Brother Omar has found another ugly for us. DB
below text from graphene agenda. thanks guys.
Patent: Water-based graphene oxide nanopesticide and method for its production and application
Patent CN111149798A
Summary
The invention belongs to the field of nanotechnology and relates in particular to a water-based nano-pesticide of graphene oxide for the prevention and control of fungal diseases in crops as well as a process for its production and application.
The bactericide in the water-based graphene oxide nanopesticide adheres to the surface of the graphene oxide by the pi-pi conjugation effect, the hydrogen bonding effect and the electrostatic adsorption effect, the fungal cells are damaged by the graphene oxide, and then the drug is released accurately, so that efficient use of the drug is realized, and the graphene oxide and the pesticide show an excellent synergistic mechanism.
When the water-based graphene oxide nanopesticide produced by the emulsification freeze-drying method is used to prevent and control plant fungal diseases, the drift problem of the nanopesticide is alleviated. And the water-soluble nano pesticide has good water solubility and anti-drift performance, and is a novel water-based nano pesticide.
Description
Water-based graphene oxide nanopesticide, as well as methods for its preparation and application
Technical area
The invention belongs to the field of nanotechnology and relates in particular to a water-based graphene oxide nanopesticide for the prevention and control of fungal diseases in crops as well as to a production process and its application.
Background
The conventional pesticide has the problems of poor dispersibility, poor stability, low biological activity, low degradation rate and the like due to the fact that the drug-laden particles of the conventional pesticide are large, the use rate of the target plants is less than 30%, and the dosage of the harmful organisms is less than 0.1%.
The data show that the pesticide can be sprayed in the field, and the loss of the pesticide by dripping, dust drift, rain washing and the like can be more than 70%.
The use of a large amount of pesticides leads to significant environmental pollution and excessive pesticide residues, and seriously threatens the physical and mental health of people.
Nanotechnology can effectively reduce pesticide residue pollution and improve the effective use rate of pesticides. In addition, the nano drug delivery system has the advantages of improving the dispersibility, stability and rate of use of the pesticide, extending the shelf life, reducing the residual amount, and the like more.
Graphene is a two-dimensional nanomaterial consisting of a single layer of carbon atoms, first described in 2004 by British scientists Novoselov and Gemm et al. has been discovered. Graphene oxide is a derivative of graphene and has a surface rich in oxygen-containing functional groups, so the graphene oxide has good water solubility and stability.
At the same time, the graphene oxide also has the ability to load the medicine with a structure similar to a benzene ring by pi-pi accumulation, hydrophobic effect and hydrogen bond effect, so the graphene oxide is widely used in the field of biological medicine.
The blade of the two-dimensional graphene oxide nanomaterial is called a nanometer and can cut through cell membranes of bacterial cells. The normal metabolism of bacterial cells can be impaired by an oxidative stress mechanism, which leads to cell death.
When a large amount of graphene oxide nanosheets is adsorbed on the surface of bacterial cells, the bacteria can be completely enveloped, so that they are physically isolated from the environment, and the microorganisms slowly die. The sterilization mechanism shows that the two-dimensional graphene oxide can be used as a drug carrier to achieve antibacterial synergistic effect.
The invention patent application with the application number 201310550703.7 discloses a manufacturing process for thiophanate methyl nanopesticides, which reduces the dosage and improves the effect of the pesticide. However, the existing patents on nano-pesticides are mainly concerned with the synergy of nano-pesticides, and the problem of nano-pesticide drift cannot be solved.
Disclosure of the invention
In order to overcome the shortcomings of the conventional pesticides and solve the environmental and social problems caused by the conventional pesticides, the invention is mainly aimed at providing a method for producing a water-based graphene oxide nanopesticide for the prevention and control of fungal diseases in crops.
The invention also aims to provide the water-based graphene oxide nanopesticide produced by the manufacturing process. The nano pesticide has good water solubility and anti-drift performance, can obviously improve the sterilization ability of the pesticide, and realizes the reduction and synergism of the pesticide.
The invention further aims at enabling the use of the water-based graphene oxide nanopesticide.
To achieve the purpose, the technical scheme adopted by the invention is as follows:
A production process for a water-based graphene oxide nanopesticide comprises the following steps:
(1) Dissolving graphene oxide in water and stirring vigorously to form an aqueous graphene oxide dispersion; dissolving the bactericide in dimethyl sulfoxide, N-N-dimethylformamide or methanol to form a bactericide solution in organic phase;
the concentration of the aqueous graphene oxide dispersion is 0.5-1 g / L;
the concentration of the bactericidal solution is 1.25: 1-3.75: 1;
(2) dropwise addition of the bactericidal solution into the aqueous graphene oxide dispersion with vigorous stirring and vigorous stirring for 24-48 hours after the dropwise addition to obtain a mixed solution, removing the free pesticide molecules by dialysis or purification of the reaction liquid, removing the supernatant by high-speed centrifugation and freeze-drying to obtain a product, namely the solid water-based graphene oxide nanopesticide;
the mass ratio of the bactericide to graphene oxide in the mixed solution is 2: 1-2: 3;
(3) Dispersing the solid water-based graphene oxide nanopesticide in an aqueous solution in the ratio of 1:100-1000, adding 1% tween 80 and oscillating to obtain an emulsion, namely the water-based graphene oxide nanopesticide.
The bactericide is preferably carbendazim or epoxiconazole, which is suitable for the prevention and treatment of fungal diseases.
The dialysis time is preferably 6 hours.
The number of washing operations with the reaction solution is preferably 3.
The rotational speed of the high-speed centrifugation is preferably 10,000 rpm.
The invention also provides the water-based graphene oxide nanopesticide produced by the production process.
The invention further provides for the use of the water-based graphene oxide nanopesticide in the prevention and control of fungal diseases of cultivated plants, wherein the fungal diseases of cultivated plants include rice blastosis, banded sclerotial rot, powdery mildew, damping off, anthracnose or leaf spot.
Compared with the prior art, the invention has the following advantages and advantageous effects:
The bactericide in the water-based graphene oxide nanopesticide (GO-carbendazim) produced by the invention adheres to the surface of the graphene oxide by the pi-pi conjugation effect, the hydrogen bonding effect and the electrostatic adsorption effect, and the graphene oxide damages the fungal cells, so that the drug is released accurately, the efficient use of the drug is realized, and the graphene oxide and the pesticide have an excellent synergistic mechanism.
If the water-based graphene oxide nanopesticide produced by the emulsifying freeze-drying process is used for the prevention and control of fungal diseases in plants, the hydrophobic surface of the two-dimensional leaf structure of the graphene oxide can easily attach to the plant leaves, so that the entrained nanopesticide can easily attach to the surface of the plants, and the problem of the drift of the nanopesticide is solved.
Detailed description
The present invention is described in more detail with reference to examples, but the embodiments of the present invention are not limited thereto. For process parameters that are not explicitly mentioned, reference can be made to conventional techniques.
