Photo-Fenton degradation of carbamazepine and ibuprofen by iron-based metal-organic framework under alkaline condition

Metal-organic frameworks have been widely used as photocatalytic materials. In this paper, a novel photocatalyst HSO 3 -MIL-53(Fe) with acidity regulating groups was successfully synthesized by the solvothermal method and applied to remove carbamazepine (CBZ) and ibuprofen (IBP). The photodegradation efficiency of vis/H 2 O 2 /HSO 3 -MIL-53(Fe) can reach 100% when the pH value is 8 or 9. The free radical capture experiment and electron paramagnetic resonance analysis proved that hole (h + ), hydroxide radical ( · OH), singlet oxygen ( 1 O 2 ), and superoxide Radical ( · O 2 - ) are the main active species for pollutants degradation . In the vis/H 2 O 2 /HSO 3 -MIL-53(Fe) system, the high pollutant degradation efficiency under alkaline conditions was attributed to two factors: (1) the acidity adjusting group -HSO 3 adjusts the pH value of the whole system, which is beneficial to the photo-Fenton process. (2) The photogenerated electrons of HSO 3 -MIL-53(Fe) can be captured by Fe (III), H 2 O 2 and O 2 to accelerate the reduction of Fe (III) and generate · OH, 1 O 2 , and · O 2 - . Besides, H 2 O 2 can also be activated by Fe (II) and Fe (III). The above processes synergistically improved the photocatalytic efficiency. Based on liquid chromatography-mass spectrometry (LC-MS) analysis, the possible degradation pathways of the two pollutants were proposed.