Study On A New Synthesis Method Of ZSM-5 And Preparation Of Luminescent Compounds Of Er

Part One:ZSM-5,a high silica zeolite developed by Mobil Corporation,has found various industrial applications because of its high thermal stability and strong acid stabilities.ZSM-5 is a ten-membered ring zeolite structure made up of two types of straight and zig-zag channel systems.The straight channels have a circular opening of 0.53×0.56 nm and the zig-zag ones have an elliptical opening of 0.51×0.55 nm. ZSM-5 was firstly synthesized using expensive tetrapropylammonium hydroxide (TPAOH)solution.Thereafter,the same structure was synthesized using several different organic templates.Up to now,there has no report on the synthesis ZSM-5 using cyclic amine as a structure-directing agent(SDA).In this work,ZSM-5 zeolite is skillfully hydrothermally synthesized from an inorganic silica source and hexamethyleneimine(HMI)as an SDA)(or without any SDA)with the assistant of active seeds of ZSM-5 precursor and alkali metal ions.The addition of a precursor gel containing the primary and secondary building units of MFI structure is the key step of the synthesis.The nature of precursor and the preparation conditions have great influence on the incorporation of silica into the framework.Other synthesis parameters such as silica sources,aluminium sources, crystallization time,Si/Al ratio,HMI/Si ratio,Na/Si ratio and H₂O/Si ratio have been investigated in detail.It is revealed that the crystallinity and crystal size were affected greatly by the synthesis conditions.Part Two:Erbium-doped Optical Fiber Amplifier(EDFA)is an essential part in communication systems.The fabrication of EDFA is a hot subject.During the fabrication,the proper support is needed to load rare earth to gain better luminescence. Considering the physical and optical properties of the support,we tested two different types of porous materials which were then modified to obtain the compounds with good luminescence.Both the supports of Y zeolite and SBA-15 showed the same absorption spectra,but showed different fluorescence spectra.Fluorescence was observed only on Er/SBA-15 compound.We modified the rare earth compound further with bis-(perfluoro methyl sulfonyl)-amine and achieved improved fluorescence.