Method for killing hydranths of aurelia jellyfish through photocatalysis

Abstract

The invention relates to a method for killing aurelia hydranths by photocatalysis. According to the method, an Ag2O coated P-g-C3N4 composite material is used as a photocatalyst to kill aurelia hydranths; the Ag2O coated P-g-C3N4 composite material is prepared by successively synthesizing g-C3N4 and P-g-C3N4 and then adding AgNO3 into the g-C3N4 and the P-g-C3N4. When the aurelia hydranth is killed under visible light, the Ag2O coated P-g-C3N4 composite material with the mass fraction of Ag2O being 5.0% is selected, and the optimal use dosage is 0.5 g.L <-1 > to 1.0 g.L <-1 >. The method is suitable for preventing and controlling the outbreak source of the aurelia, and a green and environment-friendly method is provided for preventing the outbreak source of the aurelia by disinfecting and killing the hydranths through photocatalysis.

Description

Technical Field

[0001] The present invention relates to the field of marine ecological disaster prevention and control research, and particularly relates to a method for photocatalytically killing the polyps of Aurelia aurita. Background Art

[0002] In the past two decades, Aurelia aurita ( Aureli a spp.) has frequently broken out in the global coastal waters, seriously damaging the sustainable development of the coastal economy and the health of the ecological environment, and even threatening human life safety. Therefore, in order to reduce the threat of the outbreak of Aurelia aurita disasters, it is urgent to carry out research on its prevention and control technologies.

[0003] There is an obvious phenomenon of alternation of generations in the life history of Aurelia aurita, which is divided into the planktonic medusa stage and the benthic polyp stage. The polyps are tiny, up to about 1 mm at most, and attach to the surface of hard substrates. Polyps can not only release a large number of ephyrae through strobilation, thus leading to jellyfish outbreaks, but also maintain and even increase the population through asexual reproduction methods such as budding and podocysts. Therefore, polyps are the key to determining the outbreak of Aurelia aurita and are the "source" of the outbreak of its medusae. Research on prevention and control methods for polyps can reduce the risk of jellyfish outbreaks in advance and achieve source prevention.

[0004] Although there are currently some patents on killing the polyps of Aurelia aurita by ultrasonic waves and saponin, considering their toxicity and secondary hazards to the ecosystem, they still cannot meet the current requirements for ecological environment safety. The commonly used physical methods for removing polyps also cause great damage to the structure of the sessile biological community on the substrate surface. Developing an environmentally friendly method for killing polyps is an inevitable trend in the field of jellyfish disaster prevention and control to meet the current requirements of ecological safety.

[0005] Chinese invention patent CN117730809A (publication date: March 22, 2024) discloses the application of PI3K agonists in inhibiting the metamorphosis of jellyfish. This patent verifies through experiments that YS-49 has great potential in the application of preventing jellyfish metamorphosis / outbreak, providing a new technical means for preventing jellyfish metamorphosis / outbreak.

[0006] Chinese invention patent CN117426383A (publication date: January 23, 2024) discloses the application of α-Lindenic acid in inhibiting the metamorphosis process of Aurelia aurita; this invention establishes the intervention of α-Lindenic acid on Aurelia aurita ( A.coerulea)Metamorphosis experiment model. It was found that when α-Lindenic acid was used in combination with 5-methoxy-2-methylindole to induce the metamorphosis of Aurelia aurita polyps, a mixed solution with a final concentration of 1 μM had an obvious effect of inhibiting the metamorphosis of Aurelia aurita; at the same time, α-Lindenic acid could reduce the number of ephyrae released, providing a new theoretical basis for preventing jellyfish blooms.

[0007] In view of the defects of the current methods for inhibiting the metamorphosis of Aurelia aurita polyps, photocatalytic technology, with its advantages of environmental friendliness, high efficiency, low cost, and good degradation effect, has become a green technology with important application prospects in the environmental field. Photocatalytic technology uses specific catalytic materials to generate strongly oxidizing free radicals under the action of light. It can not only effectively degrade environmental pollutants in water bodies, but also has been proven to be able to effectively inactivate microorganisms and algae in water in recent years; however, whether it has a good disinfection effect on polyps has not been reported. Therefore, in order to develop a green and environmentally friendly technology for disinfecting polyps, the present invention relates to a method for photocatalytic disinfection of Aurelia aurita polyps. Summary of the Invention

[0008] The purpose of the present invention is to overcome the shortcomings of the existing methods for killing Aurelia aurita polyps that cannot meet the current ecological environment safety requirements, and to provide a method for photocatalytic disinfection of Aurelia aurita polyps. This method can not only prevent the outbreak of Aurelia aurita from the source, but also will not produce secondary pollutants that harm the environment during the photocatalytic generation of strongly oxidizing free radicals to disinfect polyps.

