Synthesis and application of a new carboxylated cellulose derivative. Part II: Removal of Co(2+), Cu(2+) and Ni(2+) from bicomponent spiked aqueous solution.

In the second part of this series of studies, the competitive adsorption of three binary systems Cu(2+)-Co(2+), Cu(2+)-Ni(2+) and Co(2+)-Ni(2+) on a carboxylated cellulose derivative (CTA) was evaluated in binary equimolar (1:1) metal-ion aqueous solutions. Bicomponent adsorption studies were developed as a function of contact time and initial metal ion concentration. Bicomponent adsorption kinetic data was modeled by monocomponent kinetic models of pseudo-first- (PFO) and pseudo-second-order (PSO) and a competitive kinetic model of Corsel. Bicomponent adsorption isotherm data was modeled by the ideal adsorbed solution theory (IAST) and real adsorbed solution theory (RAST) models. The monocomponent isotherm models implemented into the IAST were the Langmuir and Sips models, whereas for the RAST model only the Langmuir model was implemented because this model provided the best prediction of the bicomponent isotherm data. The surface of the CTA adsorbent after bicomponent adsorption of metal ions was also examined by SEM-EDX. The effect of one metal ion on the adsorption capacity of another metal ion was discussed in detail with basis on the kinetic and thermodynamics parameters. The selectivity and performance of the CTA adsorbent for the removal of Cu(2+), Co(2+) and Ni(2+) was also evaluated and discussed.