Removal of Elemental Mercury Using Seaweed Biomass-Based Porous Carbons Prepared from Microwave Activation and H2O2 Modification

Abstract

In this article, two kinds of seaweed biomass-based porous carbons were prepared by a green and efficient method of microwave activation/H2O2 synergistic modification from seaweed biomass resources. The Hg0 capture performance of seaweed-based porous carbons was tested in a fixed-bed reactor system. The results show that microwave activation greatly increases the surface area of porous carbons. The porous carbons (S8W30 and E8W30) modified with 30% H2O2 exhibit excellent Hg0 removal capacity at 120 °C. NO, O2, and low concentrations of SO2 in flue gas have a positive effect on the removal of Hg0. Water vapor and high concentrations of SO2 exhibit a negative effect on the process of Hg0 capture. The oxygen-containing functional groups (C═O and C–OH/C–O–C groups) on the surface of the modified porous carbon, which are mainly produced by H2O2 modification, are considered to be the main active sites for Hg0 capture. The X-ray photoelectron spectroscopy (XPS) analysis shows that the adsorbed Hg0 can be oxidized to Hg2+. The modified porous carbons exhibit good development and application prospects compared with commercial activated carbon (AC) or other activated carbons.