly aquatic plants, such as water celery and other aquatic plants with strong purification capacity. The aquatic plant layer 9 can not only absorb nutrients in water through the root system of the aquatic plants, thereby reducing the risk of eutrophication of the water body, but also release oxygen through photosynthesis, thereby increasing the dissolved oxygen content of the water body and providing a good living environment for microorganisms, and further enhancing the self-purification capacity of the water body.
[0042] The reaction tank 6 can be sized as 100 cm in length, 50 cm in width, and 50 cm in height, or other sizes as needed.
[0043] As shown in FIGS. 1 to 3, based on the above device, the water inlet pipe 2 is arranged below the front end on the left side of the reaction tank 6, and the plurality of water outlet pipes 4 are vertically and spacedly arranged above the rear end on the right side of the reaction tank 6. In this way, the tail water to be purified can be conveniently drained from bottom to top and from front to back, thereby increasing the purification effect of the tail water. Figure 5 Figure 6 Figure 7 As shown in FIGS. 1 to 3, based on the above device, the water inlet pipe 2 is arranged below the front end on the left side of the reaction tank 6, and the plurality of water outlet pipes 4 are vertically and spacedly arranged above the rear end on the right side of the reaction tank 6. In this way, the tail water to be purified can be conveniently drained from bottom to top and from front to back, thereby increasing the purification effect of the tail water.
[0044] Based on the above device, the device further comprises a support 1 and a fixed grid 7, the fixed grid 7 is arranged inside the reaction tank 6 through the support 1 and is located above the photocatalytic gel layer 8, and the aquatic plant layer 9 is arranged above the fixed grid 7 and can pass through the fixed grid 7 to connect with the photocatalytic gel layer 8. In this way, the fixed grid 7 installed at the bottom of the reaction tank 6 can stably support and fix the photocatalytic gel layer 8, thereby ensuring uniform distribution of the photocatalytic gel layer 8 during the entire reaction process and avoiding gel accumulation or displacement, so as to affect the photocatalytic effect.
[0045] In another specific embodiment, the device provided in the embodiment further comprises a plurality of base supports 3, and the bottom of the reaction tank 6 is provided with the plurality of base supports 3, and the light source 5 can penetrate into the inside of the reaction tank 6 from the intervals of the plurality of base supports 3.
[0046] When the tail water or the wastewater to be treated enters the reaction tank 6 from the water inlet pipe 2 of the device, the system can be automatically started to turn on the bottom light source 5. The light source 5 can be selected as a 100W to 300W halogen lamp, which is located 8 cm away from the photocatalytic reaction area 5, so as to ensure that the photocatalytic gel layer 8 can play a role under the best conditions. The turning on of the light source 5 not only triggers the photocatalyst in the photocatalytic gel layer 8 to perform the advanced oxidation reaction, but also simulates the natural light conditions to promote the growth and photosynthesis of the aquatic plants.
[0047] Embodiment Four:
[0048] According to the application of the photocatalytic material of embodiment one or the photocatalytic gel of embodiment two, it can be applied to sewage treatment, water purification or photocatalytic degradation of organic matter.
[0049] The application of the photocatalytic material and the gel thereof provided by the application relates to the following aspects: Photocatalytic technology: photocatalytic technology is a technology that uses photocatalysts to produce reactive oxygen species (ROS) under light conditions to degrade organic pollutants. Photocatalysis excites the photocatalysts in the gel layer to produce a large amount of ROS, which can not only directly degrade organic pollutants, but also convert organic nitrogen and organic phosphorus into inorganic nitrogen and inorganic phosphorus through redox, achieving pollution removal, purifying the aquatic environment, and providing available nutrients for aquatic plants, and ultimately realizing harmless treatment of aquaculture tail water.
[0050] Phytoremediation technology: phytoremediation is a technology that uses plants to absorb, accumulate and transform pollutants, and is particularly suitable for treating large areas and low-concentration pollution sites, with low cost and high safety. In the aquaculture environment, phytoremediation mainly uses aquatic plants or algae to absorb and extract nitrogen, phosphorus and other pollutants in the aquaculture tail water to achieve the purpose of purifying water quality.
[0051] Application of aquatic plants in wastewater treatment: studies have shown that various aquatic plants such as cattail, fox tail, and potamogeton can treat eutrophic water bodies, effectively reducing chemical oxygen demand (COD Cr ) and 5-day biochemical oxygen demand (BOD5), and treating nitrogen and phosphorus in water. In addition, large seaweeds show high efficiency and low cost in seawater aquaculture tail water treatment.
[0052] ICPB technology: ICPB is a wastewater treatment technology that combines photocatalytic materials, porous carriers and biology to improve the purification capacity of wastewater and save costs. This technology breaks the traditional concept of separately performing photocatalytic reaction and biodegradation in different reactors, and improves the treatment efficiency through synergistic effect.
