Activation of Molecular Oxygen and Peroxodisulfate for Removal of Water-Soluble Antibiotics Using Metal-Organic Framework-Derived CoNx@NC Catalyst

Advanced oxidation process using reactive oxygen species (ROS) can be efficiently utilized to remove soluble contaminants from water. Herein, we have reported a facile method for the activation of molecular oxygen to produce ROS using Prussian blue analog (PBA)-derived catalyst CoNx@NC. The two-electron reduction of O-2 by CoNx@NC produces H2O2, which is further dissociated into & sdot;OH radicals and decomposes water-soluble organic dye (methylene blue) and antibiotics (ciprofloxacin and amoxicillin). CoNx@NC is capable of removing 98 % of ciprofloxacin in a short period of time (65 minutes) in the presence of oxygen. Further, CoNx@NC can activate peroxodisulfate in the aqueous medium to produce ROS (SO4 & sdot;(-), and & sdot;OH) and catalyzes the decomposition of the antibiotics and organic dye. The efficiency of the degradation of antibiotics and dye is improved when peroxodisulfate is used for the formation ROS. The higher oxidation potential and longer life-time of SO4 & sdot;(-) than & sdot;OH improves the rate oxidation with peroxodisulfate. The Co-N coordination in CoNx@NC stabilizes the system against leaching and shows excellent stability for recycling (for five cycles) during the removal of contaminants.

Automated summary

A facile method for the activation of molecular oxygen to produce reactive oxygen species (ROS) using a Prussian blue analog-derived catalyst CoNx@NC has been reported. The catalyst can efficiently remove soluble contaminants from water, including organic dyes and antibiotics. The use of peroxodisulfate further improves the degradation efficiency of the contaminants.