Changes in the Properties of Humic Acids Due to the Effects of High Temperatures

Changes in the properties of humic acids (HAs) have been studied at high temperatures. The process of hydropyrolysis of HAs was investigated and its thermal stability was estimated. The experimental data on thermal destruction of alkaline HA solutions at 150, 200, and 250°C and water vapor saturated pressure were obtained. It has been shown that hydropyrolysis changes the degree of condensation of molecules, significantly increases the number of functional groups, and decreases the average molecular weight. Our experimental results allowed the calculation of the parameters of thermal stability of HAs.