Investigation on the chemical bonding of copper ions on different soil samples

摘要

The mobility and bioavailability of heavy metals depend heavily on their physical and chemical forms and their interactions with the different soil phases. Sorption capacity of different soils (brown forest, carbonaceous sandy, calcareous chernozjom) using Cu2+ as a model ion was studied. The time of the equilibrium between solid and liquid phases was determined as 48 h. The optimum initial pH-range was found as pH 3.5-6 and it was very much dependent on the soil types. From the pH changes taken place during the equilibrium process it was concluded that either protons or hydroxyl ions were released into the solution. The study of effect of ion strength on the adsorption of metal ions has concluded that the Na-ions showed two different effects, namely they decreased the adsorption of Cu2+-ions by occupying the sorption sites and, on the other hand, the Na-ions considerably destroyed the mineral phases of the soils and increased the adsorption capacity. The effect of changes of the concentration on the adsorption process was investigated in the range of 1-10 mmol/l initial concentration using the optimum pH values. The linear Langmuir isotherm fitted into the initial parts of the adsorption isotherms for 1-4.5 mmol/l Cu2+-ions. (C) 2000 Elsevier Science B.V. All rights reserved. [References: 17]