Reduction and Immobilization of Potassium Permanganate on Iron Oxide Catalyst by Fluidized-Bed Crystallization Technology

A manganese immobilization technology in a fluidized-bed reactor (FBR) was developed by using a waste iron oxide (i.e., BT-3) as catalyst which is a by-product from the fluidized-bed Fenton reaction (FBR-Fenton). It was found that BT-3 could easily reduce potassium permanganate (KMnO4) to MnO2. Furthermore, MnO2 could accumulate on the surface of BT-3 catalyst to form a new Fe-Mn oxide. Laboratory experiments were carried out to investigate the KMnO4-reduction mechanism, including the effect of KMnO4 concentration, BT-3 dosage, and operational solution pH. The results showed that the pH solution was a significant factor in the reduction of KMnO4. At the optimum level, pHf 6, KMnO4 was virtually reduced in 10 min. A pseudo-first order reaction was employed to describe the reduction rate of KMnO4.