[0009] A method for photocatalytic disinfection of Aurelia aurita polyps, characterized by comprising the following steps: Step S1: Prepare Ag 2 O@P-g-C 3 N 4 composite material, that is, the photocatalyst for disinfecting Aurelia aurita polyps; Step S2: Prepare Ag 2 O with a mass fraction of 5.0% of Ag 2 O@P-g-C 3 N 4 composite material; Step S3: Under visible light, use the photocatalyst to disinfect polyps.

[0010] Furthermore, in the above step S1, the Ag 2 O@P-g-C 3 N 4 composite material is prepared by successively synthesizing g-C 3 N 4 and P-g-C 3 N 4 materials, and then adding AgNO3 Solution obtained.

[0011] Furthermore, the preparation method of the g-C 3 N 4 material is as follows: Mix urea and melamine evenly according to a mass ratio of 1:1, grind thoroughly using an agate mortar, sieve through a 200-mesh sieve, place in a muffle furnace for calcination, and naturally cool to room temperature after the calcination program ends to obtain g-C 3 N 4 material.

[0012] Furthermore, the preparation method of the P-g-C 3 N 4 material is as follows: In an agate mortar, mix the g-C 3 N 4 powder and (NH 4 ) 2 HPO 4 evenly according to a mass ratio of 40:3, grind thoroughly in an agate mortar, place in a muffle furnace for calcination, and naturally cool to room temperature after the calcination ends to obtain P-g-C 3 N 4 material.

[0013] Furthermore, the calcination conditions in the preparation method of the g-C 3 N 4 material and the preparation method of the P-g-C 3 N 4 material are both: starting at room temperature of 25 °C, heating up to 550 °C at a rate of 5 °C·min -1 and holding for calcination at this temperature for 4 hours.

[0014] Furthermore, the preparation method of the Ag 2 O@P-g-C 3 N 4 composite material is specifically as follows: Mix the solution according to the ratio of adding 0.6 g of P-g-C 3 N 4 powder into 90 mL of ultrapure water, disperse in an ultrasonic crusher for 40 min under dark conditions, then slowly add solid NaOH powder to the solution and stir evenly to make the solution pH reach 14, and then dropwise add AgNO 3 solution to obtain a suspension, centrifuge the suspension at 8000 rpm, collect the precipitate, wash the precipitate with absolute ethanol and ultrapure water, and then place it in a vacuum drying oven and dry at 60 °C for 24 h to obtain Ag 2 O@P-g-C 3 N 4 composite material.

[0015] Further, in step S2, Ag 2 The preparation method of Ag 2 O@P-g-C 3 N 4 composite material is as follows: Prepare a mixed solution according to the ratio of adding 0.0439 g of AgNO 3 to 20 mL of ultrapure water, and then dropwise add it to the mixed solution prepared according to the ratio of adding 0.6 g of P-g-C 3 N 4 powder to 90 mL of ultrapure water.

[0016] Further, under visible light, using Ag 2 The optimal dose of Ag 2 O@P-g-C 3 N 4 composite material for killing the hydroid of Aurelia aurita is 0.5 - 1.0 g·L -1 .

[0017] Further, the prepared Ag 2 The Ag 2 O@P-g-C 3 N 4 composite material is dried and stored in a desiccator.

[0018] Compared with the prior art, the advantages and effects of this application are as follows: 1. The present invention can not only effectively kill the hydroid of Aurelia aurita in water under visible light conditions, prevent the outbreak of Aurelia aurita from the source, but also will not produce secondary pollutants harmful to the environment during the photocatalytic generation of strongly oxidizing free radicals to kill the hydroid.

[0019] 2. The present invention is applicable to the prevention and control of the outbreak source of Aurelia aurita, and provides a new green and environmental protection technology for the source treatment and prevention of the outbreak of Aurelia aurita.

[0020] The above description is only an overview of the technical solution of this application. In order to be able to understand the technical means of this application more clearly, so as to be implemented in accordance with the content of the specification, and in order to make the above and other purposes, features and advantages of this application more obvious and understandable, the following takes the preferred embodiments of this application and combines with the drawings to describe in detail as follows.

[0021] Those skilled in the art will understand the above and other purposes, advantages and features of this application more clearly according to the following detailed description of the specific embodiments of this application in conjunction with the drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] To more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the accompanying drawings required for the description of the embodiments or the prior art. Obviously, the accompanying drawings in the following description are some embodiments of the present application. For those of ordinary skill in the art, without creative efforts, other accompanying drawings can be obtained based on these drawings. In all the drawings, similar elements or parts are generally identified by similar reference numerals. In the drawings, the elements or parts are not necessarily drawn to actual scale.

