SYNTHESIS AND PROPERTIES OF CARBON GELS BASED ON PINE AND CEDAR POLYPHENOLS

New methods for obtaining porous carbon gels by carbonization of corresponding organic xerogels synthesized by sol-gel condensation of polyphenols (tannins and ethanol lignin) of pine and cedar with various crosslinking agents (formaldehyde, glutaraldehyde and furfuryl alcohol) in a weight ratio of 1:1.5 are proposed. The influence of the nature and composition of the initial components on the formation of the porous structure, apparent density and adsorption properties of carbon gels is established. A comparison of the characteristics of the porous structure of tannin-formaldehyde and tannin-furfuryl carbon gels obtained under the same conditions from tannins isolated from different types of tree bark - pine and cedar is made. Among the tannin-formaldehyde gels, the carbon gel obtained using cedar tannins has the highest specific surface area (540 m2/g), while the surface area of ​​the gel from pine tannins does not exceed 184 m2/g. The carbon tannin-furfuryl gel based on pine tannins has the highest specific surface area (585 m2/g) and pore volume (0.7 cm3 / g). The use of glutaraldehyde for crosslinking cedar tannins leads to a decrease in the specific surface area of ​​the carbon gel to 377 m2/g compared to the tannin-formaldehyde gel. The addition of lignin to pine tannins contributes to an increase in the specific surface area of ​​the carbon tannin-formaldehyde gel by 2.6 times (from 184 m2/g to 482 m2/g). Using low-temperature nitrogen adsorption and scanning electron microscopy methods, it was found that when lignin macromolecules are introduced into the composition of tannin-formaldehyde gel, the size of the particles that form the carbon gel matrix increases, as does the size of the resulting pores.