Graphene Oxide-Supported Three-Dimensional Cobalt-Nickel Bimetallic Sponge-Mediated Peroxymonosulfate Activation for Phenol Degradation

Advanced oxidation processes (AOPs) based on peroxymonosulfate (PMS) have been effective techniques for wastewater treatment. However, the recovery of powder catalysts and their granulation are limiting the application of heterogeneous AOPs technology. To tackle these issues, recoverable graphene sponges (SCNGs) were synthesized via a simple dipping process. Thermogravimetric analysis confirmed that the bimetal content of SCNGs was only 7.7%. The SCNGs/PMS system was proved to be greatly effective to treat various organic pollutants, achieving over 71% and 94% of degradation efficiency for phenolic substances (phenol and 4-chlorophenol) and antibiotics (tetracycline and sulfadiazine) in 5 min over a wide initial pH range of 4.0-9.0, respectively. The correlative quenching experiments and electronic paramagnetic resonance tests verified the existence of multiple reactive oxygen species (O-1(2), SO4'-, HO', and O-2'-), whereas O-1(2) that originated from PMS self-decomposition and O-2'- conversion played the most important role in the degradation processes. Overall, this study provides a prospect for the industrial application of 3D bimetallic materials based on PMS activation in wastewater treatment.

Automated summary

Advanced oxidation processes (AOPs) based on peroxymonosulfate (PMS) have been effective techniques for wastewater treatment. The study synthesized recoverable graphene sponges (SCNGs) to tackle limitations in heterogeneous AOPs technology. The SCNGs/PMS system showed high efficiency in degrading various organic pollutants, with O-1(2) and O-2'- playing important roles in the degradation processes.