Adsorption/desorption behavior of carbonyl sulfide gas on Scheelite type MWO4 adsorbent
Adsorption/desorption behavior of carbonyl sulfide gas on Scheelite type MWO4 adsorbent
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DOI：
10.1016/j.seppur.2018.06.040
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发表时间：
2018-12-22
影响因子：
8.6
通讯作者：
Kang, Misook
中科院分区：
文献类型：
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作者：
Kim, Junyeong;Do, Jeong Yeon;Kang, Misook
本研究以金属氧化物吸附剂脱除煤气化过程中少量的羰基硫化物(OCS)为研究对象，为整体气化燃料电池的运行奠定了基础。本研究试图通过引入碱土金属(M=Ca、Mg、Sr、Ba)和W两种金属物种来改善吸附剂的性能，制备出白钨矿类型的MWO4晶体。CoS气体在吸附剂表面被分解成CO和S段，然后被吸附到碱性侧和W侧。COS的去除量依次为CaWO4>；SrWO4>；BaWO4>；MgWO4>；WO3。当吸附剂具有理想的碱度时，CO和S在吸附剂表面吸附良好，导致CO和S键容易断裂。但是，这项研究表明，最优对齐吸附物和吸附剂表面的影响更大。对于白钨矿型CaWO4吸附剂，吸附活性中心Ca-O-W的距离与COS吸附分子的大小相似，表明在吸附剂的C轴附近有很好的取向。此外，本研究的一个重要结果是，当COS在MWO4表面吸附饱和时，吸附的COS气体可以与比COS毒性更大的CO2、SO2、CS和CS2气体一起从MWO4表面解吸出来。这可以考虑到其他二次环境污染物。
This study focused the metal oxide adsorbents to remove small amounts of carbonyl sulfide (OCS) during coal gasification, which was a preliminary step for Integrated Gasification Fuel Cell operation. This study attempted to improve the function of the adsorbent by introducing two kinds of metal species, alkaline earth metals (M = Ca, Mg, Sr, and Ba) and W, fabricated as a Scheelite-typed MWO4 crystal. COS gases were broken down into CO and S segments on the surface of the adsorbents, and were then adsorbed onto the alkaline and W sides. The COS removals decreased in the order of CaWO4 > SrWO4 > BaWO4 > MgWO4 > WO3. When the adsorbent had an ideal basicity, the CO and S adsorbed well on the surface of the adsorbent, resulting in easy breakage of the CO and S bonds. But, this study indicated that it was more influential to optimally align the adsorbate and adsorbent surface. For the Scheelite-type CaWO4 adsorbent, the distance of the adsorbing active site, Ca-O-W, was similar in size to the COS adsorbate molecule, suggested a good alignment approaching the C-axis of the adsorbent. Moreover, an important result in this study determined by mass spectroscopy was that when COS adsorption was saturated on the MWO4 surface, the adsorbed COS gases could desorb from the MWO4 surface with CO2, SO2, CS, and CS2 gases, which are more toxic than COS. This can be considered to other secondary environmental pollutants.