光谱学与光谱分析, 2012, 32 (4): 1118, 网络出版: 2012-04-16
XRD和FTIR对沸石合成机制的光谱学解析
Spectroscopic Analysis of the Crystallization Mechanism of Synthesized Zeolite with XRD and FTIR Approaches
摘要
以粉煤灰为原料, 采用优化的水热晶化一步法合成沸石。 比较晶化反应过程沸石产物CEC值及化学成分的变化, 推断固液体系中物质转换及元素迁移方式和途径。 借助XRD, SEM, FTIR等表征反应过程沸石的晶型变化及成核特性, 提出可能存在的沸石生成机制。 合成产物主要为NaP1型沸石, 反应24 h后CEC值最大为135 mmol/100 g。 12 h后, 产物中初步发现NaP1沸石相特征峰和亚晶结构, 48 h后出现羟基方钠石的特征弱峰。 沸石生成过程涉及到固液体系间的物质流动: 碱熔融作用将粉煤灰组分侵蚀进入液相体系, 为沸石形成提供了原料组分, 而固相体系为沸石生长提供骨架结构, 液相体系和固相体系分别为晶化反应的“源”和“汇”, 这是液相转化机制和固相转化机制的客观反映。
Abstract
Zeolites were synthesized from fly ash using modified one-stage method. The changes in cation exchange capacity (CEC) and chemical elements of zeolite were investigated during the synthesis process to reveal the materials and elements transformation in solid-liquid system. The approaches of XRD, SEM and FTIR were used to indicate the crystallization characteristics and mechanism. The zeolite NaP1 was synthesized, and the CEC value reached to the maximum of 135 mmol/100g at 24 h. After the hydrothermal reaction for 12 h, the characteristic peak and metastable crystalline structure of zeolite NaP1 appeared, then the hydroxy sodalite products formed at 48 h. The crystallization process was the result of materials transformation: the elements of fly ash released into the liquid system for the melting effect of alkali solution, and the solid system played the role of skeleton in crystallization process, being the “source” and the “sink” of the reaction, respectively, and the achievements presented the crystallization mechanism of liquid-phase and solid-phase transformation.
范春辉, 马宏瑞, 花莉. XRD和FTIR对沸石合成机制的光谱学解析[J]. 光谱学与光谱分析, 2012, 32(4): 1118. FAN Chun-hui, MA Hong-rui, HUA Li. Spectroscopic Analysis of the Crystallization Mechanism of Synthesized Zeolite with XRD and FTIR Approaches[J]. Spectroscopy and Spectral Analysis, 2012, 32(4): 1118.