Intensification of van der Waals interaction for efficient peroxymonosulfate activation and accuracy re-evaluation of quenching experiments for reactive oxidation species identification

Abstract

The heterogeneous peroxymonosulfate (PMS) activation process usually suffers from low consumption efficiency of PMS, rendering incomplete activated oxidation performance. Herein, we report a PMS activation process by Co-incorporated N-carbon nanotubes (Co-NCNTs). Reactive oxidation species (ROS) identification demonstrated that PMS activation by Co-NCNTs initiated concurrent radical and non-radical pathway processes. Moreover, mechanism investigation by quenching experiments with various pollutants was shown to cause possible erroneous confirmation of degradation pathway due to the different reactivity between various target organics and ROS. The rapid diffusion of accumulated PMS from the distal ends and within fissures of the Co-NCNTs to the interior of Co-NCNTs and the elevated van der Waals interactions in the confined inner-surface of Co-NCNTs facilitated faster PMS activation, whereby more than 41 μmol of PMS could be decomposed by 10 mg Co-NCNTs within 15 min. This work urges re-evaluation of the accuracy of the standard ROS scavenging method for mechanism investigation and proposes the importance of van der Waals interactions for effective PMS adsorption and activation.