Critical role of zero-valent iron in the efficient activation of H 2 O 2 for 4-CP degradation by bimetallic peroxidase-like

Peroxidase-like based on double transition metals have higher catalytic activity and are considered to have great potential for application in the field of pollutant degradation. First, in this paper, a novel Fe 0 -doped three-dimensional porous Fe 0 @FeMn-NC-like peroxidase was synthesized by a simple one-step thermal reduction method. The doping of manganese was able to reduce part of the iron in Fe-Mn binary oxides to Fe 0 at high temperatures. In addition, Fe 0 @FeMn-NC has excellent peroxidase-like mimetic activity, and thus, it was used for the rapid degradation of p-chlorophenol (4-CP). During the degradation process, Fe 0 was able to rapidly replenish the constantly depleted Fe 2+ in the reaction system and brought in a large number of additional electrons. The ineffective decomposition of H 2 O 2 due to the use of H 2 O 2 as an electron donor in the reduction reactions from Fe 3+ to Fe 2+ and from Mn 3+ to Mn 2+ was avoided. Finally, based on the experimental results of LC-MS and combined with theoretical calculations, the degradation process of 4-CP was rationally analyzed, in which the intermediates were mainly p-chloro-catechol, p-chloro resorcinol, and p-benzoquinone. Fe 0 @FeMn-NC nano-enzymes have excellent catalytic activity as well as structural stability and perform well in the treatment of simulated wastewater containing a variety of phenolic pollutants as well as real chemical wastewater. It provides some insights and methods for the application of peroxidase-like enzymes in the degradation of organic pollutants.