Accelerating the Fenton Reaction with a Magnetic Microswarm for Enhanced Water Remediation

Abstract The Fenton reaction, among one of the advanced oxidation processes, has been widely employed for water remediation. Here, we report using magnetic Fe₃O₄ nanoparticles to accelerate the degradation of the simulative organic pollutant (i. e., Rhodamine B) in a collective manner, featuring an enhanced Fenton reaction. Fe²⁺ ions released from Fe₃O₄ nanoparticles function as a reducing agent to trigger the Fenton reaction in an acidic environment. A large number of Fe₃O₄ nanoparticles form the microswarm by applying a rotating magnetic field, which would further improve the intermixing and reaction diffusion as a result of the hydrodynamic vortex created by magnetic chains. Moreover, the microswarm possesses the ability of targeted degradation achieved by the collective locomotion, and such a collective manner would ultimately avoid the loss of Fe₃O₄ nanoparticles during the whole process. Besides, Fe₃O₄ nanoparticles can be magnetically collected and rinsed for recycling use, with a retained dye degradation rate of 73.5% after 3 degradation cycles. As a result, the magnetic microswarm holds advantages in terms of low cost, enhanced degradation, recyclability, and targeted decontamination, which is promising for the removal of organic pollutants.