The adsorption and Fenton catalytic degradation of tetracycline by Fe3+ and Fe2+ modified bentonite

Fe3+ modified bentonite was firstly prepared by ion change method and Fe2+ modified bentonite was then synthesized by reduction of Fe3+-bentonite. The modified bentonites were characterized with XRD and SEM. The adsorption ability of Tetracycline (TC) of Fe3+-bentonite and Fe2+-bentonite was compared with raw bentonite. The catalytic activity of two Fe-bentonites used as heterogeneous Fenton catalyst are also examined. The resulted shows that both of Fe3+-bentonite and Fe2+-bentonite exhibited superior removal performance of TC. The removal capacities of Fe3+-bentonite and Fe2+-bentonite in the 400 mg/L TC solution reached 98.15% and 96.55%, respectively. The Fe3+-bentonite and Fe2+-bentonite remains 75% removal abilities after 3 rounds under Fenton condition. The mechanisms of adsorption and Fenton degradation of Fe modified bentonite were also discussed.