Removal of elemental mercury by iodine-modified rice husk ash sorbents  

作　　者：Pengfei Zhao,Xin Guoff,Chuguang Zheng State Key Laboratory of Coal Combustion,Huazhong University of Science and Technology,Wuhan 430074,China 

出　　处：《Journal of Environmental Sciences》2010年第10期1629-1636,共8页环境科学学报（英文版）

基　　金：supported by the National Natural Science Foundation of China(NSFC)(No.50506011, 50936004);the partial funding from the Science Foundation of Huazhong University of Science and Technology (No.M2009009);the Ministry of Science and Technology of China(No.2006CB705806)

摘　　要：Iodine-modified calcium-based rice husk ash sorbents （I2/CaO/RHA） were synthesized and characterized by X-ray diffraction, X-ray fluorescence, and N2 isotherm adsorption/desorption. Adsorption experiments of vapor-phase elemental mercury （Hg^0） were performed in a laboratory-scale fixed-bed reactor. I2/CaO/RHA performances on Hg^0 adsorption were compared with those of modified Cabased fly ash sorbents （I2/CaO/FA） and modified fly ash sorbents （I2/FA）. Effects of oxidant loading, supports, pore size distribution, iodine impregnation modes, and temperature were investigated as well to understand the mechanism in capturing Hg^0. The modified sorbents exhibited reasonable efficiency for Hg^0 removal under simulated flue gas. The surface area, pore size distribution, and iodine impregnation modes of the sorbents did not produce a strong effect on Hg^0 capture efficiency, while fair correlation was observed between Hg^0 uptake capacity and iodine concentration. Therefore, the content of 12 impregnated on the sorbents was identified as the most important factor influencing the capacity of these sorbents for Hg^0 uptake. Increasing temperature in the range of 80-140℃ caused a rise in Hg^0 removal. A reaction mechanism that may explain the experimental results was presumed based on the characterizations and adsorption study.Iodine-modified calcium-based rice husk ash sorbents （I2/CaO/RHA） were synthesized and characterized by X-ray diffraction, X-ray fluorescence, and N2 isotherm adsorption/desorption. Adsorption experiments of vapor-phase elemental mercury （Hg^0） were performed in a laboratory-scale fixed-bed reactor. I2/CaO/RHA performances on Hg^0 adsorption were compared with those of modified Cabased fly ash sorbents （I2/CaO/FA） and modified fly ash sorbents （I2/FA）. Effects of oxidant loading, supports, pore size distribution, iodine impregnation modes, and temperature were investigated as well to understand the mechanism in capturing Hg^0. The modified sorbents exhibited reasonable efficiency for Hg^0 removal under simulated flue gas. The surface area, pore size distribution, and iodine impregnation modes of the sorbents did not produce a strong effect on Hg^0 capture efficiency, while fair correlation was observed between Hg^0 uptake capacity and iodine concentration. Therefore, the content of 12 impregnated on the sorbents was identified as the most important factor influencing the capacity of these sorbents for Hg^0 uptake. Increasing temperature in the range of 80-140℃ caused a rise in Hg^0 removal. A reaction mechanism that may explain the experimental results was presumed based on the characterizations and adsorption study.

关 键 词：MERCURY sorbents fly ash rice husk ash IODINE IMPREGNATION 

分 类 号：X50[环境科学与工程—环境工程]