Elemental mercury (Hg0) removal from containing SO2/NO flue gas by magnetically separable Fe2.45Ti0.55O4/H2O2 advanced oxidation processes

Abstract

Elemental mercury (Hg0) removal from containing SO2/NO simulated flue gas was systematically investigated, making use of Fe2.45Ti0.55O4/H2O2 advanced oxidation processes. The effectiveness follows from the hydroxyl radicals (OH) with the inherent character of non-selectivity and high activity, which can oxidize and remove Hg0 under solvent free conditions. The magnetically separable Fe2.45Ti0.55O4 catalyst was prepared by chemical co-precipitation method, and characterized by the techniques of inductively coupled plasma-atomic emission spectrometry (ICP-AES), scanning electron microscopy (SEM), Brunauer–Emmett–Teller (BET) surface area, vibrating sample magnetometer (VSM), and electron spin resonance (ESR). The performance of Hg0 removal in Fe2.45Ti0.55O4/H2O2 solutions was carried out, and the effects of the most relevant operational parameters, such as solution pH values, catalyst dosage, and solution temperature, of the advanced oxidation processes were specifically studied. A high efficiency of Hg0 removal was obtained under optimum operational parameters (about 96% with 0.5M H2O2 at weak acid medium). The optimal pH value, catalyst dosage, and solution temperature are found at about 6, 0.6gL−1, and 50°C, respectively. The presence of SO2 in simulated flue gases has little effect on Hg0 removal, while NO intensively promotes Hg0 removal in advanced oxidation reactions. The activity of Fe2.45Ti0.55O4 catalyst undergoes decay to some extent after three consecutive experiments have been conducted.