Interaction of Humic Substances with Organic Pollutants and its Influence on the Concentration of these Pollutants from Water

Abstract

The influence of fulvic acids (FAs) and humic acids (HAs) of different origin on liquid-liquid and solid-phase extraction of hydrophobic organic compounds (HOCs) with broadly varying values of octanol-water partition coefficients K_ow has been investigated. It is shown that the solubilization by dissolved FAs and HAs can lead to a significant decrease in recovery of some HOCs even from very dilute (10–20 mg/l) aqueous solutions of these acids. The results of these investigations and an analysis of the relevant literature data, demonstrate that the extent of solubilization of HOCs by humic substances is determined not only by K_ow, but also by the specific structure of the HOCs. The hypothesis of the formation of intramolecular micelles (IMMs) by unaggregated FAs and HAs, and the partition of HOCs between water and the IMMs is put forward to explain the solubilization of HOCs.