The equilibrium data for biosorption of Zn(II), Co(II) and Cd(II)
ions onto the biosorbent were employed for competitive Langmuir,
Freundlich, Temkin and Sips isotherm models. The experimental
data that best fitted the competitive Temkin isotherm for
Zn(II) and Co(II) and competitive Langmuir isotherm for Cd(II)
were the best models that represented the biosorption data. The
model parameters obtained in this study can be used to approximate
the working volume, the required biomass dosage for niger. It could be concluded, based on these results, that treated
biomass of A. niger may be used as an inexpensive, effective and
easily cultivable biosorbent for the removal of Zn(II), Co(II) and Cd
(II) ions from aqueous solution. A single-stage batch adsorber
design was developed using the Temkin isotherm model to predict
the minimum dosage of A. niger biosorbent required to achieve a
95% removal of Zn(II), Co(II) and Cd(II) ions from aqueous solution.
However, more complete studies should be performed on the
operative parameters such as temperature, agitation and on the
chemical composition of the fungal cell walls. An alternative
modeling with genetic algorithm and nonlinear multicomponent
isotherms was presentd and the results demonstrated that this
technique could be a promising tool to represent ternary equilibrium
data