Rapid degradation of organic pollutants by Fe3O4@PDA/Ag catalyst in advanced oxidation process

Over the past decades, the development of novel catalysts on the degradation of organic pollutants has attracted increasing attention. In this work, we synthesized silver decorated magnetic nanoparticles (Fe3O4@PDA/Ag NPs) to activate H2O2 for organic pollutants removal via advanced oxidation processes (AOPs). The catalyst was prepared through in-situ reduction of AgNO3 by the polydopamine (PDA) layer on Fe3O4 NPs. Chemiluminescence results obtained from luminol/H2O2 system revealed that the catalyst exhibited excellent catalytic effect on the decomposition of H2O2 into reactive oxygen species (ROS) and superoxide radical (O2-) was mainly responsible for the oxidative degradation. Importantly, the fast evolution frequency of oxygen gas bubbles produced in the reaction of Ag NPs and H2O2 could generate vigorous fluid convection and autonomous motion of catalyst when H2O2 concentration reached 1%. Additionally, the catalyst can suspend in solution for several minutes. Therefore, by coupling the vigorous motion with slow sedimentation velocity, the catalyst can realize rapid degradation of organic pollutants without external mixing force. The Fe3O4@PDA/Ag NPs catalysts not only showed a high removal efficiency of malachite green, but also can be applied for the degradation of other dyes, making it to be a promise candidate for environmental remediation. With the merits of excellent catalytic effect, fast degradation speed, and simplicity of operation, the prepared catalysts exhibits great potential in the practical field.