Synergistically enhanced heterogeneous activation of persulfate for aqueous carbamazepine degradation using Fe3O4@SBA-15

The exploration of low-cost, high-performance and stable catalytic materials for sulfate radical-based advanced oxidation processes (SR-AOPs) is of great importance. This study presents Fe3O4-wrapped SBA-15 mesoporous silica catalyst (Fe3O4@SBA-15) for persulfate (PS) activation. The Fe3O4@SBA-15 with an Fe3O4 to SBA-15 weight ratio of 3:1 exhibited an impressive carbamazepine (CBZ) removal efficiency of similar to 100% after 30 min of SR-AOP at an initial pH of 3.0, a temperature of 25 degrees C, an initial PS concentration of 300 mg L-1 and a catalyst concentration of 0.50 g L-1. The primary oxidizing species produced in the system were identified as SO4 center dot- and HO center dot by electron paramagnetic resonance spectra and radical quenching experiments. Benefiting from the synergetic effects of improved Fe3O4 dispersion and enhanced adsorption of CBZ and PS by SBA-15, the as-obtained heterogeneous Fe3O4@SBA-15 catalysts offer large numbers of active sites for free radical generation and high surface concentrations of CBZ and PS for SR-AOPs, as verified by physicochemical characterization and Langmuir-Hinshelwood model analysis. In addition, the activity of Fe3O4@SBA-15 was maintained throughout six successive cycling tests. Various inorganic anions, including Cl-, NO3-, HCO3-, and CO32-, as well as organic material in natural water, exert a negative impact on the Fe3O4@SBA-15 catalyzed SR-AOPs and deserve special attention. (C) 2020 Elsevier B.V. All rights reserved.

Automated summary

The exploration of low-cost, high-performance, and stable catalytic materials for sulfate radical-based advanced oxidation processes is crucial. The Fe3O4@SBA-15 catalyst demonstrated impressive removal efficiency and maintained activity throughout six successive cycling tests. However, inorganic anions and organic material in natural water pose a negative impact on Fe3O4@SBA-15 catalyzed SR-AOPs and require special attention.