表面活性剂修饰蒙脱土可控构建及其农药控释机制研究

As Controlled release formulation of pesticides is an effective approach to achieve the desirable purpose of increasing the utilization of pesticides and reducing the environmental residuals. Due to the low price, eco-friendly nature and strong adsorption ability, the montmorillonite presented potential applictiaon in the carriers of the pesticides.This project is based on the hydrophobic nature of pesticide and the ionic charateristic of the earth, depending on the adjustable morphology and mesopore of montmorillonite,intended to prepare high efficient surfactant modified inorganic clay carrier for pesticides and construct host(montmorillonite)-bridge(surfactant)-guest(pesticide) controlled-release systems to overcome the disadvanges of inorganic clay in controlled release, adsorption amount and desorption ability. The effect of the pore characteristic and surface feature on the distribution in the confined pores of montmorillonite would be investigated. The migration mechanism of the molecules in the confined pores would be explored, and he effect of pore and surface features on the adsorption rate and the controlled released ability will be studied. Through this project the high efficent pesticide carrier would be obatianed and the scientific theories and pricnciples about the migration in the ordered pores would be established. This study will broaden new theories and instuctions in pesticide carrier area, and be of great signficant to ensure the high utilization and low emission of the pesticides.

农药控制释放技术已成为了提高农药利用率，降低环境残留的有效手段。蒙脱土具有价格低廉、环境友好和吸附能力强等优势，在农药载体应用方面有广阔的应用前景。基于无机黏土作为农药载体载药量较低和释放难以控制的问题，本项目依据农药分子的疏水性和土壤的离子特征，利用蒙脱土的形貌和孔径可控，通过表面活性剂改性的蒙脱土为载体负载各类农药，构建主体（蒙脱土）—桥梁（表面活性剂）—客体（农药）缓释体系，研究蒙脱土孔道特征、表面性质对农药在孔道限域空间中的分布行为，探索蒙脱土孔道内受限迁移机理、孔道与表面结构对其吸附率和控释能力的影响。通过本项目的研究，将获得高性能的农药控释载体，解释孔道中农药的分子迁移特性，为农药高效缓释载体的制备提供新思路和理论指导，为我国实现农药减排增效提供有力保障。

蒙脱土材料是最具代表性的层间黏土材料之一，其来源丰富，并由于其具有独特的天然二维层间结构、高溶胀能力、高活性位点、高比表面、离子交换能力及易插层改性等优点从而成为材料研究的热点之一。本项目采用与土壤的成分接近且廉价无毒的蒙脱土作为农药的载体，设计一种以离子响应开关控制、的“智能”缓释农药。以疏水作用、限域效应及离子交换等协同效应对农药负载量和释放速率的影响为核心，研究智能缓释农药的构筑及机理，揭示主体-客体间作用机制，探讨农药缓释机理。完成主体—活性位—客体缓释体系的构建，初步建立载体与农药负载的构效关系。同时研究环境调制（农药的浓度、温度、时间、介质、表面活性剂浓度等）对载药的影响，优化纳米材料负载农药的制备条件，获得对蒙脱土等载体载药量的调控途径。开展载药农药缓释动力学研究，考察载体组成及孔结构参数、缓释介质的性质对农药释放的影响，建立农药在载体中的扩散模型，获得对农药可控释放的调控途径。为克服蒙脱土结构单一，载药量低的缺点，本研究利用水热方法改性成功插层，或通过离子交换将具有空轨道的过渡金属离子与带有N原子的有机农药通过配位作用增强载体-药物相互作用，从而增强了载体对有机农药的吸附能力20%以上。并通过进一步表征探讨蒙脱土材料孔径、孔容和比表面及表面性质的构效关系，从而解决农药分子与载体间的作用方式和作用强度的控制问题。相关数据及研究成果在SCI收引杂志上正式发表八篇研究性论文，并有一篇已接收，预计在2020年末正式发表。