Kazuki MITSUMA

Evaluation of Crystalline Pore Structure of AFX-Type Zeolite

Syuji HIMENOAToshiya KOMATSU
@In Japan, the Kyoto Protocol, the predecessor of the Paris Agreement, has been adopted.
In Japan, the Kyoto Protocol, the predecessor of the Paris Agreement, was adopted and set a 
medium-term goal of reducing greenhouse gas emissions by 25.4 percent from the FY2015 level in 
FY2030. Then, based on the Paris Agreement, the long-term goal was set to reduce greenhouse gas 
emissions by 80% by 2080. In addition, the introduction of renewable energy and the widespread use 
of next-generation automobiles are cited as measures to combat global warming. The total emission 
of CO2 accounts for about 80% of the total greenhouse gas emissions in Japan, and it can be said 
that CO2 emission control is an effective way to reduce greenhouse gas emissions.
In this study, we compared DDR zeolite and AFX zeolite as CO2 separation adsorbents, and found 
that DDR zeolite has a pore size of 0.36~0.44 nm and can separate CO2 from CO2/CH4 mixture by 
molecular sieving effect. The AFX-type zeolite has a pore diameter of 0.34 ~ 0.36 nm, which is close 
to that of CO2 (0.33 nm), and is considered to be suitable for CO2 separation.
@Although the above zeolites can be used as materials for CO2 separation from CO2/CH4 and 
CO2/N2 mixtures, the pore structure and other physical properties of AFX have not yet been 
clarified because it is relatively new. Therefore, the purpose of this study was to evaluate the pore 
structure of AFX zeolite by comparing its physical properties with those of existing DDR zeolite.
In Chapter 1, the background of the study, related technologies, adsorption phenomena and research 
objectives are presented. In Chapter 2, the framework structure of zeolite, adsorption phenomena, 
and previous studies on zeolite, which are the basis of this study, are described. Chapter 3 outlines 
the experimental equipment and instruments used in this study, as well as the synthesis procedure 
and experimental methods. In Chapter 4, the experimental results and discussion of DDR and AFX 
zeolites are presented. Chapter 5 summarizes the experimental results obtained in this study and 
discusses the insights gained from them.