Effect of sorbent concentration on Pb(II) sorption on Mg-Al-EDTA layered double hydroxides

The sorption of Pb(II) on a Mg-Al-EDTA layered double hydroxide (LDH) sample was investigated at different sorbent concentrations and the sorbent concentration effect (C-s-effect) was observed. The sorption isotherm and kinetic process at a given C-s value can be adequately described by the classic Freundlich model and a pseudo-second-order kinetic equation. However, the classic Freundlich model cannot describe the C-s-effect observed in the studied sorption system. We believe that the C-s-effect can be attributed to the deviation of the real sorption system from an ideal one. It was confirmed that the surface component activity (SCA) model can adequately describe the C-s-effect observed in sorption experiments.