中文摘要：

应用同步辐射真空紫外圆二色光谱、紫外-可见及红外光谱等技术研究了氧化石墨烯（Graphene Oxide,GO）与腐殖酸（Humic Acid,HA）在水溶液中的相互作用,探讨了不同配比、溶液p H及不同温度条件下GO与HA之间的相互作用对GO在水溶液中形态的影响。研究表明,一定条件下GO在水溶液中显示出圆二色性,其强弱与GO在水溶液中的形态结构有关。HA可通过极性相互作用和π-π相互作用吸附在GO表面,形成GO-HA复合物,改变体系的圆二色性,这种影响与二者的质量比、水环境p H和温度相关。GO-HA与GO相比,厚度增加,分散性提高,圆二色信号降低;GO-HA体系p H值升高和温度降低,有利于GO-HA折叠构象的形成,使得体系的圆二色信号升高。

英文摘要：

Background： Graphene Oxide （GO） is a type of two-dimension carbon nanomaterial with promising environmental application due to its good solubility in water, high absorbability and catalytic activity. Humic Acid （HA） is the main component of Natural Organic Matter （NOM） in water, which could be adsorbed on the surface of GO nanosheets via π-π interaction and then affect the physicochemical properties of GO in aqueous system. Purpose： Investigating the interaction between GO and HA will provide some insights for environmental application of GO. Methods： We employed Synchrotron Radiation Circular Dichroism spectroscopy （SRCD）, Ultraviolet-Visible spectroscopy （UV-Vis） and Fourier Transform Infrared spectroscopy （FTIR） to explore the interaction between GO and HA under different mass ratio of HA to GO, environmental pH and temperature. Results ＆ Conclusion： UV-Vis spectroscopy of GO-HA showed that the intensity of the absorption peak at 228 nm gradually increased when the mass ratio of HA to GO increased to 4：1 from 1：4 and the FTIR C-O stretching vibration shifted and decreased, indicating the strong n-n interaction and hydrogen bonding between GO and HA. GO showed a broad peak at about 240 nm in SRCD spectra which origin from its surface O-containing functional groups, folding or curl of the nanosheets. SRCD indicated the interaction between GO and HA could change the dispersion behavior of GO and then affect CD activity of GO-HA, depending on the mass ratio of HA to GO, environmental pH and temperature. GO-HA showed higher CD activity with the increased pH and decreased temperature （4 ~C） due to the increase of folding state.