Preparation And Application Of Controlled Release Pesticides And Fertilizers Based On Attapulgite

Agricultural production is an important basic industry for any country,this point has been accepted around the world.Especially for China,a country has 1.3 billion people,agriculture has become the lifeblood of the country and the foundation of people's life.In the process of agricultural production,there are all kinds of problems.In order to prevent diseases,pests and weeds damage to crops,farmers will use a lot of pesticides during agricultural production.And in order to increase the yield of food,they will also use a lot of fertilizer in the process of growing crops to increase the nutrient intake of plants.However,using lots of pesticide and fertilizer also brought some bad influence to the environment.Such as pesticide residues will threaten human's and animal health and extensive use of fertilizer could make the soil harden and improve the agricultural production cost.In order to reduce the harm of pesticide and fertilizer on the environment and improve their efficiency,this paper used attapulgite as the main carrier and decorated different materials to make smart nanocomposites.Achieve the purpose of controlling release of materials carried in the material though adjusting temperature.Our work of this thesis is as follows:1.In this work,temperature-responsive controlled-release herbicide particles(TCHP)with a core-shell structure were developed using a nanocomposite consisting of attapulgite(ATP),NH4HCO3,amino silicon oil(ASO),polyvinyl alcohol(PVA),and glyphosate(Gly).Therein,the ATP-NH4HCO3-Gly mixture acts as the core,and ASO-PVA acts as the shell.ATP possesses a porous micro/nano networks structure and thus can bind a large amount of Gly molecules.NH4HCO3,as a foaming agent,can produce CO2 and NH3 bubbles to make plenty of micro/nano pores in the ASO-PVA shell,which facilitates the release of Gly.The pore amount can be efficiently adjusted by temperature,meanwhile the PVA shell tends to dissolve in aqueous solution at a high temperature,so that the release of Gly can be easily controlled.Importantly,this technology could effectively decrease the loss of Gly under simulated rainfall and thus improve the control efficiency on weeds.The hydrophobic ASO endows TCHP a high stability in aqueous solution for at least three months.This work provides a promising approach to control the release and loss of pesticide,which has a potential application to enhance the utilization efficiency,and thus lower the environmental pollution.2.In this work,a temperature-controlled-release and collectable iron fertilizer(TCIF)with a core-shell structure was developed using a nanocomposite consisting of attapulgite(ATP),ferroferric oxide(Fe3O4),ferrous ammonium sulfate hexahydrate(FASH),ethylene oxide/propylene oxide block copolymer(F-127),and amino silicon oil(ASO).Therein,the core was made up of ATP-Fe3O4-FASH mixture,and the shell was composed of ASO-F-127.ATP with a porous micro/nano networks structure could bind a great many of Fe2+ through electrostatic attraction.FASH,as the iron fertilizer and a foaming agent in this system,can produce NH3 at 100? to make a plenty of micro/nano pores in the ASO-F-127 shell,which facilitated the release of Fe2+.F-127,a thermally sensitive polymer,can open and close the pores through the liquid-gel transition under different temperature to adjust the release of Fe2+.The hydrophobic ASO endowed TCIF a high stability in aqueous solution for at least 100 days.Fe3O4 made TCIF own a relatively high magnetism so that TCIF could be conveniently collected from water and soil.Significantly,this technology could improve the utilization efficiency of iron fertilizer and promote the absorption of Fe2+by maize.Besides,TCIF displayed a good reuse performance,which could favor to lower the cost and decrease the residual.