Light mediated the interface interaction of commercial graphene oxide in natural surface water: photo-transformation, microbial diversity and metabolism

Abstract

This study investigated the impact of light on the environmental behavior and interaction mechanism of commercial graphene oxide (CGO) in natural surface water. Additionally, it systematically studied the effect of CGO's environmental behavior on the microbial diversity and metabolic mechanisms of microorganisms. Under UV light conditions, the change in the colloidal properties and stability of CGO in natural surface water mainly depends on aggregation rather than photo-transformation. UV exposure induces the formation of edges or “border defects” in the CC framework that promotes CC vibration and interaction between CGO and cations, thereby promoting the aggregation–sedimentation process. The aggregation–sedimentation process of CGO has a greater effect on lower abundance phyla (Bacteroidota etc.) and genera (Cyanobium_PCC-6307 etc.). The metabolomics results show that CGO affects photorespiration, energy and carbohydrate metabolism, maintaining energy status and perturbing oxidative stress, resulting in biotoxicity. Meanwhile, UV exposure affects the microbial metabolism of xenobiotic pollution. The combined effect of CGO and UV exposure further disturbs glycine, serine, and threonine metabolism. This project will help provide a theoretical basis and support for assessing the potential ecological health and environmental risks of graphene-based nanoparticles in real water environments.