高比表面积MgO颗粒制备及其CO_2吸附性能研究

Synthesis of MgO Pellets With High Specific Surface Area and Its CO_2 Adsorption Property

以羧甲基纤维素钠(CMC)为黏结剂制备了具有高比表面积和较好机械强度的柱状MgO颗粒吸附剂。研究了煅烧温度、CMC质量分数对成型MgO颗粒的孔结构分形特性,CO_2吸附量回收率以及机械强度的影响。结果表明,煅烧温度为500℃、CMC添加量为20%的MgO颗粒具有较高的比表面积,其在50℃,常压下的CO_2吸附量回收率和机械强度分别达到78.66%和0.39 MPa。FHH分形模型可以很好地定量分析成型颗粒的孔道结构特征,分形维数越小,颗粒孔道结构越规则有序,吸附剂的吸附效率越高。MgO颗粒的分形维数与其平均孔径和比表面积分别呈现一定的负相关和正相关关系,而与孔体积没有直接关系。5次循环后MgO颗粒的吸附量仅减少了3.6%,因此该MgO颗粒适合用于CO_2气体的捕集。

MgO pellets with high specific surface area and good mechanical strength were fabricated by using sodium carboxymethyllcellulose（CMC） as binder.The effects of calcination temperature and CMC mass ratio on the fraction characters,CO2 adsorption capacity recovery and mechanical strength of the MgO pelletized adsorbents were investigated.The results showed that the MgO pellets with 20% CMC mass ratio calcined at 500℃ had a high surface area.Its CO2 adsorption capacity recovery and mechanical strength up to 78.66% under 50℃,101 kPa and 0.39 MPa,respectively.The FHH model was well to quantitatively describe the texture structure of the pellets.The pore structure got to be regular when the fractal dimension decreased,thus increasing the adsorption efficiency.The fractal dimension showed certain negative correlation with the average pore diameter and positive relationship with the surface area,respectively.However,the fractal dimension was irrelevant with the pore volume.The adsorption capacity of the selected MgO pellet only decreased by 3.6% after 5 cycles,indicating that it would be suitable for CO2 capture.