A bimetallic co-doped iron and copper in polymeric graphitic carbon nitride to enhance catalytic activity and reusability of Fenton-like oxidation

In this study, a new Fenton-like catalyst was developed through incorporating iron and copper in polymeric graphitic carbon nitride (FeCu/CN) for catalytic activity and reusability enhancement. With theoretical Fe/Cu ratio of 7:3 (Fe7Cu3/CN) and pH of 5, the bimetallic catalyst system showed a pseudo-first-order rate constant of 0.07294 min-1 for bisphenol S (BPS) degradation, which was near double the sum of values in monometallic catalyst systems. Moreover, the new catalyst showed much better performance for reuse, BPS removal of which catalyzed system decreased from 98.0 % to 87.3 % after five cycles used. Comparatively, BPS removal declined from 69.5 % to 45.0 % in Fe/CN catalyzed system. Characterization results indicate the superiority of Fe7Cu3/CN for Fenton-like catalysis is mainly attributed to the intrinsic advantage of CN support, Fe(II) formation, copper catalysis, and synergistic effect between iron and copper. Furthermore, hydroxyl radicals were determined as the main species for pollutant degradation, and their accumulation was monitored. The destruction pathways of BPS were analyzed by detection of degradation intermediates, and the results further confirm the main active species of hydroxyl radicals. Moreover, the new Fenton-like system also exhibited good performance for different pollutant removal and real wastewater treatment. This study provided a new catalyst with superior catalytic activity and favorable reusability, and also sheds new light on supported bimetallic catalyst development.