Nitrogen coordination modulation of single-atom CoN4 enables dual-active-sites catalyst featuring synergistic organics adsorption and peroxymonosulfate activation

Spatial Confinement of Co Nanoparticles in N-Doped Carbon Nanorods for Wastewater Purification via CaSO3 Activation

“…The Fenton-like oxidation process, in which peroxysulfates were used as the oxidants to generate reactive oxygen species (ROS) (e.g., SO 4 •– and • OH), − had been deemed as a green and promising technology for the degradation of organic pollution. − However, excessive use of peroxysulfates could cause potentially biotoxicity, thus leading to secondary pollution. − Recently, sulfite has been deemed as a promising potential substitute to peroxysulfate for generating SO 4 •– in wastewater treatment due to its inexpensiveness and low toxicity. − Among these sulfites, CaSO 3 is regarded to be most suitable for wastewater treatment because CaSO 3 could slowly and persistently discharge SO 3 2– due to its low solubility (compared to Na 2 SO 3 and NaHSO 3 ), thus avoiding the depletion of the generated SO 4 •– and • OH under the high concentration of sulfite ions. − In this direction, a large number of heterogeneous catalysts, such as Fe–Cu, FeS, Fe- g -C 3 N 4 , ferrate, and siderite, have been designed and developed for activating CaSO 3 on wastewater treatment. However, the inherent defect of the heterogeneous Fenton-like oxidation process is the limitation of mass transfer, which is often overlooked in sulfate radical-based advanced oxidation processes. − The mass transfer of ROS (e.g., SO 4 •– and • OH) from its generation sites on the surface of heterogeneous catalysts into chemical pollutants in wastewater is severely restricted by its supershort lifetime (1 ns to 1 μs), greatly impeding their practical applications. − Moreover, these ROS are often quenched by natural organic matter and background inorganic anions in real wastewater . Hence, the development and implementation of nanotechnologies for enhancing the service efficiency of ROS (e.g., SO 4 •– and • OH) in the heterogeneous Fenton-like oxidation process is highly demanded. − …”