Surface complexation model of boron adsorption by calcareous soils|
Ranjbar, F. & Jalali, M.
This study aimed to evaluate boron (B)
adsorption and the capacity of a surface complexation
model for simulating this process in calcareous soils. Ten
surface soils were collected from different land use areas in
Hamedan, Western Iran, to characterize B sorption by soils.
The mean B adsorbed by the sample soils varied from 8.9
to 32.8 %. Two empirical models including linear and
Freundlich equations fitted well to the experimental data.
The linear distribution (Kd) values varied from 1.32 to
6.86 L kg-1, while the parameters of Freundlich equation
including n and KFr ranged from 1.16 to 1.33 and
3.31–16.81, respectively. The comparison of two empirical
models indicated that B adsorption followed a nonlinear
pattern. The soil organic matter had positive correlations
with Freundlich and linear distribution coefficients. However,
empirical models were not suitable for explaining the
mechanism of B adsorption, so a surface complexation
model was used to simulate and predict the B adsorption
process. B adsorption modeling was conducted using
Visual MINTEQ and PHREEQC, based on the assemblage
of major surface components (hydrous ferric oxides, aluminum
hydroxides, calcium carbonate, and humic acids). B
adsorption was successfully modeled by surface complexation.
The significant contribution of organic matter to B
complexes was resulted from both experimental data and
Boron; Surface complexation; Adsorption; MINTEQ; PHREEQC