Synthesis And Characterization Of Inorganic Micso-Mesoporous Materials

Micro-mesoporous materials are ideal for scientific study. But it is difficult forus to tranform zeolite into micro-mesoporous material while conserving its stabilityand catalysis activity. At present, the study of hierarchical molecular sieve materials isbasically focused on those alkali-aluminosilicate materials, reports on hierarchicalAlPO and SAPO materials are very limited. Therefore, we have studied the sythesis ofAlPO and SAPO micro-mesoporous materials and the increase of their acid activityand stability.In this thesis,through the interaction under alkaline conditions betweensecondary building units of the guiding agents of zeolite sieve and Cetyl trimethylammonium chloride surfactant, we successfully synthesized highly ordered micro-mesoporous SAPOs material ia the guiding agents method. In comparison with theconventional SAPO materials, the hole-walls of the hierarchical pores Al-JQW arethicker. The degree of mesoporous skeleton condensation is also very high. Thus, thismesoporous material is of high thermostability. In addition, since the guiding agentscan introduce hierarchical pores into Al-JQW, it has both the weak acid and strongacid active centers and acidity is stronger.It is also worth noting that the acidity of thedifferent JQW samples varies when they are assembled from different Zeoliteprecursors. The order of acid strength are as follows: Al-JQW-5> Al-JQW-6>Al-JQW-7> Al-JQW-8, this result agrees with the conversion rate in the catalyticexperiment of isopropyl benzene and the acidity of the zeolite achieved in previousstudies as follows: MFI> BEA>Y>L.In the second section of experiment,the mesoporous SAPO-5guiding agentswere used as inorganic species and CTAC as the template.And after the pretreatmentby ultrasonic wave, we successfuly imbedded the SAPO-5molecular sievenanocrystallines into the highly ordered mesoporous walls and synthesizedmicro-mesoporous molecular sieve SAPO-5-uw under the hydrothermal condition.Ithas been shown that using triethylamine and CTAC as templates can synthesize themicro-mesoporous molecular sieves SAPO-5-UW of pure phase.TEM photos showed a very high degree of order. And due to the higher stability with thicked walls and thestrong acid and weak acid centers in the products, it has a great potential applicationvalue in acid catalysis.In the synthesis, ultrasonic auxiliary function greatly increasedthe production rate of the mesoporous phase and the mixing between reactants waswell realized, which promoted the formation of a new solid phase. Therefore, it is avery convenient and quick auxiliary technique that suitable for wide application in thesynthesis of nanomaterials.In our synthetic steps, by changing the order of ultrasonicassistance, we dissolved the surfactant in ultrasonic environment and then added theguide agents. After the further hydrothermal crystallization, vesicles iof sapo-5singlecrystal walls were achieved with pore diameters in15to20nm.This is avery idealhierarchical pore materials. However, part of the materials are amorphous aluminumphosphate materials without pores.Nowadays, the ecological environment in China has been severly damaged bychemical pollutions, in which water pollutions and atmospheric haze are the imminentthreat to the health of human. The control and recovery of ecological pollutions are themain issue in Environmental chemistry. In the first two chapters of porous materialsynthesis, the author noted that it would consume a lot of inorganic materials tosynthesize the composite mesoporous material while the ordering and stability ofgeneral micro-mesoporous composite materials are not ideal either. Therefore, theauthor pointed out that how to break through the traditional method and technology forthe preparation of microporous, mesoporous, and composite porous materials andimprove the reaction yield should be the focus of current research.Hence, in the third section of experiment, the author is aiming at finding a cheapnatural body framework to facilitate small amount of the secondary structural unit ofthe zeolite being inserted into the body framework and further crystallized. By doingthis, the mesoporous composite materials of high stability can be obtained. Manykinds of natural ore is found to be suitable for the idea, such as bentonite, mica and soon.In line with the idea of environmental protection and saving, industrial sodium basebentonite was employed as the mesoscopic body framework and just a small amountof the guiding agents of microporous zeolites was used to innovatively sythesize themesoporous composite ordered mesoporous materials of high thermostability and acidactivity, AMC-ZSM-5, AMC-Beta and AMC-TEOS. After testing our new syntheticmaterials high thermal stability was comfirmed. The reasons for this high thermostability include that the stable framework of bentonite being the up and down walls of the pores and that guiding agents making the left and right pore walls partiallycrystallize. In addition, adding the guiding agents gives the new materialmicroporosity and the acidity of the corresponding zeolite. Above all, to use lessinorganic chemical raw materials can be regarded as green chemistry and theapplication of bentonite is in general more common in the area of sewage disposal,from preparation to application bentonite is a kind of eco-friendly new material.