基于石墨烯协同增强近红外吸收比色传感材料的构筑及应用

Nowadays, the situation of environmental contamination by heavy metals is getting more and more serious. To develop a novel method for rapidly detecting and separating heavy metal ions will possess important theory and practice significance, which is necessary to protect the environment, maitain human health and promote the social sustainable development..To investigate and validate the rationality of structural design of the target colorimetric sensing composites, a theoretical calculation is conducted using the Gaussian 04 software suite with a B3LYP/6-31G level of theory, which is used to understand the geometrical characters of the candidates. On the basis of calculation results, some near infrared absorbing organic dyes such as squaraine, azo and crown ether are controllably modified to the graphene substrates via covalent bonding, hydrogen bond or π-π stacking self-assembly. The resulting near infrared absorbing colorimetric sensing composites are proposed to possess little background absorption, friendly to environment and strong enrichment ability..The effects of the structure and arrangement of chromophores, and the size and specific surface area of nano substrates on the sensing property of the target composites will be studied in details. The synergetic enhancement mechanism of π-conjugated substrates to chromophore sensing are to be revealed, which can provide theoretical basis for constructing high performance sensing composites..The selective recognition mechanism of composites to heavy metal ions and their effect on absorption spectra are investigated to realize naked eye detection of heavy metal ions under the optimized conditions. The adsorption and desorption mechanism of nano composites to heavy metal ions are studied to further separate heavy metal ion and recycle sensing composites..In conclusion, a new preparation and application technology for green colorimetric sensing composites has been developed.

针对当前日趋严重的环境重金属污染，研究开发快捷检测与分离重金属的新方法，对保护环境、维护人类健康和促进社会可持续发展都具有重要的理论和实践意义。本项目在理论计算的基础上，通过共价键、H键、π-π堆叠自组装等方法将菁、偶氮和冠醚等近红外吸收染料可控修饰到纳米石墨烯基底上，构建一类背景吸收小、环境友好、富集力强的近红外吸收纳米比色传感材料；研究生色团的结构与排列方式、基底的纳米尺寸与比表面积等结构因素对传感性能的影响规律，揭示大π-共轭基底对生色团传感效应的协同增强机制，为高效传感材料的构建提供理论依据；分析传感材料与不同重金属离子的选择性识别机理及对吸收光谱的影响，优化检测条件，实现对重金属离子"裸眼"检测；探讨纳米材料对重金属离子的吸附与解吸附机理，实现富集分离重金属离子和循环利用传感材料的目的；消除因检测对环境造成二次污染，开发一类无污染的比色传感材料制备及应用的新技术。

本项目针对当前日趋严重的环境重金属污染，研究开发一类比色检测与分离重金属的新方法，保护自然环境、促进社会可持续发展。在相关研究领域发表SCI论文16篇，IF>3.5 的论文11篇，IF>6的论文2篇。申请国家发明专利5项，已授权3项。.① 比色传感材料的构筑、结构与性能研究方面：在Gaussian程序上对拟设计材料的结构、性能、键合能力及轨道能级进行推导、论证的基础上，设计构筑了系列有机（方酸菁类、偶氮类、Schiff碱和荧光素等衍生物）、无机纳米和超分子组装生色团，进一步与石墨烯基底复合，构筑不同的复合材料；通过结构的控制可以增强传感材料对金属离子的选择性配位能力，同时染料分子的偶极矩减小，π-电子更加离域，HOMO与LUMO间的△E降低，利于电子跃迁。为光学性能优良、识别能力强的功能材料设计制备提供了新的依据。.② 重金属离子比色分析检测方面：以重金属Hg2+比色富集检测为例，探讨将所构建的比色传感材料，分别应用于环境水Hg2+的比色富集检测上，检测限逐步提高到5.6 ×10−9 mol•L−1，远远低于国际卫生组织（WHO）所规定3.0×10–8 M的健康标准；在此基础上，对环境水中Fe3+, Fe2+, Sn2+和F−的比色检测的检测限均满足WHO所规定的健康标准；实现了对水环境中常见重金属离子的比色检测。.③ 重金属离子的分离和传感材料回收再利用方面：在详细探讨复合材料对重金属离子的吸附与解吸附机理的基础上，将其有效地应用到环境重金属富集与分离上，实现富集分离重金属离子和循环利用传感材料的目的。即：比色检测汞离子之后，利用纳米效应和物理吸附，经0.1 μm的微孔膜过滤，即可对水样中重金属Hg2+ 进行快速有效分离；ICP检测分析，汞离子的富集分离率可以达到94%以上，选择性好；富集检测完成后，传感器与EDTA作用，可回收再利用；石墨烯复合材料在较高的浓度下，仍然有80%以上的待测细胞存活，无毒无污染。为新型比色富集传感复合材料的应用奠定坚实的实践基础。