Removal of Cu(II) and Cd(II) From Aqueous Solutions by Polyaniline on Sawdust

Abstract

The present work deals with the removal of Cu(II) and Cd(II) ions from aqueous solutions in a batch mode system using polyaniline doped sawdust (PANI/SD). The effects of various experimental conditions such as pH, initial metal ion concentration, time, and temperature were studied. The sorption system follows a second-order kinetic model, and adsorption equilibrium was achieved within 40 min. The maximum adsorption capacities obtained from the Langmuir isotherm model are 208.77 mg/g and 136.05 mg/g for Cu(II) and Cd(II), respectively, at pH 5.0 and a temperature of 293 K. Thermodynamic parameters such as ΔH°, ΔS°, and ΔG° were evaluated for the adsorption process, and the results show that the adsorption of Cu(II) and Cd(II) is spontaneous and endothermic. Desorption of metal ions and regeneration of adsorbent is achieved in 2 M hydrochloric solution. It is therefore reasonable that PANI/SD could be used for the removal of Cu(II) and Cd(II) ions from waste water.