Development of LnMn03+σ perovskite on low temperature Hg0 removal

• 作者: Qicheng Shen Jiacheng Zhou Chenglong Ma Jie Yang Limei Cao Ji Yang
• 来源期刊: 环境科学学报（英文版）
• 年，卷（期）: 2022,（3）
• 页码范围: 141-151
• 页数: 11页
• 语种: 英文

摘要

LnMnO3+σ (Ln =La,Pr,Nd,Sm,Eu,Gd or Dy) perovskites synthesized by sol-gel method were employed for gaseous elemental mercury (Hg0) removal from coal-fired flue gas.Char-acterization results revealed the structure of the perovskites presented a phase transition process from rhombohedral system to O-and O'-orthorhombic structure with the change of A-site rare earth elements.The perovskites showed satisfactory Hg0 removal capacity in a narrow temperature range of 100-150℃.NdMnO3+σ with an O-O'orthorhombic struc-ture presented the best Hg0 removal performance,which markedly depends on four fac-tors:crystal structure,oxygen vacancy density,Mn4+/Mn3+ ratio and surface element seg-regation.The Hg0 removal mechanism was illustrated based on the mercury temperature programmed desorption experiment and X-ray photoelectron spectroscopy characteriza-tion.Both chemisorption and catalytic oxidation played a role in the Hg0 removal process.Chemisorption dominated the Hg0 removal,due to the slow catalytic oxidation rate at low temperature.This work preliminarily established the relation between the structure of rare earth manganese perovskite and Hg0 removal performance.