Iron-Exchanged Zeolite Micromotors for Enhanced Degradation of Organic Pollutants

Self-propelled iron-exchanged zeolite (Fe-zeolite) micromotors have been developed for efficient degradation of organic pollutants via a Fenton-like reaction. The incorporation of iron ions into the zeolite framework, which was achieved by solid-state ion exchange, imparts catalytic properties to the microporous structures. The co-reagent for Fenton oxidation, hydrogen peroxide, also works as the fuel to propel the motion of the Fe-zeolite micromotors. The asymmetrically deposited platinum layer on the Fe-zeolites catalyzes the fuel decomposition, generating oxygen bubbles to propel the autonomous motion of the heterogeneous catalysts. The self-propelled motion together with the bubble formation leads to effective fluid mixing and consequent improvement in the degradation efficiency, making up the low diffusivity of heterogeneous catalysts. The advantage of a micromotor-based degradation strategy was verified by Fenton oxidation of phenol performed with a small percentage of Fe-zeolite micromotors. With the ability to be collected and reused, the Fe-zeolite micromotors avoid secondary contamination and wastage. In combination with the advantages of both homo- and heterogeneous catalysts, the self-propelled Fe-zeolite micromotors provide a highly efficient and environmentally friendly strategy for degradation of organic contaminants.