Properties of water adsorbed in porous silica gels with different shapes of microparticle

A comparison was made of the relaxation, diffusion and calorimetric characteristics of samples with different water content in the pores of Separon SGX and Silasorb 600 silica gels, which differ in the shape (regular and irregular) of microparticles. It has been shown that the layer of water experiencing the relaxation effect of the surface in the pores has constant dimensions for these silica gels. It has been established that the surface relaxation efficiency, the ratio of relaxation times T1 /T2, which reflects the phase state of water, does not change depending on the water content in the sample. It was found that the patterns of changes in the time of spin-lattice T1 and spin-spin T2 relaxation of water protons, the amount of freezing (FW) and non-crystallizing (NFW) water when changing the moisture content in samples with different shapes of silica gel microparticles have a similar character. The dependence of diffusion coefficients on the water content in silica gels made it possible to calculate the value of the characteristic pore parameter S/V and compare it with the characteristics declared by the manufacturer. The noticeable deviation for Silasorb 600 can be explained both by the difference in the distribution of pore sizes and by the difference in the nature of diffusion processes, which is a consequence of the irregular shape of the microparticles.