[0023] Wherein: Figure 1 is Ag 2 Ag with an O mass fraction of 5.0% 2 O@P-g-C 3 N 4 composite material; Figure 2 is the disinfection and killing effect of Ag 2 O@P-g-C 2 N 3 composite material with different Ag 4 O mass fractions and addition doses under strong visible light (4000 Lux); (a): The catalyst addition amount is 1.0 g·L -1 ; (b): The catalyst addition amount is 0.5 g·L -1 ; (c): The catalyst addition amount is 0.25 g·L -1 ; Ag 2 O-PCN-1: Ag with a 2.5% Ag 2 O mass fraction 2 O@P-g-C 3 N 4 ; Ag 2 O-PCN-2: Ag with a 5% Ag 2 O mass fraction 2 O@P-g-C 3 N 4 ; Ag 2 O-PCN-3: Ag with a 10% Ag 2 O mass fraction 2 O@P-g-C 3 N 4 ; Figure 3 is, under weak visible light (240 Lux) and darkness, with an addition amount of 0.5 g·L -1 when different Ag 2 O mass fraction Ag 2 O@P-g-C 3 N 4Disinfection and killing effect of composite materials on hydras; (a): Disinfection and killing effect of Ag -1 O@P-g-C3N4 composite materials with different Ag 2 O mass fractions at an addition amount of 0.5 g·L 2 under weak visible light (240 Lux); (b): Disinfection and killing effect of Ag -1 O@P-g-C3N4 composite materials with different Ag 2 O mass fractions at an addition amount of 0.5 g·L 2 in the dark. Specific implementation manners

[0024] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions in the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings in the embodiments of this application. Apparently, the described embodiments are some but not all of the embodiments of this application. In the following description, specific details such as specific configurations and components are provided only to assist in a comprehensive understanding of the embodiments of this application. Therefore, those skilled in the art should clearly understand that various changes and modifications can be made to the embodiments described herein without departing from the scope and spirit of this application. Additionally, descriptions of known functions and structures are omitted in the embodiments for clarity and conciseness.

[0025] It should be understood that the "one embodiment" or "this embodiment" mentioned throughout the specification means that a specific feature, structure, or characteristic related to the embodiment is included in at least one embodiment of this application. Therefore, the "one embodiment" or "this embodiment" that appears throughout the specification does not necessarily refer to the same embodiment. Additionally, these specific features, structures, or characteristics can be combined in one or more embodiments in any suitable manner.

[0026] Furthermore, this application may repeat reference numerals and / or letters in different instances. This repetition is for the purpose of simplicity and clarity and does not in itself indicate the relationship between the various embodiments and / or arrangements discussed.

[0027] The term "and / or" in this document is merely a description of the associated relationship of the associated objects, indicating that three relationships can exist. For example, A and / or B can represent: A exists alone, B exists alone, and both A and B exist simultaneously. The term " / and" in this document describes another associated object relationship, indicating that two relationships can exist. For example, A / and B can represent: A exists alone, and both A and B exist. Additionally, the character " / " in this document generally indicates that the associated objects before and after are in an "or" relationship.

[0028] In this text, the term "at least one" is merely a description of the association relationship of associated objects, indicating that there can be three relationships. For example, at least one of A and B can represent: A exists alone, A and B exist simultaneously, and B exists alone, these three situations.

[0029] It should also be noted that in this text, relational terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the term "comprising", "including" or any other variant thereof is intended to cover non-exclusive inclusion.

[0030] Example 1 This example introduces Ag 2 O with different mass fractions of Ag 2 O@P-g-C 3 N 4 The preparation method of the composite material is as follows: g-C 3 N 4 Material synthesis: Weigh 2 g of urea and 2 g of melamine, put them into an agate mortar, mix well and grind thoroughly, and then screen them through a 200-mesh sieve. Subsequently, put this powder into a ceramic crucible and place it in a muffle furnace for calcination. The calcination program starts at room temperature of 25 °C, heats up to 550 °C at a rate of 5 °C·min -1 and keep it calcined at this temperature for 4 h. After the calcination is completed, the sample is naturally cooled to room temperature in the furnace to obtain g-C 3 N 4 material.

[0031] P-g-C 3 N 4 Material synthesis: Weigh 2 g of g-C 3 N 4 powder and 0.15 g of (NH 4 ) 2 HPO 4 and grind them thoroughly in an agate mortar, and then place them in a muffle furnace for calcination. The calcination conditions and procedures are the same as those for the synthesis of g-C 3 N 4 material mentioned above. After completion, the sample is naturally cooled to room temperature in the furnace to obtain P-g-C 3 N 4 material.

