Ca掺杂对硅酸锂吸收CO2性能的影响

摘要

以固相法为基础，添加不同比例的CaCO3合成了一系列硅酸锂材料．利用XRD、BET和SEM分析了Ca元素的掺杂对硅酸锂结构和形貌的影响，用热重分析仪和固定床反应器探究了硅酸锂的 CO2吸附性能．结果表明，适量的 Ca 掺杂改善了硅酸锂的 CO2吸附性能．Ca 掺杂引入了 Li2,CaSiO4，包裹在硅酸锂颗粒表面，熔融烧结受到明显的抑制，促进了硅酸锂的吸附和脱附反应的进行．Ca 元素的最佳掺杂比例为 x＝0.03．Li4,SiO4(x＝0.03)的最佳吸附温度是650,℃，饱和吸附量达29.96%，且其循环稳定性优于纯硅酸锂．%Calcium-doped lithium silicate was synthesized by solid-state reaction method.The influence of Ca-doping on the crystal structure and morphology of lithium silicate was analysized by X-ray diffraction(XRD), specific surface area(BET)and scanning electron microscopy(SEM).The CO2-absorption properties of lithium sili-cate were studied by a thermogravimetric analyzer and a fixed bed reactor.Results show that a Li2,CaSiO4phase forms when Ca is doped.Li2,CaSiO4particles cover the surface of lithium silicate particles,which can reduce the sintering degree and make it easier for samples to desorb and absorb CO2.An appropriate amount of Ca-doping could improve the CO2absorption ability of Li4,SiO4.When the doping amountx=0.03,Ca dopant has the greatest carbon dioxide absorption capacity.When the temperature is 650,℃,Ca dopant has the greatest carbon dioxide absorption capacity equal to 29.96%and Li4,SiO4(x=0.03) shows better cycle stability than Li4,SiO4.