Cobalt ferrite nanoparticle-loaded nitrogen-doped carbon sponge as a magnetic 3D heterogeneous catalyst for monopersulfate-based oxidation of salicylic acid.

As salicylic acid (SAL) is increasingly consumed as a pharmaceutical product, release of SAL into the environment poses threats to ecology because of its low bio-degradability. Thus, SO-based chemical oxidation processes have been proposed for degrading SAL. Since monopersulfate (MPS) represents a primary reagent for generating SO, and Co is the most capable metal for activating MPS to generate SO, CO NPs are frequently proposed for activating MPS but they are difficult to recover from water. Thus CoFeO is considered as a magnetic alternative to CoO, and loading of CoFeO NPs on substrates could further improve dispersion and avoid aggregation of NPs. Therefore, this study proposes a 3-Dimensional (3D) hierarchical catalyst which is fabricated by loading CoFeO NPs on nitrogen-doped carbon sponge (NCS). The NCS is not only adopted as a support for CoFeO NPs but also provides additional catalytic sites and enhances catalytic activities of CoFeO NPs for MPS activation. As a result, CoFeO NPs loaded on NCS (CFNCS) exhibits substantially higher catalytic activities than CoFeO NPs and NCS individually with 100% of SAL could be afforded within 30 min. E of SAL degradation of 47.4 kJ/mol by CFNCS-activated MPS is also lower than those by other reported catalysts, whereas the RSE was 11.1%, which was also much higher than most of reported values. These features demonstrate that CFNCS is a promising 3D catalyst for enhancing MPS activation to degrade SAL. The findings obtained here are also insightful to develop efficient MPS-activating catalysts for eliminating contaminants.