THE NMR-STUDY OF PORE CONNECTIVITY

A new method to study the pore connectivity of meso- and macrporous ma terials was proposed. The dependence of the melting temperature of a f rozen liquid in a pore on its size was used to single out the pores of a given size in a sample and to estimate the pore size. The sample wa s heated after preliminary freezing of a liquid (adsorbate) that was i ntroduced into sample pores. Adsorbate melts in pores with smaller (th an definite) sizes. The state of adsorbate was controlled by the data on NMR relaxation; the pore connectivity was determined by the data on self-diffusion of liquid molecules in selected pores studied by the p ulse field gradient (PFG) NMR method. The applicability of the method of the estimation of pore sizes was considered using the mesoporous ca rbonaceous adsorbent-cyclohexane system, and that of the method of stu dying pore connectivity using the anhydrous cement-cyclohexane system as examples.