Research on the Adsorption of Heavy Metal Ions from Model Solutions by Humic Acids Isolated from Sapropel

Abstract

The article presents the results of research on adsorption of Cu2+, Ni2+ and Pb2+ ions from model solutions with concentrations of 2–25 mg/dm3 under static conditions using humic acids isolated from the sapropel of Lake Lipovo, Novgorod region as an adsorbent. Adsorption equilibrium in the model solution-adsorbent systems occurs in 2 hours. The kinetic curves of adsorption of Cu2+, Ni2+ and Pb2+ ions from model solutions by humic acids are described with a pseudo-second order kinetic model; consequently, the limiting stage of the adsorption process is the chemical interaction between heavy metal ions and functional groups of humic acids in a 1:1 ratio. The kinetic constants of the adsorption of heavy metal ions by humic acids have been calculated. It was found that the adsorption of Cu2+, Ni2+ and Pb2+ ions occurs on the surface of the sorbent; the Langmuir equation is most acceptable for describing the process. The constants of adsorption equilibrium in the model solution-sorbent systems are calculated according to the Langmuir equation. The study of the adsorption of heavy metal ions on humic acids isolated from the sapropel of Lake Lipovo, Novgorod region, has shown the perspective of using sorbents for purifying industrial wastewaters.