Characterization of Electromagnetic Catalysis and Degradation of Algogenic Odor Using Fe3O4 Nanoparticles with Tannin Coating

Eutrophication in water supply systems results in harmful algal blooms and water pollution such as unpleasant taste and odor, especially in summer seasons. 2-Methylisoborneol (2-MIB) and geosmin are two typical musty odor compounds produced by blue-green algae. This study evaluated an electromagnetic catalysis process that involves the use of the electromagnetic field (EMF) to catalyze surface reactions on Fe3O4 nanoparticles with/without tannin coating (Fe3O4@tannin). The EMF field distribution from different induction coil types and heating of the solution or catalyst were characterized. The effects of coil type, exposure time, and catalyst type on the removal rates were then evaluated and optimized with methylene blue. Further, the removal mechanisms of 2-MIB and geosmin were analyzed with different combinations of solution heating and additions of H2O2, EMF, and Fe3O4@tannin. The highest removal (97% and 98%) for 2-MIB and geosmin was obtained when Fe3O4@tannin nanoparticles were exposed to H2O2 and EMF, which resulted in a potential Fenton-like reaction based on radical detection. The findings support water treatment innovations with nontraditional catalysis processes.