薄膜梯度扩散技术中捕收相微/纳结构材料的构筑及与无机离子作用的机制

The diffusive gradients in thin-films technique (DGT) provides an in situ means of quantitatively accumulating and measuring trace ions and labile species. The core part of this technique is the adsorption or coordination ability of the binding phase, which is related to the DGT performance for measuring pollutants. However, low adsorption selectivity and efficiency of traditional adsorbents in DGT technique generally result in inaccurate results. To solve the above questions, this project will carry out the preparation of micro/nanostructured adsorbents, such as zinc sulfide (ZnS), titanium dioxide (TiO2), iron oxide (Fe3O4 or Fe2O3) and composites, with the property to measure trace inorganic ions (as As, Cd, Cu, Pb and Hg) quickly and efficiently. And this research explored the basic principles and rules for capturing the trace inorganic ions via adsorption, metathesis and redox reaction effectively. It includes reaction parameters, such as solvent, temperature, concentration, pH, various surfactant and time, etc, on the synthesis of nano units (as nanoparticles and nanopores, etc.); micro/nanostructured materials can selective adsorb inorganic ions by modifying the function groups and the morphology; the relationship between the active faces of the micro/nanostructures unit and the Ag content for the inorganic ions removal rate, etc. This research not only offers a method of real-time monitoring trace inorganic ions in aqueous and soil systems, but also supplies a novel micro/nanostructured materials system for DGT technology.

薄膜梯度扩散技术（DGT）是一种原位定量采集并测量痕量污染物及其有效态的方法，其核心部分捕收相的吸附或配位能力高低决定了DGT技术定量采集污染物离子的能力；而传统捕收相会因吸附效率低或选择性不高，造成监测结果的不准确。本课题针对上述问题，通过水热或微波方法合成微/纳结构硫化锌、氧化钛、氧化铁及其复合材料，实现对无机离子砷、铜、镉、铅、汞、铬等的快速、痕量（ppb量级）监测。围绕吸附、置换与氧化还原反应捕获无机离子等关键问题进行原理规律和方法的探索研究。主要包括：不同合成参数（溶剂、温度、pH等）对微/纳结构中纳米结构单元（纳米颗粒和孔洞等）的影响；通过对微/纳结构形貌、官能团的修饰及结构的调控，实现对无机离子的选择性和快速富集；研究纳米结构单元活性面等对无机离子的富集量及富集速率的影响等。通过研究，旨在实现对水体等环境中痕量无机离子的实时监测，为DGT实际应用提供有效的微/纳结构材料体系。

本基金的总体目标是微/纳结构及其复合材料DGT捕收相的构筑，采用DGT 装置，利用吸附和置换反应实现对痕量无机离子的原位快速监测。深入认识微/纳结构材料的结构与作为DGT的捕收相性能之间的耦合关系，为其在环境治理领域的应用提供原理与技术支撑。本项目四年来完成了以下研究工作：（i）、获得了多种微/纳结构材料（ZnS纳米球、Fe3O4、碳纳米颗粒）及复合结构材料（纳米纤维素-聚吡咯复合材料、Fe3O4/C、Fe3O4@硅酸镁球、NH2-MIL-88(Fe)、β-FeOOH NRs/CF）的构筑及其结构参数、表面功能化修饰(巯基修饰)的方法，拥有新型DGT装置的自主知识产权；（ii）、确立了不同结构、形貌、表面修饰等与目标污染物离子（Cd2+、Cu2+、Pb2+、As(III)、As(V)、Hg2+、Cr(VI)和磷酸根）之间选择性富集的联系；（iii）、基于所获得的高效快速强富集和选择性的微/纳结构UiO-66材料，建立一个适用的新型DGT监测器，开展了对巢湖实际水体活性磷的检测与监测，为痕量原位监测无机离子提供材料体系和新方法。