Siberian Federal University

A new method for the synthesis of mixed organic gels based on larch bark tannins and pine wood cellulose, and formaldehyde as a crosslinking agent has been developed. The effect of cellulose content on the morphology, porous structure, thermochemical and adsorption properties of tannin-cellulose gels was studied by thermogravimetry, SEM and BET methods.The isotherms of nitrogen adsorption–desorption on tannin–cellulose gels correspond to materials with a predominantly mesoporous structure. In the case of samples prepared using a cellulose solution, the porous structure of the gels is represented by mesopores uniform in shape, with predominant sizes from 10 to 30 nm. In mixed gels prepared using cellulose powder, the predominant number of mesopores has 5–10 nm in size. The introduction of a cellulose solution in an amount of 10 and 20 wt% during the synthesis of tannin-formaldehyde gels increase their specific surface area from 4 m2/g to 87 and 118 m2/g, the volume of mesopores up to 0.39 and 0.50 cm3/g, and decrease their apparent density from 0.60 to 0.21 and 0.24 g/cm3, respectively. According to scanning electron microscopy data, the gel containing 10 wt% cellulose has a more uniform three-dimensional structure than the sample containing 20 wt% cellulose. The rate of thermal decomposition of tannin-cellulose gel in the temperature range of 280–380 °C (–6.4 %/min) is significantly higher than that of a cellulose-free tannin-formaldehyde gel sample (–1.4 %/min)