辐照引发的凹凸棒土纳米网络控制吡啶类农药分子迁移的作用机理研究

Clay could control the release of pesticide, which is important for the reduction of environment pollition. The present work mainly focuses on the release-control performance of clay composites on pesticide, however the interaction between clay itself and pesticide molecules, and the influence of the microstructure and surface groups of clay on the migration of pesticide molecules are unclear. It was found that attapulgite nanonetworks induced by electron beam irradiation could effectively control the migration of pyridine pesticide molecules. Based on this, we proposed that there could be some interactions existing between attapulgite nanonetworks and pyridine pesticide molecules, and these interactions were favorable to cause the pesticide molecules absorbed to the nanonetworks which could be retained by leaf surface or soil to achieve the control of migration. In this project, we will study the effect of electron beam irradiation on the microstructure and surface groups of attapulgite through traditional methods, investigate the the control effect of nanonetworks induced by electron beam irradiation on the migration of the molecules of pyridine pesticide as a model pesticide, and analyze the chemical bonds and molecular force between nanonetworks and pesticide molecules to obtain the mechanism how to control the migration of pyridine pesticide molecules by attapulgite nanonetworks. This work is significant for obtaining the control effects of clays on pesticide molecules, and meanwhile provides a new modification method for nano materials, which are beneficial for the development of new high-performance environmentally-friendly pesticide formulations based on clays.

黏土可以控制农药释放，对于降低环境污染具有显著作用。现有研究主要关注黏土复合物对农药的释放控制，然而黏土自身与农药分子的相互作用，黏土微观结构和表面基团对农药分子迁移的影响都还不清楚。我们研究发现电子束辐照引发的凹凸棒土纳米网络可以明显控制农药分子的迁移，据此我们认为纳米网络与农药分子之间应存在一定相互作用，这些作用可促使农药分子结合在网络结构中，借助叶面和土壤对纳米网络的阻滞，实现控制农药分子的迁移。项目拟通过常规手段研究电子束辐照对凹凸棒土微观结构及表面基团的作用规律；以吡啶类农药为代表，考察辐照引发的凹凸棒土纳米网络对农药分子迁移的控制作用，解析纳米网络与农药分子之间的化学键及分子力，借此阐明凹凸棒土纳米网络控制吡啶类农药分子迁移的机理。本研究对于揭示黏土对农药分子的控制规律具有重要意义，同时也展示了一种新型纳米材料改性方法，为开发高效黏土基纳米环保农药制剂提供借鉴。

针对传统农药低附着、高流失引发的环境污染关键共性问题，项目组前期利用凹凸棒土和硅藻土为主体材料，经过高能电子束改性研发出农药控失剂，可显著提高农药附着力，降低流失，但机理尚不清楚。项目研究了高能电子束结合水热法对两种黏土的改性规律，考察了控失剂对农药控失性能，并分析了控失剂与农药分子之间的相互作用，揭示了控失机理。研究发现，改性处理可显著提高凹凸棒土分散性，清除了硅藻土纳米孔道中的杂质，明显提高空隙率，暴露更多的表面基团，从而通过氢键作用将更多的农药分子装载入空隙中，制成控失农药。控失农药易被作物叶面粗糙结构阻滞，具有较强的附着力，从而表现出低流失、高效率、低污染。该工作初步建立了纳米材料对农药迁移控制理论，突破了农药高效利用技术瓶颈，有力指导了农药控失剂的产业化应用，为农药减施增效提供了坚实理论依据和有效技术支撑，对于生态农业建设及农药行业转型发展具有重要意义。