Returnable MoS2@carbon nitride nanotube composite hollow spheres drive photo-self-Fenton-PMS system for synergistic catalytic and photocatalytic tetracycline degradation

Construction of a Visible-Light-Response Photocatalysis–Self-Fenton Degradation System of Coupling Industrial Waste Red Mud to Resorcinol–Formaldehyde Resin

“…Meanwhile, the TC degradation performance was contrasted with common Fenton, photo-Fenton and photo-self-Fenton systems, as shown in Figure 2c, and it was concluded that the photo-self-Fenton system possessed the best degradation efficiency of TC under visible light irradiation, which is 1.52 and 6.11 times that of Fenton and photo-Fenton systems, respectively. Compared with the Fenton reaction, the cause of the enhanced performance of the self-Fenton reaction is the faster valence state circulation of iron ions to further affect the rate of hydroxy radical ( • OH) formation of the major degradative active species (Figure 2d) [35], which is ascribed to the following reasons: (i) compared with ordinary Fenton systems, photo-self-Fenton systems employ semiconductor materials as the catalyst, which are excited by the external light source to produce photo-induced electrons, and thus quickly realize the valence state transition to activate H2O2 to produce • OH [36]; (ii) simultaneously, electrons participate in the formation of H2O2 intermediates and provide raw materials for iron ion conversion [37]; (iii) in contrast, although both use the assistance of photocatalysis, the in situ generation of H2O2 in self-Fenton system increases the H2O2 content in the fixed environment, thus facilitating the valence cycle and H2O2 activation to produce highly oxidized • OH, compared with photo-Fenton systems. From the analysis of the above results, the RF-based photo-self-Fenton system possessed a strong degradation performance, which stemmed from the synergy of photocatalysis and the Fenton method, so as to effectively generate and utilize H2O2, effectively promoting the separation of photo-induced carriers and effective conversion to • OH [38,39].…”