Co Adsorption of Pb(II) and Cu(II) ions onto Bentonite-Chitosan Composites: Equilibrium Isotherm Modelling and Desorption Studies

Lead (Pb) and copper (Cu) ions are frequently encountered together in drinking water and wastewater. Adsorption with the use of composite materials made from bentonite clays and biodegradable polymers seems to be a promising cost-effective technique for the removal of heavy metals from water. This study investigated the co‑adsorption of Pb(II) and Cu(II) ions onto Bentonite-Chitosan (Bt-Ch) composites from binary aqueous solutions using batch procedure. The experimental adsorption data from equilibrium studies were subjected to various single- and multi-component equilibrium isotherm equations for the best fits, and the obtained parameters were compared. The multi‑component non‑modified Langmuir model predicted Qmax values for both Pb(II) and Cu(II) ions in the binary system that were quite similar to those obtained from the single‑component Langmuir model. The Qmax values obtained from the single‑component Langmuir model for Pb(II) ions were about 60% higher than those obtained for Cu(II) ions. Desorption studies (even though subsequent adsorption efficiency decreases after the second cycle) demonstrated that Bt‑Ch composites exhibited good potential for re-use after five cycles of regeneration, thus, indicating their potential as an effective adsorbent for simultaneous removal of Pb (II) and Cu (II) ions from water sources.