海泡石原位晶化合成NaY分子筛的研究

Synthesis of NaY Zeolite on Sepiolite by in-situ Crystallization

首次用海泡石为硅源、高岭土为铝源,在水热条件下原位晶化合成NaY分子筛,采用粉末X射线衍射仪、电子扫描电镜等测试手段对所合成样品进行表征分析,着重考察晶化温度和投料配比对产品相对结晶度的影响.研究结果表明,NaY分子筛的形成受晶化温度的影响最大,随温度的升高,产品的相对结晶度显著提高,晶化温度升至100℃时,得到结晶度较高的NaY分子筛晶体.在原位晶化体系中,随n(SiO2)/n(Al2O3)减小,其相对结晶度增大;增加体系的n(Na2O)/n(SiO2)和减小n(H2O)/n(Na2O)都增大产品的相对结晶度;n(SiO2)/n(Al2O3)在投料比影响因素中占主导地位.

A new approach for the synthesis of microporous molecular sieves was realized. The microporous NaY zeolite has been hydrothermally synthesized by in-situ crystallization using sepiolite as silica source and kaolin as aluminum source,and characterized by XRD and SEM. The effects of molar ratios of precursors and crystallization temperature were investigated. The crystallization temperature is the most important factor for the synthesis of zeolite NaY. The relative crystallinity of the samples markedly increased with crystallization temperature going up. When the reaction temperature increased up to 100 ℃,excellent zeolite crystals were obtained. The results showed that the relative crystallinity of NaY zeolite increased with the molar ratio of SiO2/Al2O3 declining. The increasing of molar ratio of Na2O/SiO2 and the decling of molar ratio of H2O/Na2O in the reaction system were favorable to the formation of NaY zeolite. It was found that the molar ratio of SiO2/Al2O3 played a dominant role in the molar ratios of precursors.