卤化钾改性Mn-Co-Fe尖晶石脱除气相Hg0的性能研究

Study on the Performance of Potassium Halide Modified Mn-Co-Fe Spinel for Removing Hg0 in Gas Phase

为提高Mn-Co-Fe尖晶石吸附剂的脱汞性能,该研究首先采用溶胶凝胶自燃烧法和浸渍法结合制备了KX(X表示Cl、Br和I)改性的Mn-Co-Fe尖晶石吸附剂。然后,分别利用SEM、SEM结合EDS能谱Mapping、BET、XRD和VSM来表征其表面形貌、表面元素占比及分布、比表面积及总孔容积、晶相结构和比饱和磁化特性。并通过固定床探究了卤化钾种类、KI负载量、吸附温度和入口汞浓度对模拟燃煤烟气中汞脱除性能的影响。最后,通过动力学模拟、XPS表征和程序升温脱附实验研究了吸附剂对汞脱除的控制步骤、机制以及汞在吸附剂表面的存在形态。研究结果表明:在相同实验条件下,0.10KX@MCFS对汞的平均脱除效率KI(92.84%)>KBr(88.39%)>KCl(86.61%)。此外,增加KI的负载量、吸附温度和入口汞浓度在一定程度上能够促进改性MCFS的脱汞性能。虽然KI的负载导致了MCFS的磁性能下降,但综合分析得出:0.10KI@MCFS具有一个相对优异的汞脱除性能和饱和磁化强度值(34.0 emu/g)。因此,该研究的这一发现对汞污染排放控制和吸附剂磁回收的实践研究具有重要的参考价值。

In this study,in order to improve the mercury removal performance of Mn-Co-Fe spinel adsorbent,KX(X represents Cl,Br and I)modified Mn-Co-Fe spinel adsorbent is prepared by using sol-gel self-combustion method and impregnation method at first.Then,the surface morphology,the proportion and distribution of surface elements,the specific surface area and total pore volume,the crystal phase structure and the specific saturation magnetization characteristics are characterized by SEM,SEM combined with EDS energy spectrum mapping,BET,XRD and VSM,respectively.The effects of potassium halide type,potassium halide loading,adsorption reaction temperature and initial mercury concentration on mercury removal performance in simulated coal-fired flue gas are investigated through a fixed bed.Finally,the control mechanism of mercury removal by adsorbent and the present valence state of mercury on the adsorbent surface are studied based on dynamic simulation,XPS characterization and temperature programmed desorption experiment.The results show that under the same experimental conditions,the average mercury removal efficiency of 0.10KX@MCFS is KI(92.84%)>KBr(88.39%)>KCl(86.61%).Additionally,with the increase of the KI loading,adsorption temperature and inlet mercury concentration,the mercury removal performance of modified MCFS can be improved to a certain extent.Although the loading of KI leads to the decrease of the magnetic properties of MCFS,the comprehensive analysis shows that 0.10KI@MCFS has a relatively excellent mercury removal performance and saturation magnetization(34.0 emu/g).Therefore,the findings of this study have an important reference value for the practice of mercury pollution emission control and magnetic recovery of adsorbents.