水热法合成NaP1型粉煤灰沸石的性能表征

通过碱性介质中的水热反应,由粉煤灰合成了单一沸石矿物种的NaP1沸石,并对合成产品进行了表征.经粉晶X射线衍射鉴定,合成产物中主要矿物成分为NaP1沸石,另有少量尚未反应的石英和莫来石.在电子显微镜下,粉煤灰颗粒呈球形且表面光滑,而合成产物颗粒表面粗糙.粉煤灰合成沸石含有大量的交换性Ca2 ,且与粉煤灰原料相比,SiO2含量明显减少,Al2O3稍有增加,SiO2/Al2O3比值由3.3降至1.8.红外光谱分析和差热分析证实了合成的粉煤灰沸石中沸石水的存在.NaP1型粉煤灰沸石的阳离子交换容量(CEC)达213 cmol/kg,比表面积达29 m2/g,分别比粉煤灰高约100倍和26倍.

Property Characterization of NaP1 Zeolite From Coal Fly Ash by Hydrothermal Synthesis

Coal fly ash was transformed to NaP1 zeolite through hydrothermal reaction in NaOH medium and the synthesized product was characterized. The main crystalline mineral in zeolitized coal fly ash was NaP1, with small amount of partially dissolved residual quartz and mullite as identified by XRD. SEM photographs showed that the particle of raw coal fly ash was spherical and smooth, while zeolitized one was rough. The synthesized product contained large amount of exchangeable cation (Ca~(2+) in this case). The amount of SiO_2 decreased markedly and that of Al_2O_3 increased slightly during the synthesis process, which reduced SiO_2/Al_2O_3 ratio from 3.3 for the raw material to 1.8 for the product. IR spectrum and DTA curves indicated the presence of zeolitic water in the synthesized product. The CEC of zeolitized coal fly ash was 213 cmol/kg, and specific surface area was 29 m~2/g, 100 times and 26 times greater than those of raw coal fly ash respectively.