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White Carbon으로부터 A, Y 및 Mordenite 형 Zeolite의 합성
Synthesis of A, Y and Mordenite Type Zeolite from a White Carbon
HWAHAK KONGHAK, October 1987, 25(5), 477-485(9), NONE
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Abstract
무정형 silica 분말인 White carbon（Zeosil 45 : 한불화학제품）을 사용하여 A, Y 및 Mordenite형 Zeolite를 수열합성하였으며, 반응기질의 조성, 숙성시간 반응온도 및반응시간 등이 각 Zeolite 생성에 미치는 영향을 검토하였다.
본 연구에서 위의 zeolite가 생성될 수 있는 반응기질의 조성은 다음과 같았다.
NaA : Na2O/SiO2=0.6-3.5, SiO2/Al2O3=0.5-2.5, H2O/Na2O=20-40,
NaY : Na2O/SiO2=0.5-1.5, SiO2/Al2O3=6.26, H2O/Na2O=30-60,
Na-Mordenite:Na2O/SiO2=0.15-0.35, SiO2/Al2O3=8-80, H2O/Na2O=100-190.
NaA와 NaY의 합성에 있어서는 실온숙성과정이 필수적이나, Na-Mordenite의 합서어에는 역효과를 나타내었다.
NaA와 NaY가 각각 고순도 생성되는 영역에서도 실온숙성시간과 생성반응시간이 지나치게길면, NaA는 Hydroxy sodalite로 NaY는 P형 zeolite로 변화하는 경향이 있었다.
A 및 Faujasite형 zeolite의 생성에 있어서는 실온숙성과저어에서 그 zeolite 의 전구체가 형성되는 것으로 믿어지나, Mordenit의 경우에는 실온에서는 핵이 생성되지 않고 보다 온도가 높은 수열반응과정에서 silica 입자를 중심으로 하여 핵이 이루어지고 결정이 생성되는 것으로 해석된다.
NaA, NaY 및 Na-Mordenite의 핵생성과정 및 결정화과정에서의 활성화에너지는 각각 17, 42, 67 KJ/mole 및 34, 42, 57 KJ/mole이었다.
본 실험에서 사용한 Zeosil은 zeolite 합성을 위한 silica원으로서 활성이 높고 특히 Mordenite 나 Pentasil류 등 silica함량이 높은 zeolite의 합성원료로서 적합하다고 생각된다.
본 연구에서 위의 zeolite가 생성될 수 있는 반응기질의 조성은 다음과 같았다.
NaA : Na2O/SiO2=0.6-3.5, SiO2/Al2O3=0.5-2.5, H2O/Na2O=20-40,
NaY : Na2O/SiO2=0.5-1.5, SiO2/Al2O3=6.26, H2O/Na2O=30-60,
Na-Mordenite:Na2O/SiO2=0.15-0.35, SiO2/Al2O3=8-80, H2O/Na2O=100-190.
NaA와 NaY의 합성에 있어서는 실온숙성과정이 필수적이나, Na-Mordenite의 합서어에는 역효과를 나타내었다.
NaA와 NaY가 각각 고순도 생성되는 영역에서도 실온숙성시간과 생성반응시간이 지나치게길면, NaA는 Hydroxy sodalite로 NaY는 P형 zeolite로 변화하는 경향이 있었다.
A 및 Faujasite형 zeolite의 생성에 있어서는 실온숙성과저어에서 그 zeolite 의 전구체가 형성되는 것으로 믿어지나, Mordenit의 경우에는 실온에서는 핵이 생성되지 않고 보다 온도가 높은 수열반응과정에서 silica 입자를 중심으로 하여 핵이 이루어지고 결정이 생성되는 것으로 해석된다.
NaA, NaY 및 Na-Mordenite의 핵생성과정 및 결정화과정에서의 활성화에너지는 각각 17, 42, 67 KJ/mole 및 34, 42, 57 KJ/mole이었다.
본 실험에서 사용한 Zeosil은 zeolite 합성을 위한 silica원으로서 활성이 높고 특히 Mordenite 나 Pentasil류 등 silica함량이 높은 zeolite의 합성원료로서 적합하다고 생각된다.
The A, Y and Mordenite type zeolites were synthesized in high purity and good yield by hydrothermal method with Zeosil 45 （a White carbon） as a silica source. And the effect of the factors such as reactants composition, aging time, reaction temperature and reaction time which can influence on the crystallization of the zeolites were investigated.
In this experiment, the composition of substrates able to produce these zeolites were as follows; for NaA : Na2O/SiO2=0.6-3.5, SiO2/Al2O3=0.5-2.5, H2O/Na2O=20-40, for NaY : Na2O/SiO2=0.5-1.5, SiO2/Al2O3=6-26, H2O/Na2O=30-60, for Na-Mordenite : Na2O/SiO2=0.15-0.35, SiO2/Al2O3=8-80, H2O/Na2O=100-190.
For the synthesis of NaA and NaY, aging at room temperature was an essential step, but it exhibited negative effect of the synthesis of Na-Mordenite. However, even in the borderland of suitable substrate compositions for the synthesis of NaA and NaY, the aging time at room temperature and the time of hydrothermal reaction were prolonged, NaA transformed to Hydroxy-sodalite and NaY to P-type zeolite.
For the crystallization of A and Faujasite type zeolite, it was believed that the precursors of the zeolite were formed in the aging step at room temperature.
But for the nucleation of Na-Mordenite, it was seemed that the nuclei were formed during a hydrothermal reaction at high temperature rather than at room temperature through the formation of precursors with reactive silica particles as core.
The activation energies for the nucleation and the crystal growth step of NaA, NaY and Na-Mordenite were 17, 42, 67 KJ/mole and 34, 42, 57 KJ/mole, respectively.
Zeosil, which was used in this experiment, was very reactive and seemed to be a useful silica raw material particularly for the synthesis of high silica zeolites, such as Mordenite and the Pentasil-family.
In this experiment, the composition of substrates able to produce these zeolites were as follows; for NaA : Na2O/SiO2=0.6-3.5, SiO2/Al2O3=0.5-2.5, H2O/Na2O=20-40, for NaY : Na2O/SiO2=0.5-1.5, SiO2/Al2O3=6-26, H2O/Na2O=30-60, for Na-Mordenite : Na2O/SiO2=0.15-0.35, SiO2/Al2O3=8-80, H2O/Na2O=100-190.
For the synthesis of NaA and NaY, aging at room temperature was an essential step, but it exhibited negative effect of the synthesis of Na-Mordenite. However, even in the borderland of suitable substrate compositions for the synthesis of NaA and NaY, the aging time at room temperature and the time of hydrothermal reaction were prolonged, NaA transformed to Hydroxy-sodalite and NaY to P-type zeolite.
For the crystallization of A and Faujasite type zeolite, it was believed that the precursors of the zeolite were formed in the aging step at room temperature.
But for the nucleation of Na-Mordenite, it was seemed that the nuclei were formed during a hydrothermal reaction at high temperature rather than at room temperature through the formation of precursors with reactive silica particles as core.
The activation energies for the nucleation and the crystal growth step of NaA, NaY and Na-Mordenite were 17, 42, 67 KJ/mole and 34, 42, 57 KJ/mole, respectively.
Zeosil, which was used in this experiment, was very reactive and seemed to be a useful silica raw material particularly for the synthesis of high silica zeolites, such as Mordenite and the Pentasil-family.
