Degradation of methyl orange by Zn0 assisted with silica gel.

The degradation of methyl orange (MO) by Zn(0) assisted with silica gel was investigated under different conditions. The results show that the degradation of MO by Zn(0) alone was slow and incomplete due to the rapid corrosion of Zn(0) particles on surface. However, the degradation of MO can be markedly enhanced when Zn(0) and silica gel coexist, even under neutral and alkaline conditions. MO removal was improved with a pH decrease, an increase of the initial amount of silica gel and Zn(0), and specific surface area of silica gel. The degradation of MO by Zn(0) assisted with silica gel can be described by a pseudo-first-order kinetic. And the surface of Zn(0) before and after the reaction was characterized by the microscopic analysis of morphology, revealing the potential mechanism responsible for the enhanced reactivity of silica gel.