[0032] Ag 2 O@P-g-C 3 N 4 Composite material synthesis: Take 0.6 g of P-g-C 3 N4 The powder was added to 90 mL of ultrapure water. Subsequently, under dark conditions, it was dispersed using an ultrasonic crusher for 40 min. Then, solid NaOH powder was slowly added and continuously stirred evenly to adjust the pH value of the solution to 14. Then, 0.02195 g, 0.0439 g, and 0.0878 g of AgNO 3 were dissolved in 20 mL of ultrapure water to prepare AgNO 3 solutions with different mass ratios. Then, under dark conditions, they were respectively added dropwise to the above solution with pH = 14 to obtain suspensions. The suspensions were centrifuged at 8000 rpm, and the precipitates were collected. The obtained precipitates were washed three times with absolute ethanol and ultrapure water and then placed in a vacuum drying oven and dried at 60 °C for 24 hours to obtain Ag 2 O with mass fractions of 2.5%, 5%, and 10% of Ag 2 O@P-g-C 3 N 4 composites.

[0033] Example 2 Based on Example 1, in this example, the disinfection and killing effects of Ag 2 O@P-g-C 2 O@P-g-C 3 N 4 composites on hydras were studied under different mass fractions of Ag

[0034] (1)Disinfection and killing experiments of Ag 2 O@P-g-C 2 O@P-g-C 3 N 4 composites with different mass fractions of Ag on hydras 3 N 4 、Ag 2 O and Ag 2 O@P-g-C 2 O@P-g-C 3 N 4 composites with mass fractions of 2.5%, 5%, and 10% of Ag -1 were selected. The polyvinyl corrugated plates with attached hydras that had been starved for 24 h were used. The corrugated plates were cut into pieces to ensure that the number of hydras on each piece of corrugated plate was about 50 - 60. They were counted and recorded under a stereoscopic dissecting microscope. 30 mg of P-g-C, so that the materials can be evenly dispersed in seawater, and three replicates are made for each material. Then, the corrugated plates with attached hydras are placed in quartz tubes, kept in the dark for 30 min first, and then the 500 W mercury lamp light source is turned on, and the light source power is adjusted to a light intensity of 4000 Lux. A filter is set at the light source to filter out ultraviolet light with λ > 400 nm. The corrugated plates are taken out every 1 h, and the number of hydras on the corrugated plates is recorded under a stereoscopic dissecting microscope, and the hydra survival rate is calculated.

[0035] (2) Effect of the dosage of different Ag 2 O@P-g-C 3 N 4 Composite materials on the disinfection experiment of hydras During the experiment, the addition doses of the photocatalytic materials are 7.5 mg, 15 mg, and 30 mg of P-g-C 3 N 4 , Ag 2 O and 2.5%, 5%, and 10% Ag 2 O mass fraction of Ag 2 O@P-g-C 3 N 4 composite materials, which are dissolved in a photoreaction instrument (a quartz tube containing 30 mL of seawater). The selection of Aurelia aurita hydras and other photocatalytic reaction conditions are the same as in (2).

[0036] (3) Disinfection experiment of Ag 2 O@P-g-C 3 N 4 composite materials on hydras under different light conditions Except under strong light (4000 Lux), during the experiment, weak light (240 Lux) and dark conditions are also selected to carry out the disinfection experiment of Ag 2 O@P-g-C 3 N 4 composite materials on hydras. Weigh 15 mg of P-g-C 3 N 4 , Ag 2 O and 2.5%, 5%, and 10% Ag 2 O mass fraction of Ag 2 O@P-g-C 3 N 4 composite materials, which are dissolved in a photoreaction instrument (a quartz tube containing 30 mL of seawater). The selection of Aurelia aurita hydras and other photocatalytic reaction conditions are the same as in (1).

