Preparation of M-γAl2O3 (M = Fe, Zn) photocatalyst for the photo-Fenton process: Performance evaluation and mechanistic insights for the efficient degradation of acrylonitrile wastewater

This study synthesized an Fe 2 O 3 &ZnFe 2 O 4 /γAl 2 O 3 catalyst (FO-ZFO-Al) using the wet impregnation method to degrade organic wastewater with high concentrations of acetonitrile and acrylonitrile via a photo-Fenton catalytic process. The catalyst's degradation performance and mechanisms were thoroughly investigated. Characterization techniques included XRD , SEM-EDS, XPS , FTIR and EPR , which identified α-Fe 2 O 3 and ZnFe 2 O 4 as the main active species. Under optimal conditions-a chemical dosage ratio (wastewater/catalyst/H 2 O 2 ) of 400:1:240 (mL/g/mL), pH 7.0, 50 °C, 60 min, and UV intensity of 107 μW/cm 2 -the removal efficiencies achieved were 92.31 % for acetonitrile , 94.36 % for acrylonitrile and 87.22 % for COD , 82.89 % for TOC . In the Fenton-like system, H 2 O 2 interacts with α-Fe 2 O 3 to generate hydroxyl radicals ( · OH) for degradation. In the photo-Fenton system, · OH, e − /h + are the primary reactive species for the degradation of acetonitrile and acrylonitrile. FO-ZFO-Al enhances · OH generation through photoexcitation while simultaneously facilitating the Fe 2+ /Fe 3+ cycle, thereby improving degradation efficiency. During the degradation process, acetonitrile and acrylonitrile are initially converted into amides , further oxidation to carboxylic acid compounds until they were completely oxidized to CO 2 and H 2 O. • A novel synthesized Fe 2 O 3 &ZnFe 2 O 4 /γAl 2 O 3 photo-Fenton catalyst. • It shows significant effect in the treatment of acrylonitrile wastewater. • Proposed Fe(III)/Zn(II) synergistic degradation mechanism based on various analysis.