在固定床实验台上考察了三种不同来源粉煤灰对单质汞的吸附性能,采用X射线荧光光谱仪、X射线光电子能谱仪、激光粒度分析仪、扫描电子显微镜等对不同粉煤灰的物化性质进行了表征,并探讨了物化性质对汞吸附性能的影响。结果表明,粉煤灰对汞的吸附包括物理吸附和化学吸附;粉煤灰中未燃尽碳是影响粉煤灰汞吸附性能的重要因素之一,其中,表面C元素与Ti、Si等元素(M)相互作用形成的“C—M”化学键促进了单质汞的氧化,同时粉煤灰中含有的无机化合物Fe2O3等也对单质汞的氧化有促进作用;增大比表面积和减小孔径,及适中的颗粒粒径均有利于提高粉煤灰单质汞吸附性能。
The effect of physicochemical properties of three fly ash samples on the mercury adsorption performance is investigated using a fixed-bed with a simulated gas by means of X-ray fluorescence spectroscopy, X-ray photoelectron spectroscopy, laser particle size analyzer, scanning electron microscopy and other analytic methods. The results indicate that the mercury adsorption on the fly ash mainly proceeds in physisorption and chemisorption. Uncompleted burned carbon is an important factor for the improvement of mercury removal efficiency, and the C-M bond that is formed via the reaction between C and Ti, Si and other elements may promote the oxidation of mercury. Meanwhile, the inorganic compound such as Fe203 in the fly ash can also improve the oxidation of mercury. Higher specific surface areas, smaller pore diameter, and moderate particle diameter are all beneficial for the high mercury removal efficiency.