FeCo bimetallic metal organic framework nanosheets as peroxymonosulfate activator for selective oxidation of organic pollutants

Abstract

Singlet oxygen (1O2) and superoxide radicals (O2•–) are active species that can selectively oxidize organic pollutions. A two-dimensional FeCo-based bimetallic metal organic framework (MOF) nanosheet was rationally designed to activate peroxymonosulfate (PMS) for selective oxidation of organics in water. The FeCo MOF nanosheets (FeCo-BDC) achieved a 99.1% degradation efficiency of RhB in 5 min, showing a high kinetic constant of 0.884 min−1 that is 1.6 and 294.7 times higher than those of the monometallic MOFs, i.e., Co-BDC and Fe-BDC. Radical scavenging experiments and electron paramagnetic resonance measurements revealed that 1O2 and O2•– are predominant reactive oxygen species in the FeCo-BDC/PMS system. These nanosheets thus preferentially oxidize organics with electron donating groups (e.g., –NH2, –OH and -NR2), whereas having low reaction activities towards substances with electron withdrawing groups (e.g., –NO2). The oxidation process also proved to resist interference from co-existing dissolved species in water, such as Cl−, SO42- and humic acids.