以粉煤灰为原料制备微介孔分子筛及对特征污染物的吸附研究
从粉煤灰中提硅，以CTAB为模板剂，反应物的摩尔比为Si: CTAB: H2O=1: 0.2: 120，在碱性介质中合成有序介孔分子筛MCM-41。氮气吸附/脱附分析表明，产物具有介孔结构，比表面积为1000.2m2/g，孔径单一，为3.18nm。经X射线衍射和IR分析，产物是有序度较高的稳定的吹冰方相MCM-41介孔分子筛。吸附剂用量，初始pH值，吸附温度均能影响吸附剂吸附性能，MCM-41的吸附等温线符合Langmuir等温吸附模型，对氯酚的吸附过程符合伪二级动力学方程。调节Si:CTAB:H2O摩尔比为1:0.45:50，制备介孔分子筛MCM-48。XRD和IR分析表明，产物是长程有序的立方相MCM-48介孔分子筛。TG/DSC分析表明，合成MCM-48具有较好的热稳定性。
关键词 粉煤灰 NaX型沸石 MCM-41 MCM-48 重金属 对氯酚 吸附
毕业设计说明书（论文）外文摘要
Title The synthesis of microporous and mesoporous molecular sieves from fly ash and the sorption properties for Cd(Ⅱ) and p-chlorophenol.
Abstract
The research objective of this thesis is to investigate synthesis process of microporous, mesoporous molecular sieves from fly ash (FA) and their sorption properties. Single-phase zeolites NaX were synthesized from fly ash using alkaline fusion method via hydrothermal reaction. Analysis of XRD and IR spectra shows that the synthesized products possess the structure of zeolites NaX without the presence of other phases. SEM observation illustrates that the synthetic products are octahedral zeolitic particles. TG/DSC curves indicate the good thermo stability of the synthetic products. Initial pH value of the solution, temperatures and adsorbents dosage are influential parameters on the adsorption process. The suitability of Langmuir and Freundlich isotherms to the equilibrium data were studied in the solid-liquid system while the Langmuir model produces the best results. The adsorption processes of Cd(Ⅱ) follow a second-order kinetic model.
Mesoporous MCM-41 molecular sieves were synthesized by hydrothermal method using inorganic silica sources from FA and CATB as template in alkaline solutions. Analysis of XRD and SEM observation illustrates that the highly-ordered synthetic products are hexagonal mesoporous particles. initial pH value of the solution, temperatures and adsorbents dosage have impacts on the adsorption process. The Langmuir isotherms showed a better suitability to the equilibrium data compared with the Freundlich isotherms. The adsorption processes of p-chlorophenol follow a pseudo-second-order kinetic model. Mesoporous MCM-48 molecular sieves were produced by adjusting the Si/CTAB/H2O molar ratio. The observation of XRD and IR shows that the synthetic products are cubic mesoporous materials. Analysis of TG/DSC reveals the thermo stability of synthetic products.
Keywords fly ash zeolites NaX mesoporous MCM-41/48 molecular sieves heavy metal ion p- chlorophenol Adsorption
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