Nuclear magnetic relaxation of adsorbed liquids in porous media containing paramagnetic impurity

Pulse NMR was used to measure nuclear magnetic relaxation times of diethylene glycol molecules in porous Vycor glasses with a diameter of pores of 11 nm in the temperature interval of 99–342 К and of water molecules in bentonite (Dash-Salakhly deposits, Azerbaijan) at temperatures of 178–293 K. The concentration of diethylene glycol in porous glasses was close to the monolayer content of 11.1 wt %, and the water content in bentonite was kept at 22 wt %. In the range of low temperatures, spin-lattice relaxation time $T_1$ of diethylene glycol is determined by the relaxation times of an electron spin of impurity ions and the spin diffusion mechanism both in original and HCl-washed porous glasses. This work discusses nature of the strong difference in temperature dependences of relaxation times $T_1$ of diethylene glycol molecules in original and HCl-washed porous glasses. Spin-lattice relaxation of the water molecules depends on the paramagnetic ions concentration and the correlation time of the water molecular motions.