晶格铁在含铁水镁石碳酸盐化中的作用

Role of Lattice Iron in Carbonation of Fe-containing Brucite

实验制备了含铁水镁石,利用X射线衍射仪(XRD)、扫描电子显微镜(SEM)、X射线光电子能谱仪(XPS)和X射线荧光光谱仪(XRF)等技术手段进行表征,探索其在CO_(2),O_(2)和CO_(2)混合气体存在下,形成产物种类和含量,通过与水镁石演化产物种类进行对比,研究了晶格铁在含铁水镁石反应中的作用,证明了在O_(2)和CO_(2)存在下,含铁水镁石中晶格铁可以被氧化,被氧化后使层板带正电,导致其与CO_(2)溶于水生成的CO_(2)^(3-)作用力增强,生成了MgFe-CO_(2)^(3-)-LDHs,含量达到61.7%;而相同条件下Mg(OH)_(2)与CO_(2)反应仅有少量MgCO_(3)或MgCO_(3)(H_(2)O)_(3)形成。利用Materials Studio软件通过分子模拟,从结合能和电荷密度的角度验证了晶格铁能促使含铁水镁石与CO_(2)作用增强,加速碳酸盐化;含铁水镁石中铁的晶格替代利于其对CO_(2)的吸附和固定。

Fe-containing brucite was prepared successfully in laboratory and characterized by XRD,SEM,XPS and XRF.The kinds and contents of the products of Fe-containing brucite after being treated by CO_(2),O_(2)and CO_(2)mixture were explored and the role of Fe^(2+)in the reaction was also studied by comparing with brucite.In O_(2)and CO_(2)mixture,the Fe^(2+)in Fe-containing brucite could be oxidized to be Fe^(3+)and react with CO_(2)^(3-)generated from CO_(2)to form MgFe-CO_(2)^(3-)-LDHs due to the electrostatic attraction.Finally,the content of MgFe-CO_(2)^(3-)-LDHs reached 61.7%.For Mg(OH)_(2),only MgCO_(3)and MgCO_(3)(H_(2)O)_(3)formed under the same conditions.Molecular simulation was carried out by Materials Studio software to verify the enhancement of the lattice iron in the interaction between Fe-containing brucite and CO_(2),and the acceleration function in the carbonation process through binding energy and charge density.The substitution of magnesium by iron in Fe-containing brucite contributed to the adsorption and fixation of CO_(2).