Salt assistant bimetallic sludge-derived porous carbon for efficient peroxymonosulfate activation

The development of cost-effective, environmentally benign, and high-performance peroxymonosulfate (PMS) activation towards wastewater treatment is still considered a challenge. In this work, the sludge-derived porous carbon loaded with bimetal oxides (DSC-FeMn) was fabricated by molten salt assistant strategy using the combination of zinc chloride, metal ions and Fe containing sludge. The obtained DSC-FeMn exhibited high catalytic activity for nearly 100% 4-chlorophenol (4-CP) removal within 30 min with the k of 0.304 min−1, which was 1.07 and 11.94 times that of the single Fe and Mn-sludge-derived carbon (DSC-Fe, DSC-Mn), respectively. Quenching experiments, electron paramagnetic resonance tests (EPR), X-ray photoelectron spectroscopy (XPS), H2-temperature programmed reduction (H2-TPR) and electrochemical experiments proved that the radical pathway, dominated by OH and SO4−, led to the excellent degradation performance of DSC-FeMn, which was attributed to the redox cycling between Fe and Mn. This study provides a new idea for sludge resource utilization, and it deepens the understanding of the mechanism of PMS activation by the synergistic interaction between bimetal.