Preparation And Application Of Three Slow/Controlled Release Pesticide Delivery Carriers

Sustained-release formulations have taken on added significance in the pesticide industry in recent years because of these formulations have advantages like:reducing worker exposure by means of reduction in pesticide toxicity and reducing environment evaporation/leaching afer application.In this study,three types of slow release formulations of pesticide were prepared by environmentally friendly process and their physical/chemical properties were studied.The main findings were as follows:(1)Encapsulation of pesticides with polymeric materials is a promising approach to improve the efficacy of pesticide application and reduce the potential risks of pesticides to the environment and humans.In this study,a novel imidacloprid microcapsule was prepared by depositing a polydopamine(PDA)layer on imidacloprid via oxidative self-polymerization followed by a polyurea(PU)layer on PDA via copolymerization.No organic solvent or surfactant was used in the preparation process.The entrapment rate of imidacloprid was determined to be 47.28±0.87%,and the pesticide loading of microcapsule was 68.36±1.113%.Several characterization assays,such as Fourier infrared transform analysis,thermogravimetric analysis and contact angle analysis,were conducted to confirm the encapsulation of imidacloprid.Dynamic light scattering showed that the microcapsule size ranged from hundreds of nm to several mm,which was similar to the results obtained by scanning electron microscopy.The microcapsule had a stable dispersion up to one month in the aqueous solution.Moreover,the microcapsule was able to release imidacloprid in a sustainable manner,as the release was much slower than the non-encapsulated imidacloprid.(2)A new fluorescence enhancement mechanism based on Schiff base ligand and magnesium complexation is established.The co-ordination number of the Schiff base ligand-magnesium complex(2:1)can be tuned to(1:1)in the presence of amines to induce significant fluorescence enhancement.Using this approach,a novel and easily available fluorescent chemosensor was designed,which showed highly selective recognition toward magnesium and amines in ethanol.Based on the mechanism,the pesticide fluorescent carrier was designed.Through the fluorescence intensity to establish the standard working curve,to achieve the quantitative evaluation of pesticide release.(3)Two kinds of slow-release pesticide granules were prepared,and the active ingredients of pesticides were compounded by compound fertilizer granulation,inclusion compound,adsorption coating,etc.,and the fertilizer and pesticide in granules were scientific compatibility.The Membrane materials using thermosetting resin materials,by adjusting the process parameters to achieve in situ coating process,the preparation process is simple,environmentally friendly,easy to control.The results showed that the granules had high homogeneity,and the slow release period was 21 days,and the sustained release period was 14 days.In the field application test,showing a good target chemical control and crop yield effect,Rice yield increased by 25.75%.