Modelling of breakthrough curves of single and binary mixtures of Cu(II), Cd(II), Ni(II) and Pb(II) sorption onto grape stalks waste

Few studies deal on metal sorption from multi-metal solutions, though in real situations more than one metal ion are present in solution and interactions between them occur. Interaction takes place when the different metal ions compete for the same sorbent active sites. In this work, sorption of Cu(II), Cd(II), Ni(II) and Pb(II) onto grape stalks waste in single and binary mixtures has been investigated. Sorption studies were carried out in continuous mode by using packed columns with grape stalks waste. The obtained metal ions breakthrough curves in binary mixtures showed that lead is not overshoot in binary mixtures with copper, cadmium and nickel. Copper is only overshoot in binary mixtures with lead. Nickel and cadmium suffer >60% overshoot metal sorption loose in binary mixtures with copper and lead. A model based on the Homogeneous Surface Diffusion Model (HSDM) has been developed to describe breakthrough curves. Langmuir model and Extended Langmuir Model (MEL) have been incorporated into the kinetic HSDM for breakthrough curves prediction of single and binary systems, respectively. The proposed model fits successfully the breakthrough curves of metal sorption from single and binary mixtures. In binary mixtures, the model also satisfactorily fits the elution profile of the overshoot metal ion.

Experimental data and predictive breakthrough curves for metal sorption onto grape stalks from Cu–Ni binary mixture.Figure optionsDownload as PowerPoint slideHighlights
► Cu, Cd, Ni and Pb sorption in grape stalks packed columns.
► Metal sorption breakthrough curves modelling (single and binary mixtures).
► Except Pb all the other metal ions suffer overshoot in binary mixtures.
► Satisfactory fit of breakthrough curves.
► Satisfactory fit of elution profile of overshoot metal ion.