热压交换单一稀土元素-Y型沸石的物理化学性能

THE PHYSICO-CHEMICAL PROPERTIES OF THE HIGH TEMPERATURE ION-EXCHANGED INDIVIDUAL RARE EARTH Y TYPE ZEOLITES

系统的研究了经水热加压交换的La、Ce、Pr、Nd、Sm、Eu、Gd、Dy、Ho、Er、Tm、Yb与Y十三种Ln Y的一些主要物化性能,发现存在着一些规律与特点。1.水热加压交换度(a)与相对结晶度间成很好的对应关系,其中Ce Y具有高交换度与高结晶度的特点。2.LnY的晶胞常数,脱水温度,比表面随Ln原子序数的增大其变化趋向与Ln3+的ΔH水合变化趋向基本一致。3.Ln Y的晶格崩解温度随Ln3+离子碱度(φ=Z/r)的增大而提高。本文从结构的观点讨论了上述规律与特点的出现。

We investigated systematically some of the main physicochemical properties of 13 individually ion-exchanged LnY zeolites(LaY,CeY,We investigated systematically some of the main physicochemical properties of 13 individually ion-exchanged LnY zeolites(LaY,CeY,PrY,NdY,SmY,EuY,GdY,DyY,HoY,ErY,TmY,YbY,and Y-Y),prepared by high temperature ion-exchange method(180℃)(10kg/cm^(2)).It was found that there are some obvious rules and features among the main physico-chemical properties of high temperature ion-exchanged LnF zeolites.1.A11 rare earth elements(Ln^(+3))can exchange with Na+on St-sites inβcage of NaF type zeolite at 180℃and under treatment in autoclave.There is a very strong correlation between the degree of ion-exchange of individual LnY and their relative crystallinity2.From the change of various main physico-chemical properties of LnF with the atomic mumber of elements,we found that the dependence of lattice constant,as,specific surface area(S.A.)and dehydration temperature upon the atomic number of elements show the similar features,and such features are particularly obvious for light and mid-rare earth elements and we also found the appearance of gadolinium break.Exist peaks among Gd,Dy and Ho on respective curves.We also found the similar phenomena in enthalpy change of individual Ln^(+3).3.The thermostabilities of LnF vary with the changing ofθ-value(Z/r)of Ln^(+3) ions.A much higher thermostability of heavy LnY and Y-Y appears.We suggested that the reason of this phenomenon lies in the easiness of diffusion of heavy Ln^(+3) ions with smaller radius from St-sites inβ-cage onto that of double six-ring(D6R)in high temperatures.This fact leading to the structural stability has been identified by the increasing of infrared vibrational frequenies in D6R of heavy LnF and Y-Y,PrY,NdY,SmY,EuY,GdY,DyY,HoY,ErY,TmY,YbY,and Y-Y),prepared by high temperature ion-exchange method(180℃)(10kg/cm^(2)).It was found that there are some obvious rules and features among the main physico-chemical properties of high temperature ion-exchanged LnF zeolites.1.A11 rare earth elements(Ln^(+3))can exchange with Na+on St-sites inβcage of NaF type zeolite at 180℃and under treatment in autoclave.There is a very strong correlation between the degree of ion-exchange of individual LnY and their relative crystallinity2.From the change of various main physico-chemical properties of LnF with the atomic mumber of elements,we found that the dependence of lattice constant,as,specific surface area(S.A.)and dehydration temperature upon the atomic number of elements show the similar features,and such features are particularly obvious for light and mid-rare earth elements and we also found the appearance of gadolinium break.Exist peaks among Gd,Dy and Ho on respective curves.We also found the similar phenomena in enthalpy change of individual Ln^(+3).3.The thermostabilities of LnF vary with the changing ofθ-value(Z/r)of Ln^(+3) ions.A much higher thermostability of heavy LnY and Y-Y appears.We suggested that the reason of this phenomenon lies in the easiness of diffusion of heavy Ln^(+3) ions with smaller radius from St-sites inβ-cage onto that of double six-ring(D6R)in high temperatures.This fact leading to the structural stability has been identified by the increasing of infrared vibrational frequenies in D6R of heavy LnF and Y-Y.