石墨烯担载纳米零价铁去除水中Cr(Ⅵ)的耦合效应与增强机理研究

Currently, chemical reduction technology based on zero-valent iron (ZVI) has been considered to be a promising pathway for the in situ remediation of heavy metals in water. However, reaction activity of the zero-valent iron during the treatment is diminished over time due to the inevitable passivation of the reactive iron surfaces. How to effectively solve the contradiction between electron transfer and surface passivation in zero-valent iron is a great task in the field of pollution control. This study proposes to construct a novel graphene/nanoscale zero-valent iron (NZVI) composite system for the removal of Cr(VI) pollutant in water. The objectives of this project are the following: (i) immobilization of NZVI onto graphene improves the stability of the NZVI; (ii) coupling with graphene facilitates the electron transfer in the NZVI and retards the surface passivation of the NZVI, thus enhancing the reactivity and prolonging lifetime of the NZVI. It also investigates the properties and influencing factor of the removal of Cr(VI) onto the composite system in order to deeply understand not only the relationship between structure coulping effect and reactivity of the NZVI but also the interaction between composite system and model pollutant. It is expect to provide reliable scientific and theoretical basis to develop a new type of the highly efficient NZVI-based composite system.

基于零价铁（ZVI）的化学还原技术是当前水环境中重金属污染原位修复的有效途径，然而零价铁在反应过程中伴生着难以克服的表面钝化而丧失反应活性。如何有效解决零价铁中电子转移与表面钝化之间的矛盾是污染控制领域中的一个重要课题。本研究提出构建一个新型石墨烯/纳米零价铁复合系统用于去除水中Cr(VI)污染物，旨在通过石墨烯的负载功能提高纳米零价铁的分散性和稳定性；通过石墨烯的结构耦合介导纳米零价铁中高活性电子的转移，有效缓滞在反应过程中所伴生的纳米零价铁的表面钝化，提高纳米零价铁反应活性和延长工作寿命。本项目还将深入研究该复合系统去除Cr(VI)的性能及其影响因素，探索结构耦合效应与反应活性之间的构效关系，揭示复合系统与目标污染物间的相互作用机理，期望藉此为开发新型高效纳米零价铁复合系统提供提供可靠的科学依据和理论基础。

本项目主要研究了石墨烯/纳米零价铁复合系统，通过材料的设计、优化和合成，获得了该系统去除水中Cr(VI)的优异性能，并对其去除水中Cr(VI)的机制进行了详细研究。石墨烯载体和表面活性剂的引入能够提高纳米零价铁的分散性和稳定性，耦合石墨烯亦能介导纳米零价铁中的电子转移，有效缓滞纳米零价铁的表面钝化和腐蚀，从而提高纳米零价铁反应活性和工作寿命，金属镍的引入有利于进一步增强该复合系统去除Cr(VI)的能力。受到石墨烯/纳米零价铁合成过程中自催化现象的启发，我们还设计了一类担载纳米金属的高效复合催化剂，并研究了它们在碱性条件下催化NaBH4水解产氢的性能。我们还制备了其它的含铁化合物，如MIL-53(Fe)、FeWO4、MIL-53(Fe)/Fe3O4、石墨烯/ MIL-53(Fe)，将其作为环境催化剂用于活化H2O2降解水中有机污染物和生物传感。