Degradation of amyl xanthate by manganese dioxide.

Amyl xanthate (AX), a widely used reagent in sulfide mineral flotation, has caused serious environmental problems. Manganese dioxides (MnO), ubiquitous in natural soils and sediments, are one kind of important oxidant or catalyst in facilitating organic pollutant decomposition. In this study, the oxidative degradation of AX by MnO was investigated in batch experiments. It was found that up to 90% AX was decomposed by MnO in 30 min and the removal efficiency of AX depended strongly on the loading of MnO and pH value in the solution where the reactions closely followed a pseudo-first-order model. The reaction orders with respect to the initial AX concentration, MnO concentration and pH value were 0.4573, 0.2034, and -0.1701, respectively. Coexisting metal ions, such as Mn, Fe, Ca and Mg, displayed suppressive effects and the inhibitive capacity of the metal ions followed the order Mn > Fe > Ca > Mg. However, the effect of humic acid (HA) on reaction rates was significant only at higher concentrations. This study provided meaningful information to elucidate the oxidative degradation of AX by MnO