Highly efficient photo-degradation for tetracycline elimination in pharmaceutical wastewater by α-Fe2O3/V2O5/BC assisted peroxymonosulfate activation

In this study, a novel α-Fe 2 O 3 /V 2 O 5 /BC catalyst with high   peroxymonosulfate (PMS)   activation performance was constructed by co-pyrolysis method and 99.58% of tetracycline is degraded within 120 min. The electrons conversion of Fe-V on biochar surface induces the continuous generation of sulfate radical   and singlet oxygen molecules ( 1 O 2 ).   The XPS results show that it is Fe 3+   and Fe 0   rather than Fe 3+   and Fe 2+   in the iron cycle after the introduction of vanadium, indicating a more efficient electron transfer efficiency between interface. The optical properties characterization and density function theory calculation (DFT) of α-Fe 2 O 3 /V 2 O 5 /BC reveal that the electrons of the entire α-Fe 2 O 3   and the vanadium atoms are redistributed to new molecular orbitals due to strong interfacial chemical bonding, inducing a direct transfer of electrons to generate   1 O 2   for tetracycline removal that is the main cause of selective degradation. Besides, the possible degradation mechanism and tetracycline degradation pathways were also proposed. The α-Fe 2 O 3 /V 2 O 5 /BC maintains a high removal efficiency of tetracycline only decrease by 7.09% after six cycles. This study provides a better strategy and recyclable purification material for the efficient treatment of antibiotic pharmaceutical wastewater.