氧化石墨烯在水环境条件下的化学转化及其地球化学响应：悬浮、吸附和毒性

Graphene oxide（GO）is the most important derivative of graphene, and its application potentials in many fields such as biomedicine, environmental protection are even higher than graphene itself. However, GO is a type of sub-stable and complicated material, and its chemical structure and composition could be altered spontaneously. This alteration becomes a main limitation on application and storage of GO. Then, how will GO be transformed in natural aqueous environments? How will the environmental geochemical behaviors of GO be altered during the transformation processes? This proposal will answer these two scientific questions through the following systematic researches. For the (photo)chemical transformation of GO, this proposal will study the transformation rate and mechanism of GO under ultraviolet-visible irradiation, buffering systems, and the presence of natural reductants, respectively. The synergistic effect of these three conditions will also be studied, and the endpoint of GO transformation in natural aqueous environment will be obtained. For the environmental geochemical behaviors of GO after transformation, the following geochemical behaviors and related altering mechanisms will be addressed: dispersion/ sedimentation behaviors, adsorption behaviors towards heavy metals and organic contaminants, and toxicity to different organism species such as bacteria, algae and aquatic plants. The data obtained from this proposal will provide important theoretical support for the storage and environmental application of GO in aqueous phase. This proposal will also provide important information on better understanding geochemical behaviors and toxicity of GO in natural aqueous environments.

氧化石墨烯（GO）是石墨烯最重要的一种衍生物，它在生物医学、环境保护等众多领域的应用潜力甚至超越了石墨烯。然而，GO是一种亚稳态的复杂材料，其化学结构和组成能够自发的改变，已成为制约GO应用的重要因素。那么，GO在水环境条件下将会如何转化呢？GO的化学转化过程将会对其环境地球化学行为产生怎样的影响呢？本项目拟针对这两个科学问题展开系统研究。在GO的（光）化学转化方面，拟分别研究GO在光照、缓冲水相体系和环境还原剂存在下GO的不同转化效率和转化机理，并得到三类条件协同作用下GO的转化终点；在转化后GO的环境地球化学行为方面，拟系统研究GO转化后，以下地化行为的改变和变化机制：悬浮/沉降行为、对重金属离子和有机污染物的吸附行为、对细菌、藻类和水生植物等不同类型生物的毒性行为。本项目将为GO的保存和环境应用提供理论支持，为深入理解GO在自然水环境中的地球化学行为和生态安全提供重要信息。

石墨烯等纳米颗粒在生物医学、环境保护等众多领域具有巨大的应用潜力。然而，氧化石墨烯（GO）等纳米颗粒的化学结构和组成能够在环境中自发的改变，已成为制约GO等纳米颗粒应用的重要因素。本项目深入研究了米颗粒在水环境中的悬浮-沉降、吸附和转化等关键环境过程，阐明了纳米颗粒的的悬浮/沉降行为、对重金属离子和有机污染物的吸附行为的调控作用；并以藻类、植物细胞和人体细胞等不同生物个体为受试生物，揭示了GO等材料的致毒机制、跨膜运输过程和蓄积规律；阐明了天然有机质和矿物颗粒等环境介质通过影响GO的转化过程和地化行为调控其毒性效应的主要机制。本项目为GO等纳米颗粒的保存和环境应用提供理论支持，为深入理解纳米颗粒在自然水环境中的地球化学行为和生态安全提供重要信息。