Abstract

The article considers the hydrothermal formation of micrometric crystals of zeolite type FAU in aluminosilicate gels obtained from water suspension of natural phillipsite, treated with hydrochloric acid, mixed with sodium hydroxide, and followed by aging during several days at room temperature. At a high concentration of sodium in the reaction mixture, zeolite X with a high aluminum content (Si/Al = 1.4) is formed, having a high specific surface area (590 m²/g) and micropore volume (0.3 cm³/g), as well as a system of cylindrical pore channels (0.28 cm³/g) with an average diameter of 55 nm. Crystallization of a diluted gel with an average sodium content leads to the formation of zeolite X with a higher silicon content (Si/Al = 2.5), having a lower specific surface area (440 m²/g) and micropore volume (0.23 cm³/g), and irregular system of mesopores (0.15 cm³/g) with a diameter of 20–30 nm. The secondary porous network ensures the delivery of reagents to active sites on the surface and determines the possibilities of using the obtained materials as catalysts, especially since they have a fairly high ion exchange capacity and can be easily modified by the introduction of transition metals.

中文翻译：

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天然硅铝酸盐凝胶中高度分散的八面沸石的形成

摘要

该文章考虑了铝硅酸盐凝胶中水合形成的FAU型沸石微晶晶体的水热作用，该硅酸盐凝胶是由天然磷灰石的水悬浮液制得的，用盐酸处理，再与氢氧化钠混合，然后在室温下老化数天。在反应混合物中高钠浓度下，形成具有高铝含量（Si / Al = 1.4），高比表面积（590 m ² / g）和微孔体积（0.3 cm ³ / g ）的沸石X ），以及圆柱孔道系统（0.28 cm ³/ g），平均直径为55 nm。具有平均钠含量的稀释凝胶的结晶导致形成具有较高硅含量（Si / Al = 2.5），具有较低比表面积（440 m ² / g）和微孔体积（0.23 cm ³）的沸石X / g）和直径为20–30 nm的不规则中孔系统（0.15 cm ³ / g）。次级多孔网络确保将试剂传递到表面上的活性位点，并确定使用获得的材料作为催化剂的可能性，特别是因为它们具有相当高的离子交换能力，并且可以通过引入过渡金属轻松进行修饰。