TiO2改性的镁基中温吸附剂及其CO2吸附性能的研究

TiO2 modified magnesium-based adsorbents for intermediate-temperature CO2 capture

  • 摘要: 采用沉淀法合成一系列TiO2改性的镁基吸附剂,利用XRD、SEM和氮气吸附等方法对吸附剂进行表征,通过变温吸附-脱附动态循环实验考察其CO2吸附性能。随着TiO2含量的增加,样品的结晶度逐渐下降,同时由于焙烧后生成钛酸镁,样品比表面积逐渐减小。当TiO2添加量为2%(质量分数),此时吸附剂呈直径为4.0~5.0μm的球形,局部为纳米片状结构,该吸附剂自第二次循环开始吸附能力无明显变化;经过50次变温吸附脱附循环实验后,动态吸附容量可达6.64%(质量分数),这是由于TiO2改性后生成的钛酸镁为该吸附剂提供了刚性骨架,促进了活性组分的分散,并提高了吸附剂的稳定性。

     

    Abstract: A series of TiO2-modified magnesium-based sorbents, for thermo-swing absorption process in intermediate-temperature working range (250~500℃), were prepared by precipitation, and characterized by XRD, SEM and N2 absorption etc. The sorbents were evaluated by dynamic absorption-desorption cyclic tests. With the increase of TiO2 amount, the crystallinity of the sample decreased, and the BET surface area also decreased due to the formation of MgTiO3.When the TiO2 content was 2%, uniform particle size (nanostructured spheres with 4.0~5.0μm in diameter) was obtained. The absorption capacity was stabilized from the second cycle of the absorption-desorption cyclic test, and the capacity could reach 6.64% after 50 cycles, suggesting good stability of the sorbent. This should be attributed to the formation of MgTiO3, which provided a rigid framework for the sample and improved the dispersion of active species.

     

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