Complexation of metal ions with solid humic acids, humic colloidal solutions, and humic hydrogel.

článek v časopise ve Web of Science, Jimp

angličtina

The complexation kinetics of Co(II), Cu(II), and Ni(II) ions with humic acids is studied in this work. Humic acids were used in three different forms: solid powder, colloidal solution (sol), and hydrogel. The pseudosecond- order rate equation was used as the basic equation for the mathematical description of the complexation kinetics in the humic systems. Three different methods were applied to monitor the concentration changes in studied systems (conductometry, potentiometry, and UV/VIS spectroscopy). The double-linear fit was obtained in all cases. This is an indication that there are two principal types of metal binding sites in humic acids in all used forms. The strongest active centers are probably occupied in the first step, and slower interactions with less preferable binding sites and the rearrangement of formed complex follow in the second step. The values of rate constants were much higher for the first step in all cases. The highest values were obtained for humic sol and Cu(II) ions and the lowest ones for humic solid powder and Ni(II) ions. In general, the complexation rate increased in the following order: humic powder, sol, and hydrogel for all used metal ions and analytical methods.

colloid; complexation; humic acids; kinetics; metal ions

KLUČÁKOVÁ, M.

2014

15. 10. 2014

Mary Ann Liebert, Inc.

1092-8758

ENVIRONMENTAL ENGINEERING SCIENCE

31

11

Spojené státy americké

612

620

9