Magnetite (Fe3O4) Supported on Bagasse Sugarcane Fibers as Catalyst for Plasma-Degradation of Organic Pollutant in Water: Effect of Oxidation Inhibitor Agents on the Particles’ Shape and Catalytic Activity

To easily recover and reuse nano-magnetite (Fe3O4) during the catalytic process, Fe3O4 is successfully dispersed by coprecipitation of Fe(II, III) salts on anchoring sites of bagasse-sugarcane fibers generated by gliding-arc plasma. Previously, we explored the effect of ascorbic acid (ASC), hydrochloric acid (HCl) and plasma-activated water (PAW) acting as oxidation inhibitors of Fe(II) solution. Prepared materials were characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy coupled with energy dispersive X-ray spectroscopy (SEM-EDX). The obtained results show that the oxidation inhibitor agent influences the morphology, texture and activity of the synthesized bulk-magnetite, where Fe3O4-nanorods, Fe3O4-nanospheres and Fe3O4-nanosheets were, respectively, obtained with PAW, HCl and ASC. The Fenton-plasmacatalytic treatment of amaranth red dye used as a model pollutant for 30 min revealed degradation rates of 53, 79 and 80%, respectively, for Fe3O4-ASC, Fe3O4-HCl, and Fe3O4-PAW each coupled to plasma. The deposition of nano-magnetite on the plasma-activated bagasse-sugarcane fibers (BM) using PAW as the best oxidation inhibitor agent exhibited characteristic FTIR-absorption bands of -OH, -CH2 and Fe-O, attesting the bagasse-sugarcane-Fe3O4 linkage. The supported magnetite revealed a pollutant degradation rate of 99%, which deeply highlights an activity improvement after Fe3O4 deposition on plasma-activated bagasse sugarcane. The reusability of supported-Fe3O4 catalyst revealed a pollutant degradation rate of 95% after the fourth cycle, thus highlighting its easy recovery and catalytic stability (reuse).