Facile Synthesis of AgFeO2-Decorated CaCO3 with Enhanced Catalytic Activity in Activation of Peroxymonosulfate for Efficient Degradation of Organic Pollutants

The development of green and sustainable technologies for wastewater treatment is highly desirable but remains challenging. Herein, a self-assembly strategy to stabilize AgFeO2 on the surface of CaCO3 (AgFeO2@CaCO3) is demonstrated. This structure is discovered to significantly prohibit the agglomeration of AgFeO2 nanoparticles and strengthen the interaction between AgFeO2 and CaCO3. When utilized in advanced oxidation processes (AOPs), AgFeO2@CaCO3 exhibits excellent catalytic performance in activating peroxymonosulfate (PMS) to degrade multiple organic pollutants. For example, complete Rhodamine B (RhB) decomposition can be achieved by AgFeO2@CaCO3 in the presence of PMS at a degradation rate of 0.312min(-1), which is 44.6 times that of bare AgFeO2. In addition, AgFeO2@CaCO3 demonstrates excellent stability, recyclability, general applicability, and strong resistance to the solution pH. O-1(2) and O-2(-) are the predominant reactive oxygen species in RhB degradation. The rapid RhB degradation can be attributed to the mesoporous structure and high specific surface area of AgFeO2@CaCO3, the cycling of Fe(III)/Fe(II) and Ag(I)/Ag(0), and the presence of hydroxyl groups that facilities PMS activation, which is validated by density functional theory calculations. This study provides a feasible and scalable strategy to synthesize green and recyclable heterogeneous catalysts for wastewater remediation via PMS-based AOPs.