[0053] The application can effectively degrade organic pollutants in water bodies, improve the biodegradability of aquaculture tail water, and effectively remove organic pollutants, total nitrogen and total phosphorus to achieve water purification. At the same time, the combined technology of photocatalytic oxidation degradation and plant growth promotion to absorb carbon and nitrogen-containing small molecule organic matter realizes real-time treatment of aquaculture tail water. This method integrates photocatalytic technology and biological treatment, not only improves the treatment efficiency, reduces energy consumption and operating cost, but also realizes the resourceization and harmless treatment of aquaculture tail water.
[0054] The application is used for treating aquaculture tail water. The aquaculture tail water is a kind of wastewater containing nutrients such as nitrogen and phosphorus. The improper use of antibiotics leads to their widespread presence in aquaculture tail water, causing great pressure on the environment. Photocatalysis technology uses light to excite valence band electrons to jump to the conduction band, forming unpaired electrons-holes that promote the degradation of pollutants such as antibiotics such as tetracycline, which are oxidized into inorganic substances such as CO2 and water, achieving harmless treatment of pollutants. Aquatic plants such as water celery have strong ecological adaptability and can absorb organic nitrogen and organic phosphorus in aquaculture tail water for adsorption and enrichment, providing a more efficient treatment environment for the oxidative degradation of photocatalysts, while also having economic characteristics. The advanced oxidation-biological coupling technology can fix the nitrogen, phosphorus and other nutrients in the aquaculture tail water through the photocatalytic gel layer 8 to provide the necessary substances for the growth of aquatic plants; at the same time, the photocatalyst can degrade antibiotic organic pollutants in the aquaculture tail water, thereby achieving harmless treatment of the aquaculture tail water.
[0055] The photocatalytic gel coupling aquatic plant technology for purifying aquaculture tail water has the following advantages over the prior art: Efficient removal of organic pollutants: The photocatalytic gel coupling technology can effectively remove refractory organic matter, including azo dyes, natural organic matter and other toxic organic matter. This technology improves the removal efficiency by generating ROS through photocatalysts under light conditions to degrade organic pollutants and organic nitrogen and phosphorus.
[0056] Resource recycling: The photocatalytic gel coupling aquatic plant technology not only treats wastewater, but also provides nutrients for aquatic plants through the oxidation and reduction of organic nitrogen and phosphorus, reducing waste generation.
[0057] Environmentally friendly: This technology has little impact on the environment, can deeply mineralize pollutants into inorganic products such as CO2 and H2O, does not cause secondary pollution, and has few remaining problems, making it an environmentally friendly treatment method.
[0058] Easy to operate and low cost: The photocatalytic gel coupling technology is easy to operate and can be treated on site, reducing land area and capital costs. The operating cost and energy consumption are relatively low, and the treatment cost is only 30%-50% of that of physical and chemical methods.
[0059] Strong adaptability: Aquatic plants and microorganisms have strong adaptability and can adapt to various aquaculture tail water, toxic industrial wastewater and domestic sewage environments. Through cultivation and domestication, they can adapt to different wastewater treatment needs.
[0060] Improving transparency and reducing color: In addition to removing organic matter and toxic substances, this technology can also improve water transparency and reduce color, improving water quality.
[0061] System coupling advantage: the coupling of photocatalytic gel technology and aquatic plants can take advantage of each other. Through photocatalytic degradation of refractory organic matter and emerging pollutants, the redox of nutrients is further absorbed and transformed by aquatic plants to achieve more efficient wastewater purification.
[0062] In summary, the photocatalytic gel coupled with aquatic plants to purify aquaculture tail water technology shows obvious advantages in removal efficiency, cost, environmental friendliness, and resource reuse compared to existing technologies.
[0063] The photocatalytic material and its gel provided by the application have good application prospects in the field of aquaculture tail water treatment and river management due to their low cost, environmental friendliness, and sustainability. This technology can be applied to the degradation of various organic pollutants and can be applied on a larger scale in actual industrial wastewater treatment, such as coal chemical wastewater, methanol-to-olefin wastewater, and hydrazine wastewater.
[0064] In the application, the photocatalyst contained in the photocatalytic gel can generate strong oxidizing free radicals under light conditions, especially under visible light excitation. These free radicals can attack macromolecular organic pollutants such as antibiotics in the aquaculture tail water, and decompose them into low-toxic or non-toxic small molecular substances such as carbon dioxide and water through oxidation. This process not only reduces the organic load in the water body, but also reduces the direct toxicity of these pollutants.
[0065] The small molecular substances produced in the photocatalytic oxidation process, such as carbon dioxide, can be used as a carbon source for aquatic plants to support photosynthesis, thereby promoting plant growth and development. This carbon recycling method helps to build a sustainable aquatic ecosystem and improves the self-purification capacity of the water body.
[0066] The photocatalytic effect of photocatalytic gel can destroy the chemical structure of macromolecular pollutants such as antibiotics, reduce their biological inhibition, and make these substances less toxic and more easily degraded by subsequent biological treatment processes. This is of great significance for improving the treatment efficiency of the entire system and reducing environmental risks and reducing the toxicity of pollutants.
