Jingyun Qian,Wenna Zhang,Xue Yang,Kexin Yan,Meikun Shen,Hongyue Pan,Hongjun Zhu,Lei Wang
Constructing the metal cation-mediated low-cost inorganic sorbent with high separation efficiency in CO 2 , N 2 , and CH 4 remains a major challenge. Herein, we developed a series of alkali metal cations (Na + , K + , Rb + , Cs + )-exchanged ERI zeolites and adopted in the separation process of CO 2 among the gas mixture. Among the ion-exchanged zeolites, the zeolite K-ERI showed a high adsorption volume of 70.84 cm 3 g −1 and an IAST selectivity of CO 2 /CH 4 : 6254, CO 2 /N 2 : 2872 at 298 K, respectively, far outweighed the reported metal cation exchanged zeolites. Combining powder X-ray diffraction crystallography and density functional theory calculations, we unequivocally unveiled that the metal cations located at s 8 r effectively tailored zeolite aperture, and metal cation-gas molecules interactions synergically restrained the pass-through capacity of CO 2 in ion-exchanged ERI framework. Such a unique host–guest interaction governed by metal cations in aluminosilicate zeolite ERI affords a general strategy for gas separation.
Xu Zhang,Yaquan Wang,Xiao Wang,Hengbao Chen,Hongyao Li,Chao Sun,Liying Sun,Chunyang Fan,Cui Wang
In this study, an efficient route was developed to prepare high quality erionite (ERI) zeolite by hydrothermal conversion of faujasite (FAU) zeolite as an aluminosilicate source in the presence of N,N -dimethylpiperidinium hydroxide (DMPOH). Pure ERI zeolite was successfully synthesized within only 8 h by carefully controlling the alkalinity (OH − /SiO 2 ) of the initial gel and the proportion of DMP + and K + . Compared with the conventional ERI zeolite synthesized via a Charge Density Mismatch method, the FAU-derived ERI zeolites show superior properties such as higher crystallinity , smaller crystal size, larger micropore volume and better hydrothermal stability. In addition, catalytic test in the ethanol dehydration reaction shows that the ERI zeolites obtained from FAU exhibit extraordinary performances to those of the conventional one. Finally, crystallization process from FAU to ERI was investigated in detail by UV Raman and XRD . The results show that the framework of ERI zeolite is formed by rearrangement of 4-rings generated from the initial FAU zeolite.
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