A series of elemental mercury removal experiments were performed at different temperatures to explore the elemental mercury oxidation efficiency on alpha-Fe2O3 and gamma-Fe2O3 in the presence of H2S. Our experimental results indicated that the alpha-Fe2O3 and gamma-Fe2O3 similarly played important roles in removing elemental mercury. The reaction temperature around 230 degrees C is a critical turning point in effectively capturing elemental mercury, above which the Hg-0 removal efficiency would decrease. According to our previous researches, H2S will preferentially adsorb on the Fe2O3 surface, forming active sulfur sites to react with Hg-0. In this paper, we analyzed the contrastive samples before and after removing Hg-0 to further investigate the probable products by the Hg-0 re-release experiments, as well as thermogravime try-differential scanning calorimeter (TG-DSC) and X-ray photoelectron spectroscopy (XPS) analysis. The test results of morphological characterization showed that mercury compounds and new substances generated in the Fe2O3 samples after adsorbing Hg-0. At the same time, the detection results showed that Hg2+, sulfur, S2-, S- and Fe2+ had appeared, which demonstrated the probable mercury products, and the H2S pre-adsorption and Hg-0 oxidation could be confirmed as well by the different groups of comparative tests. In conclusion, our experimental results are in good agreement with our previous experiments and computational results. (C) 2015 Elsevier Ltd. All rights reserved.