State Key Laboratory of Pollution Control and Resource Reuse/School of the Environment, Nanjing University, Jiangsu 210093, People's Republic of China.
Environ Sci Technol. 2013 May 7;47(9):4204-10. doi: 10.1021/es304872k. Epub 2013 Apr 12.
The main objective of this study was to test the possibility that graphene-based nanomaterials can mediate environmentally relevant abiotic redox reactions of organic contaminants. We investigated the effect of graphene oxide (GO) on the reduction of nitrobenzene by Na2S in aqueous solutions. With the presence of GO (typically 5 mg/L), the observed pseudofirst-order rate constant (kobs) for the reduction of nitrobenzene was raised by nearly 2 orders of magnitude (from 7.83 × 10(-5) h(-1) to 7.77 × 10(-3) h(-1)), strongly suggesting reaction mediation by GO. As reflected by the combined spectroscopic analyses, GO was reduced in the beginning of the reaction, and hence the reduced GO (RGO) mediated the reduction of nitrobenzene. It was proposed that the zigzag edges of RGO acted as the catalytic active sites, while the basal plane of RGO served as the conductor for the electron transfer during the catalytic process. Furthermore, changing the pH (5.9-9.1) and the presence of dissolved humic acid (10 mg TOC/L) were found to greatly influence the catalytic activity of RGO. The results imply that graphene-based nanomaterials may effectively mediate the reductive transformation of nitroaromatic compounds and can contribute to the natural attenuation and remediation of these chemicals.
本研究的主要目的是检验基于石墨烯的纳米材料是否能够介导有机污染物的环境相关非生物氧化还原反应。我们研究了氧化石墨烯（GO）对水溶液中硝基苯被硫化钠还原的影响。在 GO 的存在下（通常为 5mg/L），硝基苯的表观假一级速率常数（kobs）提高了近两个数量级（从 7.83×10-5 h-1提高到 7.77×10-3 h-1），强烈表明 GO 介导了反应。通过综合光谱分析表明，反应开始时 GO 被还原，因此还原的 GO（RGO）介导了硝基苯的还原。提出 RGO 的锯齿边缘作为催化活性位点，而 RGO 的基面在催化过程中充当电子转移的导体。此外，发现改变 pH 值（5.9-9.1）和溶解态腐殖酸（10mgTOC/L）的存在极大地影响了 RGO 的催化活性。结果表明，基于石墨烯的纳米材料可能有效地介导硝基芳烃化合物的还原转化，并有助于这些化学物质的自然衰减和修复。
