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纳米多孔材料-层柱粘土制备研究现状及趋势 总被引:3,自引:0,他引:3
层柱粘土是一种新型的纳米多孔材料,本文着重介绍了层柱粘土制备的基本原理、主要制备工序、各工序工艺条件及其对层柱粘土结构与性能的影响。阐述了一些新的制备方法。 相似文献
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以蒙脱石为原料,利用共聚法合成了铜铁复合层柱粘土催化剂。通过XRD、FTIR和N2吸附-脱附等检测方法对其结构进行了表征。结果证实,交联剂成功插入到蒙脱石层间,所得催化材料具有较大的比表面积。将其作为催化剂,采用催化湿式过氧化物氧化处理含酚废水,实验结果表明,与铁、铁铝等层柱粘土相比,铜铁复合层柱粘土在苯酚处理浓度、催化剂用量、反应时间以及初始pH适用范围等方面都有较大的改善。在最佳工艺条件下,苯酚去除率可达99%,pH=3~9都具有较高的去除效果,平均去除率达97%以上,循环使用四次后去除率仍大于90%。 相似文献
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由RMgCl制备了烯烃聚合载体催化剂。SiCl4作为氯化试剂制备的载体催化剂的活性较高。在载钛过程中,以氯苯为溶剂制备的催化剂性能最好。用这种方法制得的复合载体催化剂具有良好的共聚性能。 相似文献
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Catalytic activity of pillared clays in methanol conversion 总被引:4,自引:0,他引:4
A number of pillared clay based catalysts have been used in methanol conversion and the obtained results related to the physico-chemical characteristics of the samples. Zr-PILCs samples have proven to be quite effective in dehydration to dimethyl ether and hydrocarbons due to their acidity and porosity. In special, well-pillared samples are suitable to obtain hydrocarbons. Doping with Cu does not improve dehydration due to the loss in acidity caused by Cu addition, but it renders the materials useful for methanol dehydrogenation. Cu/pillared clays have shown promising catalysts for methanol dehydrogenation to methyl-formate, despite the existence of interactions with the acid–base properties of the support, which contribute to dimethyl ether formation and degradation of methyl-formate to CO2, CO and formaldehyde. X-ray diffraction, chemical analysis, N2 and pyridine adsorption and XPS helped to understand the catalytic performance of the prepared catalysts. 相似文献
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以莱西钙基膨润土为原料,研究了常规离子交换法、微波合成法、超声合成法和水热合成法对制备柱撑蒙脱石(PILM)的影响。为了得到大层间距的PILM,引入自制的有机硅溶胶,并将Fe3+和Cr3+负载到硅溶胶上,制备了一系列的Fe/Cr-Si-PILM,并用XRD、DTA-TG和SRF等进行了表征。结果表明,微波、超声和水热法均是具有应用前景的合成方法;常规离子交换法中,引入有机硅溶胶可以显著增大PILM的层间距,经300 ℃焙烧2 h后,最大的层间距为4.33 nm,热稳定性可达643 ℃。探索了Fe/Cr-Si-PILM催化剂在煤炭液化中的应用,希望能开拓PILM催化剂应用的新领域。 相似文献
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Pillared clays(Ti-PILCs)were synthesized from Na-type montmorillonite through intercalation with polymeric hydroxy-titanium.The mechanism of the pillaring course was studied by means of magic angle spinning nuclear magnetic resonance(MAS NMR)and diffuse reflectance infrared spectroscopy(DRIFTS)techniques.DRIFTS suggested that after Ti-pillaring,the silicon-oxygen tetrahedral Si—O—Si bond and aluminum oxide octahedral Si—O—Al bond were broken.Meanwhile,NMR also showed the change of the silicon-oxygen tetrahedral structure and aluminum oxide octahedral structure in the pillared clay.In the pillaring process,the titanium hydroxy-oligomeric cations entered the layers of the montmorillonite by ion-exchange,the Si—O—Al bond of the raw clays were broken,the silicon-oxygen tetrahedron structure were overturned,and the reactive oxygen species(structural hydroxyl)reacted with titanium hydroxy-oligomeric cations to form Si—O—M bond.This led to the incorporation of pillaring species of Ti in the layers of the clay.After further heat treatment,the TiO2 pillars were formed in the layers to obtain Ti-PILCs. 相似文献
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采用XRD和SEM表征了层状粘土催化剂样品,考察了制备条件对层状粘土催化剂性能的影响。在0.5 MPa、543 K、800 h-1和合成气n(H2)∶n(CO)=2的F-T合成条件下,在连续搅拌釜式反应器中反应6 h,收集液相产物。气相色谱仪分析液相产物中的成分,计算出液相产物的碳数分布。考察了催化剂制备条件对F-T合成产物选择性的影响,结果表明,铁源、沉淀剂、加料次序和pH等对催化剂性能影响较大。当以Fe3+铁盐为原料,NaOH为沉淀剂,pH=8.7,动态水热合成制备的催化剂在浆态床F-T合成后,液相产物中C9~C25烃类的选择性可达80%以上。 相似文献
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柱撑黏土(PILC)由于其结构可控的二维层状多孔特性,在选择性催化还原(SCR)技术中已得到广泛应用。本文综述了近年来PILC和改性PILC的结构特性、化学性质、层间掺杂活性物质及脱硝效率的研究成果,分析表明,经过添加不同活性物质改性后的PILC具有更高的比表面积、更大的层间距和良好的耐热稳定性等特点,催化剂的表面活性及催化活性得到明显的提高,对NOx具有更好的脱除效果。此外,本文还介绍了基于密度泛函理论(DFT)的改性PILC的吸附机理研究进展。由此指出,对PILC的改性和理论的深入研究,为设计和改造高效SCR脱硝催化剂具有重要意义,而将密度泛函理论引入PILC改性及脱硝机理研究中也为PILC的改性研究提供了新的理论思路。 相似文献
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Paula Zapata Raúl Quijada Cristian Covarrubias Edwin Moncada Jaime Retuert 《应用聚合物科学杂志》2009,113(4):2368-2377
Catalytic activity during the formation of polyethylene (PE)/clay nanocomposites by in situ polymerization with metallocenes was studied. Ethylene polymerization was carried out with the homogeneous metallocene in the presence of the clay particles and using the clay‐supported metallocene catalyst. It was found that the catalytic activity of the homogeneous metallocene does not decrease in the presence of the clay particles and only a slight decrease of activity occurs using the clay‐supported catalyst. The modification of the clay with MAO cocatalyst as well as its intercalation with ODA surfactant were found to play an important role during the in situ formation of the PE/clay nanocomposite. ODA‐intercalated clay apparently facilitates the activation and monomer insertion processes on zirconocene centers located in internal sites of the clay structure. Although metallocene supported on MAO‐treated clay exhibited somewhat lower catalytic activity than that supported directly on the ODA‐intercalated clay, both systems favored the production of PE nanocomposites containing highly exfoliated clay particles. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009 相似文献