磁性硅铁载铜吸附Hg^(0)动力学机制及密度泛函研究  

Kinetic mechanism and density functional theory of Hg^(0) removal by Cu0-loaded magnetic Ferrosilicon

作　　者：周发山 刁永发[1] 杨炳文 ZHOU Fashan;DIAO Yongfa;YANG Bingwen(School of Environmental Science and Engineering,Donghua University, Shanghai 201620, China)

机构地区：[1]东华大学环境科学与工程学院,上海201620

出　　处：《功能材料》2021年第4期4160-4165,共6页Journal of Functional Materials

基　　金：国家重点研究与发展资助项目(2018YFC0705300);中央高校基本科研业务费专项资金和重点资助项目(2232017A-09,CUSF-DH-D-2017097);上海市科学技术委员会基础研究资助项目(14XD1424700)。

摘　　要：采用粉末冶金法将纳米单质铜(Cu^(0))、硅铁(FeSi)、四氧化三铁硅涂层(Fe_(3)O_(4)@SiO_(2))混合煅烧并制备出新型磁性硅铁载铜吸附剂MagFeSi-Cu^(0)。实验研究不同烟气温度下MagFeSi-Cu^(0)的汞吸附能力基础上,结合颗粒内扩散模型、准二阶动力学模型、Elovich模型及Bangham模型分析了MagFeSi-Cu^(0)吸附Hg^(0)过程的主要控制步骤。在此基础上,依据密度泛函理论(DFT)研究了不同反应温度下FeSi表面Cu^(0)原子与Hg^(0)原子的汞齐作用机制。研究结果表明,Bangham模型的拟合值与MagFeSi-Cu^(0)汞吸附实验值拟合度最高,MagFeSi-Cu^(0)表面痕量Hg^(0)吸附由汞的外扩散和表面铜汞齐吸附共同控制;通过密度泛函计算,发现Cu^(0)颗粒表面Cu-Hg齐吸附能为-0.534 eV,当烟气温度从80℃上升至200℃时,Hg^(0)原子与单质Cu原子的吸附自由能从-22.47 kJ/mol下降至-13.96 kJ/mol,这些结果为深入了解Hg^(0)在Cu(111)表面的反应机理提供了理论基础。The FeSi,the nano-copper and the silica-coated magnetic Fe_(3)O_(4) nano-particles were mixed and calcinated at 300℃by powder metallurgy method to prepare a novel magnetic sorbent(MagFeSi-Cu^(0)).The intra-particle diffusion model,quasi-second-order kinetic model,Elovich model and Bangham model were used to analyze the control steps in the process of Hg^(0) removal.On this basis,according to density functional theory(DFT),the amalgam interaction mechanism of Cu^(0) atoms and Hg^(0) atoms on the FeSi surface at different reaction temperatures was studied.The research results showed that the fitting value of Bangham model and the experimental value of mercury adsorption was the highest.The adsorption of trace Hg^(0) on the surface of MagFeSi-Cu^(0) was controlled by the external diffusion and copper amalgam.In addition,it was found that the adsorption energy of Cu-Hg on the surface of Cu^(0) was-0.534 eV.When the temperature of flue gas rose from 80℃to 200℃,the adsorption energy of Hg^(0) dropped from-22.47 kJ/mol to-13.96kJ/mol.These results provide a theoretical basis for in-depth understanding of the reaction mechanism of Hg^(0) on Cu(111)surface.

关 键 词：单质铜 痕量Hg^(0) 铜汞齐 密度泛函 吸附动力学模型 

分 类 号：X511[环境科学与工程—环境工程]