Equilibrium studies of the sequential removal of reactive blue 19 dye and lead (II) on rapeseed waste

Abstract

This study investigates the effect of pollutant initial concentration on the sequential biosorptive removal of Reactive blue 19 dye and Pb(II) ions on rapeseed waste. The initial concentrations of both organic and inorganic pollutants positively influence the sequential biosorption of the dye and metal ion under study on rapeseed meal waste. The most significant increase was found in the removal of Reactive blue 19 dye by using rapeseed previously loaded with lead ions. In this case, the increase of the initial concentration from 15 mg/L to 100 mg/L results in an increase of the biosorption capacity of almost 6.8 times. Taking into account the frequent quantification of the wastewater treatment efficiency through the biosorption capacity generated from equilibrium studies, the obtained experimental data have been modelled by using five two-parameters (Langmuir, Freundlich, Halsey, Temkin and Harkins-Jura) and five three-parameters (Sips, Redlich-Peterson, Toth, modified BET and Hill) nonlinear isotherms. Linearized forms of Langmuir and Freundlich were also discussed. The optimal description for the sequential biosorption of the reactive dye is provided by the Hill and Langmuir isotherms, whereas the retention of lead on rapeseed waste is provided by the Freundlich isotherm.