Spatial confinement of Co-N/O nanocatalyst into hollow carbon nanosphere for water purification and its biotoxicity assessment

Abstract

Spatial confinement of reactive oxygen species (ROS) with short life period and environmental contaminants into the theoretical diffusion scale has been undoubtedly deemed as a significantly promising strategy for intensifying mass transfer of ROS and environmental contaminants in heterogeneous advanced oxidation processes. Herein, the nanoconfined strategy was employed to encapsulate short-lived ROS at nanoscale for boosting the utilization efficiency of ROS in advanced oxidation processes. The nanoconfined Co-HCNs was synthesized by partial encapsulation of Co-N/O catalyst into hollow carbon nanospheres (HCNs) to activate peroxymonosulfate (PMS) for water decontamination. Fully physical characterizations highlighted that Co-HCNs exhibited a structure of hollow nanosphere, and Co-N/O catalyst, whose chemical charge was between 0 and 2, had been partially encapsulated into hollow carbon nanospheres. This kind of hollow nanospheres structure was successfully applied for interception of macro-molecule and access of small molecule in the selective degradation of 3-aminophenol (3-AP). Experiments collectively illustrated that SO₄^•- and ¹O₂ were the major reactive oxygen species in the Co-HCNs/PMS system. The bio-toxicity of 3-AP to wheat seeds and zebrafish greatly decreased to ecological environment safety standards after degradation by Co-HCNs/PMS system, which was illustrated by Ecological Structure Activity Relationship (ECOSAR) Model, seed germination experiments and zebrafish toxicology assays. This confinement of Co-N/O nanocatalyst into hollow carbon nanosphere is expected to provide a viable strategy for selective degradation of organic pollutants via size-exclusion.