构建以环糊精为基体的超分子识别膜用于水体被动采样技术的研究

The concentration of contaminants in environment is indispensable for ecological risk assessment and their environmental management decision. Passive sampling technology is a critical new technology to obtain the environmental concentrations of contaminants. Herein, screening of proper sorbent and construction of sampling device are the key for its feasible applications. In this study, on the basis of the special structure of cyclodextrin with hydrophobic cavity and hydrophilic exterior, a cyclodextrin-polymer film with supramolecular recognition property will be synthesized, and a diffusive gradients in thin-films based passive sampling device will be constructed by employing the synthesized polymer films as sorbent, which can be used to in-situ monitor the concentration of emerging weak hydrophobic organic chemicals. Specifically, triclocarban, triclosan and methyl triclosan will be chosen as model chemicals, and the molecular recognition mechanism of cyclodextrin to the three chemicals will be probed using experiment combined with molecular modeling method. Secondly, the passive sampling parameters of the self-developed device will be optimized in laboratory microsystem, and a quantitative method for detecting the concentrations of the three chemicals will be established. Finally, the device will be field deployed on the Nanjing section of Yangtze River, to investigate the occurrence of three chemicals in lateral and vertical directions. Thereby, we can reveal the pollution status of the three contaminants in regional scale, analyze the characteristics of input source, and evaluate quantitatively the ecological risk, which will help us to assess the regional environmental fate of the emerging organic chemicals.

环境中污染物的浓度是进行生态风险评估和制定环境管理决策的基础数据。被动采样技术是获取污染物浓度的新型技术，其中决定该技术应用的关键在于主体吸附相的选择和采样装置的构建。本项目基于环糊精内疏水外亲水的特殊结构，拟制备具有超分子识别性能的环糊精聚合膜，并以此为主体吸附相构建薄膜梯度采样装置，用于对新兴弱疏水性有机污染物浓度的原位监测。首先，选用新兴污染物三氯卡班、三氯生、甲基三氯生为模型化合物，采用实验与分子模拟相结合的方法揭示聚合膜对这类污染物的分子识别机制。其次，使用室内微系统优化被动采样参数，建立测定上述污染物浓度的定量方法。最后，将该装置应用于长江南京段，原位监测三氯卡班、三氯生、甲基三氯生沿径流方向和垂直方向的浓度变化，揭示该类污染物在区域尺度上的污染状况、解析输入源特征、定量评估生态风险，从而客观评价该类新兴有机污染物的区域环境行为。

环境中污染物的浓度是进行生态风险评估和制定环境管理决策的基础数据。被动采样技术是获取污染物浓度的新型技术，其中决定该技术应用的关键在于主体吸附相的选择和采样装置的构建。本项目研制了一种具有选择性识别功能的被动采样技术，用于水体中有机污染物浓度的原位监测。首先选取合适的环糊精种类和含量，制备了环糊精聚合膜，通过多种手段对膜材料进行表征，结果表明环糊精聚合膜具有良好的亲水性、热稳定性和富集性能。其次，基于环糊精聚合膜良好的理化性质和吸附性能，研制了一种以环糊精聚合膜为结合相的薄膜扩散梯度被动采样装置。优化采样其扩散速率、采样速率、吸收速率和吸能力。最后，将采样装置野外布设于南京市的九乡河和秦淮河，同时采用主动采样-固相萃取法测定水体中污染物的浓度。通过对比，被动采样测定与主动方法得到的污染物浓度水平没有显著性差异，这证实了所研制的被动采样装置在监测水体中污染物的可行性。