[0037] (4) Results Please refer to Figure 2 , under strong visible light (4000 Lux), using different Ag 2 O mass fraction and addition dose of Ag2 O@P-g-C 3 N 4 When the composite material photocatalytically disinfects hydras, it can be found that: at the same addition dosage, 5% mass fraction of Ag 2 O@P-g-C 3 N 4 the composite material has the best disinfection effect on hydras ( Figure 2 shown by the black line in), under strong visible light irradiation, when the addition dosage is 1.0 g·L -1 the disinfection rate of hydras reaches 82.46% in 2 h ( Figure 2 a), when the addition dosage is 0.5 g·L -1 the disinfection rate of hydras reaches 92.36% in 2 h ( Figure 2 b), when it is 0.25 g·L -1 the disinfection rate of hydras reaches 67.86% in 2 h ( Figure 2 c). Thus, it can be seen that 5% mass fraction of Ag 2 O@P-g-C 3 N 4 the composite material has the best disinfection effect on hydras when the addition dosage is 0.5 g·L -1 . The research also finds that under weak light (240 Lux) conditions, 5% mass fraction of Ag 2 O@P-g-C 3 N 4 the composite material can also effectively photocatalytically disinfect hydras, and the disinfection rate of hydras reaches 84.93% in 5 h (please refer to Figure 3 a).

[0038] The above is only the preferred embodiment of the present invention, and it does not limit the protection scope of the present invention. For those skilled in the art, the present invention can have various changes and modifications. All changes, modifications, substitutions, integrations, and parameter changes made to these embodiments by means of conventional substitutions or capable of achieving the same functions without departing from the principle and spirit of the present invention fall within the protection scope of the present invention.

Claims

1. A method for photocatalytically disinfecting the polyps of moon jellyfish, characterized in that: The following steps are involved: Step S1, preparing a Ag2O@Pg-C3N4 composite material, i.e., a photocatalyst for disinfecting polyps of moon jellyfish; Step S2, preparing an Ag2O@Pg-C3N4 composite material with an Ag2O mass fraction of 5.0%; Step S3: using a photocatalyst to disinfect the polyps under visible light.

2. The method for photocatalytically disinfecting the polyps of moon jellyfish according to claim 1, characterized in that: In the step S1, the Ag2O@Pg-C3N4 composite material is obtained by successively synthesizing g-C3N4 and Pg-C3N4 materials and then adding AgNO3 solution.

3. The method for photocatalytically disinfecting the polyps of moon jellyfish according to claim 2, characterized in that: The preparation method of the g-C3N4 material is: urea and melamine are uniformly mixed in a mass ratio of 1:1, placed in a muffle furnace for calcination, and naturally cooled to room temperature after the calcination process is completed to obtain the g-C3N4 material.

4. The method for photocatalytic disinfecting of moon jellyfish polyps according to claim 3, characterized in that: The preparation method of the Pg-C3N4 material is as follows: g-C3N4 powder and (NH4)2HPO4 are uniformly mixed in a mass ratio of 40:3, and after being fully ground in an agate mortar, the mixture is placed in a muffle furnace for calcination, and after the calcination is completed, the mixture is naturally cooled to room temperature to obtain the Pg-C3N4 material.

5. A method for photocatalytically disinfecting polyps of moon jellyfish according to claim 3 or 4, characterized in that: The calcination conditions are: starting at room temperature 25°C, 5°C·min -1 The temperature was raised to 550°C at a rate of 1000 ℃ and calcined at this temperature for 4 hours.

6. The method for photocatalytic disinfecting of moon jellyfish polyps according to claim 5, characterized in that: The preparation method of the Ag2O@Pg-C3N4 composite material is specifically as follows: a mixed solution is prepared by adding 0.6 g of Pg-C3N4 powder to 90 mL of ultrapure water, dispersing the solution in an ultrasonic crusher for 40 minutes under dark conditions, adding a small amount of NaOH solid powder and stirring evenly to make the pH of the solution reach 14, then adding AgNO3 solution dropwise to the solution, collecting the precipitate by centrifugation, washing the precipitate with anhydrous ethanol and ultrapure water, placing the precipitate in a vacuum drying oven, and drying it at 60°C for 24 hours to obtain the Ag2O@Pg-C3N4 composite material.

7. The method for photocatalytically disinfecting the polyps of moon jellyfish according to claim 6, characterized in that: The preparation method of the Ag2O@Pg-C3N4 composite material with an Ag2O mass fraction of 5.0% in step S2 is: prepare a mixed solution in a ratio of adding 0.0439g of AgNO3 to 20mL of ultrapure water, and then add it dropwise to a mixed solution in a ratio of adding 0.6g of P-g-C3N4 powder to 90mL of ultrapure water.

8. The method for photocatalytically disinfecting the polyps of moon jellyfish according to claim 7, characterized in that: The optimal dosage of Ag2O@Pg-C3N4 composite material with a mass fraction of 5.0% Ag2O to disinfect the polyps of moon jellyfish under visible light is 0.5-1.0 g·L -1 .

9. The method for photocatalytically disinfecting the polyps of moon jellyfish according to claim 7, characterized in that: The Ag2O@Pg-C3N4 composite material with an Ag2O mass fraction of 5.0% is stored in a dry manner.

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