In-situ carbon decoration of MgFe-layered double oxide for enhanced activation of peroxymonosulfate towards organic pollutant degradation

Peroxymonosulfate (PMS)-based advanced oxidation processes (AOPs) are the current trends for remediation of refractory organic pollutants. In this study, a carbon-decorated MgFe-layered double oxide (C/MgFe-LDO) was constructed by using Congo Red dye as a carbon precursor to modify the surface of MgFe-layered double hydroxides (MgFe-LDH), followed by calcination. The phase composition, microstructure, and chemical state of the catalyst was characterized in detail. Compared with pure MgFe-layered double oxide (MgFe-LDO), the optimal C/MgFe-LDO exhibited significantly enhanced PMS activation performances, achieving nearly full degradation of Acid Red 1 (AR1) in 60 min and a total organic carbon (TOC) removal efficiency of 83.0%. Additionally, the C/MgFe-LDO synthesized at 600°C demonstrated a PMS utilization efficiency of 90.2% in the solution, which was 11.8% higher than that of the undecorated MgFe-LDO. The enhanced catalytic performance was attributed to the larger specific surface area, higher electrical conductivity, and synergistic effects between carbon and the Fe 2+ /Fe 3+ redox cycle of the catalyst. The catalyst also showed good stability, recyclability, and applicability to complex water matrices as well as continuous-flow systems. This work provides a new approach towards green and efficient PMS-activating catalysts through structural engineering.