Water-stable MOFs-based core-shell nanostructures for advanced oxidation towards environmental remediation

Metal organic frameworks (MOFs) find many potential applications because of their versatile physicochemical properties. Advanced oxidation is an important way for wastewater remediation to realize sustainable supply of clean water. However, due to the lack of water-stable MOFs with sufficient catalytic activity, the application of MOFs in advanced oxidation processes (AOP) for wastewater treatment is greatly hindered. In this study, by taking advantage of the rich pores of water stable MOFs, we develop a MOFs-based core (water stable MOFs)-shell (NiP) structure as an efficient catalyst for peroxymonosulfate (PMS) activation in AOP. Here, water stable MIL-96 as the MOFs is synthesized by a hydrothermal method, and the core-shell structured MIL-96@NiP is facilely synthesized through electroless coating of the NiP layer. The as-prepared core-shell structure demonstrates superior performance in catalytic degradation of rhodamine B (RhB), over performing the individual MOFs and NiP parts, suggesting the appearance of synergistic effect between MOFs and NiP in the core-shell structure. Furthermore, the catalyst demonstrates four consecutive runs without losing significant catalytic activity. Temperature has a significant role in faster degradation of RhB. A plausible degradation mechanism is proposed through classical quenching tests study, and oxygen singlet is found to play imperative part in removal of RhB.