Removal of elemental mercury by bio-chars derived from seaweed impregnated with potassium iodine
Removal of elemental mercury by bio-chars derived from seaweed impregnated with potassium iodine
复制标题
碘化钾浸渍海藻生物炭去除元素汞
DOI：
10.1016/j.cej.2018.01.148
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发表时间：
2018-05-01
影响因子：
15.1
通讯作者：
Liu, Yangxian
中科院分区：
文献类型：
--
作者：
Liu, Ziyang;Yang, Wei;Liu, Yangxian
采用卤化物浸渍法对马尾藻和浒苔两种海藻生物炭进行了改性。改性的生物炭用于从模拟烟气中捕获Hg-0。通过各种表征技术，包括近似分析和最终分析，布鲁诺尔-埃米特-泰勒（BET），扫描电子显微镜（SEM）和x射线光电子能谱（XPS），研究了样品的物理和化学性质。研究了不同类型卤化物浸渍、卤化物负荷量、不同烟气组分和吸附温度对吸附剂上Hg-0脱除的影响。研究了脱除Hg-0的机理和动力学。结果表明，与氯化钾和溴化钾改性的生物炭相比，碘化钾改性的生物炭具有更好的Hg-0吸附性能。最佳碘化钾负荷值为3wt %。随着反应温度的升高，Hg-0的脱除效率显著提高。O-2促进Hg-0的去除。SO2的加入抑制了肠形态炭中Hg-0的去除，并对糖质炭中Hg-0的去除表现出双重影响。低浓度的NO和H2O有利于Hg-0的去除，而高浓度的NO和H2O则抑制Hg-0的去除。通过动力学模拟分析，发现化学吸附是120℃和160℃下Hg-0吸附的主要控制因素。共价基（C-I）和化学吸附的氧和/或弱键氧参与了Hg-0的去除过程，是碘化物修饰海藻生物炭表面的主要化学吸附位点。
Two kinds of bio-chars derived from seaweed, such as sargassum and enteromorpha, are modified by halides impregnation. The modified bio-chars are used to capture Hg-0 from simulated flue gas. The physical and chemical properties of the samples are investigated by various characterization technologies, including proximate and ultimate analysis, Brunauer-Emmett-Teller (BET), Scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS). The effects of different types of halides impregnation, halide loading values, individual flue gas component and adsorption temperature on removal of Hg-0 over adsorbents were studied. The mechanism and kinetics of Hg-0 removal were also studied. The results show that potassium iodide modified biochars have better Hg-0 adsorption performance than bio-chars modified by potassium chloride and potassium bromide. The optimal potassium iodide loading value is 3 wt%. As the reaction temperature increases, Hg-0 removal efficiency significantly increases. O-2 promotes the Hg-0 removal. Addition of SO2 inhibits Hg-0 removal over enteromorpha-chars, and shows a double impact on Hg-0 removal over sargassum-chars. Low concentrations of NO and H2O are beneficial to Hg-0 removal, whereas high concentrations of NO and H2O inhibit Hg-0 removal. Chemisorption is found to be the main control factor for Hg-0 adsorption at 120 degrees C and 160 degrees C based on kinetic simulation analysis. The covalent groups (C-I) and the chemisorbed oxygen and/or weakly bonded oxygen species participate in the Hg-0 removal process and are the dominant chemical adsorption sites on the suface of the iodide modified seaweed bio-chars.