Abstract：
Graphene oxide (GO) is widely employed due to its outstanding properties, leading to an increasing release into the environment and natural waters. Although some studies have reported on the photo-transformation of GO, its behavior in complex natural waters remains inadequately explored. This study demonstrates that different types of ions may promote the photoreduction of GO in the order of Ca2+ > K+ > NO3- > Na+ by interacting with the functional groups on the surface of GO, and the photoreduction is enhanced with increasing ion concentrations. Additionally, natural organic matter (NOM) can inhibit the photoreduction of GO by scavenging reactive oxygen species. However, with increasing NOM concentrations (≥ 5 mgC/L), more NOM adsorb onto the surface of GO through hydrogen bonding, Lewis acid-base interactions, and π-π interactions, thereby enhancing the photoreduction of GO. On this basis, our results further indicate that the combined effects of different ions, such as Ca2+, Mg2+, NOM, and other complex hydrochemical conditions in different natural waters can promote the photoreduction of GO, resulting in a reduction in oxygen functional groups and the formation of defects. This study provides a theoretical basis for assessing the long-term transformation and fate of GO in natural waters.
摘要：
氧化石墨烯(GO)因其优异的性能而被广泛应用,导致越来越多的释放到环境和自然水域。尽管一些研究报道了GO的照片转换，它在复杂的自然水域中的行为仍未得到充分探索。这项研究表明，不同类型的离子可能通过与GO表面的官能团相互作用，以Ca2>K>NO3->Na的顺序促进GO的光还原。并且光还原随着离子浓度的增加而增强。此外,天然有机物(NOM)可以通过清除活性氧来抑制GO的光还原。然而,随着NOM浓度的增加（≥5mgC/L），更多的NOM通过氢键吸附到GO表面，路易斯酸-碱相互作用，和π-π相互作用，从而增强GO的光还原。在此基础上,我们的结果进一步表明，不同离子的综合作用，如Ca2+，Mg2+,NOM,和其他复杂的水化学条件在不同的自然水域可以促进光还原GO，导致氧官能团的减少和缺陷的形成。本研究为评估GO在自然水域中的长期转化和命运提供了理论依据。
