Abstract:
The fate of toxic metallic cations in the soil environment depends
largely on the interactions of these metals with inorganic and organic
surfaces. The extent to which a metallic cation interacts with these surfaces
determines the concentration of metal in solution and, consequently, the
potential for movement into groundwater or uptake by plants. A considerable
amount of work has been done to evaluate the adsorption of various heavy
metals by soils and soil constituents, such as clays and organic matter
fractions.
The objectives of this work were to determine the sorption capacity of
four soil categories, in absence and presence of different quantities of the
yeast Saccharomyces cerevisiae, during the sorption ability of copper ion.
Also, the semi-batch experiments were set in order to find how much time the
sorbent is active during copper sorption process.
The mobility of heavy metals in soil was described by the distribution
coefficient, Kd, defined as the ratio of metal concentration in the solid phase
to that in the liquid phase at equilibrium, determined from the slope of the
linear part of the adsorption isotherms.
The results show that there are differences between sorption
capacities of various soils, and the sorption process kinetics and dynamics
are influenced by the presence of S. cerevisiae, which can act both as
biosorbent and as organic matter in soil.
The sorption process kinetics can be described by a pseudo-second
order model, indicating that the rate limiting step is a chemical sorption
process between copper and soil.
