Eutrophication in potable water supplies often results in algal blooms and associated water quality issues such as unpleasant taste and odor in drinking water, especially in summer seasons. 2-methylisoborneol (2-MIB) and geosmin are two typical musty odor compounds produced by blue-green algae (cyanobacteria) and filamentous bacteria. The present study evaluated an electromagnetic catalysis process that involves the use of the electromagnetic fields (EMF) to induce localized heating and catalytic reactions on the surface of ferromagnetic Fe3O4 nanoparticles with/without the coating of tannin acid. Compared to traditional photocatalysis, EMF irradiation can effectively penetrate non-polar materials (e.g., reactor cover or case) and directly excite catalysts for reactions. The electromagnetic field properties such as the magnetic field, heating of the solution or catalyst, and penetration depth were first characterized. The effects of electromagnetic power, exposure time, and magnetic catalyst dose on the removal efficiencies were evaluated with methylene blue dye, 2-MIB, and geosmin. The comparative study indicate that the combination of EMF/H2O2/Fe3O4@tannin achieved the highest removal (97% and 98%) for 2-MIB and geosmin within 1 h. The degradation reactions followed the pseudo-first-order kinetics model. The degradation mechanism was attributed to the formation of reactive oxygen species (ROS) produced by a Fenton-like reaction.

Catalytic degradation of algogenic odor using Fe3O4 nanoparticles under long-wavelength electromagnetic irradiation

ACS Fall 2021

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