TY - JOUR

T1 - Revision of Charnell's procedure towards the synthesis of large and uniform crystals of zeolites A and X

AU - Yang, Xiaobo

AU - Albrecht, Daniel

AU - Caro, Jürgen

PY - 2006/3/20

Y1 - 2006/3/20

N2 - A critical replication and re-evaluation of Charnell's procedure to the synthesis of zeolites A and X has been carried out, aiming at reliable protocols for preparation of large and uniform crystals of the respective zeolites in a scale of 50 g per batch. Triethanolamine, as an organic additive to the reacting sodium aluminosilicate hydrogel, increases the viscosity of the system, and reduces the reactivity of aluminium species towards nucleation and crystal growth through forming chelated complex compounds. The reactivity of silicate species has to be accordingly adjusted, by choosing proper source materials. Zeolite A crystals, which possess shapes of edge-truncated cubes, and sizes of 35-40 μm in edge-length, have been synthesized with a starting gel having the composition 1.7Na2O:Al2O 3:0.7SiO2:165H2O:6.1TEA in 2-l batch-size, using dissolved metallic aluminium and colloidal silica. The crystallization has been accomplished at 85 °C within 21 days. When the gel has a starting composition 2.3Na2O:Al2O3:1.3SiO 2:300H2O:10TEA (1-l batch), 70-80 μm large zeolite X crystals can be obtained at 85 °C in 35 days. Both starting gels are prepared at 0 °C, then quickly heated to the crystallization temperature.

AB - A critical replication and re-evaluation of Charnell's procedure to the synthesis of zeolites A and X has been carried out, aiming at reliable protocols for preparation of large and uniform crystals of the respective zeolites in a scale of 50 g per batch. Triethanolamine, as an organic additive to the reacting sodium aluminosilicate hydrogel, increases the viscosity of the system, and reduces the reactivity of aluminium species towards nucleation and crystal growth through forming chelated complex compounds. The reactivity of silicate species has to be accordingly adjusted, by choosing proper source materials. Zeolite A crystals, which possess shapes of edge-truncated cubes, and sizes of 35-40 μm in edge-length, have been synthesized with a starting gel having the composition 1.7Na2O:Al2O 3:0.7SiO2:165H2O:6.1TEA in 2-l batch-size, using dissolved metallic aluminium and colloidal silica. The crystallization has been accomplished at 85 °C within 21 days. When the gel has a starting composition 2.3Na2O:Al2O3:1.3SiO 2:300H2O:10TEA (1-l batch), 70-80 μm large zeolite X crystals can be obtained at 85 °C in 35 days. Both starting gels are prepared at 0 °C, then quickly heated to the crystallization temperature.

KW - Charnell's procedure

KW - Growth of large crystals

KW - Optimized synthesis

KW - Triethanolamine additive

KW - Zeolite A

KW - Zeolite X

UR - http://www.scopus.com/inward/record.url?scp=32644450554&partnerID=8YFLogxK

U2 - 10.1016/j.micromeso.2005.10.044

DO - 10.1016/j.micromeso.2005.10.044

M3 - Article

AN - SCOPUS:32644450554

VL - 90

SP - 53

EP - 61

JO - Microporous and Mesoporous Materials

JF - Microporous and Mesoporous Materials

SN - 1387-1811

IS - 1-3 SPEC. ISS.

ER -