Enhancement on peroxymonosulfate activation by Fe-Al layered double hydroxide loaded on super activated carbon for the degradation of organic pollutants

The development of highly dispersed metal-based materials loaded on carbon is of great importance for environmental remediation. However, their catalytic activities face huge challenges. In this study, a series of super activated carbon-supported Fe-Al layered double hydroxides (FeAl-LDH@SAC x ) were prepared, and the peroxymonosulfate (PMS) oxidation performance and activation mechanism were probed with Rhodamine B (RhB) as a representative pollutant. Results showed that FeAl-LDH@SAC 0.02 composites exhibited superior ability in activating PMS compared to other catalysts, as evidenced by the rate constants for RhB degradation, which followed the order: FeAl-LDH@SAC 0.02 (0.5507 min −1 )>FeAl-LDH@SAC 0.04 (0.4738 min −1 )>FeAl-LDH (0.4121 min −1 )>FeAl-LDH@SAC 0.01 (0.3512 min −1 )>FeAl-LDH@SAC 0.08 (0.2701 min −1 ). The optimal doping amount for SAC depended on the ratio of active FeAl-LDH and its dispersion on the SAC, which helped to promote interfacial electron transfer. Impressively, the sulfate radicals (SO 4 · − ), hydroxyl radical (·OH), and singlet oxygen ( 1 O 2 ) made major contributions to RhB removal. The results of the toxicity assessment showed that the overall toxicity of the system tended to decrease as the catalytic oxidation proceeded. Finally, the effective removal of aromatic proteins and soluble microbial metabolites in actual dye wastewater within 60 min demonstrated that the catalytic oxidation system involving FeAl-LDH@SAC 0.02 was promising for water treatment.