Ionic mercury captured by H_2S sulfurized biochar in liquid hydrocarbons: Mechanism and stability evaluation

摘要

Three kinds of biochar, tobacco, rice and wheat, were treated with H2S to remove Hg(II) from hydrocarbons. The removal efficiency of the three biochars without H2S treatment was less than 12%. The removal efficiency of H2S treated tobacco had the best performance, and the removal efficiency increased by more than 87%. The characteristics of H2S treated biochar were analysed by FTIR, XPS, and TPD. The inorganic sulphides played a major role through ion exchange with metals. The sulphur-containing functional group C-S in organic sulphides and the carbonyl group C = O played a secondary role in the process of mercury removal through functional group complexation. In addition, the chemical and physical properties of gasoline before and after adsorption were compared to demonstrate that the sorbents had little effect on the heating value and the structure of hydrocarbons. The modified biochar also showed good stability after a life cycle test.