Removal and recovery of Cu(II), Cd(II) and Pb(II) ions from single and multimetal systems by batch and column operation on neem oil cake (NOC)

NOC, a byproduct obtained after extraction of oil from neem fruit was used as an adsorbent for the removal of Pb(II) from wastewater. The adsorption of Pb(II) was found to be maximum (98%) at pH 4. The lower value of Langmuir constant (b) indicates strong binding of Pb(II) on NOC surface. The Freundlich constant n indicates beneficial adsorption. Thermodynamic parameters (ΔH° and ΔG°) suggest endothermic and spontaneous process. Kinetic studies show better applicability of second order kinetic model. The practical utility of NOC was demonstrated by removing Pb(II) along with Cd(II) and Cu(II) from single metal and multimetal systems by batch and column process. It was found that removal efficiency of NOC was better by column operation in multimetal system. The breakthrough capacities of Cu(II), Cd(II) and Pb(II) on NOC are found to be 10, 15 and 30 mg/g, respectively.