[0067] The small molecular substances degraded by photocatalytic gel, especially inorganic nitrogen and inorganic phosphorus converted by oxidation and reduction, can be efficiently absorbed into plants through the active absorption mechanism of plant roots due to their small molecular weight and chemical form. This absorption process not only provides essential nutrients to plants, promotes biomass accumulation and physiological activity, but also realizes the directional migration of nitrogen and phosphorus pollutants in the water body through plant assimilation, ultimately significantly reducing the concentration of nitrogen and phosphorus in the water body and promoting plant absorption.
[0068] The use of photocatalytic gels reduces the need for chemical treatment agents, avoiding the risk of secondary pollution, and is an environmentally friendly water treatment technology. It simulates natural photosynthesis, using solar energy as a clean energy source to achieve harmless treatment of organic pollutants, which is environmentally friendly.
[0069] Secondly, carbon nitride is a fully organic semiconductor material with excellent chemical stability and biocompatibility. It does not contain heavy metal elements, so it has no toxic effects on the environment and plant growth. During the photocatalytic process, carbon nitride can decompose organic pollutants in water bodies into carbon dioxide and water, which are harmless to plants and can even be used as raw materials for plant photosynthesis. The photocatalytic activity of carbon nitride can be enhanced by modification, allowing it to work under visible light and reducing its dependence on ultraviolet light, thereby reducing potential harm to aquatic organisms.
[0070] Titanium dioxide is a widely used photocatalyst that can generate strong oxidizing hydroxyl radicals under light, effectively degrading various organic pollutants. Titanium dioxide itself is lowly toxic to plants, but further research is needed on certain intermediate products produced during its photocatalytic process to ensure that it is harmless to plants. The photocatalytic action of titanium dioxide can be controlled at specific wavelengths to reduce negative effects on plant growth while improving water purification efficiency.
[0071] Bismuth oxide is a material with high photocatalytic activity that can effectively degrade pollutants in water and is environmentally friendly. The photocatalytic action of bismuth oxide can reduce harmful substances in water, providing a cleaner growing environment for plants. The photocatalytic performance of bismuth oxide can be enhanced by combining it with other materials such as titanium dioxide to form a composite photocatalyst, improving its photocatalytic efficiency and selectivity and reducing potential impacts on plants.
[0072] The above three materials can reduce organic pollutants in water during the photocatalytic process, providing cleaner water sources for plants, and their impact on plant growth is relatively small, making them environmentally friendly materials.
[0073] The above only describes the preferred embodiments of the present application. It should be noted that for those skilled in the art, without departing from the technical principles of the present application, several improvements and modifications can be made, which should also be considered within the scope of protection of the present application.
Claims
1. A method for preparing a photocatalytic material, characterized in that, include: Trithiocyanate, oxalic acid, Bi2O3 and TiO2 are mixed according to a preset mass ratio; The mixed raw materials are then calcined. The calcined product was cooled to obtain O,Sg-C3N4 / Bi2O3 / TiO2 photocatalytic material.
2. The method for preparing the photocatalytic material according to claim 1, characterized in that, The preset mass ratio of trithiocyanate, oxalic acid, Bi2O3 and TiO2 is (15-25):(6-10):(1-2):(1-2).
3. The method for preparing a photocatalytic material according to claim 1, characterized in that: The predetermined mass ratio of trithiocyanate, oxalic acid, Bi2O3 and TiO2 is 20:8:1:
1.
4. The method for preparing a photocatalytic material according to claim 1, characterized in that, The calcination temperature is at least 550°C, the calcination time is at least 120 min, and the heating rate to reach the calcination temperature is 5°C / min.
5. A photocatalytic material, characterized in that, The photocatalytic material is prepared according to any one of claims 1-4.
6. A method for preparing a photocatalytic gel, characterized in that, include: The O,Sg-C3N4 / Bi2O3 / TiO2 photocatalyst material prepared by the method according to any one of claims 1-4 is dispersed in water, a gel matrix is added, and the mixture is stirred, aged, frozen, freeze-dried and cross-linked to obtain the O,Sg-C3N4 / Bi2O3 / TiO2 photocatalyst gel.
7. The method for preparing photocatalytic gel according to claim 6, characterized in that, The gel matrix comprises sodium carboxymethyl cellulose, α-cellulose, and polyacrylic acid; the mass ratio of the photocatalytic material, sodium carboxymethyl cellulose, α-cellulose, and polyacrylic acid is 1:(2-3):(2-3):(0.5-1.5).
8. The method for preparing the photocatalytic gel according to claim 6, characterized in that, The vacuum freeze-drying temperature is -45℃ to -35℃, and the time is 12 hours; the crosslinking treatment temperature is 80℃ to 120℃, and the time is 4 to 8 hours.
9. A photocatalytic gel, characterized in that, The photocatalytic gel is prepared according to any one of claims 6-8.
10. The application of the photocatalytic material according to claim 5 or the photocatalytic gel according to claim 9, characterized in that, The applications include wastewater treatment, water purification, or photocatalytic degradation of organic matter.