Adsorption of atrazine on humic acids

Abstract
The adsorption of atrazine on four fractions of humic acids with different molecular weights was investigated at the range of pH value 2.5–6.2. The amounts of adsorbed atrazine decreased with increasing pH for all humic acids fractions. No adsorption was observed at pH 5.5 and higher. The increase of relative nitrogen percentages and also decreases of C/N ratios in adsorption products were investigated. Changes of these parameters were influenced by the acidic functional group content in the different fractions of humic acids. The atrazlne adsorption kinetics was investigated also. No appreciable changes in adsorbed amounts were observed after 20 hours. The adsorption process involved two phases ‐ rapid followed by slow adsorption.