Spontaneous Liquid-Gas Imbibition On Porous Materials

The gas adsorption capacity of porous materials may be mainly caused by the micropore texture and surface properties.Hence,to develop porous materials widely used,an accurate means for characterizing the micropore structure of the porous materials is needed.N2 adsorption at 77 K is currently employed as a standard technique for the pore structure determination.However,the application of this technique to ultramicropore is limited because N2 is adsorbed at slow rates in this kind pore at cryogenic temperature.Therefore,a new method is needed to characterize the microporous structure of porous materias.The pore size distribution of carbon molecular sieves(CMSs)is uniform and narrow,which can be used to separate gas according to its kinetic selectivity.In the industrial production of CMSs,the control of the end of the reaction entirely by experience.Which is greatly increased energy consumption and production costs during the process.Therefore,it is particularly important to develop a new method to characterize the microporous structure of CMSs.In this dissertation,we did experiments on porous materials by spontaneous liquid-gas imbibition method with gas and water at room temperature.The effects of different conditions on the spontaneous liquid-gas imbibition process of ZSM-5 zeolites were studied,at the same time,three zeolite molecular sieves were selected to study the kinetic mechanism of them;different CMSs were selected for experiments to determine the adsorption density of the gas in the molecular sieves,and its pore structure parameters were characterized to guide the preparation of industrial CMSs;at the same time,air was used to study the competitive adsorption of multi-component gases.The results demonstated that with the increase of temperature,the amount of adsorbed gas is reduced,the amount of gas is increased with the decrease of particle size.The density of the adsorbed gas was determined and a new method for determining the pore volume of micropores on CMSs was established,the relative error of the micropores volume on CMSs is less than 5%.The adsorption capacity of CMSs was obtained by spontaneous liquid-gas imbibition,this method can be used to guide the preparation of industrial CMSs.