Preparation of carbon nanofibrous mats encapsulating zero-valent Fe nanoparticles as Fe reservoir for removal of organic pollutants

Abstract

Zero-valent iron nanoparticles (ZVI NPs) display promising potential in the removal of organic pollutants and heavy metal ions for environmental remediation. However, it is crucial to prevent the oxidation of ZVI NP and control the release of Fe ions under storage and working conditions. In this study, ZVI NPs are encapsulated in single-axial and co-axial carbon nanofibers by electrospinning polyacrylonitrile (PAN)/Fe³⁺ nanofibrous mats with different structures and then annealing the PAN nanofibrous mats in reduction atmosphere. SEM images show that the diameter of the carbon nanofibers is affected by the structure of the nanofibers and the ZVI NPs content after the annealing treatment. The formation of ZVI NPs is confirmed through XPS spectra and HRTEM characterization. The catalytic degradation of organic pollutants by ZVI NPs encapsulated in the carbon nanofibrous mats is evaluated using methylene blue (MB). The results show that the degradation rate of MB is significantly improved when the ZVI NP content encapsulated in the nanofibers increased. MB is completely degraded by the nanofibrous mats with either the single-axial structure or the co-axial structure, but at a higher degradation rate by the single-axial structure than that by the co-axial structure. These results provide alternatives to utilize the carbon nanofibrous mats encapsulating ZVI NPs as Fe reservoir for the removal of organic pollutants in an emergent or long-term situation for environmental remediation.