FeCl3改性MOFs在低温下对Hg0的吸附性能

为提高吸附剂对Hg0（零价汞）的吸附效率，利用MOFs（金属有机框架）材料发达的孔隙结构和高比表面积（1 997.010 0 m2/g），采用FeCl₃溶液浸渍改性，制备了吸附剂FeCl₃@MIL-101（Cr）用于脱除Hg0.在小型固定床反应器上考察了浸渍浓度、反应温度、氧含量等对Hg0去除的影响.结果表明:FeCl₃@MIL-101（Cr）在进口ρ（Hg0）为2×10-3 mg/L，c（FeCl₃）为0.2 mol/L，反应温度60℃，气体流速400 mL/min，φ（O₂）为1%的条件下，吸附穿透时间长达62 h，相应的吸附容量为14.27 mg/g.在此基础上，进一步利用BET（比表面积测试）、SEM（扫描电镜）-EDX（能量色散X射线光谱）、XRD（X射线衍射）、XPS（X射线光电子能谱）等常用表征手段研究了改性前后吸附剂的物理化学特性，证明了吸附剂FeCl₃@MIL-101（Cr）吸附零价汞是物理吸附与化学吸附共同作用的结果，含氯官能团在吸附Hg0过程中也发挥了相当大的作用，并且氧气可促进其吸附效果.最后，分析了其吸附机理.研究显示，该种吸附剂在低温条件下具有较为优良的脱汞性能，应用前景良好. 

Adsorption Performance of Elemental Mercury on MOFs Modified with FeCl3 at Low Temperatures

In order to improve the adsorption efficiency of adsorbent for removal of Hg0 in flue gas, the sorbent of FeCl₃@MIL-101(Cr) is prepared by impregnating metal organic frameworks (MOFs) materials with FeCl₃ solution for modification. The MOFs material possesses well-developed pore structure and high specific surface area (1997.0100 m2/g). The effects of the impregnation concentration, reaction temperature and oxygen content for removal of Hg0 were investigated on a small fixed bed reactor. It was found that the maximum adsorption breakthrough time of Hg0 was 62 h, and the corresponding adsorption capacity was 14.27 mg/g, when the FeCl₃ impregnation concentration was 0.2 mol/L, the reaction temperature was 60℃, the carrier gas flow rate was 400 mL/min, the impregnation temperature was 115℃ and the oxygen content was 1%. The physical and chemical characteristics of the adsorbent before and after modification were further studied by using Brunauer-Emmett-Teller (BET), Scanning Electronic Microscopy (SEM)-Energy dispersive X-ray spectroscopy (EDX), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). It was proved that the adsorption of Hg0 by modified MOFs materials is the result of the interaction between physical adsorption and chemical adsorption. What is more, the chlorine functional group has also played a considerable role in Hg0 adsorption, and oxygen can promote the adsorption effect. The mechanism of adsorption was analyzed lastly. The experimental results show that the adsorbents have excellent performance of mercury removal at low temperatures and present great application prospects.