Functional and Elemental Composition of Humic Acids of Sapropels of the River Ob’s Left Bank of Khmao-Yugra

Abstract

This article describes qualitative and quantitative characteristics of chemical elements and acidbase functional groups of humic acids (HA) in five lakes of the left bank of the Ob of Khanty-Mansi Autonomous Okrug-Yugra. The data on their elemental composition (CNHO), atomic ratios (H/C, O/C) carboxyl (COOH) and phenolic (OH) functional groups have been presented. The relationship between the elemental and functional composition of HA has been traced. It is found that with increasing hydrogen content, the percentage of carboxyl groups in the macromolecule of HA increases, the proportion of aromatic moieties reduces, and with increasing oxygen content the number of phenolic hydroxyls increases. According to the chart of atomic ratios describing the content of aromatic and aliphatic parts, HA are placed in the sequence, characterizing the maximum proportion of aromatic structures. Clearly there is a group of HA of lake Shchuchye sapropel, which is characterized by a maximum degree of aromaticity, followed by in decreasing order according to the contents of the Carom humic acids of sapropels of lakes Srednesatyginskiy Tuman, Nyartur, Medvezhye and Satyginskiy Tuman. The highest content of the Carom is typical for the more formed, “mature” HA.