Fabrication of reactive flat-sheet ceramic membranes for oxidative degradation of ofloxacin by peroxymonosulfate

A novel CoFe2O4-decorated flat-sheet ceramic membrane (CFCM) was prepared via a facile one-step hydrothermal method and utilized for peroxymonosulfate (PMS) activation in the catalytic degradation of ofloxacin (OFX) in a dead-end filtration mode. Several characterization methods confirmed the successful deposition of a CoFe2O4 layer on the surface of a pristine Al2O3 ceramic membrane. The CFCM possessed a considerably smaller average pore size (45 nm) and contact angle (20 degrees) than a pristine Al2O3 flat-sheet ceramic membrane (80 nm and 50 degrees) after modification. The catalytic degradation results revealed that nearly 100% removal of 40 mu M OFX could be achieved within 20 min at pH 6.0, with 2 mM PMS and 100 kPa of transmembrane pressure (TMP). Moreover, the CFCM suffered little interference from co-existing SO42- and Cl- in the water matrix, but was significantly hindered by HCO3- and humic acid. The low concentration of metal-leaching by CFCM will makes it reliable for catalytic degradation processes. Sulfate radicals were found to be the predominant reactive radicals that drove OFX degradation, and according to density functional theory (DFT) calculations they were generated via electron transfer from CoFe2O4 to chemisorbed PMS.