Removal of Zinc from Wastewater Using Green Pea Pods as Bio-adsorbent

In this study, the removal of Zn (II) ions from wastewater using an agro-waste, green pea (Pisum sativum) pod as low-cost adsorbent material was investigated. Green pea pod (Pisum sativum) is as an organic solid waste material that has high adsorbing capacity in removal of heavy metal ions from wastewater and can be very effective in treating industrial aqueous solutions that are important sources of water and soil pollution. The removal studies were done as a function of pH, contact time, adsorbent amount and initial metal ion concentration in the batch system. With increasing pH of the solutions, the adsorption of zinc by green pea pods also increased and adsorption capacity attained a maximum value at pH=8. By increasing the contact time, the amount of zinc adsorbed increased and reached equilibrium after 60 min. However, by increasing the amount of adsorbent to the solution, the adsorption of zinc decreased. By increasing initial concentration of zinc ions, the percentages of adsorption decreased but the metal uptake increased. Langmuir and Freundlich adsorption isotherm models were applied to determine the efficiency of pea pods used as an adsorbent. The linear regression analysis showed that the experimental data perfectly fit both models.