Cellulose as a Key Biomass Component for the Preparation of Nano Zero-Valent Iron by Carbothermal Reduction: Application to Peroxydisulfate Activation

Abstract

In carbothermal reduction, the influence regulations of biomass components on the performance of preparing nano zero-valent iron (nZVI) are not clear, and the mechanism of action remains to be explored. Biomass components such as cellulose, hemicellulose, lignin, and amylum were used to prepare various of carbon-loaded nano zero-valent iron (Fe0/C). The pyrolysis process of the mixtures showed that cellulose promotes the production of nZVI in the prepared materials by generating more reducing gases (e.g. CO, CH4, and H2). The swelling effect of cellulose facilitates the preservation of nZVI. It was demonstrated that increasing the cellulose content of the mixture led to higher zero-valent iron content and greater activation efficiency of peroxydisulfate (PDS). nZVI prepared by carbothermal reduction using natural biomass bagasse (Fe0/CB) removed 99.8% of metronidazole in 60 min. The bagasse's cellulose content was found to be 59.5%, while the experimental results demonstrated that the prepared materials exhibited excellent properties when the cellulose content of the mixture exceeded 60%. This demonstrates that cellulose is a critical component in the preparation of nZVI during carbothermal reduction. Furthermore, in metronidazole removal experiments it was shown that c-Fe0/C has the same active sites as Fe0/CB and produces the same type and amount of reactive oxygen species. This further confirmed the determinant role of cellulose in material properties. This study provides instructions for preparing carbothermal reduced nZVI and provides a theoretical basis for its engineering application.

Keywords: Zero valent iron, Carbothermal reduction, Cellulose, Peroxydisulfate, Antibiotics