The regulation of electron distribution on Fe Lewis acidic sites within silicon skeleton and its contribution to Ketoprofen ozonation

Lewis acid site was vital center for activating O 3 during catalytic ozonation process. Herein, we proposed a strategy to enhance the Lewis acid strength of Fe-MCM-48 (FeM) by fluorination. Fluorinated Fe-MCM-48 (FFeM) exhibited the better catalytic ozonation efficiency towards Ketoprofen (KET), a kind of nonsteroidal anti-inflammatory drug. 87.4 % TOC removal was obtained by F 2.5 Fe 0.8 M/O 3 process, but only 27.5 % and 52.7 % were found by sole ozonation and Fe 0.8 M/O 3 processes, respectively. Comparative characterizations, experiments and DFT calculations showed that fluorinated FFeM was regular sphere with three dimensional duct channel and large S BET . Doping of F reduced particle size, implanted electron withdrawing Si-F group and formed the electron poor center around Fe atom, which enhanced Lewis acid strength of FFeM. Protonated hydroxyl groups on Lewis acid sites were the main active sites for O 3 activation. Greater amount of O 3 were absorbed on the surface of FFeM and the greater O 3 utilization rate, •OH and •O 2 – generation rates were obtained by FFeM/O 3 process. Common anions such as Cl − , SO 4 2− and NO 3 – and Humic acids (HA) had little effect on KET removal but inhibited TOC removal in FFeM/O 3 process. •OH, •O 2 – and Fe(IV) = O oxidation were accounted for KET degradation. 16 kinds of intermediates generated from KET degradation and 4 pathways were deduced.