3.3. Effect of contact time
Typical biosorption kinetics exhibits a rapid initial uptake,
followed by a slower process. It has been observed that maximum
removal took place within the first 20 min (Figs. 3–6). After this
period, the amount of bound metal ions did not change during the
course of the process.
In order to analyze the biosorption kinetics of Cr(III) and Cu(II)
ions, kinetic models can be applied to fit the experimental data
(Figs. 3–6). Four kinetic models with different reaction orders were
used and nonlinear fitting was performed to determine the model
parameters.
The experimental results pertaining to the biosorption kinetics
were compared to four kinetic models, allowing determining the
parameters of these models (Table 1). Correlation coefficients and
ERRSQ values allow for the assessment of the correlation of the model
with the experimental data. The pseudo-first order model is poor in