Equilibrium and thermodynamic studies of Pb(II), Zn(II), Cu(II) and Cd(II) adsorption onto mesembryanthemum activated carbon

Adsorption of Pb(II), Zn(II), Cu(II), and Cd(II) ions onto Mesembryanthemum activated carbon in a batch experimentby taking the consideration of adsorbent particle size, initial concentration, temperature, and pH was studied. Langmuir and Freundlich isotherm models were tested to fit the equilibrium data. Freundlich isotherm model gave a better fit to our experimental data than the Langmuir model. The adsorption capacity values were ۶۶.۶۷, ۵۲.۶۳, ۴۵.۴۵, and ۴۰.۰۰ mg/g for Pb(II), Zn(II), Cu(II), and Cd(II), respectively. The ideal pH for all metal ions adsorption was at pH ۵. The obtained thermodynamic parameters suggested that the adsorption process was physical, spontaneous (ΔGo< ۰), and endothermic (ΔHo> ۰).

Keywords:

heavy metals , Adsorption , Equilibrium , Thermodynamics