Experimental Study on the Mercury Removal of a H2S-Modified Fe2O3 Adsorbent

Owing to the massive mercury emission from coal-fired power plants and other nonpower industries worldwide, it is imperative to develop non-carbon-based adsorbents for mercury removal. In this work, an efficient sulfur-loaded Fe2O3 adsorbent for mercury removal was developed by H2S modification. The optimum modification parameters were determined at the vulcanization temperature of 200 degrees C and the vulcanization time of 2 h. The effect of reaction temperature and initial mercury concentration on mercury removal was investigated. Through the fixed-bed experiment, it was found that the adsorbent exhibits good mercury removal performance. The mechanism of mercury adsorption was deeply studied based on the characterization analyses of Brunauer-Emmett-Teller (BET), scanning electron microscopy (SEM), X-ray diffraction (XRD), thermogravimetry (TG), and X-ray photoelectron spectroscopy (XPS). The results show that the abundant and well-dispersed active sulfur sites on the surface of samples could enhance the chemical bonding to Hg-0. The interaction between gaseous H2S and Fe2O3 could lead to the formation of active Sad and FeSx (FeS, FeS2) during the modification process. Those active sulfur species can further boost the adsorption and oxidation of Hg-0 to HgS during the mercury adsorption process.