Gaseous elemental mercury removal through heterogeneous Fenton-like processes using novel magnetically separable Cu0.3Fe2.7−xTixO4 catalysts

Abstract

A series of novel magnetic Cu0.3Fe2.7−xTixO4 composites was synthesized and used as recyclable heterogeneous Fenton-like catalysts for gaseous elemental mercury (Hg0) removal from simulated flue gases. The technique of inductively coupled plasma-atomic emission spectroscopy (ICP-AES), scanning electron microscopy (SEM), and X-ray photoelectron spectrometry (XPS) were used, and Brunauer Emmett Teller (BET) analysis was achieved to determine the chemical composition, pore structure, and surface chemistry of the catalysts. The performance of heterogeneous Fenton-like reactions for Hg0 removal was investigated in a bench-scale bubbling reactor under neutral condition. Some main parameters such as Cu/Ti ratio in the catalysts, H2O2 concentration, solution pH, and gas flow were systematically studied to establish optimal reaction conditions. The effects of SO2 and NO on Hg0 removal were also analyzed. Vibrating sample magnetometer (VSM) analysis suggested the Cu0.3Fe2.7−xTixO4 catalysts can be manipulated by an external magnetic field, and have potential advantages in terms of separation and recovery. Hg0 removal remained efficient after five repeated experiments with only a slight decrease. Electron spin resonance (ESR) was applied to confirm the active hydroxyl radical (OH) generated during heterogeneous Fenton-like reactions.