Hierarchical Co-Fe layered double hydroxides (LDH)/Ni foam composite as a recyclable peroxymonosulfate activator towards monomethylhydrazine degradation: Enhanced electron transfer and 1O2 dominated non-radical pathway

The growing application of rocket propellants (e.g., monomethylhydrazine (MMH)) leads to awful water pollution, and thus it is urgent to develop efficient remediation methods to remove it from wastewater. Although persulfate-based catalytic technologies are promising for refractory organic compounds decomposition, the undesired aggregations, high cost and troublesome separation of powder catalysts still limit their wide-applications. To address these issues, we prepared Co-Fe layered double hydroxides (CoFe-LDH)/Ni foam (NF) composite as a recyclable peroxymonosulfate (PMS) activator to decontaminate MMH with high robustness to the high-strength co-existing pollutants within a wide pH range. The interfacial synergism between CoFe-LDH and NF could promote the charge transfer in the catalysis. DFT and XPS analysis elucidated the introduction of Ni and Co greatly facilitate charge transfer from LDH/NF to PMS. This work offers profound insights propellant-containing wastewater via non-radical (1O2 and electron transfer) pathway in the presence of PMS with reclamation of cost-effective heterogeneous catalysts.