Biomass Carbon Magnetic Adsorbent Constructed by One-Step Activation Method for the Removal of Hg⁰ in Flue Gas

Abstract

Elemental mercury (Hg 0 ) emission from industrial boilers equipped in factories such as coal-fired power plants poses serious hazards to the environment and human health. Herein, an iron-modified biomass carbon (Fe/BC) magnetic adsorbent was prepared by a one-step method using pepper straw waste as raw material and potassium oxalate and ferric nitrate as activator and catalyst precursor, respectively. A fixed-bed reactor was used to evaluate the Hg 0 removal performance of the Fe/BC adsorbent. The synthesized adsorbent showed a wide temperature window for Hg 0 removal. In a N 2 + O 2 atmosphere, the removal efficiency toward Hg 0 was 97.6% at 150 °C. Further, O 2 or SO 2 could promote the removal of Hg 0 , while NO could inhibit the conversion of Hg 0 over the Fe/BC adsorbent. The consequence of XPS and Hg-TPD showed that lattice oxygen in Fe 2 O 3 and chemisorbed oxygen were the main active sites for Hg 0 removal, and HgO was the main mercury species on used Fe/BC. Moreover, Fe/BC adsorbent showed a good regeneration and magnetization performance, which was conducive to the cost reduction of actual industrial application. This study provides a facile approach for efficient removal of Hg 0 using biomass-derived carbon material.

Preparation and Mercury Removal Performance of Mg-MOF-74 Composites

“…Studies have shown that materials such as fly ash, mineral substances and biochar can be used for mercury adsorption [5][6][7]. Jiali et al [8] found that walnut shell biochar modified by metal doping has an abundant surface structure and functional groups, which makes it more effective for the removal of gaseous elemental mercury, and can be used as an alternative material for activated carbon mercury removal agents.…”