Kinetic and mechanism study of UV/pre-magnetized-Fe0/oxalate for removing sulfamethazine

In this study, UV irradiated photochemical reactions of oxalate (Ox) with premagnetized-Fe 0 (pre- Fe 0 ) as the catalyst was used to degrade sulfamethazine (SMT). Magnetic field promoted the release of iron ion from Fe 0 thus enhanced SMT and Ox removal in UV/pre- Fe 0 /Ox process. X-ray photoelectron spectroscopy demonstrated that the presence of UV and Ox promoted the transformation of Fe 3+ to Fe 2+ on Fe 0 , which enhanced the surface bound •OH (•OH surf ) generation. Ox inhibited the formation of iron (hydro)xides and enhanced the hydroxylation of Fe 0 surface. •OH surf was mainly responsible for SMT removal (44%), while UV direct photolysis and •OH in the solution both caused around 28% SMT removal. The process with Ox exhibited much higher efficiency in SMT degradation than that added with H 3 PO 4 , citric acid and ethylenediaminetetraacetic acid, which greatly expanded the chelate-modified Fenton processes and their treatment efficiency.