The wet FGD system is widely recognized as the co-effective removal system for oxidized Hg vapor species and SO2. In this study, a purpose-built device was designed for this experiment and several factors potentially affecting the Hg-0 removal efficiency were systematic investigated, including different types of oxidants, pHs and concentrations of potassium permanganate, reaction temperatures, Hg-0 inlet concentrations, O-2, SO2 and NO concentrations, and different types of absorption solutions. Results indicate that pHs and KMnO4 concentrations, reaction temperatures, SO2 and NO concentrations all have a strong influence on the removal of Hg-0, and the inlet concentrations of Hg-0 and O-2 contribute little to the removal of Hg-0 center dot SO2 could significantly inhibit the removal of Hg-0, the negative effect is serious especially at lower SO2 concentration, and SO2 could lead to the re-emission of Hg-0 center dot Hg-0 could be removed effectively by using CaCO3 + KMnO4 solution, when the KMnO4 concentration in the CaCO3 + KMnO4 solution was 1.5 mmol/L, the removal efficiencies of SO2, NO and Hg-0 were 100%, 40.69% and 90.58%, respectively. So, considering the application to the practical engineering, adding 1.5-2 mmol/L KMnO4 into limestone-gypsum flue gas desulfurization systems is necessary. This technology is a promising method for the simultaneous removal of NO, SO2 and Hg-0. (C) 2012 Elsevier B.V. All rights reserved.