College of Environmental Science and Engineering, Ministry of Education Key Laboratory of Pollution Processes and Environmental Criteria, Tianjin Key Laboratory of Environmental Remediation and Pollution Control, Nankai University, Wei Jin Road 94, Tianjin 300071, China.
College of Environmental Science and Engineering, Ministry of Education Key Laboratory of Pollution Processes and Environmental Criteria, Tianjin Key Laboratory of Environmental Remediation and Pollution Control, Nankai University, Wei Jin Road 94, Tianjin 300071, China.
Water Res. 2016 Oct 15;103:416-423. doi: 10.1016/j.watres.2016.07.051. Epub 2016 Jul 22.
The rapidly increasing and widespread use of graphene oxide (GO) calls for immediate attention on the environmental fate of this material. To date, very little is known about the environmental transformation of GO. This study explored the changes of physicochemical properties of GO from chlorination and chloramination, which simulated the reactions occurring in water and wastewater treatment systems. Significant changes of GO surface O-functionalities occurred and scrolling of graphene sheets (those of very large sizes) were observed upon the treatments. Chloroform, a byproduct from chlorination was also detected, indicating the ring-opening on the edge of GO nanosheets. The changes of GO surface O-functionalities were attributable to the oxidation of quinone groups of GO by chlorine or chloramine. The scrolling of large-sized GO sheets may be attributable to the destruction of benzene rings at the edge of the GO. The results of membrane filtration experiments and column transport experiments indicated that chlorination and chloramination enhanced the mobility and transport of GO, likely by increasing the colloidal stability and inhibiting the agglomeration of GO nanosheets. The findings of this study further underline the significant implications of GO transformation on the fate and transport of this new nanomaterial.
氧化石墨烯（GO）的应用迅速普及，对其在环境中的归宿应立即引起重视。目前，对于 GO 的环境转化知之甚少。本研究通过氯化和氯胺化模拟水处理和废水处理系统中的反应，探讨了 GO 理化性质的变化。处理后，GO 表面的含氧官能团发生了显著变化，并且观察到石墨烯片的卷曲（尺寸非常大）。氯化反应的副产物氯仿也被检测到，表明 GO 纳米片边缘的开环反应。GO 表面含氧官能团的变化归因于氯或氯胺对 GO 中醌基团的氧化。大尺寸 GO 片的卷曲可能归因于 GO 边缘苯环的破坏。膜过滤实验和柱传输实验的结果表明，氯化和氯胺化通过增加胶体稳定性和抑制 GO 纳米片的团聚，增强了 GO 的迁移和传输能力。本研究的结果进一步强调了 GO 转化对这种新型纳米材料的归宿和迁移的重要影响。
