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以沉积-沉淀法制备的MnOx-CoOy/TiO2(MCT)为吸附剂,在固定床实验台架上研究了制备过程中煅烧温度(200-800℃)对MCT脱除单质汞(Hg0)的影响;采用N2吸附/脱附、扫描电子显微镜(SEM)、X射线衍射(XRD)、H2-程序升温还原(TPR)、傅里叶变换红外光谱(FTIR)和X射线光电子能谱(XPS)等手段表征了吸附剂的理化特征。研究表明,MCT吸附剂的脱汞效率与煅烧温度密切相关,400℃煅烧时,吸附剂的脱汞效率最高。吸附剂的煅烧过程包含吸附态水的蒸发、锰钴碳酸盐或氢氧化物的分解、MnOx和CoOy的形成及MnOx、CoOy和TiO2晶相的转变。随着煅烧温度的增加,MCT吸附剂的比表面积和总孔容积逐渐减小,平均孔径逐渐变大,且吸附剂发生团聚,颗粒尺寸增大;MnO2和Co3O4向Mn2O3和CoO的转变,吸附态氧含量的降低,致使吸附剂的脱汞活性下降。
The effect of calcination temperature (200-800 ℃) on the removal of elemental mercury (Hg0) from MCT was studied on a fixed bed laboratory bench using MnOx-CoOy / TiO2 (MCT) prepared by deposition- ; N2 adsorption / desorption, scanning electron microscopy (SEM), X-ray diffraction (XRD), temperature programmed reduction with H2-TPR, Fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy Means the physical and chemical characteristics of the adsorbent. The results show that the mercury removal efficiency of MCT adsorbent is closely related to the calcination temperature. When calcined at 400 ℃, the mercury removal efficiency of adsorbent is the highest. The calcination process of adsorbent includes the evaporation of adsorbed water, the decomposition of manganese, cobalt carbonate or hydroxide, the formation of MnOx and CoOy, and the transformation of MnOx, CoOy and TiO2 crystalline phases. With the increase of calcination temperature, the specific surface area and total pore volume of MCT adsorbent decrease gradually, the average pore diameter gradually increases and agglomeration of adsorbent occurs, and the particle size increases. The transition of MnO2 and Co3O4 to Mn2O3 and CoO, Oxygen content decreased, resulting in decreased mercury removal activity of the adsorbent.